Distance between honey bee Apis mellifera colonies regulates populations of Varroa destructor at a landscape scale

Maxcy P Nolan,Keith S Delaplane

doi:10.1007/s13592-016-0443-9

Abstract

Inter-colony distance of Apis mellifera significantly affects colony numbers of the parasitic mite Varroa destructor. We set up 15 apiaries, each consisting of two colonies. Each apiary pair was assigned an inter-colony distance of 0, 10, or 100 m. Colonies were rendered nearly mite-free, then one colony in each pair was seeded with 300 female mites (mite-donor colony), while the other remained uninoculated (mite-recipient colony). After 4 months of monitoring, a whole-model analysis showed that apiaries in which colonies were spaced 100 m apart contained lower average mite numbers than 0 or 10 m apiaries. There were interactions among colony type, distance, and sampling date; however, when there were significant differences, mite numbers were always lower in 100 m apiaries than 10 m apiaries. These findings pose the possibility that Varroa populations are resource regulated at a landscape scale: near-neighbor colonies constitute reproductive resource for mites in the form of additional bee brood.

Highlights

Varroa destructor is the most damaging parasite of the European honey bee (Apis mellifera L.) in the world today (Rosenkranz et al 2010)
In the context of a honey bee colony, we presume for our present purposes that evolution is acting primarily at the colony level (Wilson and Sober 1989; Queller and Strassmann 1998) which means that horizontal transmission is best understood as action
Our results add to a growing base of evidence that spatial structure of honey bee communities, in particular inter-colony distance, significantly affects colony Varroa mite numbers

Summary

Introduction

Varroa destructor is the most damaging parasite of the European honey bee (Apis mellifera L.) in the world today (Rosenkranz et al 2010). Drifting is caused by homing errors made as foraging honey bees return to the colony (Free 1958); Forfert et al (2015) showed that colonies with high mite infestation had significantly enhanced acceptance of drifters. They postulate that the increase in drifter acceptance is attributed to an impaired ability for guard bees to assess incoming heterocolonial foragers. A model calculated by Pfeiffer and Crailsheim (1998) predicted that hives placed linearly 26 cm apart and facing the same direction contain up to 42 ± 6 % alien workers

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Results

Conclusion