-The small hive beetle (SHB) is a parasite and scavenger of honeybee colonies. Here we provide the first comprehensive systematic data on colony infestation levels with adult SHB for 226 colonies at 31 apiaries in South Africa, Australia, Florida and Maryland. Inside colonies, SHB distribution was influenced by the presence of bees with more SHB in the brood nest in the absence of bees. SHB distribution among colonies at an apiary was different from a random distribution but colony phenotypes (number of bees, amount of brood or stores) did not influence infestation levels. Apiaries next to large scale honey extraction facilities (honey houses) showed higher infestation levels and regions with more damage had higher SHB population levels. Consequently, methods of reducing SHB populations, such as the removal of dead colonies and the prevention of SHB reproduction in honey houses, seem to be important for pest management.Aethina tumida / Apis mellifera / honeybees / infestation level / small hive beetle

No abstract

1. The small hive beetle, Aethina tumida , is a parasite of honeybee ( Apis mellifera ) colonies native to sub-Saharan Africa and has become an invasive species. In North America the beetle is now sympatric with bumblebees, Bombus , not occurring in its native range. Laboratory studies have shown that small hive beetles can reproduce in bumblebee colonies but it was not known whether infestations occur in the field.2. For the first time, infestation of bumblebee colonies by small hive beetles was investigated in the field. Commercial Bombus impatiens colonies ( n = 10) were installed in proximity to infested apiaries. Within 8 weeks, all colonies that were alive in the 5-week observation period ( n = 9) became naturally infested with adult small hive beetles and successful small hive beetle reproduction occurred in five colonies.3. In four-square choice tests, the beetles were attracted to both adult bumblebee workers and pollen from bumblebee nests, suggesting that these odours may serve as cues for host finding.4. The data indicate that bumblebee colonies may serve as alternative hosts for small hive beetles in the field. To foster the conservation of these essential native pollinators, investigations on the actual impact of small hive beetles on wild bumblebee populations are suggested.

Native to sub-Saharan Africa, Aethina tumida Murray (Coleoptera: Nitidulidae) is now an invasive pest of honey bee, Apis mellifera L., colonies in Australia and North America. Knowledge about the introduction (s) of this beetle from Africa into and among the current ranges will elucidate pest populations and invasion pathways and contribute to knowledge of how a parasite expands in new populations. We examined genetic variation in adult beetle samples from the United States, Australia, Canada, and Africa by sequencing a 912-base pair region of the mitochondrial DNA cytochrome c oxidase subunit I gene and screening 10 informative microsatellite loci. One Canadian introduction of small hive beetles can be traced to Australia, whereas the second introduction seems to have come from the United States. Beetles now resident in Australia were of a different African origin than were beetles in North America. North American beetles did not show covariance between two mitochondrial haplotypes and their microsatellite frequencies, suggesting that these beetles have a shared source despite having initial genetic structure within their introduced range. Excellent dispersal of beetles, aided in some cases by migratory beekeeping and the bee trade, seems to lead to panmixis in the introduced populations as well as in Africa.

Although the principal mechanisms of insect flight are well understood, knowledge about the influence of environmental factors on flight performance is scarce. We show that ambient temperature (TA) and illuminance have an influence on the flight performance of hornets. Moreover, the regulation of flight speed at different environmental conditions is sex specific. In roundabout experiments with tethered hornets, the flight speed of workers was independent of TA, while that of drones was negatively correlated with TA. We hypothesize that the reasons for these differences may lie in sex-specific cooling mechanisms; workers might regulate their body temperature through forced heat loss, whereas drones might reduce their heat production rates. At low illuminance, workers reduced their flight speed, whereas drones did not. Reduced flight speed at low illuminances is probably a behavioral mechanism of compensation for disadvantages caused by changing neuronal processes in the sensory neurons in darkness.