Apidologie最新文献

Crepuscular and/or nocturnal bees are rarely sampled and consequently poorly studied. These bees have exceptional adaptations concerning their visual system to navigate under low light conditions. However, their foraging success may as well be associated with an enhanced chemoreception. In fact, nocturnal bees find flowers in the dark based on the strong scent released by plants at night, which suggests special adaptations of the bees’ sense of smell. Our study aimed at comparing olfaction-related morphological and morphometric traits between nocturnal (six species) and diurnal bees (five species) in Brazil. In addition to determining the length of the species’ flagella and flagellomeres, we used scanning electron microscopy to classify the antennal sensilla and to estimate their density. Despite a general decrease in relative flagellum length with increasing body size (intertegular distance), nocturnal bees had longer flagella and flagellomeres than diurnal bees. Moreover, sensilla associated with CO₂ detection, mechanoreception, and chemoreception were larger in size, number, and density in nocturnal than in diurnal species. Our findings suggest that, during evolutionary history, the nocturnal environment has selected bees with morphological features that improve scent perception, which is crucial for the foraging activities under dim light conditions.

In bee diets, nectar is the primary source of carbohydrates. During scarcity of bee flora, such as in winter, beekeepers typically provide supplemental sugar syrup as a nectar substitute. We examined four types of sugars (sucrose, fructose, glucose, and a mixture of fructose and glucose) on bee longevity, bee appetitive, and their impact on pollen digestion. The results showed that sucrose and glucose had extended the longevity in cages. Bees preferred sucrose at a 50% concentration since they consumed more than the other sugar types in cages and in the multiple-choice test experiment in apiary. Bees given sucrose solution consumed the most pollen. In contrast, the cages provided the fructose solution consumed the least amount of pollen, increasing body fat percentage, which can be considered evidence of a digestive disorder. Generally, the type of sugar affects bee’s benefits from nutrition. Finally, sucrose is the best type of sugar and is considered the ideal substitute for nectar.

The first case of gynandromorphism in Euglossa chalybeata is described in this study. We document a gynander of Euglossa chalybeata exhibiting mosaic-type asymmetry. This specimen was collected using a methyl salicylate bait at the Usina Hidrelétrica de Belo Monte in Vitória do Xingú, Pará, Brazil, and was compared to a regular male of the species. Photographs of both the gynander and the regular male are provided for reference. We also compare this case with previously reported records of gynandromorphism within the genus Euglossa. The gynander displays typical characteristics of both sexes, with deviations observed in the left and right metatibiae, pre-genital sterna, and genital capsule. Notably, the gynander of Euglossa chalybeata is distinguished from the six previously recorded cases in Euglossa by its deformed metatibiae and almost complete rudimentary genital capsule.

The influence of gene expression on female caste determination in social Hymenoptera is one of the best-characterized examples of developmental polyphenism. We used mRNA-seq to profile differentially expressed genes (DEGs) between workers and queens at four development stages (early larvae: 1-day-old larvae; mid larvae: 5-day-old larvae; late larvae: 9-day-old larvae; and 7-day-old adult bee) of Bombus terrestris. When DEGs of different female castes were compared, it was found that there were more DEGs at the mid larval and adult stages than at other stages. Caste differentiation may be linked to candidate genes such as Vitellogenin, Kr-h1, Dnmt3, Hexamerin, Yellow, and Chymotrypsin-2. Additionally, the gene expression profiles were observed differently among the four development stages. Comparing one stage to the next showed that, more number of DEGs were found in queens than workers. In the investigation of how gene expression affects larval caste determination, WGCNA showed that five modules were closely associated with larval caste determination. The functions of genes were mainly enriched in energy metabolism and energy production within mitochondria, suggesting that the energy requirements during the larval development process varied between caste determination. The current study sheds light on the patterns of gene expression in the female caste of Bombus terrestris, which will be useful for future research on polyphenism through differential gene expressions.

