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Brood Cells (brood + cell)
Selected AbstractsSeasonal change in offspring sex and size in Dawson's burrowing bees (Amegilla dawsoni) (Hymenoptera: Anthophorini)ECOLOGICAL ENTOMOLOGY, Issue 3 2005John Alcock Abstract., 1.,Nesting females of Dawson's burrowing bees, Amegilla dawsoni, produce a large size class of offspring, which includes daughters and major sons, and a small size class, which consists entirely of minor sons averaging half the weight of their larger siblings. Female allocation patterns change over the flight season such that the initial pattern of producing daughters shifts toward the production of both daughters and major sons in the middle of the season, and then the production of primarily minor sons in the latter part of the nesting season. 2.,In Dawson's burrowing bees, this pattern is correlated with declines in pollen and nectar availability as the nesting season progresses as well as a heightened risk of dying before the final brood cell is completed. Here, the relation between these factors and the provisioning tactics of nesting Dawson's burrowing bees is discussed. [source] Females of the European beewolf preserve their honeybee prey against competing fungiECOLOGICAL ENTOMOLOGY, Issue 2 2001Erhard Strohm Summary 1. Females of the European beewolf Philanthus triangulum (Hymenoptera, Sphecidae) provision brood cells with paralysed honeybees as larval food. Because brood cells are located in warm, humid locations there is a high risk of microbial decomposition of the provisions. Low incidence of fungus infestation (Aspergillus sp.) in nests in the field suggested the presence of an anti-fungal adaptation. 2. To test whether the paralysis caused the protection from fungus infestation, the timing of fungus growth on bees that were freeze-killed, paralysed but not provisioned, and provisioned regularly by beewolf females was determined. Fungus growth was first detected on freeze-killed bees, followed by paralysed but not provisioned bees. By contrast, fungus growth on provisioned bees was delayed greatly or even absent. Thus, paralysis alone is much less efficient in delaying fungus growth than is regular provisioning. 3. Observations of beewolves in their nests revealed that females lick the body surface of their prey very thoroughly during the period of excavation of the brood cell. 4. To separate the effect of a possible anti-fungal property of the brood cell and the licking of the bees, a second experiment was conducted. Timing of fungus growth on paralysed bees did not differ between artificial and original brood cells. By contrast, fungus growth on bees that had been provisioned by a female but were transferred to artificial brood cells was delayed significantly. Thus, the treatment of the bees by the female wasp but not the brood cell caused the delay in fungus growth. 5. Beewolf females most probably apply anti-fungal chemicals to the cuticle of their prey. This is the first demonstration of the mechanism involved in the preservation of provisions in a hunting wasp. Some kind of preservation of prey as a component of parental care is probably widespread among hunting wasps and might have been a prerequisite for the evolution of mass provisioning. [source] Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestryJOURNAL OF ANIMAL ECOLOGY, Issue 2 2006ALEXANDRA-MARIA KLEIN Summary 1Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0,1415 m), light intensity (37·5,899·6 W/m,2) and number of vascular plant species (7,40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3A total of 13 617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey. [source] Experimental study on the toxicity of imidacloprid given in syrup to honey bee (Apis mellifera) coloniesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2005Jean-Paul Faucon Abstract Two groups of eight honey bee colonies were fed with two different concentrations of imidacloprid in saccharose syrup during summer (each colony was given 1 litre of saccharose syrup containing 0.5 µg litre,1 or 5 µg litre,1 of imidacloprid on 13 occasions). Their development and survival were followed in parallel with control hives (unfed or fed with saccharose syrup) until the end of the following winter. The parameters followed were: adult bee activity (number of bee entering the hive and pollen carrying activity), adult bee population level, capped brood area, frequency of parasitic and other diseases, mortality, number of frames with brood after wintering and a global score of colonies after wintering. The only parameters linked to feeding with imidacloprid-supplemented saccharose syrup when compared with feeding with non-supplemented syrup were: a statistically non-significant higher activity index of adult bees, a significantly higher frequency of pollen carrying during the feeding period and a larger number of capped brood cells. When imidacloprid was no longer applied, activity and pollen carrying were re-established at a similar level for all groups. Repeated feeding with syrup supplemented with imidacloprid did not provoke any immediate or any delayed mortality before, during or following the next winter, whereas such severe effects are described by several French bee keepers as a consequence of imidacloprid use for seed dressing in neighbouring cultures. In any case, during the whole study, mortality was very low in all groups, with no difference between imidacloprid-fed and control colonies. Further research should now address several hypotheses: the troubles described by bee keepers have causes other than imidacloprid; if such troubles are really due to this insecticide, they may only be observed either when bees consume contaminated pollen, when no other sources of food are available, in the presence of synergic factors (that still need to be identified), with some particular races of bees or when colonies are not strong and healthy. Copyright © 2004 Society of Chemical Industry [source] Food wrapping by females of the European Beewolf, Philanthus triangulum, retards water loss of larval provisionsPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2008GUDRUN HERZNER Abstract Females of the European beewolf, Philanthus triangulum F. (Hymenoptera, Crabronidae), embalm the provisions of their larvae, paralyzed honeybees, with a secretion from a postpharyngeal gland prior to oviposition. This food wrapping is known to delay fungus infestation of the prey. In the present study, the hypothesis that the food wrapping has an additional function, namely the prevention of prey desiccation, is tested. Water loss of paralyzed but unembalmed honeybees and embalmed honeybees is measured and the composition and quantity of their cuticular hydrocarbons analyzed by coupled gas chromatography,mass spectrometry. Water loss is significantly lower in embalmed compared with unembalmed bees. This might have important advantages for the larvae under the warm and dry conditions that prevail in some brood cells. The embalming by beewolf females increases the total amount of hydrocarbons on the surface of the bees by almost ten-fold. Moreover, the proportion of unsaturated and short-chained hydrocarbons is significantly increased. Unsaturated and short-chain hydrocarbons are usually less effective against water loss, so the increased protection against water loss appears to be mediated mainly by the thickness of the hydrocarbon layer. [source] Fragrances, male display and mating behaviour of Euglossa hemichlora: a flight cage experimentPHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003Thomas Eltz Abstract., Male euglossine bees (Apidae: Euglossini) collect volatile substances (fragrances) from floral and nonfloral sources and store them in hair-filled cavities in their hind tibiae. Over time, males accumulate large quantities of complex and species-specific blends of fragrances. Various hypotheses have been put forward to explain this behaviour, including the idea that fragrance stores reflect the genetic quality of individual males and have evolved through sexual selection and female choice. Clear support of this hypothesis is lacking, largely because male,female interactions are both rare and difficult to observe in nature. Here, we report a flight cage experiment performed in Panama that permitted mating between virgin females (raised from brood cells) and males captured in the forest at fragrance baits. In the cage, eight individually marked males defended small territories around vertical perch sites and showed a characteristic display, which included a previously unreported ,leg-crossing' movement, possibly related to fragrance release. A total of six copulations and three copulatory attempts by Euglossa hemichlora were observed and partly recorded on video. The copulations, all of which were initiated by the female landing on a male perch, were short (4,10 s) and showed no signs of the transfer of chemical substances from male to female. In some cases, the male hovered directly over the female before descending to mount her, possibly facilitating fragrance evaluation by the female. After the experiment, the contents of the males' hind legs were analysed by gas chromatography-mass spectroscopy, which detected complex mixtures of terpenoids and aromatics (totalling 70 different compounds) dominated by hexahydrofarnesyl acetone, farnesene epoxide, ocimene and p -dimethoxy benzene. Individual total amounts of fragrances were neither related to display activity or perch occupancy by given males, nor to the frequency of matings achieved. Display activity was the only positive correlate of mating frequency. Generally, individuals had uniformly large amounts of stored fragrances in comparison to a previous study of three other species of Panamanian Euglossa. [source] Potential mechanism for detection by Apis mellifera of the parasitic mite Varroa destructor inside sealed brood cellsPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2002Caroline Martin Abstract The parasitic mite Varroa destructor Anderson & Trueman is a major pest of the honeybee Apis mellifera L. throughout the world. Chemical agents currently used for mite control leave contaminating residues and promote pesticide resistance. As an alternative means of control, it would be useful to identify natural substances enabling bees to detect Varroa inside brood cells. These substances could then be used to trigger mite hygienic behaviour by bees. In this study several techniques were used to screen substances that might allow detection of infested brood cells by bees. Gas chromatography-mass spectrometry analysis was performed on substances extracted in dichloromethane from the contents of brood cells. Solid phase microextraction and solid injection were performed on substances obtained from living and dead Varroa, respectively. Electroantennography was performed to assess the sensitivity of olfactory receptors in bee antennae to some of these substances. Principal component analysis based on proportions of cuticular substances allowed discrimination between bees and other cell contents. Foundress Varroa exhibited the greatest dissimilarity to healthy pupae that were used as controls. Immature Varroa and faecal material were intermediate. High molecular weight compounds, mainly dimethylalkanes, were proportionally the most characteristic components of foundress Varroa. This finding suggests that these compounds would be the most apt to induce uncapping of cells infested by Varroa. Solid-phase microextraction and solid injection demonstrated the presence of aliphatic acids, esters, and one alcohol, eicosenol, in Varroa. Electroantennographic recordings showed that mite-resistant bees were more responsive to some acids and one ester. We speculate that these compounds may be involved in recognition of living Varroa by honeybees. [source] | ||||||||||