Acute exposure to sublethal doses of neonicotinoid insecticides increases heat tolerance in honey bees

The European honey bee, Apis mellifera L., is the single most valuable managed pollinator in the world. Poor colony health or unusually high colony losses of managed honey bees result from a myriad of stressors, which are more harmful in combination. Climate change is expected to accentuate the effects of these stressors, but the physiological and behavioral responses of honey bees to elevated temperatures while under simultaneous influence of one or more stressors remain largely unknown. Here we test the hypothesis that exposure to acute, sublethal doses of neonicotinoid insecticides reduce thermal tolerance in honey bees. We administered to bees oral doses of imidacloprid and acetamiprid at 1/5, 1/20, and 1/100 of LD50 and measured their heat tolerance 4 h post-feeding, using both dynamic and static protocols. Contrary to our expectations, acute exposure to sublethal doses of both insecticides resulted in higher thermal tolerance and greater survival rates of bees. Bees that ingested the higher doses of insecticides displayed a critical thermal maximum from 2 ˚C to 5 ˚C greater than that of the control group, and 67%–87% reduction in mortality. Our study suggests a resilience of honey bees to high temperatures when other stressors are present, which is consistent with studies in other insects. We discuss the implications of these results and hypothesize that this compensatory effect is likely due to induction of heat shock proteins by the insecticides, which provides temporary protection from elevated temperatures

Pan traps and bee body size in unmanaged urban habitats

Pan traps are among the most popular methods employed to survey bees and changes in some functional traits, such as body size, are increasingly used to understand how bee communities and species respond to landscape changes. Herein we assess body size differences between bees captured at ground-level and elevated (70 cm) pan traps in unmanaged urban habitats in northwestern Turkey. We compare body size at the community level as well as for the sweat bee Lasioglossum malachurum (Kirby) (Halictidae: Halictini), the most abundant species. We also compare the diversity, richness and abundance of bees sampled at both heights. A total of 31 species (13 genera of three families) were captured. We did not find significant differences in the abundance nor in the species richness between heights, and Simpson's indices were similar. At the community level, average intertegular distance was significantly greater in bees collected at the elevated traps than on the ground. Intertegular distances in L. malachurum did not differ between elevated and ground-level pan traps. Our results show an effect of pan trap height on bee body size in the urban habitat surveyed, thus suggesting that assessing bee body size from samples collected with either ground-level or elevated pan traps alone might result in biased estimates of this functional trait.National Science Foundation's REU program - DBI 126332

Recovery of the Parasite Triarthria Spinipennis (Meigen) (Diptera: Tachinidae) from an Inland California Population of the Introduced European Earwig

A tachinid parasite, Triarthria spinipennis (Meigen), introduced over 50 years ago to control populations of the introduced European earwig in coastal California, is reported for the first time in California\u27s Central Valley. Both the parasite and its host prefer cooler, more humid environments near water. Parasites were found during two consecutive years and abundance patterns within each year indicate they are multivoltine. The parasite has successfully accompanied its host\u27s inland invasion from the coastal region of California

Recovery of the parasite Triarthria spinipennis (Meigen) (Diptera: Tachinidae) from an inland California population of the introduced European earwig

Volume: 71Start Page: 137End Page: 14

Nest Usurpation Among Females of an Introduced Leaf-Cutter Bee, Megachile Apicalis

We compared female nest usurpation and size variation in a population of the introduced leaf-cutter bee Megachile apicalis Spinola. Both behavioral and morphological evidence was gathered from three types of females: 1) those that occupy and defend nest holes, 2) those that patrol the nesting substrate while attempting to displace the latter group and 3) pollen-foraging bees that apparently had already established nests elsewhere in the environment. Females occupying holes and patrolling nesting sites were, on average, larger than foraging females. In addition, female densities at nest sites correlated positively with the average size of females found at those sites

FLOWER ABUNDANCE IN A POPULATION OF SKY LUPINE (LUPINUS NANUS) OVER THREE YEARS IN CENTRAL COASTAL CALIFORNIA

Volume: 43Start Page: 85End Page: 9