Intraclonal Trade-Off between Reproductive Investment and Size of Fat Body in the Vetch Aphid, Megoura viciae Buckton

Abstract

Aphids offer an excellent test-bed for life-history theory. As individuals of the sane clone can exhibit mixed reproductive strategies, the costs and benefits of reproductive decisions can be quantified in genetically identical individuals. This study investigates the relationship between lipid content, the size of the fat body, and reproductive investment in apterous virginoparae of the vetch aphid. Megoura viciae Buckton. In this species an increase in the number of ovarioles from 14 to 20 was associated with an increase in the relative biomass of the gonads, and an increase in the proportion of the total lipid present in the gonads. The total lipid content of adult aphids of the same weight, but of different ovariole number, was equal. Associated with an increase in reproductive investment, there was a directly proportional decrease in the size of the somatic fat body and of the soma, and a decrease in the proportion of the total lipid in the soma.