Bees play a crucial role in pollination but are exposed to various pesticides during nectar and pollen collection, which can impact their health and pollination efficiency. This study aimed to investigate morphological and histochemical changes in the hypopharyngeal glands of Scaptotrigona postica after exposure to three chemical compounds: glyphosate, fipronil, and Tween. Nurse bees of S. postica were divided into four experimental groups and fed with sucrose syrup containing the compounds for 24 h. After the exposure period, the hypopharyngeal glands were analyzed for morphology using light microscopy and transmission electron microscopy. The hypopharyngeal glands of S. postica exhibited a tubuloacinar structure, with unicellular acini approximately 54 µm in diameter. Exposure to fipronil resulted in changes in the organization of the rough endoplasmic reticulum (RER) and increased area and sphericity of the acini compared to all other groups, as well as a higher presence of proteins in the cytoplasm compared to other pesticides, potentially due to increased food consumption. Bees exposed to glyphosate showed alterations in the mitochondria compared to all groups. The Tween group did not exhibit significant changes in cellular ultrastructure, only a smaller area and sphericity compared to the control group. The hypopharyngeal glands are highly sensitive to pesticides and are efficient bioindicators. Significant changes in these glands can compromise the maintenance of the colony.

Paratetrepedia is the richest genus in the tribe Tapinotaspidini and its species have a wide distribution in the Neotropical region; however, little is known about the nesting biology of its species. Here, we report information about two species: Paratetrapedia (Lophopedia) nigrispinis (Vachal) and P. (Paratetrapedia) leucostoma (Cockerell) in Argentina. Nests of both species were similar: brood cells were elongated ovals and were excavated in the wood, arranged in linear series of one to three. Brood cells were internally shiny (varnish-like), possibly due to the lining carried out by the females, and were partitioned with the sawdust obtained from the excavated cells. Our data suggest that both species showed a strong association with Malpighiaceae flowers (however, the number of brood cells analysed was very low [1 and 2 brood cells] and this fact suggests that the assumption of oligolecty can be speculative) and could have bivoltine life cycles with one rapid spring/early-summer generation, and a second generation in late-summer/autumn. These Paratetrapedia species shared common behavioural traits with other studied wood-nesting species of the genus, which we suggest calling them “carpenter oil-collecting bees”.

The honey bee subspecies native to Saudi Arabia, Apis mellifera jemenitica Rutter, is currently being threatened by genetic pressure from exotic subspecies imported by commercial beekeepers. Uncontrolled interbreeding between native and exotic subspecies could dilute advantageous adaptations and give rise to new haplotypes that are not well suited for Saudi Arabia’s harsh climate. In this study, we analyzed the mitochondrial haplotypes and parasitization patterns by Varroa destructor mites in commercial beekeeping operations across Southwestern Saudi Arabia. We sampled 300 workers from five randomly chosen colonies at each of the eleven apiaries from December 2022 to February 2023. We extracted DNA from two workers per colony for analysis of the mitochondrial COI-COII region and assessed the remaining workers for mite infestation levels. We also haplotyped a subgroup of mites. All 55 colonies analyzed belonged to the A. m. jemenitica subspecies, which is part of the Z subgroup of the A lineage. Mitochondrial genome analysis revealed ten distinct haplotype sequences at four of the eleven locations. The average (± SEM) number of mites per 100 workers across all sites was 1.95 ± 0.96 and was below a 3% infestation threshold at nine of the eleven locations. All tested mites belonged to the Korean haplotype. The Al-Riyan, Al-Radha, and Khaitaa apiaries had both, no novel haplotypes, and the lowest Varroa mite infestation levels. This study could ultimately inform a colony selection process for the implementation of a breeding program aimed at improving honey bee productivity in Southwestern Saudi Arabia.

Extreme temperature events, such as heat waves, are increasing in frequency, magnitude, and duration. These events are believed to contribute to pollinator decline. Critical thermal maxima (CT_max) is a key physiological trait for understanding an organism’s ecology and predicting its responses to changes in climate. In this study, we investigated whether different life stages with distinct thermoregulatory behaviors differ in their CT_max in the solitary bee Osmia bicornis, one of the most common and important pollinators in Central Europe. Additionally, we tested the influence of excessively high temperatures, heat waves, on the CT_max in Osmia bicornis. We found CT_max varied among life stages, with adults exhibiting higher CT_max than larvae. Both females and males of adult bees showed a negative correlation between CT_max and body mass. Interestingly, adult bees exposed to different heat waves during their larval stage did not exhibit significant shifts in CT_max. These results suggest that bees may have limited capacity to enhance heat tolerance in response to prior heat exposure.