Embryonic development of parthenogenetic and sexual eggs in lower termites Running title Differences of parthenogenetic ability in two termite species

Termites are ancient social insects worldwide. In this research, developmental stages of embryos in the sexual and parthenogenetic eggs of Reticulitermes chinensis and R. aculabialis were observed and categorized. The embryonic development eggs was decteted by DAPI staining, single transcriptome sequencing analysis and RT-PCR . The ovarian development of FF and FM groups in R. flaviceps occurred in the early developmental stages, whilst in R. aculabialis, this occurred mainly in the late developmental stage. The difference was significant in micropyle number between the R. flaviceps FF colony type and the R.aculabialis FF colony type. There were no significant differences in the number of micropyles between other groups. In R. flaviceps, 86% of unfertilized eggs stopped development during the formation of the blastoderm, with the yolk cell gathering extensively at the egg center. Single-cell transcriptome sequencing analysis were annotated many genes in this two species termite. According this answer we analyzed the egg-to-larvae genes expression, and found that the expression levels of PKA, MAP2K1, MAPK1/3, HGK, MKP and Pax6 gene in RaFF were significantly higher than RfFF (P<0.05). We found a significantly lower oocyte cleavage rate in R. flaviceps than in R. aculabialis, resulting in fewer developed oocytes in R. flaviceps. In both species, activation and one or two cleavage events of oocytes occurred during ovulation, but in R. flaviceps the development of unfertilized eggs stopped. We suggest that genes with significant expression differences may play an important role in oocyte and embryonic development in termites.