Insights into the mechanism of shortened developmental duration and accelerated weight gain associated with Wolbachia infection in Hylyphantes graminicola.

Abstract

Wolbachia infection is known to affect host reproduction and development. To date, however, the underlying mechanism related to the effects of Wolbachia on host development has not yet been reported. Here, we compared the developmental duration and body weight in different instars of Wolbachia-positive (W+ ) and Wolbachia-negative (W- ) spiders (Hylyphantes graminicola) and detected the relative expression levels of 6 insulin-related genes and 3 ecdysone-related genes using reverse transcription qPCR. Results showed that the developmental duration was significantly shortened in W+ spiders compared with W- spiders. Furthermore, W+ spiders were significantly heavier than W- spiders at the 3rd and 4th instars, although no significant differences in body weight were observed after maturity. We also found that the expression levels of insulin-like growth factor-2 mRNA-binding protein-1, insulin-degrading enzyme, and ecdysone-inducible protein-1 genes were significantly down-regulated in W+ spiders compared with W- spiders, whereas the expression levels of insulin-like growth factor-binding protein-1, insulin-like peptide receptor, insulin receptor substrate 2-B, insulin-like, ecdysone-induced protein-2, and ecdysone receptor genes were significantly up-regulated in W+ spiders. Our results suggest that Wolbachia may influence host development by affecting insulin and ecdysone signaling pathways.