Abstract
Background
Aedes-borne disease risk is associated with contemporary urbanization practices where city
developing structure function as a catalyst for creating mosquito breeding habitats. We lack
better understanding on how the links between landscape ecology and urban geography
contribute to the prevalence and abundance of mosquito and pathogen spread.
Methods
An outdoor longitudinal study in Bengaluru (Karnataka, India) was conducted between
February 2021 and June 2022 to examine the effects of macrohabitat types on the diversity
and distribution of larval habitats, mosquito species composition, and body size to quantify
the risk of dengue outbreak in the landscape context.
Findings
A total of 8,717 container breeding sites were inspected, of these 1,316 were wet breeding
habitats. A total of 1,619 mosquito larvae representing 16 species from six macrohabitats and
nine microhabitats were collected. Aedes aegypti and Ae. albopictus were the dominant
species and significantly higher in artificial habitats than in natural habitats. Breeding
preference ratio for Aedes species was high in grinding stones and storage containers. The
Aedes infestation indices were higher than the WHO threshold and showed significant linear
increase from Barren habitat to High dense areas. We found Ae. albopictus breeding in
sympatry with Ae. aegypti had shorter wing length.
Interpretation
The majority larval habitats were man-made artificial containers. Landscape ecology drives
mosquito diversity and abundance even at a small spatial scale which could be affecting the
localized outbreaks. Our findings showed that sampling strategies for mosquito surveillance
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must include urban environments with non-residential locations and dengue transmission
reduction programmes should focus on ‘neighbourhood surveillance’ as well to prevent and
control the rising threat of Aedes-borne diseases.
Funding
This research was financially supported by Tata Trusts funding to Tata Institute for Genetics
and Society.
Keywords
Aedes aegypti, Aedes albopictus, Bengaluru, Body size, Culicine, Ecology,
Fitness
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Research in context
Evidence before the study
The quality of mosquito larval habitats (breeding sites) is one of the most important
determinants of the distribution and abundance of mosquito species. Cities offer a
heterogeneous landscape with a gradient of temperature, vegetation, built infrastructure
(piped water access, water storage) which can vary in microclimate at fine spatial scales.
Entomological surveys are often biased towards locations or houses with high mosquito
densities. Sampling strategies for mosquito surveillance must include urban environments
with non-residential locations.
Added value of this study
Understanding the linkages between environmental conditions (e.g., hydrology,
microclimate), land use, climate change, increasing urbanization are some of the key factors
modulating the mosquito life-history traits which influence epidemiologically relevant
behaviors and their ability to transmit diseases. Our longitudinal study shows that a
combination of manmade larval habitats and landscape ecology drives mosquito diversity and
abundance even at a small spatial scale which could be affecting the incipient disease
outbreaks.
Implications of all the available evidence
From science to policy perspective, our study is first comprehensive study in Bengaluru,
India which shows that sampling strategies for mosquito surveillance must include urban
environments with non-residential locations. We demonstrate that dengue transmission
reduction programmes should focus on ‘neighbourhood surveillance’ as well to prevent and
control the rising threat of Aedes-borne diseases.
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Introduction
Mosquito-borne diseases, particularly dengue, chikungunya transmitted by Aedes mosquitoes
are rising worldwide and have been a critical public health issue. In urban ecosystems, Aedes-
borne disease risk is associated with contemporary urbanization practices where city
developing structure functions as a catalyst for creating breeding habitats for two
epidemiologically important mosquito species - Aedes aegypti [= Stegomyia aegypti] and
Aedes albopictus [=Stegomyia albopictus]1. Mosquitoes as an obligatory host of many
parasites can adapt to a wide range of ecological conditions. From a microhabitat perspective,
the quality of mosquito larval habitats (breeding sites) is one of the most important
determinants of the distribution and abundance of mosquito species2-6. Aedes species are
often associated with a specific type of breeding site, from temporary, ephemeral habitats
such as waterfilled leaf axils, coconut shells, tree holes to manmade habitats such as ground
pools, water storing containers, pots, and tyres etc.5 In an ecological context, the mosquito
breeding success is tightly linked with the stability of aquatic habitats and is exquisitely
dependent on temperature, humidity, and rainfall
7,8. Many biotic (predators, organic matter,
larval density, interspecific competition) and abiotic (temperature, rainfall and humidity)
factors influence the larval and pupa population dynamics and determines the life-history
traits (longevity, fertility, body size, and immune function). For example, predation at larval
stages has been identified as an important evolutionary force driving the habitat segregation
and niche partitioning in mosquito species
3. Numerous studies have demonstrated that wing
length is a good proxy for fitness and survival of mosquito species9. In addition, biotic and
abiotic conditions of larval habitats determine the abundance and body size of emerging
adult mosquitoes10. Larger mosquito size is positively associated with survival, blood feeding
frequency, which is likely to increase disease transmission2, 11-15.
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Globally, the number of dengue cases has increased 30-fold over the past five decades16. The
first case of dengue-like illness was reported in Chennai in 1780 and first confirmed dengue
viral infection occurred in Calcutta (now Kolkata) in 1963-196417. Since 1968, many parts of
northern India (Kanpur, Delhi) have experienced dengue outbreaks. In the early 2000s,
dengue was endemic in a few southern (Maharashtra, Karnataka, Tamil Nadu and
Pondicherry) and northern states (Delhi, Rajasthan, Haryana, Punjab and Chandigarh
18. One
of the limitations for dengue control has been the lack of structured mosquito surveillance,
diagnostics and awareness and collective efforts which has led to high number of cases
19.
Among arboviruses, dengue virus diagnosis relies on the detection of the virus or antibodies
(IgM, IgG, and NS1 antigen) directed against the virus in the blood20. In addition, the
sensitivity and specificity of these tests underestimate the ‘true’ burden of the disease which
poses a logistical challenge and limited compliance to invasive sampling procedures21.
Dengue is an annual epidemic in India. In 2019, dengue burden in India peaked at about
1,57,315 cases and Karnataka recorded 16,986 cases. Of these Bengaluru contributed ~50%
(9,029) of dengue cases (National Centre for Vector Borne Diseases Control; NCVBDC).
Like many cities, in Bengaluru, Aedes population surveillance primarily involves indoor
larval surveillance as per WHO protocols to measure house index, container index and
Breteau index to quantify the disease risk in a specific residential area
22. Source reduction
(emptying water holding containers), anti-larval spraying and providing health
education/awareness are the main intervention strategies for Aedes control (NCVBDC). The
areas with highest house indices and larval counts are considered as productive. These indices
record relative larval abundance in a locality for a specific period with no correlation with
adult abundance and without regard for seasonal fluctuation in larval abundance.
Furthermore, entomological surveys are often biased towards locations or houses with high
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mosquito densities or disease outbreaks22. Sampling strategies for mosquito surveillance must
include urban environments with non-residential locations23,24. Chen et al.25 analysis of
weekly data during COVID-19 pandemic across southeast Asia and Latin America showed a
drastic decline in dengue cases due to lockdowns and restricted movements of people. These
findings further highlighted the dengue transmission reduction programmes should focus on
‘neighbourhood surveillance’ as there is no relationship between the Breteau and house
indices of Aedes mosquitoes with dengue fever outbreaks
26.
Cities offer a heterogeneous landscape with a gradient of temperature, vegetation, built
infrastructure (piped water access, water storage) which can vary in microclimate at fine
spatial scales less than 1km x 1km27,28. These differences further affect the vector abundance,
fitness traits and virus transmission dynamics at a microhabitat level. Cities provide a diverse
gradient of larval habitats such as construction sites29, leaking connections30 among other
aquatic habitats created by anthropogenic land use modifications (e.g., bromeliads, Colocasia
plants, buckets, plastic containers etc) which are positively associated with the abundance of
Aedes species. Understanding the linkages between environmental conditions (e.g.,
hydrology, microclimate), land use, climate change, increasing urbanization are some of the
key factors modulating the mosquito life-history traits which influence epidemiologically
relevant behaviors and their ability to transmit diseases. For example, with changing water
infrastructure networks in cities like Bengaluru, freshwater wells and lakes were replaced by
formal water connections, the prime larval habitat of urban malaria vector Anopheles
stephensi, is now prevalent in water storage (cement/plastic tanks, plastic drums) and often
shared niche with Aedes species such as discarded tyres. With increasing urbanization and
availability of man-made habitat has led to establishment of Aedes species. Similarly, in
Ahmedabad (Gujarat), more malaria cases were associated with the areas with low density of
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formal water connections30. Larval habitat characteristics such as pH, temperature, salinity
predict the presence of mosquito larvae and rearing environment has impact on body size of
females, daily survival rate and susceptibility to arboviral infections31. We conducted a
longitudinal study to understand how urbanization affects mosquito ecology and how
mosquito species diversity and abundance changes across macro and microhabitats in an
urban environment. We are specifically interested in understanding:
1. What types of habitats (microhabitat and macrohabitat) and season drives larval presence
and species diversity?
