Mating and social contact change egg production and longevity in adult females of the mirid Lygus hesperus

Authors: Brent, Colin

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2018
Publication Date: 5/23/2018
Citation: Brent, C.S. 2018. Mating and social contact change egg production and longevity in adult females of the mirid Lygus hesperus. Entomologia Experimentalis et Applicata. 166:545-554. https://doi.org/10.1111/eea.12683.
DOI: https://doi.org/10.1111/eea.12683

Interpretive Summary: There is frequently a tradeoff between how fertile and animal is and how long it lives, but the relationship isn’t consistent across species and various factors can influence these traits. Previous studies of the cotton pest Lygus hesperus Knight established that a mated female increases her rate of egg production, at least temporarily, but little is known about the long-term effects of mating and non-sexual social interactions. To clarify these relationships, survivorship and oviposition rate were tracked daily in adult females that were isolated or paired with a male or another female. The number of times each female mated was also recorded. Similar information was collected for isolated females that had been collected from a field population. Results indicate that male-specific stimuli accelerate female reproductive maturation, and that mating enhances oviposition rate. However, females paired with either a female or male companion had shortened lifespans, suggesting that social contacts exact a significant cost in this solitary species. Despite the negative impact of social interactions and the finding that a singly-mated female has sufficient sperm to fertilize a lifetime supply of eggs, many laboratory and field-collected females were found to have mated multiple times. These females achieved greater oviposition rates, longer lives, and produced more eggs during their lives. Females developing under field conditions rather than the restricted laboratory diet produced many more eggs, suggesting that early diet helps determine reproductive potential. Collectively, no strong evidence was found of a direct physiological link between fecundity and longevity, but environmental factors and mating were found to significantly influence both traits.

Technical Abstract: There is frequently a tradeoff between fecundity and longevity, but the relationship is inconsistent across species and influenced by various exogenous and endogenous factors. Previous studies of Lygus hesperus Knight (Hemiptera: Miridae) established that female egg production is promoted by insemination, at least temporarily, but little is known about the long-term effects on egg production and lifespan of mating and nonsexual interactions with conspecifics. To elucidate these relationships, survivorship and oviposition rate were tracked daily in females that were isolated or paired with a fertile male or another female throughout their adult lives. Mating rates were determined by postmortem examination. Results indicate that male-specific stimuli accelerate female reproductive maturation, and that mating elevates oviposition rate. However, females paired with either a female or male companion had shortened lifespans, suggesting that social contacts exact a significant cost in this solitary species. Despite the negative impact of conspecific interactions and the finding that a singly-mated female has sufficient sperm to fertilize a lifetime supply of eggs, many females were found to have mated more than once. Multiply-mated females had higher sustained oviposition rates, lived longer, and had greater lifetime fecundities. Collectively, no strong evidence was found of a direct physiological link between fecundity and longevity, but environmental factors and mating were found to significantly influence both traits.