Remarkable uniformity in the densities of feral honey bee Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae) colonies in South Eastern Australia

Abstract

It is often assumed that the density of feral honey bee colonies in Australia is sufficient to provide adequate pollination services to the many agricultural crops that require pollination. In contrast, there is concern that the density of feral colonies is sufficiently high to have inimical effects on Australian biota. For both these reasons, it is desirable to have robust estimates of the density of feral honey bee colonies in Australian landscapes. In this study, we mated four to five queens with wild drones at disturbed and undisturbed sites in three of the major ecosystems in Victoria Australia and examined the paternities of worker offspring to estimate the density of feral colonies within mating range of the test queens. We show that the density of feral colonies differs little with land use (cleared or uncleared) and is similar across the state. Our data suggest that the density of feral colonies is probably insufficient to provide adequate pollination of agricultural crops and that neither land use nor local climate variation is a major factor determining density. Finally, our data suggest that the mating range sampled by test queens is significantly greater than previously assumed.

The density of feral honey bee (Apis mellifera) colonies in South East Australia is greater in undisturbed than in disturbed habitats

“…Colonies were present at high densities at several sites, with the highest densities in Wyperfeld National Park. The estimates of colony density are smaller than those previously reported for Wyperfeld National Park via direct observation (50-150 colonies km −2 , Oldroyd et al 1995Oldroyd et al , 1997 but consistent with the results obtained by Arundel et al (2014) (0.9 colonies km −2 ) using an indirect survey method. This difference probably arises because Oldroyd et al (1995Oldroyd et al ( , 1997 selectively surveyed the riparian woodland where the density of colonies is likely much higher than in the surrounding dry lake beds and mallee vegetation.…”

“…Our difficulties in capturing drones at the disturbed sites likely reflect the low density of colonies at these sites, as suggested by the distribution of male haplotypes. Although Arundel et al (2014) detected a significantly higher density of colonies at their disturbed Wimmera site, this can be . While each DCA attracts drones from an area of 150 km −2 based on a 7-km drone flight range (Ruttner and Ruttner 1972), the limited range of attraction of 9-ODA (100 m) means that the drone trap method is only effective in areas of high colony density or where DCAs can be reliably located.…”

“…While each DCA attracts drones from an area of 150 km −2 based on a 7-km drone flight range (Ruttner and Ruttner 1972), the limited range of attraction of 9-ODA (100 m) means that the drone trap method is only effective in areas of high colony density or where DCAs can be reliably located. Thus, in areas where a low density of colonies is expected, the indirect survey method using the progeny of queens mated at the survey site (Arundel et al 2014) will tend to identify more colonies based on an increased detection range. The Stratford Park site also had a relatively low density of feral colonies in comparison with the other sites.…”

“…Most trees within the park are too small to provide cavities suitable for honey bees to nest in, but stands of red gum (Eucalyptus camaldulensis ) and black box (Eucalyptus largiflorens ) that fringe Outlet Creek in the south east of the park provide well-developed hollows suitable for nesting by honey bees and native vertebrates (Oldroyd et al 1994). The feral honey bee population in this riparian woodland has been intensively studied (Oldroyd et al 1994(Oldroyd et al , 1995(Oldroyd et al , 1997Arundel et al 2014), providing a measure by which to evaluate the effectiveness of drone trapping for estimating the size of feral honey bee populations.…”

“…Australia also has a large population of feral honey bees (Paton 1996;Oldroyd et al 1997;Arundel et al 2014). It is often assumed by farmers that feral populations are sufficient to ensure adequate crop pollination in many agricultural systems (Gordon and Davis 2003), although this assumption is usually contradicted by empirical studies (reviewed in Free 1970;McGregor 1976;Roubik 1995;Delaplane and Mayer 2000).…”