Post‐mating enhancement of fecundity in female Lygus hesperus

Abstract

Although mated females of the western tarnished plant bug Lygus hesperus Knight are known to produce more eggs than virgins, the nature of the inducing stimuli and the specific changes occurring in the female require additional elucidation. Compared with virgin females isolated from males, those exposed to male precopulatory behaviours produce similar numbers of eggs, whereas inseminated females produce 50% more during the observation period. Although the quantity of seminal fluids received by a female does not influence egg number, mating twice within a 10-day span causes a 16% increase in fecundity, on average. Females mating more than twice during the same period do not exhibit additional increases in egg number. Because virgin females contain more chorionated eggs than are laid, mating appears to enhance the rate of oviposition. However, to achieve a sustained increase in fecundity, an augmented rate of oocyte maturation would also be required. Malederived spermatophores lack substantive quantities of nutrients that might otherwise have enhanced female fecundity. The total amounts of carbohydrate, protein and lipid, as well as eight essential minerals transferred by the male, are insufficient for producing even a single egg, and the female has already produced a large number of chorionated oocytes before she mates. Collectively, the data suggest that seminal fluid contains one or more activational molecules, such as a peptide, which triggers an increase in egg deposition. A prolonged increase in oviposition rate may be achieved through multiple matings to ensure a supply of sperm or to offset the degradation of the putative activational factor.

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

“…In contrast, multiply mated females had added gains in egg production rate. As is the case with numerous other insects (Gillot, ; Wolfner et al., ), male accessory gland products transferred in the L. hesperus spermatophore appear to trigger this rate increase (Brent, ,b; Brent et al., ). However, spermatophores of L. hesperus have limited macro‐ and micronutrient content (Brent et al., ), in contrast to the numerous species in which males provide ‘nuptial gifts’ of nutrients along with their sperm (Boggs, ; Arnqvist & Nilsson, ).…”

“…As is the case with numerous other insects (Gillot, ; Wolfner et al., ), male accessory gland products transferred in the L. hesperus spermatophore appear to trigger this rate increase (Brent, ,b; Brent et al., ). However, spermatophores of L. hesperus have limited macro‐ and micronutrient content (Brent et al., ), in contrast to the numerous species in which males provide ‘nuptial gifts’ of nutrients along with their sperm (Boggs, ; Arnqvist & Nilsson, ). This suggests that the stimulatory effect of mating on egg production may be hormonally driven, which coincides with the finding that one of the seminal components is juvenile hormone (Brent et al., ), a common systemic regulator of insect gonadal activity and reproductive behavior (Raikhel et al., ).…”

“…During insemination, L. hesperus males deliver a spermatophore that includes a complex blend of chemicals which may be of additional benefit or detriment to the female. This mix includes pheromones (Brent & Byers, ; Brent et al., ), hormones (Brent et al., ), trace amounts of micro‐ and macronutrients (Brent et al., ), and other modulators of behavior and physiology that could impact long‐term female health. Frequent mating may also maintain an elevated rate of egg production, which may influence female longevity (Strong & Sheldahl, ).…”

An insect anti-antiaphrodisiac

“…Females of the western tarnished plant bug, Lygus hesperus Knight, are polyandrous, mating repeatedly throughout their lives to ensure a steady supply of sperm and to maintain an elevated rate of oviposition (Strong et al, 1970; Brent, 2010a; Brent and Spurgeon, 2011; Brent et al, 2011). Mating also causes these females to become less attractive than virgins to males (Strong et al, 1970; Brent, 2010a).…”

A handbook for uncovering the complete energetic budget in insects: the van Handel's method (1985) revisited

“…There are some reported studies that attempt to assay proteins together with other nutrients (Zhou et al , 2004), although the procedure is often complex and notably involves specific steps (such as resolubilization) that are likely to lose some compounds before the start of the assay. This might explain why the energetic budget of an insect organism is still commonly extrapolated from partial data obtained on several individuals expected to be in the same physiological state (Brent et al , 2011). Such limitations require insects to be raised in highly controlled laboratory conditions, thereby precluding field studies of insects caught in the wild with unknown and variable life trajectories.…”