2. How do Aedes indices change by season and macrohabitat types?
3. How do abiotic factors predict the abundance of mosquito larvae across an urbanization
gradient?
4. How do abiotic factors and urbanization drive niche conservatism/habitat segregation in
Aedes species?
5. How does wing length vary between interspecific and intraspecific environments?
Methods
Bengaluru (12°58′ 44″ N, 77°35′ 30″ E), Karnataka, India, is a densely populated (~11 million
inhabitants) city at an elevation of 900 m above mean sea level, with a mosaic of urbanized
areas to plantation, barren areas representing a diverse range of land use classes (Fig.1). The
study was conducted between February 2021 and June 2022. Bengaluru experiences a semi-
arid climate with temperature between 18°C to 34°C, and southwest monsoon season (June-
September) with normal annual rainfall of 820mm. September being the peak rainfall month
and nearly 60% of the rainfall occurs during the southwest monsoon32. The retreating,
northeast monsoon also brings rain from October to December. The dry period extends from
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January to May, although convectional thunderstorms occur from March through May.
Typically, January and February receive almost no rain.
Fig.1 Map of Bengaluru showing grid locations by macrohabitat types and larval sites by mosquito species.
Our goal was to quantify seasonal variation in the Aedes larval prevalence, degree of
breeding habitat utilization (microhabitats and macrohabitats) and niche conservatism in
Culicidae mosquito species. To examine the seasonality in the larval habitat prevalence and
abundance of mosquito species, we divided the year into biologically meaningful four
seasons: dry (January-March), pre-monsoon (April-June), monsoon (July-September), post-
monsoon (October-December). Due to unprecedented COVID-19 waves (Delta and
Omicron), the fieldwork was staggered in two years (2021-2022) to capture the seasonal data.
We defined six macrohabitats with eight replicates in a 100m x 100m grid in following
categories: barren lands, lakes (lake surroundings), plantations, high dense areas (e.g., >75 %
grid coverage by households), medium dense areas (> 50% grid coverage by households),
low dense areas (> 25% grid coverage by households). These macrohabitat grids were
selected using Google Earth Pro (v.7.3) and were subsequently verified in the field.
A total of 48 index grids (fixed) were selected with eight replicates of each macrohabitat type
(low dense, medium dense, high dense, plantation, lake area, and barren land) which were
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surveyed in each season. In addition, we selected 98 random grids representing a
macrohabitat type which were surveyed in two seasons (April-June and July-September),
which allowed us to sample mosquitoes in varied ecological niches in the city while
surveying fixed grids on a seasonal basis. The minimum distance between each grid was
approximately 300m-500m to maximum 1km. We deployed ten iButton data loggers to
record temperature and relative humidity in grids representing each macrohabitat type. The
loggers were deployed in completely shaded area and were set up to record at 30 min interval
round -the- clock basis at each sampling site.
Mosquito larval habitat sampling
A grid representing a macrohabitat was sampled within 1 day. Each grid was surveyed for the
standing water i.e., microhabitat (breeding source or larval habitat) categorised as natural
(e.g., plant axils, tree holes, coconut shells) and artificial (e.g., discarded plastic containers,
discarded grinding stone, discarded tyres, plant pots, collection plates, storage containers,
stagnant water). Each microhabitat was visually inspected for the presence of mosquito
larvae. A microhabitat was determined as ‘positive’ if a larva was recorded. For each
sampling location, geo-coordinates, microclimate variables such as pH, temperature using
HM Digital pH meter and salinity using salinity refractometer were recorded. We did not use
salinity in subsequent analysis due to zero values across all habitats. Water volume of each
habitat was measured using meter stick (>10L) or by transferring it a graduated beaker. We
used leaflet package in R v.4.1.1 to map larval sites.
Breeding preference ratio (BPR) for Aedes mosquitoes across all breeding sources was
calculated to assess the preference for available breeding habitats. BPR was calculated using
the ratio of number of containers infested with Aedes larvae to the number of water-holding
containers examined
33-35.
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The mosquito larvae samples were collected and brought in collection containers for rearing
to mosquito insectary at the Tata Institute for Genetics and Society. Larvae were reared
separated by collection source where they were placed in 50-100mL of collection water and
provided with fish food. Larvae and pupae were reared to adulthood at 28±2°C and 75± 5%
relative humidity and 12:12 hour light-dark photocycle. Once emerged, mosquitoes were
frozen at -20°C, sorted by gender and identified to species following Barraud et al.36.
Adult mosquito sampling
We conducted Aedes adult sampling in four grids in high dense areas (due to high dengue
incidence) in each season. Because Aedes albopictus and Aedes aegypti are day-biting
mosquito, Biogents (BG) sentinel trap using battery operated fan was deployed for 72 hours
for one sampling period. Mosquito traps were baited with a BG-Lure cartridge (Biogents) and
an octenol (1-octen-3-ol) lure inside the trap. Traps were placed under the cover outside a
house premises to increase catch rates. The battery was changed in the morning for each trap
day and catch bags were collected and replaced with a new catch bag to reduce destruction of
samples. Adult collections were brought to the laboratory and stored at –20°C. Mosquitoes
were sorted by sex and species following Barraud et al.36. Adult mosquito abundance for
three trap days were combined to calculate the total abundance for that sampling period.
Aedes egg sampling
Ovitraps were deployed in four high dense grids (due to high dengue incidence). Each ovitrap
was a simple black plastic container of approximately 200 ml capacity and a diameter of 5 cm
and 10 cm height. Each container was lined with an oviposition slip, lining the inner wall of
each trap, which was withdrawn after exposure to oviposition for 5 consecutive days. These
traps were deployed on the ground simultaneously in a separate high dense grid to avoid
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compromising the adult sampling. In each grid, a group of five ovitraps in five replicates i.e.,
25 ovitraps. The grid was considered positive if eggs were recorded in ovitraps. The eggs
were counted using stereomicroscope and ovitrap index were calculated using the percentage
of positive ovitraps against the total number of ovitraps recovered for each site37.
Wing length as an indicator of body size
Wing length of emerged adult mosquito was recorded. The newly emerged mosquitoes were
identified and kept in -20°C and wing lengths was measured within 2 days of emergence.
Both right- and left-wing length was measured for male and female Aedes mosquitoes using a
microscope and ocular micrometer as the distance from the axillary incision to the apical
margin, excluding the fringe scales38. We used Leica stereomicroscope with the LAS X
(Leica application suite x) software platform to capture and quantify the specimen. Wing
length for the field caught Aedes mosquito in high dense urban areas was also measured in
the similar way. We considered right wing length of females in the subsequent analysis.
Data Analyses
Data were analyzed in R v.2.6.239. Exploratory analyses were first performed to identify
environmental differences between macrohabitats, as well as variations in microclimate
characteristics according to larval habitat categories.
Macrohabitat type and season
For index grids, (6 habitat types x 8 replicates x 4 seasons), a binary logistic regression model
was used to assess the relationship between larval habitat characteristics and the presence of
immature stages. We used three generalised linear mixed effect model (GLMM) where larval
presence/absence was response variable with season, macrohabitats, microhabitats, pH and
temperature as the fixed effects and grid as random effect. Similar models were considered
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for assessing the effect of these variables on the prevalence of Ae. aegypti and Ae. albopictus.
This analysis was also conducted separately for all (index + random) grids. Subsequently, all
grids were considered together (see results).
