The influence of photoperiod and mating on profiles of seminal fluid peptides from male accessory glands of Helicoverpa armigera

Abstract

After mating many female insects undergo physiological and behavioral changes including inhibition of receptivity to further matings and induction of oviposition. These changes are modulated by the transfer of proteins from male seminal fluids during mating. Here, we identified a number of proteins in the seminal fluid secretion of the moth species, Helicoverpa armigera that undergo changes in accordance to photoperiod and are reduced or depleted after mating, thereby indicating a probable functional significance during mating. Changes in seminal fluid proteins were studied using LC-MS/MS and 2D SDS PAGE to identify proteins that are both up-regulated during the scotophase and depleted after mating. A total of 98 proteins were identified using LC-MS/MS, out of which the levels of 52 were up-regulated during the scotophase. We identified many functional similarities to seminal fluids from other insects. Thus, although seminal fluid proteins are amongst the most rapidly evolving proteins, the classes they represent are relatively conserved. The proteins identified were classified into 7 different functional groups: signal transduction; immune function; lipid transporting; gene function; cytoskeletal proteins; apoptosis; metabolism; the remainder of unknown function. More than half of the identified proteins were up-regulated during the scotophase with most at a level of up to 5 fold but 7 of the proteins were up-regulated to levels of more than 20 fold. Using comparative 2D electrophoresis MAG content was further studied to identify extracted proteins that are both up-regulated during the scotophase and depleted after mating and thus may be transferred to the female during copulation. Most of the identified H. armigera proteins bore high homologies to proteins in both the Bombyx mori and the Drosophila melanogaster databases. The possible individual roles of these proteins in the mating process are discussed.

To cite: Rafaeli, A. & Hanin, O. 2014 [2013]. The influence of photoperiod and mating on profiles of seminal fluid peptides
from male accessory glands of Helicoverpa armigera. Israel Journal of Entomology 43: 51–79.