The relative importance of queen and king initial weights in termite colony foundation success

Abstract

In termites, primary reproductives proceed through dispersal flight with finite metabolic reserves. During colony foundation, the mated pair requires just enough resources to produce the first few workers, through biparental care. When alloparental care is established, the primary reproductives are fully supported by their own offspring. It was, therefore, argued that the pressure to accumulate large quantities of metabolic reserves in termite imagoes was relaxed over evolutionary time, which resulted in a progressive reduction in alate size compared to ancestral wood roaches. However, such directional reduction in size may partially be countered if mated pairs with relatively large internal metabolic resources are more successful than mated pairs with relatively low internal resources. This hypothesis was tested with Coptotermes gestroi by establishing incipient termite colonies with a wide range of combinations of female and male initial weights in laboratory conditions. Both females and males depleted most of their internal resources within 9 months, and the combined initial weight of female and male explained 27% of the variation in incipient colony growth. Mature colonies that can invest into high-quality alates may have a slight fitness advantage; however, this advantage may be secondary to other environmental factors, as during large Coptotermes dispersal flights, a vast majority of alates die within the first few days, which would increase the fitness of colonies that invested in quantity over quality. Within a given termite species, the relative size of imagoes may, therefore, reflect a reproductive strategy trade-off emerging from the life history of the species.