For all grids together, we estimated diversity indices for microhabitats (artificial vs natural)
and individual rarefaction curves. The total richness by each habitat type was estimated by
abundance based Chao1 estimator using iNEXT package40. We constructed a grid x species
mosquito abundance matrix to understand the temporal and habitat segregation of species.
One-way analysis of variance (ANOVA) was used to test difference across habitat types
(Barren Land < Lake < Plantation < Low dense < Medium dense < High dense) and season
(Jan-Mar < Apr-Jun < Jul-Sep < Oct-Dec) in two measures of species diversity: (a) species
richness, defined as total number of species sampled; (b) the Shannon-Wiener index, a
measure of species diversity weighted by relative abundance41.
We used analysis of variance to test whether temperature varied significantly between air
temperature recorded by data logger and water temperature of microhabitat. Tukey’s Honest
Significant Difference post-hoc test was used to determine the significance of a pairwise
comparison.
How do Aedes indices change by season and macrohabitat type?
The larval indices for Aedes aegypti and Aedes albopictus were calculated to assess the risk
of dengue by season and habitat type. These indices are analogous to traditional Container,
House (or Premise), and Breteau indices37 but considers non-household locations in their
calculation22:
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Container index: Number of habitats positive for Aedes larvae and/or pupae x 100 / total
potential containers inspected in each habitat.
Location index: Number of locations positive for Aedes larvae and/or pupae x 100 /total
number of locations inspected in each habitat multiplied by 100.
Breteau location index: Number of habitats positive for Aedes larvae and/or pupae x 100 /
total number of locations inspected in each habitat22.
Pupal index: Number of pupae collected of total potential containers inspected in each
habitat.
We used generalised linear model (GLM) to tease apart the effect of macrohabitat type and
season on larval indices. We fitted three separate Poisson regression models using location
index, container index and Breteau location index. The low sample size prevented inclusion
of interactive terms or random effects in the model. In addition, to account for zero values of
some larval indices, a constant value of 1 was added to fit the GLM model with a log-link
function. This did not affect the mean and variance of that variable.
How do abiotic factors predict the abundance of mosquito larvae across macro and
microhabitats?
To determine effects of larval habitat characteristics on larval abundance, we used
generalized linear mixed effects models (GLMMs) with a negative binomial link because our
count data were over dispersed. We modelled the effect of microhabitat, habitat type
(macrohabitat) and microclimate variables (pH and temperature), volume, sympatric (co-
occurring) species (yes/no), and season on the larval abundance (count) and including grid as
random effect. The microclimate variables (pH and temperature) were fitted using a basis-
spline (B-spline) function to allow for non-linear relationships with larval abundance. A
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candidate set of 128 possible models were fitted separately for total larval abundance, Ae.
aegypti and Ae. albopictus larval abundance. GLMMs were fitted using the glmmTMB
package42. Scaled residuals of the models were inspected for overdispersion and uniformity
using the DHARMa package43 (Hartig, 2019). We assessed model support based on Δ AICc,
the AIC value corrected for small sample sizes44. Models with a Δ AICc value < 2 were
considered as having greatest support, with the awareness that parameters from models with a
K-value greater than that of the top supported model may not be truly informative45.
Nevertheless, parameter estimates from all models ranking within 2 Δ AICc were averaged
using the R package “AICcmodavg” to investigate the relative significance of parameters
within this set of top supported models. We then calculated 95% conditional confidence
intervals of each parameter or model-averaged parameter and identified those that did not
overlap zero as important predictors, recognizing that parameters not occurring in the top
model may hold questionable importance.
How do abiotic factors and urbanization drive niche conservatism in Aedes species?
We used a GLMM model where the presence of Ae. aegypti species was assessed as a
function of presence of Ae. albopictus, temperature, pH (microclimate), season, and habitat
type (natural and artificial) with binomial distribution and grid as random effect. The sample
size of other mosquito species was small (<70) to be considered for this analysis. An odds
ratio value of one indicates species are associated randomly, whereas odds ratio values of
greater than one or less than one indicates a positive or negative association, respectively. All
analyses were carried out in lme4 package46.
How does wing length vary between interspecific and intraspecific environments?
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The wing lengths of Ae. aegypti and Ae. albopictus were compared between either species
originating in larval habitats with and without Aedes species. Similar comparisons between
larval and adult caught mosquito wing lengths were tested by Kruskal Wallis test as wing
length was not considered normally distributed.
We fitted Linear Mixed Models (LMM) using Gaussian distribution to explore the
association between the wing lengths (as response variable) of the Aedes mosquitoes with
microclimate (temperature, pH), larval abundance, microhabitat, macrohabitat and season as
fixed effects and grids were added as random effect. These models were fitted separately for
Ae. aegypti and Ae. albopictus.
Role of the funding source
The funders had no role in study design, data collection, data analysis, interpretation, writing
of the report.
Results
In this neighbourhood (non-residential outdoor surveillance), 242 grids were sampled for
mosquito larval habitats. Of these a total of 106 grids (48 index + 58 random) were sampled
from April to June, and 88 grids (48 index + 40 random) were sampled from July to
September. The third wave of COVID-19 disrupted the field work during October-December
which restricted sampling to 48 index grids. A total of 8,717 container breeding sites were
inspected, of these 1316 were potential wet breeding habitat. A total of 1,619 mosquito larvae
were collected from six macrohabitats and nine microhabitats. Of these 1,290 mosquitoes
emerged comprising 16 species from five genera. Ae. aegypti was the most dominant species
707 (55%), followed by Ae. albopictus 367 (28%), Culex quinquefasciatus 69 (5%),
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Armigeres subalbatus 69 (5%), Anopheles stephensi 29 (2%), Culex gelidus (1%),
Tripteroides affinis (1%). Nine mosquito species- An. vagus, An. sinensis, An. culicifacies,
Cx. bitaeniorhynchus, Cx. tritaeniorhynchus, Cx. mimeticus, Tripteroides aranoides, Ae.
vittatus, and An. varuna were sampled in less than 1%. The most abundant microhabitat type
was discarded containers followed by coconut shells and plant pots which were recorded
across all macrohabitats, and the least abundant were plant axils and tree holes (Fig. 2A).
Fig. 2. Circos plots showing macrohabitat and microhabitat niche segregation by mosquito species. A:
Proportion of microhabitat recorded in each macrohabitat type; B: Proportion of mosquito larval sites by species
recorded in each microhabitat, the larval prevalence varied significantly by microhabitat; C: Proportion of
mosquito larval sites by species recorded in each macrohabitat, the larval prevalence had no significant effect of
macrohabitat. CS=Coconut shells; DC=Discarded containers; PP=Plastic pots; DT=Discarded tyres; TH: Tree
holes; PA=Plant axils; SC=Storage containers; GS=Grinding stones
For both Aedes species, the BPR was significantly different in microhabitats (χ2 =18.47,
df=7, p<0.01) with highest in discarded grinding stones (β= 1.75, p<0.02), and storage
containers (β= 1.55, p0.19; Fig. 3).
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18
Fig. 3. Breeding preference ratio of Aedes species across microhabitats. CS=Coconut shells; DC=Discarded
containers; PP=Plastic pots; DT=Discarded tyres; TH: Tree holes; PA=Plant axils; SC=Storage containers;
GS=Grinding stones
The Stegomyia indices were higher than the WHO threshold values (>5%) suggesting a high
level of Ae. aegypti and Ae. albopictus infestation (Supplementary Table S1). The location
index, container index and breteau location index showed significant linear increase from
Barren land to High dense grids (χ2 =28.10, df=5, p<0.001) and a quadratic increase during
July-September followed by a decrease from October to December (χ2 =20.20, df=3,
p<0.001; Fig. 4). We found no significant difference in pupal index by habitat type or season.
However, ovitrap index was higher in July-September (3.17) than April-June (0.41) and
October-December (0.78).
Fig. 4. Ae. aegypti and Ae. albopictus infestation indices across a macrohabitat gradient.
In 146 BG trap nights in four high dense grids between April and December 1609 mosquitoes
representing five species were collected. In contrast to larval sampling, the adult collections
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were dominated by Cx. quinquefasciatus 1006 (63%), Ar. subalbatus 456 (28%) followed by
Ae. aegypti 109 (7%) and Ae. albopictus 24 (1%). An. stephensi was only sampled twice. In
general, males were significantly higher in abundance than females.
