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Abstract Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016–2017 and 2017–2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists. 

Abstract Lithium has been considered a potential acaricidal agent against the honey bee (Apis mellifera) parasite Varroa. It is known that lithium suppresses elevated activity and regulates circadian rhythms and light response when administered to humans as a primary therapeutic chemical for bipolar disorder and to other bipolar syndrome model organisms, given the crucial role of timing in the bee's foraging activity and the alternating sunlight vs dark colony environment bees are exposed, we explored the influence of lithium on locomotor activity (LMA) and circadian rhythm of honey bees. We conducted acute and chronic lithium administration experiments, altering light conditions and lithium doses to assess LMA and circadian rhythm changes. We fed bees one time 10 μl sucrose solution with 0, 50, 150, and 450 mM LiCl in the acute application experiment and 0, 1, 5, and 10 mmol/kg LiCl ad libitum in bee candy in the chronic application experiment. Both acute and chronic lithium treatments significantly decreased the induced LMA under constant light. Chronic lithium treatment disrupted circadian rhythmicity in constant darkness. The circadian period was lengthened by lithium treatment under constant light. We discuss the results in the context ofVarroacontrol and lithium's effect on bipolar disorder. 

Abstract Most freshwater habitats have been substantially affected by anthropogenic factors such as fish introductions, plastic pollution, and river regulation. Urban rivers are highly vulnerable to impacts associated with land use changes resulting from increasing urbanization, including altering habitat and establishing aquatic biological communities in these areas. In turn, the introduction of exotic species into sensitive and threatened ecosystems such as tropical urban streams and their rapid establishment, such asPterygoplichthys multiradiatus, was used as an ecological model to determine the relative population size of the species. Also, the species was used to evaluate the presence of microplastics (MPs) in the gastrointestinal tract (GIT) of fish in rivers with different land use history. Our results showed significant differences in pleco abundance between areas with high and low urban (LU) development in the watersheds. The study demonstrated that abiotic environmental factors directly influence the relative abundance of plecos at the range and watershed scales. In a total of 42 fish examined, only 85.7% showed MPs retained in the GIT, with fibers and fragments being the most common. A total of 22 pieces of microplastic were identified with Nile Red staining by slide analysis. A significant difference was found between the abundance of microplastic ingested per total fish length between streams with high and LU development reaches. Therefore, in relatively small amounts, microplastic ingestion appears to be common inP. multiradiatusspecies, regardless of the habitat in which they are found and the diet present. 

Abstract The effects of acute sublethal doses of coumaphos, an acaricide used againstVarroa destructorinfestation in beekeeping, on the locomotor activities of four native honeybee subspecies of Türkiye including two ecotypes (Carniolan honeybee -A. m. carnica, Syrian honeybee -A. m. syriaca, Caucasian honeybee-A. m. caucasica, and Muğla and Yığılca ecotypes of Anatolian honeybeeA. m. anatoliaca) were investigated using an individual locomotor activity monitoring system. Analysis of locomotor activity data in the first 12-h, last 12-h, and 24-h time periods showed that bees fromcaucasicaandcarnicasubspecies were not affected by coumaphos at all three acute doses (1, 2, and 5 μg coumaphos in 10 μl sucrose syrup for each bee). In contrast, bees fromA. m. syriacasubspecies showed significantly elevated locomotor activity levels at 2 and 5 μg coumaphos doses within the first 12 h. Bees from both Muğla and Yığılca ecotypes ofanatoliacasubspecies also showed elevated locomotor activity levels at 5 μg coumaphos dose but the magnitude of increase was lower in these ecotypes compared to that seen insyriacasubspecies in the first 12-h period. In general, increasing doses of coumaphos resulted in increased locomotor activity (locomotor activity), with differences in sensitivity across honeybee populations. Possible mechanisms underlying this variance and suggestions for further studies are discussed. 

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 Honey bees, as many species of social insects, display a division of labor among colony members based on behavioral specializations related to age. Adult worker honey bees perform a series of tasks in the hive when they are young (such as brood care or nursing) and at ca. 2–3 wk of age, shift to foraging for nectar and pollen outside the hive. The transition to foraging involves changes in metabolism and neuroendocrine activities. These changes are associated with a suite of developmental genes. It was recently demonstrated that antibiotics influence behavioral development by accelerating or delaying the onset of foraging depending on timing of antibiotic exposure. To understand the mechanisms of these changes, we conducted a study on the effects of antibiotics on expression of candidate genes known to regulate behavioral development. We demonstrate a delay in the typical changes in gene expression over the lifetime of the individuals that were exposed to antibiotics during immature stage and adulthood. Additionally, we show an acceleration in the typical changes in gene expression on individuals that were expose to antibiotics only during immature stage. These results show that timing of antibiotic exposure alter the typical regulation of behavioral development by metabolic and neuroendocrine processes. 

