Apidologie最新文献

Bumble bees use three main habitats to complete their life cycle: foraging habitat, overwintering habitat, and nesting habitat. Overall, the majority of bumble bee research has focused on the foraging habitat and flower preferences of bumble bees, leaving a large knowledge gap regarding nesting and overwintering habitats. These aspects of the bumble bee life cycle are notoriously difficult to observe, and the time required to locate such locations is often considered prohibitive, leaving them to be largely understudied. This lack of information on the nesting habitat requirements of bumble bees also has negative consequences regarding conservation action. Here, we set out to determine the nesting habitat preferences in a rigorous, standardized fashion. In 2022 and 2023, we conducted standardized surveys for nesting bumble bees to assess habitat preferences in forest, prairie, and edge habitats. We surveyed 21 plots for a total of 168 person hours per habitat type (63 plots, 504 h total) at sites along the St. Croix National Scenic Riverway in Minnesota and Wisconsin, USA. We found a total of 25 nests of 6 different bumble bee species. Bumble bee nests were more likely to occur in prairie and edge habitats than in forest habitat. The results of this study indicate the importance of prairie and edge habitats for nesting bumble bees. Furthermore, results from this study are useful for informing management of bumble bee nesting habitat and further developing protocol for finding bumble bee nests more efficiently.

Western honey bee (Apis mellifera) faces substantial threats from pests such as small hive beetle (SHB; Aethina tumida), greater wax moth (GWM; Galleria mellonella) and lesser wax moth (LWM; Achroia grisella). Entomopathogenic nematodes (EPNs) could serve as promising biocontrol agents to manage these pests; however, their efficacy can vary with target pest species with different body mass and life cycles, EPN species and isolates, and concentrations applied. Although numerous EPN studies have been performed on GWM and some on SHB, very few have been conducted on LWM, and none have directly compared EPN performance across these three pests. Here, we evaluated and compared the virulence, penetration rates and reproductive potential of 15 Australian isolates of five EPN species against body mass-standardised larvae of SHB, GWM and LWM. We found that SHB consistently experienced the lowest and slowest mortality across all EPNs, while GWM consistently experienced the highest and fastest mortality. Notably, Heterorhabditis indica Hi.HRN2 and Hi.HIE2 were among the most virulent isolates in SHB and GWM, whereas Heterorhabditis bacteriophora Hb.EG was the most virulent EPN isolate in LWM. Additionally, EPN isolates exhibited on average 5 × lower penetration rates and 1.5 × lower reproductive success in SHB compared to GWM and LWM. Our study found significant variation in EPN efficacy across the three honey bee pests and provides the basis for the selection of effective isolates and concentrations for targeted biological control of honey bee pests, though the evaluation of EPN safety for honey bee will also be essential.

Epanthidium tigrinum is a solitary Neotropical bee with great potential for agricultural pollination, especially of crops such as guava (Psidium guajava L.), acerola (Malpighia emarginata DC.), cashew (Anacardium occidentale L.), and cowpea (Vigna unguiculata (L.) Walp.). The availability of resources such as pollen, nectar, and resin limits the nest provisioning activity, but little is known about the plant species it use. This study investigated the flora used by nesting E. tigrinum in an urban area in northeastern Brazil over two-year period. The bee is multivoltine, alternating between periods of higher and lower nesting activity, depending on the quantity and availability of resources.Its feeding habit varies from polylectic foraging during periods of limited floral resources to the frequent use of certain plant species when these are highly abundant. Up to 25 types of pollen were identified in the nests, with seasonal variation. Bipartite networks revealed patterns of connectivity, nesting, and modularity and involved interactions between Epanthidium tigrinum and 25 pollen types from 15 botanical families, primarily Fabaceae, Bignoniaceae, Anacardiaceae, Malpighiaceae, and Euphorbiaceae. The study also identified essential plant species for nesting, such as Leucaena leucocephala and Ludwigia octovalvis, as well as cultivated species like cashew (Anacardium occidentale) and acerola (Malpighia emarginata) that may benefit from pollination. This is relevant for the conservation and management of E. tigrinum and other economically important Megachilidae species.