Larval prevalence across seasons and habitats
We surveyed a total of 8,717 potential mosquito larval sites representing nine microhabitats
(breeding sources) from February 2021 to June 2022. Out of these 7,454 (86%) were dry
(potential) habitats and 1263 (14%) were wet habitats (Supplementary Table S2). In general,
the prevalence of wet habitat was significantly higher in index grids than in random grids
(χ2= 98.25, p<0.001) and this pattern remained consistent even after combining all the grids.
The wet larval habitat was significantly high in artificial breeding sources (χ2= 57.11,
p<0.001), and this corresponded well with the finding that larval prevalence was significantly
higher in artificial habitats than in natural habitats (χ2= 7.11, p<0.001). There was a stark
seasonal difference in the prevalence of wet habitat (χ2= 43.11, df=3, p<0.001). The
prevalence of wet habitat was significantly lower in February-March (β= −1.73, p<0.001),
and October-December (β= −1.29, p<0.001). However, in monsoon season, July-September
(β= 0.53, p0.28) and temperature (χ2= 0.13, p>0.71) showed no
significant difference between the positive and negative larval habitats. There was a
significant variation in mean daily temperature across months but not across macrohabitat
types (Fig. S). Mean daily temperature were coolest in December (22°C) and warmest in
April-May (~30°C). There was a stark difference in water temperature amomg microhabitat
types (F=9.20, df=7, p<0.001; Tukey HSD post-hoc tests; Supplementary Table S3). The air
temperature was significantly lower than water temperature of larval habitats - discarded
containers (F=28.52, p<0.0001), discarded grinding stones (F=12.75, p<0.001), stagnant
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water (F=9.51, p<0.002), storage containers (F=11.82, p<0.0001), and pots (F=11.68,
p0.14), plant
axils (F=1.69, p>0.22), and tree holes (F=0.07, p>0.78) showed no significant difference with
air temperature.
Fig.5 Left panel: The wet habitat prevalence, Right Panel: Mosquito larvae prevalence by month. Inset figure
shows peak in dengue cases (aggregate from 2016-2019) as reported by Bruhat Bengaluru Mahanagara Palike.
The top models explaining mosquito larval prevalence included season + microhabitat type+
temperature + volume (Fig. 6A; Supplementary Table S4). The prevalence of mosquito larvae
showed significant difference across season (χ2= 77.30, df=3, p<0.001) by following a
similar seasonal trend as wet habitat prevalence with significantly high prevalence in April to
June (β= 0.60, p<0.02) and July to September (β= 0.51, p<0.05). However, October to
December (β= −1.49, p0.32), or macrohabitat type (χ2= 2.20,
df=5, p>0.82), the microhabitats showed significant effect on the larval presence (χ2= 60.63,
df=7, p<0.006). Human associated microhabitats, such as discarded grinding stones (β= 1.33,
p<0.002) supported significantly high larvae prevalence followed by discarded tyres (β=
0.95, p<0.05; Fig. 2B). There was a decrease in larval prevalence with increase in
temperature (χ2= 6.16, p<0.01).
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The patterns in larval prevalence were primarily driven by Ae. aegypti and Ae. albopictus
with similar ecology, albeit with contrasting seasonal and microhabitat usage (Fig. 6B and
6C; Supplementary Table S5 and S6). Ae. aegypti showed a significantly low prevalence in
February and March (β= −2.53, p<0.0001) and from October to December (β= −0.98,
p<0.01). However, no significant change in prevalence from April to June and July to
September. Ae. albopictus showed similar levels of prevalence in February and March (β=
−4.57, p<0.001) with a spike in prevalence from July to September (β= 1.50, p<0.01). Ae.
aegypti showed a positive association with coconut shells (β= 0.06, p<0.03) whereas the
prevalence of Ae. albopictus was negatively associated (β= −3.59, p<0.001) with coconut
shells as a larval habitat. Ae. aegypti had significantly positive association with discarded
grinding stones (β= 1.55, p<0.001), and storage containers (β= 1.31, p<0.01). Ae. albopictus
showed a positive association with discarded grinding stones (β= 1.47, p<0.02). Ae. aegypti
showed significantly less prevalence in lake areas (β=−1.21, p<0.03) whereas Ae. albopictus
showed a significant negative association with high dense habitat (β=−1.14, p<0.03) as well
as temperature (β= −0.09, p<0.03).
Fig. 6. Model summary of parameter estimates from the best-fit generalized linear mixed-effects model
predicting larval prevalence, based on a candidate set model combinations of the variables: macrohabitat,
microhabitat, pH, temperature, volume, season and co-occurring species. The models also include the random
effects of grid.
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Mosquito species richness across seasons and habitats
For all grids, mosquito species richness (Chao1 estimator) was higher in artificial habitats
(Observed = 16, Chao1 = 18.24; CI:16.26-35.02) than in natural habitats (Observed = 3,
Chao1 = 3; CI: 3-3.01). Among artificial habitats, storage containers harboured highest
mosquito richness (Observed= 11; Chao1=11.64; CI: 11.05-18.78) followed by stagnant
water (Observed= 9; Chao1=16.78; CI: 9.96-18.70) and discarded containers (Observed= 6;
Chao1=6; CI: 6-7.48). Our individual-based rarefaction curves indicated that we sampled
expected number of species in each habitat except mosquito community in stagnant water
remained under sampled (Fig. 7).
Fig. 7. Observed and Chao 1 estimated mosquito richness and species diversity in micro and macrohabitats.
For combined grids (index and random) analysis, both species richness (F=2.31, p<0.04) and
Shannon diversity (F=2.21, p<0.05) showed a significant negative quadratic coefficient
indicating that mosquito diversity indices do not decrease linearly but show a hump-shaped
pattern with macrohabitat type i.e., lowest in Barren land and peaks in plantation and then
declines in high dense grids. Similarly, both species richness (F=3.79, p<0.01) and Shannon
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diversity (F=3.04, p<0.03) showed a significant decline with a cubic coefficient from October
to December (Fig. 8).
For index grids, there was no significant association between richness and species diversity
with macrohabitat type. However, only species richness (F=2.54, p0.10).
Fig. 8. Mosquito species richness and diversity across season by macrohabitat types.
Abundance of mosquito larvae across micro and macrohabitats
The top model explaining total larval abundance included volume + season + co-occurring
species + a random effect of grid (weight=0.77; Supplementary Table S7). The total larval
abundance was negatively related to volume (effect size: -0.17; 95% CI: -0.27 to -0.07). In
contrast to total larval prevalence, the larval abundance showed a gradual decrease from
February to March and October-December. However, the total larval abundance was
positively related to presence of sympatric species (effect size: 0.36; 95% CI: 0.11 to 0.60)
(Fig. 9).
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Fig. 9. Model summary of parameter estimates from the best-fit generalized linear mixed-effects model
predicting larval abundance, based on a candidate set model combinations of the variables: macrohabitat,
microhabitat, pH, temperature, volume, season, and sympatric species. The models also include the random
effects of grid.
For Ae. aegypti, co-occurrence, pH, season showed significant relationship with larval
abundance. The top model explaining Ae. aegypti abundance included non-linear relationship
(B-spline fit) with pH, and a decrease from February to March and October to December
(Supplementary Table S8). The sympatry with other species showed no effect on Ae. aegypti
larval abundance. The top models explaining Ae. albopictus larval abundance non-significant
negative relationship with season (Supplementary Table S9). There was a marginally
significant effect of sympatry with other species on larval abundance. However, temperature
showed marginally significant non-linear relationship.
Abiotic factors and urbanization drive niche conservatism in Aedes species
Microhabitat sharing between Ae. aegypti and Ae. albopictus showed significant positive
association with pH (OR= 0.15, CI=0.03–0.68, Wald’s χ2=4.2, p<0.01).
How does wing length (as a proxy for body size) vary between interspecific and
intraspecific environments?
