A four‐year investigation into the efficacy of domiciles for enhancement of bumble bee populations

Abstract

Abstract1 Eighty four‐unit domiciles for introduced bumble bees (Bombus spp.) were placed in 16 field margins at Lincoln, New Zealand in the 1995–96 southern summer. Fifty‐five were placed in the margins of intensively managed fields, with the remaining 25 being in less disturbed habitats, which had more spring/summer floral resources.2 The number of nests founded over the four‐year study period increased from one to 27. Bombus hortorum was a much more frequent colonist than was B. terrestris, with B. ruderatus colonizing only in the fourth year.3 In the ‘intensive’ sites, mean four‐year occupancy was only 2%, whereas in the less disturbed sites it was 13%.4 There was a positive association between bumble bee occupancy of the domicile compartments in the previous year and occupancy in the current year. No association was found between previous occupancy by mice and subsequent occupancy by bumble bees.5 The potential for adding Bombus nest sites to agricultural land to enhance local populations, and, potentially, pollination of seed crops, is discussed. Adding domiciles in intensively managed landscapes may not be very effective unless spring floral resources are enhanced as well.

Assessing the efficacy of artificial domiciles for bumblebees

“…Given ongoing declines of bumblebee populations throughout most of their range (Williams & Osborne 2009) the lower occupancy rates observed here may be a direct reflection of lower bumblebee population sizes. This would also explain low levels of uptake reported in recent studies in other parts of the world (Barron et al 2000;Elliot 2008).…”

“…Slab domiciles were commonly occupied by mice, and since bumblebees are often found nesting in the abandoned homes of mice (Donovan & Weir 1978;Svensson & Lundberg 1977), it is possible that these domiciles might have been occupied more readily by bumblebees in subsequent years. Increasing occupancy across years is common in artificial domicile trials but the explanation for this is generally unclear (Barron et al 2000;Donovan & Weir 1978;Hobbs et al 1962).…”

A review of New Zealand's deliberately introduced bee fauna: current status and potential impacts

“…Domiciles (man-made nesting boxes) have been developed and employed to increase bumble bee abundance in agroecosystems (Donovan & Wier 1978;Pomeroy 1981;Barron et al 2000) and occupancy was found to increase over consecutive years (Donovan & Weir 1978;Pomeroy 1981; Barron et al 2000). Long-tongued bumble bees species, particularly B. ruderatus, were found to be the most common colonists Barron et al 2000).…”

“…Long-tongued bumble bees species, particularly B. ruderatus, were found to be the most common colonists Barron et al 2000). Domicile placement was found to be an important factor infl uencing bee occupation; those placed near greater fl oral resources and at sites of lower agricultural intensifi cation attracted signifi cantly more founding bees (Barron et al 2000).…”

Ecological restoration of farmland: progress and prospects

“…Weta hotels, artificial shelters which mimic coarse woody debris with cavities, harbour this specialist fauna on farmland on which this insect disappeared in association with forest clearance (Bowie et al 2006). Populations of pollinating bees and predatory wasps in agroecosystems can also be enhanced with the introduction of suitable nesting sites (Gathmann et al 1994;Tscharntke et al 1998;Barron et al 2000).…”