Behavioural responses of the small hive beetle to volatile components of fermenting honeybee hive products

The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a significant pest of managed honeybees in the USA and eastern Australia. The beetle damages hives by feeding on hive products and leaving behind fermented wastes. The beetle is consistently associated with the yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Saccharomycetales: Metschnikowiaceae), and this yeast is the presumed agent of the fermentation. Previous work has noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast K. ohmeri. In this study, we investigated how the volatile compounds from the fermenting hive products change depending upon the source of the hive material and also how these volatiles change through time. We used gas chromatography–mass spectrometry and choice‐test behavioural assays to investigate these changes using products sampled from apiaries across the established range of the beetle in eastern Australia. The starting hive products significantly affected the volatile composition of fermenting hive products, and this composition varied throughout time. We found 61.7% dissimilarity between attractive and non‐attractive fermenting hive products, and identified individual compounds that characterise each of these groups. Eleven of these individual compounds were then assessed for attractiveness, as well as testing a synthetic blend in the laboratory. In the laboratory bioassay, 82.1 ± 0.02% of beetles were trapped in blend traps. These results have strong implications for the development of an out‐of‐hive attractant trap to assist in the management of this invasive pest.     

Use of Honey Bees and Bumble Bees to Disseminate Trichoderma harzianum 1295-22 to Strawberries for Botrytis Control

The effectiveness of using honey bees and bumble bees to vector a commercial formulation of Trichoderma harzianum 1295-22 for the control of Botrytis cinerea on strawberries was evaluated from 1994 to 1997 in 2 strawberry fields at the New York State Agricultural Experiment Station in Geneva, New York and in 10 grower fields in eight counties of New York. Commercial bumble bee colonies were used to deliver the biocontrol agent in 1994 and 1995 and five-frame nuclear honey bee hives were used in 1995–1997. Each honey bee exiting the hive carried about 1 × 10⁵ colony-forming units of T. harzianum, with the majority found on the bees' legs (58%). Flowers collected from the bee-delivered treatment generally had half the density of T. harzianum as those from the sprayed treatment. However, during the 4 years of this study, T. harzianum delivered by bumble bees or honey bees provided better Botrytis control than that applied as a spray. In addition, the bee-delivered T. harzianum provided the same or a better level of control of Botrytis as commercial fungicides applied at bloom. Strawberries collected from the bee-visited treatments averaged 22% more seeds and weighed between 26 and 40% more than berries in nonvisited treatments. The number of seeds per berry and berry weight were reduced by 7–12% in plots treated with fungicides and visited by bees, indicating that the use of some commercial fungicides at bloom may impact pollination and yield. Bee delivery of T. harzianum 1295-22 is a viable option for strawberry growers interested in controlling Botrytis with minimal fungicide use.     

Local and landscape effects on bee communities of Hungarian winter cereal fields

• 1 Pollination is a key ecosystem service. Although bees are the most important pollinators, they are endangered by intensive agricultural practices. The present study investigated the effects of farmland management and environmental factors at local and landscape scales on bees in Central Hungary.
• 2 Bees were sampled in winter cereal fields that varied in the amount of applied fertilizer and insecticide use. Measurements included total, small and large bee species richness and abundance; stability of total species richness and abundance (coefficient of variation, CV); the nitrogen content of fertilizers; the number of insecticide applications; within‐field location; species richness and abundance of insect‐pollinated plants; and the percentage of semi‐natural areas in a 500‐m radius circle around the fields under study.
• 3 Increasing the amount of fertilizer decreased total and small bee abundance and increased the CV of total bee abundance. Insecticide use had a significant negative effect on total and small bee species richness and on large bee abundance. The percentage of semi‐natural habitats in a 500‐m radius did not influence bee species richness and abundance.
• 4 The results obtained confirms that the intensification of farmland management poses a threat to bee diversity, and thus may reduce pollination services. Recently‐introduced agri‐environment schemes are one potential approach for managing agricultural land use: reduced amounts of fertilizer and a cessation of insecticide application might lead to high bee species richness and abundance and ensure the pollination of wild plants and flowering crops.

     

Repeated origins of social parasitism in allodapine bees indicate that the weak form of Emery's rule is widespread,yet sympatric speciation remains highly problematic

The evolutionary origins of social parasitism are very unevenly distributed among ants, bees and wasps, but social parasite lineages are frequently close relatives of their host lineages. Two explanations for these relationships have been proposed: (1) initially, social species are more likely to become parasitic on relatively closely related social species, because they share life history, physiological and behavioural traits that allow successful integration within the host colony; and (2) social parasites have evolved directly from their host lineage via sympatric speciation. Comparative approaches, covering multiple origins and intermediate evolutionary stages, are needed to determine which of these possibilities is more likely. We use molecular phylogenetics to examine multiple origins of parasitism in the bee tribe Allodapini. We identify seven origins resulting in obligate social parasitism (inquilinism), one origin of facultative social parasitism, which was followed by subsequent speciation and where both daughter species remained facultatively parasitic, and one case of frequent facultative heterospecific co‐nesting that probably represents incipient social parasitism. All host–parasite lineage pairs show strong phylogenetic affinities, but only the case of facultative heterospecific nesting involves true sister species relationships. Our results are consistent with the range of parasitic relationships that are expected under an allopatric model for the origin of social parasitism, but are highly problematic for a sympatric speciation model. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 320–331.     

