De-alation and its influences on egg production and flight muscle histolysis in a cricket ( Velarifictorus parvus) that undergoes inter-reproductive migration

Abstract

The effects of de-alation on egg production and flight muscle development were studied in the tambo cricket, Velarifictorus parvus Chopard. Artificial de-alation at adult emergence did not influence the pre-oviposition period, fecundity and longevity, but modified the oviposition schedule. Artificially de-alated females showed intensive egg production during the early stage of adult life while unoperated females attained peak ovipositing activity much later. Dissection indicated that artificial de-alation stimulated rapid egg production in the ovaries as well as flight muscle histolysis. When no food was given, intact females developed the flight muscles but produced no eggs during the first 5 days after adult emergence. Under the same conditions, artificially de-alated females broke down the flight muscles and produced 23 eggs on average. These results indicate that intact crickets invest the energy reserves for the flight muscles rather than for reproduction, whereas de-alated females use it for reproduction. In fed crickets, natural de-alation occurred mostly after maximal ovipositing activity was attained, suggesting that natural de-alation was not the direct cause for initiation of rapid egg production. This trait, as well as the relatively short pre-oviposition period, seems related to the type of migration this cricket shows, i.e. inter-reproductive rather than pre-reproductive. The cause of natural de-alation is unknown, but flight muscle histolysis and de-alation could be induced when crickets experienced a serious damage or loss of the flight ability.