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ABSTRACT Organisms may simultaneously face thermal, desiccation and nutritional stress under climate change. Understanding the effects arising from the interactions among these stressors is relevant for predicting organisms' responses to climate change and for developing effective conservation strategies. Using both dynamic and static protocols, we assessed for the first time how sublethal desiccation exposure (at 16.7%, 50.0% and 83.3% of LD50) impacts the heat tolerance of foragers from two social bee species found on the Greek island of Lesbos: the managed European honey bee, Apis mellifera, and the wild, ground-nesting sweat bee Lasioglossum malachurum. In addition, we explored how a short-term starvation period (24 h), followed by a moderate sublethal desiccation exposure (50% of LD50), influences honey bee heat tolerance. We found that neither the critical thermal maximum (CTmax) nor the time to heat stupor was significantly impacted by sublethal desiccation exposure in either species. Similarly, starvation followed by moderate sublethal desiccation did not affect the average CTmax estimate, but it did increase its variance. Our results suggest that sublethal exposure to these environmental stressors may not always lead to significant changes in bees' heat tolerance or increase vulnerability to rapid temperature changes during extreme weather events, such as heat waves. However, the increase in CTmax variance suggests greater variability in individual responses to temperature stress under climate change, which may impact colony-level performance. The ability to withstand desiccation may be impacted by unmeasured hypoxic conditions and the overall effect of these stressors on solitary species remains to be assessed. 

Abstract Stingless bees (Hymenoptera: Apidae: Meliponini) are key pollinators of both cultivated and wild plants in tropical and subtropical areas of the world. While most species are found in lowland to mid-elevations, a few have adapted to high elevations, and their biology remains poorly understood. We assess the foraging pattern ofParapartamona zonata(Smith) in the central Andes of Colombia (2583 m.a.s.l.) and apply computer tomography to visualize and characterize its internal nest architecture. Bees foraged for pollen and nesting materials (resin and/or mud) from sunrise (5:40 h) to sunset (17:45), even at ambient temperatures as low as 11 °C. Foraging varied significantly throughout the day and temperature and sky condition explained 47% of its variance. Differences in the nest architecture, when compared with previous records, suggest that nesting behavior might be variable. These results are discussed in the context of behavioral adaptations in this unique environmental niche. 

Abstract Predicting insect responses to climate change is essential for preserving ecosystem services and biodiversity. Due to high daytime temperatures and low humidity levels, nocturnal insects are expected to have lower heat and desiccation tolerance compared to diurnal species. We estimated the lower (CT_Min) and upper (CT_Max) thermal limits ofMegalopta, a group of neotropical, forest-dwelling bees. We calculated warming tolerance (WT) as a metric to assess vulnerability to global warming and measured survival rates during simulated heatwaves and desiccation stress events. We also assessed the impact of body size and reproductive status (ovary area) on bees’ thermal limits.Megaloptadisplayed lower CT_Min, CT_Max, and WTs than diurnal bees (stingless bees, orchid bees, and carpenter bees), but exhibited similar mortality during simulated heatwave and higher desiccation tolerance. CT_Minincreased with increasing body size across all bees but decreased with increasing body size and ovary area inMegalopta, suggesting a reproductive cost or differences in thermal environments. CT_Maxdid not increase with increasing body size or ovary area. These results indicate a greater sensitivity ofMegaloptato temperature than humidity and reinforce the idea that nocturnal insects are thermally constrained, which might threaten pollination services in nocturnal contexts during global warming. 

Abstract BackgroundAluminum is the third most prevalent element in the earth’s crust. In most conditions, it is tightly bound to form inaccessible compounds, however in low soil pH, the ionized form of aluminum can be taken up by plant roots and distributed throughout the plant tissue. Following this uptake, nectar and pollen concentrations in low soil pH regions can reach nearly 300 mg/kg. Inhibition of acetylcholinesterase (AChE) has been demonstrated following aluminum exposure in mammal and aquatic invertebrate species. In honey bees, behaviors consistent with AChE inhibition have been previously recorded; however, the physiological mechanism has not been tested, nor has aversive conditioning. ResultsThis article presents results of ingested aqueous aluminum chloride exposure on AChE as well as acute exposure effects on aversive conditioning in anApis mellifera ligusticahive. Contrary to previous findings, AChE activity significantly increased as compared to controls following exposure to 300 mg/L Al³⁺. In aversive conditioning studies, using an automated shuttlebox, there were time and dose-dependent effects on learning and reduced movement following 75 and 300 mg/L exposures. ConclusionsThese findings, in comparison to previous studies, suggest that aluminum toxicity in honey bees may depend on exposure period, subspecies, and study metrics. Further studies are encouraged at the moderate-high exposure concentrations as there may be multiple variables that affect toxicity which should be teased apart further. 

