Conspecific semiochemical tracks on host plants modulate reproduction and defense in parthenium beetles

Abstract

The present study investigated the effects of conspecific semiochemical tracks, emitted by both males and females and differentiated by mating status, on the reproductive performance, biochemical assimilation, and antioxidant enzyme activities of female Parthenium beetles, Zygogramma bicolorata Pallister. Results revealed that exposure to semiochemical cues significantly reduced both fecundity and egg viability in Z. bicolorata females. Nutrient assimilation, including glucose, proteins and triglycerides, was similarly diminished following exposure to semiochemical tracks. While triglyceride assimilation was lowest in the presence of tracks from mated adults, glucose and protein assimilation were lowest in females exposed to tracks from unmated adults. Moreover, key antioxidant enzyme activities, viz. superoxide dismutase, catalase and lipid peroxidation levels, were significantly affected. Females reared without exposure to semiochemical tracks exhibited the highest enzyme activity, with progressively lower levels observed in those exposed to tracks from mated males. These findings suggest that conspecific semiochemicals, modulated by mating status, play a critical role in regulating female reproductive physiology and metabolic status, potentially through stress-mediated pathways. Understanding these interactions may provide valuable insights into the ecology and management of Z. bicolorata populations.