The evidence for and against competition between the European honeybee and Australian native bees

Abstract

In Australia, the European honeybee (Apis mellifera) is an exotic, abundant, super-generalist species. Introduced two centuries ago, it thrives in the absence of many diseases adversely impacting honeybees elsewhere. Australia’s native bees may be vulnerable to competition with honeybees, leading to reduced abundances, reproductive output or even loss of bee species. We review the literature concerning competition between honeybees and Australian native bees in order to: (1) identify the valuence and strength of honeybee associations with native bees, and how this varies according to the response variable measured; (2) assess potential research biases; (3) use ecological theory to explain variation in results; and (4) identify key knowledge gaps. We found honeybees typically comprised the majority of individuals in surveys of Australian bee communities. Data on whether honeybees outcompete native bees is equivocal: there were no associations with native bee abundance, species richness, or reproductive output in most cases. However, there were more negative than positive associations. Data indicate effects of honeybees are species-specific, and more detailed investigations regarding how different species and life-history traits affect interactions with honeybees is needed. We propose the following investigations to address deficiencies in the current literature: greater geographic and landscape representation; trait-based investigations; quantifying resource availability and overlap; disease and predator interactions; experimental feral colony removals; and studies spanning multiple seasons and years. Identifying conditions under which honeybees have negative, neutral or positive effects on native bees, and how the ecological traits of native bees are affected by honeybee competition can guide conservation and management.