Apidologie最新文献

A noteworthy feature of the Heterotrigona itama mitochondrial genomes is the absence of the control region. The mitochondrial genome of two Peninsular Malaysia taxa exhibits heteroplasmy. They, and the China taxon, have the same long inverted repeats segment comprising 13 protein coding genes (PCGs), 2 rRNA, and 22 tRNA genes. The two mitogenome variants in both the Peninsular Malaysia taxa exhibit different gene orders involving the inversion of (trnK–trnA–trnI) to (trnI–trnA–trnK). The (trnK–trnA–trnI) gene segment in the “canonical” genome of the Peninsular Malaysia taxa is rearranged as (trnI–trnA–trnK) in the China taxon; the Thailand taxon has the (trnK–trnA–trnI) gene order. The Thailand taxon has the typical 37 genes but with several rearrangements and an inverted segment of nad6–cob–trnS2–nad1 compared to nad1–trnS2–cob–nad6 genes in the Peninsular Malaysia and China taxa. The Peninsular Malaysia and China taxa have identical start and stop codons for 10 PCGs. They differ from the Thailand taxon in five start codons and four stop codons. In the Peninsular Malaysia and China taxa, trnN (asparagine) lacks the TΨC loop, and serine S1 (trnS1) lacks the DHU arm; trnS1 in the Thailand taxon lacks the DHU arm. Based on the complete COX1 gene, the two Peninsular Malaysia taxa are genetically different. The Selangor and China taxa do not show genetic differentiation, and the Thailand taxon is genetically very distinct from the Peninsular Malaysia and China taxa, indicating the possible presence of a species complex.

The endemic honey bee subspecies Apis mellifera cypria holds significant ecological and economic value in Cyprus but faces an increasing risk of genetic erosion due to the importation of non-native queens. This study applied geometric morphometrics to evaluate wing shape variation in 2400 worker bees from 160 colonies across 15 regions of Cyprus. Nineteen landmarks on the right forewing were digitized and analyzed using Procrustes superimposition, principal component analysis (PCA), and canonical variate analysis (CVA). A population from Lemnos Island, Greece, was used as an out-group. Results showed that 12 Cypriot populations clustered closely, indicating morphological homogeneity, while three populations linked to queen importation exhibited significant divergence. All Cypriot populations were clearly separated from the Lemnos out-group. These findings underscore the effectiveness of morphometric analysis in detecting population structure and support conservation measures to protect the genetic integrity of A. m. cypria.

Nocturnal bees are elusive pollinators for which little and fragmented evidence of their dietary breadth is available. Moreover, despite their assumed relevance as pollinators of tropical plants, there is no information on how nocturnal bees respond to the loss of suitable habitats and forest succession. Here, we investigated the recovery of Megalopta bees, a prominent group of nocturnal pollinators, within a forest regeneration chronosequence in northwestern Ecuador. We also assessed the group’s resource use and the recovery of interaction networks by employing next-generation sequencing on pollen loads. Megalopta bees showed low resistance and delayed recovery, as abundance had not recovered to pre-disturbance forest levels after 38 years of succession. Stratification was the strongest recovery driver, with bees strongly associated with old-growth canopies. In contrast, their diet was broad, encompassing more than 120 plant species. However, the bulk of pollen loads was constituted by pioneer species, while primary forest trees and plants with specialized nocturnal pollination systems were less represented. The use of diverse resources not necessarily tied to old-growth forests thus contributed to network stability across succession. We provide the first molecular assessment of the diet of nocturnal bees, expanding the understanding of their resource range. While dietary breadth may buffer the adverse effects of disturbance on the group, their low resilience and dependence on the canopies of old, structurally complex forests, potentially for nesting, suggest that nocturnal bees are quite vulnerable to the loss of large portions of primary habitats.

There are over 1400 Megachile species in the world, and more than 140 species in North America. Little is known about the natural history of most Megachile species. We examined nutritional, foraging, and nesting preferences of three species. M. pugnata is a native species, but M. rotundata and M. sculpturalis are introduced. Each species exhibited a unique nest cavity diameter preference. M. pugnata collected pollen for brood provisions with significantly lower protein-to-lipid ratios than the other two species. The species also varied in their pollen preferences, with M. sculpturalis collecting primarily from the genus Styphnolobium, M. rotundata from the Fabaceae family, and M. pugnata from the Asteraceae family. M. rotundata and M. pugnata collected leaf material primarily from plants in the rosid clade in contrast to the plant genera visited for pollen. This study provides insight into how these species partition resources and can inform landscape design for pollinator communities.