Abundance and Flower Visits of Bees in a Cerrado of Bahia,Tropical Brazil

Abundance, seasonal phenology and flower visits of eusocial bees were studied in Diamantina, a national park with cerrado vegetation in Bahia, tropical Brazil. About 700 bees were collected, mainly native stingless bees and the introduced Africanized honey bee. Sampling along a transect was most effective March through September during the dry season. The foraging worker bees were observed on flowers of over 60 angiosperm species of which a few were visited with high frequency. Foraging activity concentrated on flowering plants of the families Leguminosae and Asteraceae. The results are discussed under aspects of nutritional resource partitioning by bee communities in neotropical habitats and the specific composition of a cerrado apifauna.     

Major benefits of guarding behavior in subsocial bees: implications for social evolution

Parental care is a behavior that increases the growth and survival of offspring, often at a cost to the parents' own survival and/or future reproduction. In this study, we focused on nest guarding, which is one of the most important types of extended parental care; we studied this behavior in two solitary bee species of the genus Ceratina with social ancestors. We performed the experiment of removing the laying female, who usually guards the nest after completing its provisioning, to test the effects of nest guarding on the offspring survival and nest fate. By dissecting natural nests, we found that Ceratina cucurbitina females always guarded their offspring until the offspring reached adulthood. In addition, the females of this species were able to crawl across the nest partitions and inspect the offspring in the brood cells. In contrast, several Ceratina chalybea females guarded their nests until the offspring reached adulthood, but others closed the nest entrance with a plug and deserted the nest. Nests with a low number of provisioned cells were more likely to be plugged and abandoned than nests with a higher number of cells. The female removal experiment had a significantly negative effect on offspring survival in both species. These nests frequently failed due to the attacks of natural enemies (e.g., ants, chalcidoid wasps, and other competing Ceratina bees). Increased offspring survival is the most important benefit of the guarding strategy. The abandonment of a potentially unsuccessful brood might constitute a benefit of the nest plugging behavior. The facultative nest desertion strategy is a derived behavior in the studied bees and constitutes an example of an evolutionary reduction in the extent of parental care.     

Relatedness and dispersal distance of eusocial bee males on mating swarms

Stingless bee males (Hymenoptera: Apidae) aggregate themselves for reproductive purposes. The knowledge of relatedness among the males attending the aggregations and the distance that they disperse from their natal nests to aggregations may provide important data to effectively conserve these bees. Here, we estimated these properties for Tetragonisca angustula (Latreille, 1811) males. Microsatellite molecular markers were used to genotype bees sampled from local nests and in mating swarms in order to identify the nests of origin of males and maternal genotypes of concerning queens. The distances from assigned nests to the mating swarms allowed us to estimate the distances travelled by males. A genetic relationship analysis was conducted to verify whether T. angustula males were closely related to nests where they aggregated. A pairwise relatedness analysis was also performed among all T. angustula males in each mating swarm. Our results demonstrated that T. angustula mating swarms received dozens to hundreds of males from several colonies (up to 70). Only two of the five mating swarms contained any males that were closely related to the bees from the new nests in construction. The relatedness among males was also extremely low. Yet, dispersal distance of T. angustula males ranged hundreds of meters up to 1.6 km, with evidence of reaching 2.25 km according to their flight radius obtained from their foraging area for locality. These data indicate a highly efficient mating system with minimal inbreeding in this bee species, with a great dispersal capability not previously found for stingless bee males.     

Insect pollinators of the late winter flowering Rhamnus alaternus L., a candidate for honeybee-friendly scrubland spots in intensively managed agricultural areas

Insect pollinators of Rhamnus alaternus belong to 11 families, 17 genera and 20 species. The most abundant species is the honeybee followed by flies and bumblebees. Honeybee visits on R. alaternus decreased from late winter to early spring, highlighting the key role of this flowering in food paucity periods.     

Commercially formulated glyphosate can kill non‐target pollinator bees under laboratory conditions

The use of glyphosate‐based herbicides in agroecosystems has increased over the past few years because of the advent of genetically modified glyphosate‐resistant crops and resistant weeds. This is alarming because of potential damaging effects on non‐target organisms. In sub‐Saharan Africa, for example Ghana, many rural farmers have not received training in the use of glyphosate‐based herbicides, thus tend to apply higher than recommended concentrations on farms. Therefore, this study investigated the effect of glyphosate‐based herbicides on beneficial insects under laboratory conditions, using Apis mellifera L. (Hymenoptera: Apidae, Apini) and Hypotrigona ruspolii (Magretti) (Hymenoptera: Apidae, Meliponini) as models. The bees were put in contact for 24 h with the recommended concentration of Sunphosate 360 SL, a glyphosate‐based herbicide, 2× the recommended concentration, or distilled water as control. The effect of the herbicide on the bees was compared to the effect of a lambda‐cyhalothrin insecticide. Generally, more bees died after contact with plants freshly sprayed with the herbicide than on herbicide‐treated filter paper. In both cases, more bees died after contact with the higher concentration of the herbicide. These findings suggest that beneficial insects, specifically A. mellifera and H. ruspolii, may get killed if they are sprayed upon or come into contact with plants that have been freshly sprayed with (more than) the recommended concentration of glyphosate‐based herbicides. Therefore, it is important to restrict access and use of such herbicides to trained personnel who will comply with spraying guidelines, that is, recommended concentrations and timing of spray. Spraying at a time when insects are flying about may be detrimental to beneficial insects such as pollinator bees, parasitoids, and predators.