A total of 235 wings of Ae. aegypti (males= 117, females=119) and 122 wings of Ae.
albopictus (males= 38, females= 84) were measured. For both larval and adult sampled Aedes
species, female wing length was longer than male in Ae. aegypti (KW χ2= 116.32, df = 1, p<
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0.001) and Ae. albopictus (KW χ2= 52.18, df = 1, p< 0.001; Fig. 10). Comparisons between
wing lengths of adult caught (n=52) Ae. aegypti and larval originated females showed the Ae.
aegypti mosquitoes caught as adult had longer wing lengths than larval reared females (KW
χ2= 8.89, df = 1, p0.34).
Fig. 10. Comparison of wing length in male and female Aedes species as a proxy for body size. A-B: Ae. aegypti
and Ae. albopictus wing lengths measured from larva emerged populations. C-D: Ae. aegypti and Ae. albopictus
wing lengths of male and female captured as adults using BG traps.
In larval samplings, we measured the effect of sympatry with other Aedes species in the
breeding sources on the wing length of Ae. aegypti and Ae. albopictus. The wing length of
Ae. aegypti showed no significant association with the presence of Ae. albopictus (KW χ2=
0.83, df = 1, p>0.35). However, female Aedes albopictus wing lengths were significantly
shorter in pools with Ae. aegypti (KW χ2= 13.21, df = 1, p0.01) which means female wing length decreased with increase in
pH in larval habitat. In contrast, pH showed positive association with wing length of female
Ae. albopictus.
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Fig. 11 Wing length comparisons between Ae. aegypti and Ae. albopictus with and without co-occurrence in
same microhabitat.
Discussion
Understanding the ecology of mosquito-borne diseases needs a multidimensional and
multiscale approach which can connect fine-scale traits with behaviour, environmental
heterogeneity, and epidemiology for realistic predictions of disease dynamics
5. Cities are
constantly perceived as hotspots for infectious diseases47. A combination of heterogeneous
landscape, population density and socio-ecological drivers such as urbanization, change in
land use, and climate change is having indirect effects on the transmission dynamics of
infectious diseases. Therefore, combining studies with landscape ecology, microclimate and
species composition are essential for designing and monitoring vector control methods. In
this study we explored the effects of the prevalence of larval habitat, microclimate,
urbanization and traditional Stegomyia indices on the larval abundance, body size, species
diversity in urban environments.
Our neighbourhood non-residential larval survey showed that Ae. aegypti and Ae. albopictus
were the highly abundant mosquito species which was reflected in the Stegomyia indices
estimated above the WHO thresholds. Our results show that the container index, Breteau
location index and location index showed a linear increase from Barren habitat to High dense
habitat and significantly high indices from July to September. These findings further support
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27
that dengue transmission risk varies even in a heterogenous urbanised landscape and Aedes
habitat is prevalent in densely populated areas of the city. The increase in Stegomyia indices
corresponds to seasonal rise in larval prevalence which mirrored the increase in dengue cases
in the city (Fig. 5). The annual surge in dengue cases starts from early June with the onset of
pre-monsoon showers which leads to rise in cases between July and September. Our study
relies on outdoor surveillance which highlights the importance of ‘neighbourhood
surveillance’ in public places which can help in real-time forecasting of dengue cases in
urban areas
48,49. There is a little evidence on quantifiable associations between Stegomyia
indices and dengue transmission that could be reliably used for dengue outbreak prediction50.
We have no evidence on how the Stegomyia indices from indoor surveillance corresponds to
dengue outbreaks in the city. There is a need for standardised sampling protocols and well-
designed studies that can elucidate the relationship between vector abundance and spatial
heterogeneity in dengue transmission. In addition, dengue virus epidemiology is tightly
linked to serotype/genotype replacement at the population level which occurs every 2-4
years
51-53. Bengaluru has experienced triennial peaks, a decline in the total number of dengue
cases from 10,411 in 2019 to 2047 in 2020 and 1641 in 2021 (TOI News54). We need fine-
scale data on ecological drivers of disease emergence and to understand the links between
mosquito population dynamics and how vertical transmission affects the circulating serotypes
in the community.
We described significant variations over time and space in larval sites and distributions of
two Aedes species. The heterogeneity in macrohabitat types was masked by the man-made
microhabitats for Aedes species which were ubiquitous across the landscape, playing key
ecological roles. Habitat preference between two Aedes species appeared to be driven at the
microhabitat level. Whilst similar habitat association has been reported in Singapore
55,
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Brazil10, Burkina Faso34 and the USA29, Cameroon56, Lakshadweep islands6, Kolkata57, and
Bengaluru58, the domestic habitats like discarded grinding stones were the most productive
microhabitat in Bengaluru and has been recorded in other southern India cities59,60. Both
Aedes species showed high prevalence in discarded grinding stones and negative association
with stagnant water. The larval prevalence of Ae. aegypti was particularly positively
associated with discarded tires. Ae. albopictus showed negative association with storage
containers whereas Aedes aegypti was marginally positively associated. Storage containers
are actively in use but provide high disturbance ephemeral habitats for Aedes species. The
prevalence of Ae. aegypti larval habitat was positively associated with coconut shells,
whereas Ae. albopictus was recorded in plant axils and tree holes albeit at low frequency and
negatively associated with coconut shells.
The high larval prevalence in artificial breeding sites reflected in higher species richness was
in artificial sources than natural breeding sources. Storage containers, stagnant water
harboured highest mosquito richness probably due to size and water volume allows species to
co-exist in the same habitat. Our study revealed that both species richness and diversity were
significantly high in plantation and declined in urbanized areas. Similar patterns have been
observed in forest community where presence of diverse habitat types and less disturbance
supports a diversity of mosquito species61.
The larval abundance followed the similar pattern as the prevalence of larval habitat for Ae.
aegypti. The larval abundance of Ae. aegypti showed a hump-shaped patterns with an
increase from July-September. However, there was no change in abundance of Ae.
albopictus. To maximise fitness in variable environments an individual often favours a bet-
hedging strategy or risk spreading strategy62, which involves reduction in annual breeding
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performance and an increase in adult survival so that reproduction can be attempted over
more years. The phenology of Ae. aegypti and Ae. albopictus in invasive regions where they
coexist shows that the egg abundance of Ae. albopictus becomes more numerous with the
progression of wet season63,64. Because Ae. aegypti has more desiccation resistant eggs
compared to Ae. albopictus65, 66 one would expect that the frequency of oviposition on the
water by Ae. albopictus would be greater than that by Ae. aegypti. However, we observed
similar prevalence but no change in abundance of Ae. albopictus. This warrants a detailed
study in Bengaluru, where both species are sympatric, to show how two Aedes species
optimize fitness in varying environments. Water-holding container type, size, organic matters
influence in-water oviposition behaviour in Aedes species. Aedes species larval abundance
was negatively associated with volume of larval habitat. Our results are in contrast with
Barrera et al.23 which found a positive association between pupal abundance and water
volume in containers stored outside the housing. Several studies conducted indoors10,67 found
water volume in larval habitat as a positive predictor of number of immatures with container
size. Outdoor habitats are more prone to ecological and anthropological disturbance and truly
constitute an ephemeral breeding habitat for Aedes mosquitoes.
Among microclimate variables, we found a negative correlation between Ae. aegypti larval
abundance and water pH which is consistent with the study conducted in Burkina Faso
34.
Temperature showed a negative marginally significant association with Ae. albopictus
abundance. In general, we found no difference in temperature and humidity across
macrohabitat types. However, the mean temperature recorded in the larval habitat was lower
than air temperature which supports larval growth throughout the year. Temperature drives
the vector ecology by its effect on mosquito behaviour, survival, extrinsic incubation period
(EIP)
68. Temperature thereby shapes parasite transmission by defining lower and upper
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thermal limits which maintains a non-linear relationship between temperature and length of
parasite development69,70. The EIP is an important determinant of the temporal dynamics of
dengue virus transmission71. Rohani et al.72 have reported that the EIP decreases when the
extrinsic incubation temperature increases from 9 days at 26 °C to 5 days at 30 °C. We
recorded warmer larval habitat temperature (26°C-28°C) than air temperature which could
affect incubation period of viruses and longer transmission window.