Abstract Due to the Covid‐19 pandemic, the education system worldwide faced sudden and unforeseen challenges. Many academic institutions closed their doors, forcing both educators and students to transition to Emergency Remote Teaching (ERT) for the remainder of the semester. This transition eliminated hands‐on experiences, increased workload, and altered curricula. However, these aspects, as well as students' perceptions, study habits, and performance in response to ERT remain poorly documented. This contribution describes changes in the curriculum of an undergraduate cadaver‐based laboratory, and explores students' performance, self‐perceived learning, and overall satisfaction during this educational crisis. Online content delivery for this course included both asynchronous instruction and synchronous discussion sessions. While formative assessments remained the same, online spotter examinations included short answer, multiple choice, multiple answer, ordering, and true and false questions. Despite examination grades improving 20% during ERT, students reported lower levels of learning, confidence, and engagement with the course materials when compared to the face‐to‐face portion of the class. The most prevalent challenges identified by students were those related to the loss of access to cadaver‐based learning, including difficulty identifying and visualizing structures in three dimensions, and the loss of context and sensorial cues. Flexibility in taking examinations and learning the material at their own pace were recognized as positive outcomes of the ERT transition. While the resulting student perceptions and performances are unsurprising, they offer insight into the challenges of fostering a productive learning environment in a future threatened by epidemic outbreak and economic uncertainty. 

The use of invertebrate models has allowed researchers to examine the mechanisms behind alcoholism and its effects with a cost-effective system. In that respect, the honey bee is an ideal model species to study the effects of ethanol (EtOH) due to the behavioral and physiological similarities of honey bees with humans when alcohol is consumed. Although both ingestion and inhalation methods are used to dose subjects in insect EtOH model systems, there is little literature on the use of the EtOH vapor-exposure method for experiments using honey bees. The experiment presented here provides baseline data for a dose EtOH-hemolymph response curve when using EtOH vapor-inhalation dosing with honey bees (Apis mellifera). Bees were exposed to EtOH vapors for 0, 1, 2.5, or 5 min, and hemolymph was collected 1 min post EtOH exposure. Hemolymph samples were analyzed using gas chromatography (GC) for hemolymph EtOH concentration. The ethanol-hemolymph level of the bees increased linearly with exposure time. The results provide a dosing guide for hemolymph EtOH level in the honey bee model ethanol-inhalation system, and thus makes the honey bee model more robust. 

Honey bees are a commonly used species for alcohol research due to their genome being fully sequenced, their behavioral changes following consumption, and their preference for alcohol. The purpose of this article is to provide a preliminary examination of the genetic expression of heat shock protein 70 (HSP70) and big potassium ion channel protein (BKP) in honey bees following the consumption of either 0%, 2.5%, 5%, or 10% ethanol (EtOH) solutions. The foraging behaviors of the bees were observed and recorded through their return and drinking times. There were significant differences in the return and drinking times between some of the groups. The bees in the 10% condition took significantly longer to return compared to the other groups. Additionally, the bees in the 5% group spent significantly more time drinking compared to the bees in the control (0%) group. There were no significant differences in HSP70 or BKP between the different ethanol groups. Cumulatively, these findings suggest that, while bees may exhibit behavioral differences, the differences in gene expression may not be observed at the transcriptional level. 

Insecticides are a major tool for controlling pest species. Their widespread use results in damage to non-targeted insects, with honey bees particularly at risk. During foraging, honey bees learn and remember floral charac teristics that are associated with food. As insect pollinators, honey bees inadvertently contact chemicals which can have multiple negative impacts. The toxicity of two insecticides from different classes, ethion (47.79 mg a.i. L − 1 ) and hexaflumuron (500 mg a.i.L − 1 ), on learning, memory, and sensory perception were evaluated. We found that oral exposure to ethion had adverse effects on learned proboscis extension toward reward-associated odors and colors. In addition, we showed reduced sucrose consumption and sucrose responsiveness after expo sure. Hexaflumuron also impaired olfactory learning and memory and decreased responsiveness to sucrose and water. Exposure to sub-lethal concentration of the cholinergic organophosphate insecticide, ethion (47.79 mg a.i. L − 1 ), and the field-recommended concentration of hexaflumuron (500 mg a.i.L − 1 ), significantly impaired behavior involved in foraging. Our results suggest that several behavioral characteristics of honey bees be evaluated when testing an insecticide rather than relying on just one behavioral measure. 

Bees are essential pollinators and understanding their ability to cope with extreme temperature changes is crucial for predicting their resilience to climate change, but studies are limited. We measured the response of the critical thermal maximum (CTMax) to short-term acclimation in foragers of six bee species from the Greek island of Lesvos, which differ in body size, nesting habit, and level of sociality. We calculated the acclimation response ratio as a metric to assess acclimation capacity and tested whether bees’ acclimation capacity was influenced by body size and/or CTMax. We also assessed whether CTMax increases following acute heat exposure simulating a heat wave. Average estimate of CTMax varied among species and increased with body size but did not significantly shift in response to acclimation treatment except in the sweat bee Lasioglossum malachurum. Acclimation capacity averaged 9% among species and it was not significantly associated with body size or CTMax. Similarly, the average CTMax did not increase following acute heat exposure. These results indicate that bees might have limited capacity to enhance heat tolerance via acclimation or in response to prior heat exposure, rendering them physiologically sensitive to rapid temperature changes during extreme weather events. These findings reinforce the idea that insects, like other ectotherms, generally express weak plasticity in CTMax, underscoring the critical role of behavioral thermoregulation for avoidance of extreme temperatures. Conserving and restoring native vegetation can provide bees temporary thermal refuges during extreme weather events.