Virgins to the North: the precarious fate of female bagworms

We present the first rigorous empirical test of Allee effects by evaluating broad scale latitudinal variation in female mating success of female bagworms. The unusual reproductive system of bagworms, with females completing all reproductive activity within a bag they constructed as larva, provides a model system to evaluate the rate of female mating failures in discrete populations. Most (usually > 95%) females in the core distribution range (South Indiana, Kentucky, Tennessee) mated during their lifetime. The proportion of mated females declined with latitude, and in some populations in North Indiana, 100% of females did not reproduce because they fail to attract a male for mating. We are currently investigating the causes and consequences of female mating failures in terms of geographic range boundaries, and the probability of extinction of local populations.