In a landscape context, urbanization was associated with high prevalence of Aedes larval
habitat and a predominance of artificial containers as breeding sites, mostly colonized by Ae.
aegypti and Ae. albopictus. We found cement tanks used for irrigation purposes infested with
mosquito larvae and discarded grinding stones as breeding grounds in plantations and lake
areas with no housing and discarded tires as viable larval sites for both Ae. aegypti and An.
stephensi. The high prevalence of artificial habitats contributing to larval prevalence suggests
that dengue outbreaks might not only be associated with the biophysical properties (e.g.,
absence or inaccessibility of piped water supplies or irregular functioning of these piped
water systems), but household waste is playing a significant role in driving the Aedes ecology
and distribution in an urban system. Besides Aedes species, Cx. quinquefasciatus, Cx. gelidus,
Cx. bitaeniorhynchus, Cx. mimeticus, Ar. subalbatus, An. stephensi and An. culicifascies were
mainly associated with stagnant water. Therefore, systematic removal of discarded household
containers as potential standing water sources is integral to reduce mosquito abundance and
ecologically sound method to control arbovirus transmission in Bengaluru city.
Quality of larval habitat, abundance and microclimate impact mosquito body size which has
huge epidemiological implications for the carry-over effect of the immature mosquito’s life
on Ae. aegypti competence for arbovirus transmission
73. Aedes body size showed a variation
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in wing length across microhabitat and macrohabitat types. The wing length of mosquitoes
that emerged from the discarded grinding stones were significantly larger than discarded
containers or coconut shells. The best model showed a negative association between pH and
wing length for Ae. aegypti and a contrasting effect on Ae. albopictus with positive
association between pH and wing length. Small body size females cannot fly long-distance
and require multiple meals whereas large body size females can fly farther. Co-existence with
other species seems to affect only Ae. albopictus with reduction in wing length. This was in
contrast with study conducted in Brazil
10. Interspecific larval competition between Ae.
aegypti and Ae. albopictus in laboratory study have shown greater effect on survival and
wing length of Ae. albopictus, at intermediate larval density74.
Conclusions
Our longitudinal study provides insights into microhabitat and macrohabitat of two dengue
vectors i.e., Ae. aegypti and Ae. albopictus in outdoor survey across heterogeneous
landscapes. Mosquito species diversity was higher in plantation areas than in densely
populated grids. However, Aedes infestation indices were highest in urban grids between July
to September. We found artificial habitats such as discarded grinding stones and storage
containers are the major contributors for mosquito larval habitat. This further implies that
improper storage practices and unplanned waste management in the city leads to vector
breeding. We provide a robust understanding on the ecological drivers of mosquito habitat
that will help in efficient vector control and implementing innovative strategies.
Authors’ contributions
DD: conducted fieldwork, analysed the data, wrote introduction and results; PDR: conducted
fieldwork, assisted in data analyses, wrote results; IL: conducted fieldwork; SG: coordinated
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32
the field and lab data collections; KI: contributed to study design; SKG: contributed to study
design, assisted in initial field surveys. Interim monitoring of the study; FI: conceptualised
and designed the study, proposed methodological directions in analysis and lead the analysis,
wrote the manuscript. All authors read and approve the final manuscript.
Data availability
The data is available in supplementary material accessible at [https://shorturl.at/kKOZ2]
Declaration of interests
The authors have read the journal's policy. Authors declare no competing interest.
Acknowledgements
This research was financially supported by Tata Trusts funding to Tata Institute for Genetics
and Society. We would like to thank the Bruhat Bengaluru Mahanagara Palike (BBMP) for
permission and support for this study.
References
1. Reinert JF, Harbach RE, Kitching IJ. Phylogeny and classification of tribe Aedini (Diptera:
Culicidae) Zoological Journal of the Linnean Society. 2009; 157:700–794.
doi: 10.1111/j.1096-3642.2009.00570. x.
2. Rejmankova E, Grieco J, Achee N, Roberts DR (2013) Ecology of larval habitats. In:
Manguin S, editor. Anopheles mosquitoes: new insights into malaria vectors 9th. InTech;
Rijeka: pp. 397–446.
3. Laporta GZ, Sallum MA (2014). Coexistence mechanisms at multiple scales in mosquito
assemblages. BMC ecology, 14, 30. https://doi.org/10.1186/s12898-014-0030-8
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
33
4. Grech MG, Manzo LM, Epele LB, Laurito M, Claverie AÑ, Ludueña-Almeida FF, ... &
Almirón WR (2019). Mosquito (Diptera: Culicidae) larval ecology in natural habitats in the
cold temperate Patagonia region of Argentina. Parasites & vectors, 12(1), 1-14.
5. Chandrasegaran K, Lahondère C, Escobar LE, & Vinauger C (2020). Linking mosquito
ecology, traits, behavior, and disease transmission. Trends in parasitology, 36(4), 393-403.
6. Nihad M, Rohini PD, Sutharsan G, Anagha A PK, Sumitha MK, Shanmuga Priya A, Rahul
P, Sasikumar V, S Dasgupta, J Krishnan and F Ishtiaq (2022). Island biogeography and
human practices drive ecological connectivity in mosquito species richness in Lakshadweep
Archipelago. Scientific Reports 12:8060.
7. Juliano SA (2009). Species interactions among larval mosquitoes: context dependence
across habitat gradients. Annual review of entomology, 54, 37-56.
8. Reiskind MH and Lounibos LP (2014) Spatial and temporal patterns of abundance of
Aedes aegypti L (Stegomyia aegypti) and Aedes albopictus (Skuse) [Stegomyia albopictus
(Skuse)] in southern Florida. Medical and Veterinary Entomology 27, 421-429.
9. Armbruster P, Hutchinson RA (2002). Pupal mass and wing length as indicators of
fecundity in Aedes albopictus and Aedes geniculatus (Diptera: Culicidae). Journal of medical
entomology, 39(4), 699–704. https://doi.org/10.1603/0022-2585-39.4.6997.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
34
10. David M, Dantas E, Maciel-de-Freitas R, Codeço C, Prast A, Lourenço-de-Oliveira R
(2021). Influence of Larval Habitat Environmental Characteristics on Culicidae Immature
Abundance and Body Size of Adult Aedes aegypti, Front. Ecol. Evol. 9: 626757.doi:
10.3389/fevo.2021.626757
11. Clark TM, Vieira MA, Huegel KL, Flury D & Carper M (2007). Strategies for regulation
of hemolymph pH in acidic and alkaline water by the larval mosquito Aedes aegypti (L.)
(Diptera; Culicidae). The Journal of experimental biology, 210(Pt 24), 4359–4367.
https://doi.org/10.1242/jeb.010694
12. Ramasamy R, Surendran SN, Jude PJ, Dharshini S, & Vinobaba M. (2011). Larval
development of Aedes aegypti and Aedes albopictus in peri-urban brackish water and its
implications for transmission of arboviral diseases. PLoS neglected tropical diseases, 5(11),
e1369. https://doi.org/10.1371/journal.pntd.0001369
13. Morin CW, Comrie AC & Ernst K (2013). Climate and dengue transmission: evidence
and implications. Environmental health perspectives, 121(11-12), 1264-1272.
14. Garcia-Sánchez DC, Pinilla GA, & Quintero J (2017). Ecological characterization of
Aedes aegypti larval habitats (Diptera: Culicidae) in artificial water containers in Girardot,
Colombia. Journal of vector ecology: journal of the Society for Vector Ecology, 42(2), 289–
297. https://doi.org/10.1111/jvec.12269
15. Multini LC, Oliveira-Christe R, Medeiros-Sousa AR, Evangelista E, Barrio-Nuevo KM,
Mucci LF, ... & Marrelli MT (2021). The Influence of the pH and Salinity of Water in
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
35
Breeding Sites on the Occurrence and Community Composition of Immature Mosquitoes in
the Green Belt of the City of São Paulo, Brazil. Insects, 12(9), 797.
16. World Health Organization. Dengue: Guidelines for Diagnosis. Treatment, Prevention
and Control: New Edition. World Health Organization: Geneva, 2009.
17. Gupta B, Reddy BP (2013). Fight against dengue in India: progresses and challenges.
Parasitol Res. 112(4):1367-78. doi: 10.1007/s00436-013-3342-2.
18. Chakravarti A, Arora R, Luxemburger C (2012). Fifty years of dengue in India. Trans R
Soc Trop Med Hyg; 106: 273–282.
