Juvenile diet quality and intensity of sexual conflict in the mite Sancassania berlesei

Background: Differing evolutionary interests of males and females may result in sexual conflict, whereby traits or behaviours that are beneficial for male reproductive success (e.g., traits related to male-male competition) are costly for females. Since sexual conflict plays an important role in areas such as speciation, population persistence or evolution of life history traits, understanding what factors modulate the intensity of sexual conflict is important. This study aims to examine juvenile diet quality as one of the underestimated ecological factors that may affect the intensity of sexual conflict via individual conditions. I used food manipulation during the development of the mite Sancassania berlesei to investigate the effects on male reproductive behaviour and competitiveness, male-induced harm to female fitness and female resistance to this harm. Results Males that were exposed to low-quality food started mating later than the control males, and number of their mating attempts were decreased compared to those of control males. Moreover, males from the low-quality diet treatment sired fewer offspring in a competitive situation than males from the control treatment. However, the fitness of females exposed to males reared on a poor diet did not differ from that of females mated with control males. Furthermore, female diet quality did not alter their resistance to male-induced harm. Conclusion Overall, diet quality manipulation affected male reproductive behaviour and mating success. However, I found no evidence that the intensity of sexual conflict in S. berlesei depends on male or female conditions. Investigating a broad range of environmental factors will provide a better understanding of sexual conflict dynamics and its feedback into associated evolutionary mechanisms.