Male Influence on the Neuro-Endocrine Control of Egg Production in the Female Milkweed Bug, Oncopeltus fasciatus - Dallas

Abstract

The reproductive activity of male and female milkweed bugs is characterized by repeated, prolonged copulations during the whole adult life. This investigation was conducted to determine whether mating has any effect on egg reproduction. Virgin females were maintained under the three following conditions: 1) completely isolated from males, 2) visual contact with males through screening which prevented mating, and 3) physical access to one or two males at all times. The results in terms of number of eggs produced by females in each treatment demonstrates that egg production increased significantly when copulation could occur. It is postulated that in Oncopeltus fasciatus the actual physical stimulation of the female reproductive tract by the male during copulation initiates impulses in the ventral nerve cord which activate neurosecretory cells of the brain. Brain hormones activate the corpora cardiac and corpora allata to produce factors which stimulate protein synthesis in the fat body and yolk deposition in the ovary with a consequent increase in egg production.