Climate change is progressing faster in winter than in summer, contributing to an increased frequency of extreme weather events, such as winter warm spells (WWS). These events pose a significant risk to diapausing insects, potentially leading to physiological disruptions and phenological mismatches. We investigated the effects of current and projected WWS on the overwintering physiology and emergence timing of Osmia bicornis, a solitary bee and key pollinator in Central Europe. In a controlled experiment, we exposed bees to four overwintering conditions: laboratory control, current and projected WWS, and natural outdoor conditions. We monitored body mass monthly from November to March, recorded emergence phenology, and measured fat reserves post-emergence. Our results show that WWS, particularly under projected warming scenarios and outdoor conditions, which were notably warmer than laboratory simulations based on multiannual winter averages, significantly accelerated emergence. Also, body mass loss and fat reserve depletion were significantly higher in bees exposed to WWS and outdoor conditions compared to those kept under laboratory control. However, these physiological costs did not translate into increased overwintering mortality. These findings suggest that warming winters may push O. bicornis closer to its physiological limits, with potential consequences for fitness and reproductive success under future climate scenarios. Overall, our finding highlights the vulnerability of overwintering pollinators to warming winters and emphasizes the importance of incorporating extreme climatic events into models predicting insect responses to climate change.

Understanding the cognitive effects of insecticide exposure in honey bees is critical to understanding pollinator decline and its ecological and agricultural implications. This study investigates the effects of two widely used insecticides at field realistic doses, Deltamethrin (2 ng/bee) and Imidacloprid (0.5 ng/bee), on olfactory learning and memory in honey bees, alone and in combination. A proboscis extension reflex olfactory conditioning protocol was used to assess this. Both insecticides and their Combination caused similar impairments in learning ability, reducing the proportion of bees able to form olfactory associations by around 49.9%. Imidacloprid alone negatively affected the learning rate, requiring 31.4% more trials to elicit a conditioned response, while Deltamethrin or the Combination had no effect. Short-term (1 h) memory retention was unaffected, while long-term (24 h) memory retention was reduced by 48.2% by Imidacloprid and the Combination of the insecticides. We found no additive or synergistic effect of the insecticide combination; on the contrary, an antagonistic effect on learning rate was observed, raising concerns about the unpredictability of real-world insecticide interactions and their implications for risk assessment. Our results highlight the importance of considering diverse cognitive systems and incorporating mixtures of pesticides commonly detected in the environment into regulatory assessments, as well as evaluating colony- and field-level impacts to better understand the ecological and agricultural consequences of pesticide use.

Fatty acids play a crucial role in the metabolic activities, health, cognitive development, and behaviors of honeybees. The primary source of fatty acids for honeybees is the pollen consumed, though they can also produce specific fatty acids through de novo synthesis. Among the saturated fatty acids in honeybees, palmitic and stearic acids are the most abundant, while common unsaturated fatty acids include oleic, eicosenoic, palmitoleic, linoleic, and linolenic acids, which are present in various body parts and tissues. The composition and concentration of these fatty acids can be influenced by multiple biotic and abiotic factors such as developmental stage, nutrition, pathogens, season, temperature, sanitation conditions, industrial pollution, pesticides, and radiation. Therefore, monitoring the fatty acid profile of honeybees can be used as a bioindicator for monitoring the environmental conditions and the health status, enabling management actions that could improve honeybee sustainability. This study aims to provide foundational knowledge on the fatty acids identified in honeybees, examining their physiological roles, the impact of environmental stressors, and the analytical techniques used to determine their composition.

