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Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/2/2013 Publication Date: 1/3/2014 Citation: Brent, C.S., Hull, J.J. 2014. Characterization of male-derived factors inhibiting female sexual receptivity in Lygus hesperus. Journal of Insect Physiology. 60:104-110. Interpretive Summary: Shortly after mating with a male, females of the western tarnished plant bug lose interest in mating again for several days. This behavioral change appears to be caused by male-produced factors delivered along with the sperm. To better understand the source of the male factor(s) responsible for reducing female sexual activity, extracts made from different male reproductive organs were injected directly into virgin females to test their behavioral effects. Products of the testes did not seem to produce any effect, but products from the adjoining accessory glands reduced female mating activity. Treatment of the extracts before injection indicated that the active factor was inactivated with heated and was water soluble. Several unique proteins were isolated from the seminal fluid that are similar in size to known inhibitory substances in other insects. Males were also found to transfer hormones during mating which might influence female reproductive behavior and physiology. The results support the hypothesized role of males in manipulating the post-mating behavior of females, and suggest such behavioral modification is achieved through multiple components that act in concert to induce both short- and long-term effects. Technical Abstract: Newly mated females of the plant bug, Lygus hesperus Knight, enter a refractory period during which their sexual receptivity to courting males is greatly reduced for several days. This behavioral change appears to be induced by male-derived factors delivered in the spermatophore during copulation. To better understand the source of the factor(s) responsible for the inhibition, the homogenates of spermatophores, or of the individual organs that provide the constituents of the spermatophore, were injected directly into the abdomen of virgin females. The contents of the lateral and medial accessory glands both appear to produce inhibitory effects, but those of the seminal vesicle had no effect. Treatment of the homogenate also indicated that the active factor(s) is heat labile and water soluble. Several unique proteins were found in the water soluble fraction of the spermatophore, one of which is similar in size to the D. melanogaster sex peptide, a male derived compound known to inhibit receptivity in female flies. In addition, spermatophores contained a substantial quantity of juvenile hormone, a key endocrine regulator of reproductive behavior and physiology in most insects. The results support the hypothesized role of males in manipulating the post-mating behavior of females, and suggest this is achieved through multiple components that act in concert to induce both short- and long-term effects. |
