Post-mating Enhancement of Fecundity in Females Lygus hesperus

Authors: Brent, Colin; FASNACHT, MATTHEW - Southeast Missouri State University; JUDD, TIMOTHY - Southeast Missouri State University

Submitted to: Physiological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2010
Publication Date: 3/14/2011
Citation: Brent,C.S., Fasnacht,M.P., Judd,T.M. 2011. Post-mating enhancement of fecundity in females lygus hesperus. Physiological Entomology. 36:141-148.

Interpretive Summary: Although mated females of the western tarnished plant bug, Lygus hesperus, are known to produce more eggs than virgins, the nature of the inducing stimuli and the specific changes occuring in the female required additional elucidation. Compared to virgin females isolated from males, inseminated females produced 50% more. ALthough the quantity of seminal fluids recieved by a femals did not influence egg number, mating twice withing a 10 d span caused an additional increase in egg production. Females mating more than twice during the same period did not exhibit additonal benefits. The initial effect of mating was to enhance the rate at which eggs were laid, but the rate of egg maturation also increased. Male seminal fluid was found to lack substantive quantities of nutrients that might otherwise have enhanced female fecundity. The nutrients transferred by the male are insufficient for producing even a single egg, and the female has already produced a large number of eggs ready to be laid before she mates. Collectively, the data suggest that seminal fluid contains an activational substance which triggers an increase in egg laying. The prolonged increase in egg production may be achieved through multiple matings to ensure a supply of sperm to offset the degradation of any activational factor.

Technical Abstract: Although mated females of the western tarnished plant bug, Lygus hesperus, are known to produce more eggs than virgins, the nature of the inducing stimuli and the specific changes occuring in the female required additional elucidation. Compared to virgin females isolated from males, those exposed to male precopulatory behaviours produced similar numbers of eggs, while inseminated females produced 50% more. Although the quantity of seminal fluids recieved by a female did not influence egg mating more than twice during the same period did not exhibit additonal benefits. Because virgin females were found to contain more chorionated eggs than were oviposited, mating appeared to enhance the rate of deposition. However, to achieve a sustained increase in fecundity, an augmented rate of oocyte maturation would also be required. Male-derived spermatophores were found to lack substantive quantities of nutrients that might otherwise have enhanced female fecundity. The macro and micrinutrients transferred by yhe 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 sugges that seminal fluid contains an activational molecule, such as peptide, which triggers and increas 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.