Regulatory roles of biogenic amines and juvenile hormone in the reproductive behavior of the western tarnished plant bug (Lygus hesperus)

Abstract

Mating induces behavioral and physiological changes in the plant bug Lygus hesperus Knight (Hemiptera: Miridae). After receiving seminal products, which include the systemic regulator juvenile hormone (JH), females enter a post-mating period lasting several days during which they enhance their oviposition rate and lose interest in remating. To elucidate the regulation of these behavioral changes in L. hesperus, biogenic amines were quantified in the heads of females at 5 min, 1 h and 24 h after copulation and compared to levels in virgins using high-performance liquid chromatography coupled with electrochemical detection. Mating significantly increased dopamine (DA) after 1 and 24 h, and decreased octopamine (OA) after 5 min and 1 h. Serotonin did not change with mating, but tyramine was significantly reduced after 5 min. While injection of amines into virgin females did not influence sexual receptivity, OA caused a decrease in oviposition during the 24 h following injection. Topical application of the JH analog methoprene to virgins caused an increase in DA, and a decline in mating propensity, but did not influence other amines or the oviposition rate. The results suggest the decline in OA observed immediately after mating may promote egg laying, and that male-derived JH may induce an increase in DA that could account for the post-mating loss of sexual receptivity.

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

“…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

“…During this three to seven day span subsequent to insemination, a female refrains from interaction with courting males (Brent, 2010a), a behavioral transition largely driven by male seminal products (Brent, 2010a; Brent et al, 2016). Because the female may copulate several times throughout her life (Strong et al, 1970; Brent et al, 2011), she cannot afford to have prospective mates repelled by an overly persistent antiaphrodisiac.…”

Biogenic amines shift during the pre-reproductive to reproductive transition in the small carpenter bee, Ceratina calcarata

“…Standard curves were calculated from external standards of the hydrochloride forms of DA, OA, 5-HT, and TA (Sigma-Aldrich). For a full description of this system, see Brent et al (2016) and Penick et al (2014).…”