The global decline of honey bee (Apis mellifera L.) populations is a significant concern due to their crucial role in pollination. This decline is largely attributed to various stressors, particularly agrochemical exposure which demonstrably reduces bee longevity and foraging efficiency. Bees possess a sophisticated three-phase detoxification system, involving key enzymes such as cytochrome P450 monooxygenases, glutathione-s-transferases, and carboxylesterases, to counter the detrimental effects of foreign substances (xenobiotics). However, the combined exposure to insecticides, fungicides, and other agrochemicals often leads to synergistic toxicity, overwhelming these detoxification pathways. Understanding the mechanisms of these synergistic interactions is crucial for comprehending their amplified impact. Research approaches range from basic methods like bioassays and enzyme activity studies to advanced methodologies such as transcriptomics, proteomics, and functional gene analyses, all aimed at elucidating the molecular basis of pesticide detoxification. Beyond enzymatic mechanisms, diet plays a pivotal role in modulating gene expression and enhancing bee resilience. Nutritional components found in pollen, propolis, honey, and various phytochemicals are vital in mitigating the risks posed by xenobiotics. This review focuses on several key areas: the differential pesticide sensitivity between susceptible and resistant bee populations, the enzymatic mechanisms underlying xenobiotic detoxification in bees, the processes driving xenobiotic synergy, and the importance of multifaceted approaches to investigate the molecular factors contributing to pesticide tolerance. Furthermore, it explores the influence of diet-dependent gene expression on detoxification pathways, offering valuable insights to improve bee resilience and support ongoing sustainability efforts.

In the natural environment, bees are often exposed to low concentrations of pesticide mixtures while foraging. These substances can be carried back to the hive, threatening the health and life of the entire colony. For seven consecutive days, honey bee workers were fed daily with 0.5 L of sugar syrup containing a commercial formulation of acetamiprid, glyphosate, and tebuconazole, administered either individually or in two- or three-component mixtures The feed was both actively consumed by the bee colonies and stored in the combs. As a result, their exposure to the pesticides was chronic and lasted until the stored feed was fully consumed before the onset of winter. Pesticide concentrations in the syrup reflected environmental residue levels: 250 ppb for acetamiprid, 7200 ppb for glyphosate, and 147 ppb for tebuconazole. The study aims to assess the impact of these pesticides on colony health, focusing on colony size, brood, and food reserves. No statistically significant differences were found between the groups. Despite the results showing no negative effects of acetamiprid, glyphosate, and tebuconazole on the parameters studied, pesticides still pose a major risk to bees, which may contribute to a decline in their population and consequently in environmental biodiversity. Future research should focus on using acetamiprid, glyphosate, and tebuconazole, but in combination with other commonly used pesticides. The potential risks of unresearched mixtures should be investigated.

The beehive sound, a continuous signal produced by bees within the hive, has been found to correlate with different behavioral states of the colony, like being queenless and swarming. We investigated the possibility of identifying foraging-related cues in this signal. We recorded a colony’s sound while foraging from food sources located at three different distances from the hive, one at a time. The recordings were split into frames to obtain six statistics of their Mel Frequency Cepstral Coefficients. Then, we evaluated different autoencoding networks to obtain a latent space that allowed frames from different foraging sources to be easily differentiable. The high Accuracy, Silhouette score, and F1-score shown in the obtained latent spaces strongly support our approach for identifying foraging-related cues in beehive sound activity.

The microbiota associated with the reproductive tissues of insects can play an important role in altering host fitness: they can manipulate host fecundity to the microbe’s benefit, modulate their host’s immune system, or provide essential nutrients for host gamete production. Stingless bees (Apidae: Meliponini) are eusocial bees that provide pollination services in natural and agricultural systems across the global tropics and subtropics, yet their reproductive microbiome remains poorly characterized. Here, we investigated the bacterial microbiota present in the ovaries and testes of two Australian stingless bee species, Tetragonula carbonaria and Tetragonula hockingsi, using 16S sequencing. Acetic acid bacteria (Acetobacteraceae) dominated the microbiota of ovaries and testes, primarily represented by several Bombella-like strains at the genus level. Phylogenetic analysis of these Bombella-like bacteria places them with those identified from the guts of other stingless bee species, suggesting that this group may have co-evolved with Meliponine hosts. Notably, we found no evidence in Tetragonula reproductives of Wolbachia or other parasitic reproductive endosymbionts known to be capable of manipulating insect reproduction. To further investigate the incidence of such endosymbionts within stingless bees, we conducted a large in silico search of genomic sequencing data from 18 species of stingless bees (almost all workers). This also returned no evidence of known insect reproductive endosymbionts. In contrast to solitary bees, therefore, our findings suggest that parasitic reproductive endosymbionts are particularly uncommon in the stingless bees.

Honey bees collect water primarily for thermoregulation and larval food production. For these purposes, honey bees can collect water from a wide range of sources, raising concerns among beekeepers about the risks this may pose to colony health if these waters are polluted or contaminated. However, honey bee preferences for different water sources are poorly understood, except that bees prefer to collect mineral-rich water to achieve colony nutritional homeostasis. Therefore, we investigated honey bee water preferences and how ambient temperatures, which influence thermoregulation, affect these preferences. To this end, we tested, under semi-field conditions and multiple-choice conditions, waters sampled from different environmental sources (rainwater, swimming pool water, pond water and farm puddle water) likely to be collected by bees, and slurry waters (mixture of livestock feces and urine), a reported but controversial source of water and nutrients, diluted at different rates. Unexpectedly, our results showed that honey bees expressed a strong preference for distilled water and the least mineralized waters (i.e., rainwater and 0.1% dilution of slurry water). Visits to the waterers decreased with increasing mineralization of environmental waters or with increasing concentration of slurry waters. Finally, we found that, as expected, the number of bees foraging at the waterers increased with temperature, but the bees’ water preferences remained unchanged. Our study provides a better understanding of honey bee water collection as a function of temperature and sheds light on the influence of water quality on bee’s water preferences.