19. Pradeep C, Achuth KS, & Manjula S (2016). Awareness and practice towards dengue
fever in Kannamangala village, Bangalore, Karnataka, India. Int J Community Med Public
Health, 3, 1847-50.
20. Pokharel S, White LJ, Aguas R, Celhay O, Pellé KG, Dittrich S. (2020) Algorithm in the
Diagnosis of Febrile Illness Using Pathogen-specific Rapid Diagnostic Tests. Clin Infect Dis.
23;70(11):2262-2269. doi: 10.1093/cid/ciz665.
21. Tuan NM, Nhan HT, Chau NV, Hung NT, Tuan HM, Tram TV, Ha Nle D, Loi P, Quang
HK, Kien DT, Hubbard S, Chau TN, Wills B, Wolbers M, Simmons CP. Sensitivity and
specificity of a novel classifier for the early diagnosis of dengue. PLoS Negl Trop Dis. 2015
Apr 2;9(4): e0003638. doi: 10.1371/journal.pntd.0003638.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
36
22. Troyo A, Fuller DO, Calderón-Arguedas O, & Beier JC (2008). A geographical sampling
Method
for surveys of mosquito larvae in an urban area using high-resolution satellite
imagery. Journal of vector ecology: journal of the Society for Vector Ecology, 33(1), 1–7.
23. Barrera R, Amador M, Clark GG (2006) Use of the pupal survey technique for measuring
Aedes aegypti (Diptera: Culicidae) productivity in Puerto Rico. Am J Trop Med Hyg.
74(2):290-302.
24. Morrison AC, Sihuincha M, Stancil JD, Zamora E, Astete H, Olson JG, Vidal-Ore C,
Scott TW. Aedes aegypti (Diptera: Culicidae) production from non-residential sites in the
Amazonian city of Iquitos, Peru. Ann Trop Med Parasitol. 2006 Apr;100 Suppl 1:S73-S86.
25. Chen Y, Li N, Lourenço J, Wang L, Cazelles B, Dong L, et al. (2022) Measuring the
effects of COVID-19-related disruption on dengue transmission in southeast Asia and Latin
America: A statistical modelling study. Lancet Infect Dis 2022; 22: 657-667.
26. World Health Organization. Dengue and severe dengue. 2022. [Online]. Available from:
https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue
.
27. Cator LJ, Thomas S, Paaijmans KP, Ravishankaran S, Justin JA, Mathai MT, Read AF,
Thomas MB, Eapen A, 2013. Characterizing microclimate in urban malaria transmission
settings: a case study from Chennai, India. Malar J 12: 84.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
37
28. Kumar G, Pande V, Pasi S, Ojha VP, Dhiman RC (2018). Air versus water temperature of
aquatic habitats in Delhi: implications for transmission dynamics of Aedes aegypti. Geospat
Health 13:707.
29. Wilke A, Chase C, Vasquez C, Carvajal A, Medina J, Petrie WD, & Beier JC (2019).
Urbanization creates diverse aquatic habitats for immature mosquitoes in urban areas.
Scientific reports, 9(1), 15335. https://doi.org/10.1038/s41598-019-51787-5
30. Subramanian, S. V., Mavalankar, D., Kulkarni, S. P., Nussbaum, S., & Weigelt, M.
(2014). Metabolized-water breeding diseases in urban India: Socio-spatiality of water
problems and health burden in Ahmedabad. ZEF working paper series 130.
31. Nasci, R.S. & Mitchell, C.J. (1994) Larval diet, adult size, and susceptibility of Aedes
aegypti (Diptera: Culicidae) to infection with Ross River virus. Journal of Medical
Entomology, 31, 123–126.
32. Hegde GV, Chandra KS (2012) Resource availability for water supply to Bangalore city,
Karnataka. Curr. Sci., 102, 1102–1104.
33. Kumar RR, Kamal S, Patnaik SK, Sharma RC (2002) Breeding habitats and larval indices
of Aedes aegypti (L.) in residential areas of Rajahmundry town, Andhra Pradesh. J Commun
Dis. 2002; 34:50–58.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
38
34. Tuladhar, R., Singh, A., Banjara, M.R. et al. Effect of meteorological factors on the
seasonal prevalence of dengue vectors in upland hilly and lowland Terai regions of Nepal.
Parasites Vectors 12, 42 (2019). https://doi.org/10.1186/s13071-019-3304-3
35. Ouédraogo, W.M., Toé, K.H., Sombié, A. et al. Impact of physicochemical parameters of
Aedes aegypti breeding habitats on mosquito productivity and the size of emerged adult
mosquitoes in Ouagadougou City, Burkina Faso. Parasites Vectors 15, 478 (2022).
https://doi.org/10.1186/s13071-022-05558-3
36. Barraud PJ (1934) The Fauna of British India, including Ceylon and Burma. Diptera V.
Family Culicidae. Tribes Megarhinini and Culicini London: Taylor and Francis p. 463.
37. Focks, Dana A &
UNDP/World B ank/WHO S peci al Pr ogramme for Researc h an d
Tr aini ng i n T r opica l Di s eas es. ( 2 004 ) . A review of entomological sampling methods and
indicators for dengue vectors. World Health Organization.
https://apps.who.int/iris/handle/10665/68575
38. Nasci RS (1986). The size of emerging and host-seeking Aedes aegypti and the relation of
size to blood-feeding success in the field. J Am Mosq Control Assoc. 2(1):61-2.
39. R Core Team (2021). R: A language and environment for statistical computing. R
Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/.
40. Hsieh TC, Ma KH, Chao A (2016) iNEXT: an R package for rarefaction and exploration
of species diversity (Hill numbers). Methods in Ecology and Evolution. 12:1451-1456.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
39
41. Magurran, A.E. (2004) Measuring Biological Diversity. Blackwell Publishing, Oxford,
256 p.
42. Brooks, Mollie & Kristensen, Kasper & van Benthem, Koen & Magnusson, Arni & Berg,
C.W. & Nielsen, Anders & Skaug, Hans & Mächler, Martin & Bolker, Benjamin. (2017).
glmmTMB Balances Speed and Flexibility Among Packages for Zero-inflated Generalized
Linear Mixed Modeling. R Journal. 9. 378-400. 10.32614/RJ-2017-066.
43. Hartig F (2019). DHARMa: residual diagnostics for hierarchical (multi-level/mixed)
regression models. http:// flori anhar tig. github. io/DHARMa/.
44. Burnham KP, and Anderson DR (2002). Model selection and multimodel inference, a
practical information-theoretical approach. Second edition. Springer, New York, New York,
USA.
45. Arnold TW (2010). Uninformative parameters and model selection using Akaike’s
information criterion. Journal of Wildlife Management 74(6):1175-1178.
https://doi.org/10.2193/2009-367
46. Bates D., Machler M., Bolker B. & Walker S (2015) Fitting linear mixed-effects models
using lme4. J. Stat. Softw. 67, 1–48.
47. Neiderud CJ (2015) How urbanization affects the epidemiology of emerging infectious
diseases. Infect Ecol Epidemiol. 5:27060. doi: 10.3402/iee.v5.27060.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
40
48. Chen Y, Ong JHY, Rajarethinam J, Yap G, Ng LC, Cook AR (2018) Neighbourhood
level real-time forecasting of dengue cases in tropical urban Singapore. BMC Med 16(1):
129.
49. Ghosh SK & Ghosh C (2022). COVID-19's impacts on dengue transmission: Focus on
neighbourhood surveillance of Aedes mosquitoes Asian Pacific Journal of Tropical Medicine
15(8): 339-340
50. Bowman LR, Runge-Ranzinger S, McCall PJ (2014) Assessing the Relationship between
Vector Indices and Dengue Transmission: A Systematic Review of the Evidence. PLoS Negl
Trop Dis 8(5): e2848.
51. Siqueira JB Jr, Martelli CM, Coelho GE, Simplicio AC, Hatch DL. Dengue and dengue
hemorrhagic fever, Brazil, 1981–2002. Emerg Infect Dis. 2005;11(1):48–53.
52. Guzman MG, Kouri G, Valdes L, Bravo J, Vazquez S, Halstead SB. Enhanced severity of
secondary dengue-2 infections: death rates in 1981 and 1997 Cuban outbreaks. Rev Panam
Salud Publica. 2002;11(4):223–7.
