Female sex pheromone suppression and the fate of sex‐peptide‐like peptides in mated moths of Helicoverpa armigera

Abstract

Insect males produce accessory gland (MAG) factors that are transferred in the seminal fluid to females during copulation, and elicit changes in the mated female's behavior and physiology. Our previous studies showed that the injection of synthetic Drosophila melanogaster sex-peptide (DrmSP) into virgin females of the moth Helicoverpa armigera causes a significant inhibition of pheromone production. In this and other moth species, pheromone production, correlated with female receptivity, is under neuroendocrine control due to the circadian release of the neuropeptide PBAN. In this study, we show that PBAN, present in the hemolymph during the scotophase in females, is drastically reduced after mating. We also identify 4 DrmSP-like HPLC peaks (Peaks A, S1, S2, and B) in MAGs, with increasing levels of DrmSP immunoreactivity during the scotophase, when compared to their levels observed during the photophase. In H. armigera MAGs, a significant reduction in the pheromonostatic peak (Peak B) was already evident after 15 min of copulation, and depletion of an additional peak (Peak S2) was evident after complete mating. Peak A is also detected in female brains, increasing significantly 1 h after mating, at which time inhibition of pheromone biosynthesis also occurs. However, changes corresponding to the other MAG peaks were not detected in mated female tissues.

Mating changes the female dietary preference in the two-spotted cricket, Gryllus bimaculatus

“…Genetic manipulation of SP-related genes has shown that SP causes some changes in the feeding behavior of adult female D. melanogaster immediately after mating (Kubli and Bopp, 2012). In addition, SP-like peptides have also been found in some insect species such as Helicoverpa armigera (Nagalakshmi et al, 2007). In H. armigera an SP-like peptide and its receptor mediate pheromone biosynthesis and re-mating rejection behavior against courting males (Nagalakshmi et al, 2007; Hanin et al, 2011).…”

“…In addition, SP-like peptides have also been found in some insect species such as Helicoverpa armigera (Nagalakshmi et al, 2007). In H. armigera an SP-like peptide and its receptor mediate pheromone biosynthesis and re-mating rejection behavior against courting males (Nagalakshmi et al, 2007; Hanin et al, 2011). SP and SP-like peptides are not conserved across insect species.…”

Neural control of gene recruitment in metazoans

“…Secretion of pheromones in all the cases studied so far depends on neural mechanisms. In invertebrates, e.g., secretion of pheromones is neurohumorally regulated by neuropeptides such as PBAN (Christensen et al, 1991;Abernathy et al, 1996;Teal et al, 1999;Groot et al, 2005;Nagalakshmi et al, 2007), whose pheromonotropic effect is mediated by a receptor that is produced in the form of three subtypes by alternative splicing (Kim et al, 2008).…”

Myoinhibiting peptides are the ancestral ligands of the promiscuous Drosophila sex peptide receptor

“…This is unexpected, since SP itself is not well conserved. Apart from a few Drosophila species, SP-like peptides have only been identified in the moth Helicoverpa armigera [20][21][22].…”