POTENTIAL FOR POPULATION GROWTH OF THE SMALL HIVE BEETLE AETHINA TUMIDA (COLEOPTERA: NITIDULIDAE) ON DIETS OF POLLEN DOUGH AND ORANGES

The small hive beetle Aethina tumida Murray, is an African native that has become an invasive pest of honeybees in North America. The beetle is capable of rapid population growth on pollen, honey, and bee brood. It is also capable of feeding and reproducing on various kinds of fruit, but its ability to sustain population growth on diets other than bee products has remained unknown. We examined this question by observing A. tumida on 2 diets: pollen dough (inoculated with a species of yeast carried by the beetle) and orange. Age-schedules of survival (l(r)) and fecundity (m(x)) were constructed for each diet and used to calculate the intrinsic rate of natural increase (r), which was used to calculate other demographic parameters. The results showed potential for population growth on both diets (r > 0), but the potential was less on orange (r = 0.0631) than on inoculated pollen dough (r = 0.1047). The calculated multiplication per generation on pollen dough was nearly double that on orange and the generation time was shorter by more than a third. Survival of A. tumida populations on oranges, or any other alternative diet, in a given environment would depend on the value of r relative to the strength of environmental conditions opposing population increase. The ability to use alternative diets (fruit, possibly fungi, or other food resources) would confer an adaptive advantage upon beetles dispersing over a landscape in which honeybee colonies occur as small, widely scattered patches.