53. Rijal, K.R., Adhikari, B., Ghimire, B. et al. Epidemiology of dengue virus infections in
Nepal, 2006–2019. Infect Dis Poverty 10, 52 (2021).
54. https://timesofindia.indiatimes.com/city/bengaluru/bengaluru-east-tops-dengue-chart-
bbmp-blames-dense-population/articleshow/91605291.cms
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
41
55. Seidahmed OME, Eltahir EAB (2016) A Sequence of Flushing and Drying of Breeding
Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore. PLoS Negl
Trop Dis 10(7): e0004842. https://doi.org/10.1371/journal.pntd.0004842
56. Kamgang B, Happi JY, Boisier P, Njiokou F, Hervé JP, Simard F, Paupy C. Geographic
and ecological distribution of the dengue and chikungunya virus vectors Aedes aegypti and
Aedes albopictus in three major Cameroonian towns. Med Vet Entomol. 2010 Jun;24(2):132-
41.
57. Banerjee S, Aditya G, Saha GK (2015) Household Wastes as Larval Habitats of Dengue
Vectors: Comparison between Urban and Rural Areas of Kolkata, India. PLoS ONE 10(10):
e0138082. doi:10.1371/journal.pone.0138082
58. Reegan DA, Kumar KR & Devanand L (2018) Prevalence of dengue vectors in
Bengaluru city, India: An entomological analysis. International Journal of Mosquito Research
2018; 5(1): 101-105
59. Mariappan T. et al. (2008) Defective Rainwater Harvesting Structure and Dengue Vector
Productivity Compared with Peridomestic Habitats in a Coastal Town in Southern India,
Journal of Medical Entomology, 1: 148–156
60. Arunachalam N, Tyagi BK, Samuel M, Krishnamoorthi R, Manavalan R, Tewari SC,
Ashokkumar V, Kroeger A, Sommerfeld J, Petzold M. Community-based control of Aedes
aegypti by adoption of eco-health methods in Chennai City, India. Pathog Glob Health.
106(8):488-96.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
42
61. Loaiza JR, Dutari LC, Rovira JR, Sanjur OI, Laporta GZ, Pecor J.et al. (2017)
Disturbance and mosquito diversity in the lowland tropical rainforest of central Panama.
Scientific Reports. 7:1-3.
62. Ripa J, Olofsson H, Jonzén N. What is bet-hedging, really? Proc Biol Sci. 2010 Apr
22;277(1685):1153-4.
63. Leisnham, P.T. & Juliano, S.A. (2009) Spatial and temporal patterns of coexistence
between competing Aedes mosquitoes in urban Florida. Oecologia, 160, 343–352.
64. Mogi, M., Khamboonruang, C., Choochote, W. & Suwanpanit, P. (1988) Ovitrap surveys
of dengue vector mosquitoes in Chiang Mai, northern Thailand—seasonal shifts in relative
abundance of Aedes albopictus and Aedes aegypti. Medical and Veterinary Entomology, 2,
319–324.
65. Mogi, M., Miyagi, I., Abadi, K. & Syafruddin. (1996) Inter- and intraspecific variation in
resistance to desiccation by adult Aedes (Stegomyia) spp. (Diptera: Culicidae) from
Indonesia. Journal of Medical Entomology, 33, 53–57.
66. Juliano SA, Lounibos LP, O'Meara GF (2004). A field test for competitive effects of
Aedes albopictus on A. aegypti in South Florida: differences between sites of coexistence and
exclusion? Oecologia, 139:583–93.
67.
Islam S, Haque CE, Hossain S, Hanesiak J. (2021) Climate variability, dengue vector
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
43
abundance and dengue fever cases in Dhaka, Bangladesh: A Time-Series Study. Atmosphere
12, 905. https://doi.org/10.3390/atmos12070905
68. Blanford, J., Blanford, S., Crane, R. et al. (2013) Implications of temperature variation for
malaria parasite development across Africa. Sci Rep 3, 1300.
https://doi.org/10.1038/srep01300
69. Paaijmans, K. P., Read, A. F., & Thomas, M. B. (2009). Understanding the link between
malaria risk and climate. Proceedings of the National Academy of Sciences of the United
States of America, 106, 13844–13849.
70. Mozaffer F, Menon GI and Ishtiaq F (2022). Exploring the thermal limits of malaria
transmission in the western Himalaya. Ecology and Evolution, 9: e9278
https://doi.org/10.1002/ece3.9278
71. Chan M, Johansson MA. The incubation periods of dengue viruses. PLoS ONE 2012;
7:e50972.
72. Rohani A, Wong YC, Zamre I et al. The effect of extrinsic incubation temperature on
development of dengue serotype 2 and 4 viruses in Aedes aegypti (L.). Southeast Asian J
Trop Med Public Health 2009; 40: 942–950.
73. Dickson LB, Jiolle D, Minard G, Moltini-Conclois I, Volant S, Ghozlane A, et al. (2017)
Carryover effects of larval exposure to different environmental bacteria drive adult trait
variation in a mosquito vector. Sci Adv. 3:1–14.
. CC-BY-NC-ND 4.0 International licenseIt is made available under a
is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted June 20, 2023. ; https://doi.org/10.1101/2023.06.19.23291608doi: medRxiv preprint
44
74. Serpa LL, Kakitani I, Voltolini JC. Competição entre larvas de Aedes aegypti e Aedes
albopictus em laboratório [Competition between Aedes aegypti and Aedes albopictus larvae
in the laboratory]. Rev Soc Bras Med Trop. 2008 Sep-Oct;41(5):479-84. Portuguese. doi:
10.1590/s0037-86822008000500009.
Figure legends
Figure 1. Map of Bengaluru showing grid locations by macrohabitat types and larval sites by
mosquito species.
Figure 2. Circos plots showing macrohabitat and microhabitat niche segregation by mosquito
species. A: Proportion of microhabitat recorded in each macrohabitat type; B: Proportion of
mosquito larval sites by species recorded in each microhabitat, the larval prevalence varied
significantly by microhabitat; C: Proportion of mosquito larval sites by species recorded in
each macrohabitat, the larval prevalence had no significant effect of macrohabitat.
CS=Coconut shells; DC=Discarded containers; PP=Plastic pots; DT=Discarded tyres; TH:
Tree holes; PA=Plant axils; SC=Storage containers; GS=Grinding stones
Figure 3. Breeding preference ratio of Aedes species across microhabitats. CS=Coconut
shells; DC=Discarded containers; PP=Plastic pots; DT=Discarded tyres; TH: Tree holes;
PA=Plant axils; SC=Storage containers; GS=Grinding stones
Figure 4. Ae. aegypti and Ae. albopictus infestation indices across a macrohabitat gradient.
Figure 5. Left panel: The wet habitat prevalence, Right Panel: Mosquito larvae prevalence by
month. Inset figure shows peak in dengue cases (aggregate from 2016-2019) as reported by
Bruhat Bengaluru Mahanagara Palike.
Figure 6. Model summary of parameter estimates from the best-fit generalized linear mixed-
effects model predicting larval prevalence, based on a candidate set model combinations of
the variables: macrohabitat, microhabitat, pH, temperature, volume, season and co-occurring
species. The models also include the random effects of grid.
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45
Figure 7. Observed and Chao 1 estimated mosquito richness and species diversity in
microhabitat and macrohabitats.
Figure 8. Mosquito species richness and diversity across season by macrohabitat types.
Figure 9. Model summary of parameter estimates from the best-fit generalized linear mixed-
effects model predicting larval abundance, based on a candidate set model combinations of
the variables: macrohabitat, microhabitat, pH, temperature, volume, season, and sympatric
species. The models also include the random effects of grid.
Figure 10. Comparison of wing length in male and female Aedes species as a proxy for body
size. A-B: Ae. aegypti and Ae. albopictus wing lengths measured from larva emerged
populations. C-D: Ae. aegypti and Ae. albopictus wing lengths of male and female captured
as adults using BG traps.
Figure 11. Wing length comparisons between Ae. aegypti and Ae. albopictus with and
without co-occurrence in same microhabitat.
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