Smaller Bumble Bee Workers are Safeguards Against Poor Resource Environments

Abstract

Bumble bees workers (Bombus sp.) exhibit a large variation in worker body size, with up to a ten fold weight difference between full genetic sisters. Stranger still is that there appears to be little adaptive benefit for producing them as smaller workers are worse at performing colony tasks. However smaller workers can survive starvation for longer than their larger sisters. We test the hypothesis that smaller workers are either adaptations to poor resource environments or highly variable resource environments. By raising colonies in the lab of different resource regimes we find that colonies in poor resource treatments show decreased average body size, but there appears to be no tradeoff in producing either larger or more workers.