Stingless bees (Meliponini) are eusocial insects that form perennial colonies and play a vital role in plant pollination. Our understanding of their biology, ecology, and nesting dynamics remains limited, especially in urban ecosystems. Nest surveys in cities can provide insights for conservation and management strategies, particularly as urban areas experience a high vegetation loss. We evaluated the factors influencing the spatial distribution of Meliponini nests in a medium-sized city in Brazil. We assessed the effects of tree abundance, richness, and density, along with tree attributes, on the abundance of stingless bee nests in 20 sampling units. Additionally, we evaluated nest persistence over time. Over 100 nests from four stingless bee species were recorded: Nannotrigona testaceicornis, Plebeia droryana, Trigona spinipes, and Tetragonisca angustula. Our findings revealed a nest decline over time, with human-induced causes accounting for more than 50% of nest losses. Tree abundance positively affected the total nest abundance. The bee species exhibited variations in nesting substrate preferences, showing responses to tree attributes such as diameter at breast height (DBH) and height. Unregulated urban expansion threatens stingless bee populations, primarily due to the removal of large, old trees that provide nesting cavities. Therefore, conservation efforts should focus on enhancing floral resources and preserving trees in urban areas to support stingless bee populations.

Varroa destructor is the major ectoparasite of honey bees causing extensive colony losses worldwide. Despite the importance of this threat to honey bees some crucial aspects of the mite’s biology are still poorly known, including the longevity of the parasite on the different developmental stages of its host. This study aimed at determining, under standard conditions, the lifespan of V. destructor on the larvae, pupae, and adults of the honey bee. In our study, V. destructor survival varied depending on the host life stage, with the longest survival observed on honey bee larvae, where median and maximum survival up to 45 and 100 days were recorded, respectively. A declining survival of V. destructor during the summer season was also noted, possibly linked to deteriorating honey bee health, associated with higher viral infection levels. This study emphasizes the importance of establishing an artificial rearing system to advance research on V. destructor biology and facilitate the development of innovative control strategies.

Understanding bees, with their extensive morphological, phylogenetic, and behavioral diversity and their significant economic and ecological roles, requires integrating classical and modern scientific methods. Microsatellite (SSR—Simple Sequence Repeat) markers are a low-cost tool useful for various investigations at individual, colony, population, and species levels. However, a comprehensive review on the applications, trends, and Limitations of molecular markers in bee studies is lacking. We aimed to systematize the knowledge about microsatellite markers in bee research, characterize research trends, discuss their applications, and present their advantages and Limitations to address major knowledge gaps across various research themes. Additionally, we aimed to establish a preliminary database of microsatellite primers and their transferability across related species. We conducted a systematic review of research articles on microsatellites and bees published until 2023. Our review included 576 articles from all biogeographical realms, which covered 173 species from 19 families. Apidae (94.1%) and Halictidae (3.4%) were the most frequent bee families in studies, with a strong dominance of Apis and Bombus species, followed by Meliponini species. Future research should include more solitary species and additional species from underrepresented tribes. The reviewed articles spanned 11 research themes, ranging from basic bee biology to applied and multi-disciplinary research, with reproduction, conservation, behavior, evolution, breeding, and beekeeping being the most frequent themes. Microsatellite markers are a suitable choice for most research themes and show a promising trend for continued use in future bee studies.

Honey bees have a complex social structure, with many factors affecting colony survival. Mathematical models are therefore valuable for understanding how individual variables affect honey bee colony dynamics. Previous honey bee population models have shown that accelerated aging due to stress can lead to colony decline. Our previous work showed that general developmental stress causes a previously undocumented behavior whereby very young workers exit the colony before they can fly, leading them to die prematurely on the ground outside the hive. In this study, we modeled the effects of this premature hive exiting behavior on colony survival. We used parameters from previous studies to inform our model and incorporated empirical data regarding the rate of premature hive exiting behavior driven by various developmental stressors. An equation to link premature exit with accelerated aging was also introduced to mirror population dynamics across different worker age groups. We found that higher rates of premature hive exiting behavior can accelerate colony collapse. A feeding variable (provisioning colonies with extra sugar syrup) and a brood break variable (preventing the queen from laying eggs for a given time period to decrease Varroa mite levels) were added to the model to examine ways to counteract the negative effects of premature hive exiting behavior and to assess their effectiveness at regulating the progression of worker aging. Our results suggest that both supplemental feeding and implementing brood breaks can bring a colony back from the brink of collapse.