Title: Intraspecific competition effects on Aethina tumida (Coleoptera: Nitidulidae) Authors
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 10, 2011
Publication Date: January 31, 2012
Citation: Meikle, W.G., Patt, J.M., Sammataro, D. 2012. Intraspecific competition effects on Aethina tumida (Coleoptera: Nitidulidae). Journal of Economic Entomology. 105(1):26-33. Interpretive Summary: The small hive beetle is a recently introduced pest of honey bees. Because it is a new pest, and because it was not well studied in its area of origin in Africa, there are many aspects of its ecology that are not well known. Small hive beetles live most of their lives in bee hives, where they are protected from many predators and from other insects that also want to eat the pollen, bee brood, and honey in the hive. For that reason, the only insects the small hive beetle usually needs to interact with are bees, as bees protect their hive, and with other small hive beetles as they compete for the same resources. In this study, we ran experiments to find out how much small hive beetles eat and how much they grow when kept with lots of food, or when kept with little food but lots of other beetle larvae. We found that, while lots of beetles can grow on a single bee hive frame, if there are too many beetles they will grow to be very small; sometimes too small to reproduce. We will use this information to help understand the dynamics of beetle population growth.
Technical Abstract: Two kinds of experiments were conducted with larvae of Aethina tumida over a four temperatures: “consumption” experiments, in which larvae and diet were weighed to determine food consumption rates under conditions of unlimited food and few conspecifics; and “competition” experiments in which varying numbers of larvae were presented with the same amount of honey and pollen diet and those larvae weighed to determine competition effects. In consumption experiments, temperature, diet, and their interaction all had significant effects on the ratio of larval weight to the weight of food consumed, which was higher at 24ºC than at any other temperature. In competition experiments, three relationships were examined and modeled: that between the number of larvae per experimental unit and the average weight of those larvae; that between average larval and adult weights; and that between average adult weight and survivorship to adult (emergence rate). An exponential decay function was fit to the relationship between number of larvae per experimental unit and their average weight. Average adult weight was linearly correlated with larval weight. Likewise, emergence rates for adults < 11.6 mg in weight were linearly correlated with adult weights, but no significant relationship was observed for heavier adults. Using these relationships, the reproductive potential for A. tumida were estimated for a frame of honey and pollen. Information on resource acquistion by A. tumida will be useful in evaluating the impact of different factors on beetle population dynamics, such as bee hygienic behavior or control strategies employed by the beekeeper.