Abstract Freshwater snails of the genusBiomphalariaserve as intermediate hosts for the digenetic trematodeSchistosoma mansoni, the etiological agent for the most widespread form of intestinal schistosomiasis. As neuropeptide signaling in host snails can be altered by trematode infection, a neural transcriptomics approach was undertaken to identify peptide precursors inBiomphalaria glabrata, the major intermediate host forS.mansoniin the Western Hemisphere. Three transcripts that encode peptides belonging to the FMRF‐NH₂‐related peptide (FaRP) family were identified inB.glabrata. One transcript encoded a precursor polypeptide (Bgl‐FaRP1; 292 amino acids) that included eight copies of the tetrapeptide FMRF‐NH₂and single copies of FIRF‐NH₂, FLRF‐NH₂, and pQFYRI‐NH₂. The second transcript encoded a precursor (Bgl‐FaRP2;347amino acids) that comprised 14 copies of the heptapeptide GDPFLRF‐NH₂and 1 copy of SKPYMRF‐NH₂. The precursor encoded by the third transcript (Bgl‐FaRP3; 287 amino acids) recapitulatedBgl‐FaRP2but lacked the full SKPYMRF‐NH₂peptide. The three precursors shared a common signal peptide, suggesting a genomic organization described previously in gastropods. Immunohistochemical studies were performed on the nervous systems ofB.glabrataandB.alexandrina, a major intermediate host forS.mansoniin Egypt. FMRF‐NH₂‐like immunoreactive (FMRF‐NH₂‐li) neurons were located in regions of the central nervous system associated with reproduction, feeding, and cardiorespiration. Antisera raised against non‐FMRF‐NH₂peptides present in the tetrapeptide and heptapeptide precursors labeled independent subsets of the FMRF‐NH₂‐li neurons. This study supports the participation of FMRF‐NH₂‐related neuropeptides in the regulation of vital physiological and behavioral systems that are altered by parasitism inBiomphalaria. 

Abstract Honey bees (Apis melliferaL.) are the primary commercial pollinators across the world. The subspeciesA. m. scutellataoriginated in Africa and was introduced to the Americas in 1956. For the last 60 years, it hybridized successfully with European subspecies, previous residents in the area. The result of this hybridization was called Africanized honey bee (AHB). AHB has spread since then, arriving to Puerto Rico (PR) in 1994. The honey bee population on the island acquired a mosaic of features from AHB or the European honey bee (EHB). AHB in Puerto Rico shows a major distinctive characteristic, docile behavior, and is called gentle Africanized honey bees (gAHB). We used 917 SNPs to examine the population structure, genetic differentiation, origin, and history of range expansion and colonization of gAHB in PR. We compared gAHB to populations that span the current distribution ofA. melliferaworldwide. The gAHB population is shown to be a single population that differs genetically from the examined populations of AHB. Texas and PR groups are the closest genetically. Our results support the hypothesis that the Texas AHB population is the source of gAHB in Puerto Rico. 

Abstract Recent years have led to increased effort to describe and understand the peripheral nervous system and its influence on central mechanisms and behavior in gastropod molluscs. This study revealed that an antibody raised against keyhole limpet hemocyanin (KLH) cross‐reacts with an antigen(s) found extensively in both the central and the peripheral nervous systems ofBiomphalaria alexandrina. The results revealed KLH‐like immunoreactive (LIR) neurons in the cerebral, pedal, buccal, left pleural, right parietal, and visceral ganglion within the CNS with fibers projecting throughout all the peripheral nerves. Numerous KLH‐LIR peripheral sensory neurons located in the foot, lips, tentacles, mantle, esophagus, and penis exhibited a bipolar morphology with long tortuous dendrites. KLH‐LIR cells were also present in the eye and statocyst, thus suggesting the labeling of multiple sensory modalities/cell types. KLH‐LIR cells did not co‐localize with tyrosine hydroxylase (TH)‐LIR cells, which have previously been described in this and other gastropods. The results thus provide descriptions of thousands of peripheral sensory neurons, not previously described in detail. Future research should seek to pair sensory modalities with peripheral cell type and attempt to further elucidate the nature of KLH‐like reactivity. These findings also emphasize the need for caution when analyzing results obtained through use of antibodies raised against haptens conjugated to carrier proteins, suggesting the need for stringent controls to help limit potential confounds caused by cross‐reactivity. In addition, this study is the first to describe neuronal cross‐reactivity with KLH inBiomphalaria, which could provide a substrate for host‐parasite interactions with a parasitic trematode,Schistosoma. 

Neuronal signals mediated by the biogenic amine serotonin underlie critical survival strategies across the animal kingdom. This investigation identified a group of serotonergic cells in the panpulmonate snail Biomphalaria glabrata that appear to be homologous to neurons that mediate withdrawal responses in other gastropod taxa. It is proposed that an ancient withdrawal circuit has been highly conserved in three major gastropod lineages.