Octopamine signaling is involved in the female postmating state in Nilaparvata lugens Stal (Hemiptera: Delphacidae)

Mating triggers physiological and behavioral changes in female insects. In many species, females experience postmating behavioral and physiological changes that define a post-mated state. These changes are comprised of several conditions, including long-term refractoriness to re-mating and increased production and laying of eggs. Here, we report that mating led to several changes in brown planthopper (BPH) females, including increased octopamine (OA), cAMP concentrations, and activities of several enzymes. Mating also led to changes in the expression of several genes acting in female physiology, including those in the cAMP/PKA signal transduction pathway. OA injections into virgin females led to similar changes. RNAi silencing of the gene encoding tyramine beta-hydroxylase, involved in the final step in OA synthesis, led to decreased expression of these genes, and reduced the cAMP/PKA signaling. At the whole-organism level, the RNAi treatments led to reduced fecundity, body weights, and longevity. RNAi silencing of genes acting in OA signaling led to truncated ovarian development, egg maturation, and ovarian vitellogenin (Vg) uptake. The impact of these decreases is also registered at the population level, seen as decreased population growth. We infer that OA signaling modulates the postmating state in female BPH and possibly other hemipterans.

Automated summary

Mating causes physiological and behavioral changes in female insects, such as increased egg production and refractoriness to re-mating. Research on brown planthoppers showed that mating led to increased concentrations of octopamine (OA), cAMP, and enzyme activities in females, as well as changes in gene expression in the cAMP/PKA signal transduction pathway. Silencing genes involved in OA signaling resulted in decreased fecundity, body weights, and longevity in females, with an impact on ovarian development, egg maturation, and population growth.