The impact of early-life exposure to three agrochemicals on survival, behavior, and gut microbiota of stingless bees (Partamona helleri)

Over the last few decades, agrochemicals have been partially associated with a global reduction in bees' population. Toxicological assessment is therefore crucial for understanding the overall agrochemical risks to stingless bees. Therefore, the lethal and sublethal effects of agrochemicals commonly used in crops (copper sulfate, glyphosate, and spinosad) on the behavior and gut microbiota of the stingless bee, Partamona helleri, were assessed using chronic exposure during the larval stage. When used at the field-recommended rates, both copper sulfate (200 µg of active ingredient/bee; a.i µg bee^-1) and spinosad (8.16 a.i µg bee^-1) caused a decrease in bee survival, while glyphosate (148 a.i µg bee^-1) did not show any significant effects. No significant adverse effects on bee development were observed in any treatment with CuSO₄ or glyphosate, but spinosad (0.08 or 0.03 a.i µg bee ^-1) increased the number of deformed bees and reduced their body mass. Agrochemicals changed the behavior of bees and composition of the gut microbiota of adult bees, and metals such as copper accumulated in the bees' bodies. The response of bees to agrochemicals depends on the class or dose of the ingested compound. In vitro rearing of stingless bees' larvae is a useful tool to elucidate the sublethal effects of agrochemicals.

First report on the prevalence of Klossiella muris in Mus musculus for S. Miguel Island - Azores (Portugal)

Klossiella is a genus of apicomplexan coccidian parasites with a global distribution, whose members typically infect the renal tissue of a wide variety of vertebrate hosts with a high level of host specificity. The presence of this parasite has been previously associated with kidney inflammatory processes. To our knowledge, this is the first report on the prevalence of Klossiella muris in the house mouse (Mus musculus) in Portugal (São Miguel Island - Azores). The prevalence of K. muris was determined through histopathological examination of renal tissue collected during necropsy of 130 mice captured between the years of 2011-2019. K. muris was diagnosed in 45.38% (CI₉₅: 40.9-85.4) of the examined mice. Infection with this parasite was associated with mild to severe kidney inflammation, assessed by the presence of inflammatory processes in the renal cortex and medulla. CAPSULE: First record on coccidiosis caused by infection of Klossiella muris in Mus musculus in Portugal.

Behavior and gut bacteria of Partamona helleri under sublethal exposure to a bioinsecticide and a leaf fertilizer

The exposure of bees to agrochemicals during foraging and feeding has been associated with their population decline. Sublethal exposure to agrochemicals can affect behavior and the microbiota. Gut microbiota is associated with insect nutritional health, immunocompetence, and is essential for neutralizing the damage caused by pathogens and xenobiotics. Research on the effect of the bioinsecticides and fertilizers on the microbiota of bees remains neglected. In this study, we assessed the sublethal effect of both bioinsecticide spinosad and the fertilizer copper sulfate (CuSO₄) on the behavior and gut microbiota in forager adults of the stingless bee Partamona helleri (Friese), which is an important pollinator in the Neotropical region. Behavioral assays and gut microbiota profiles were assessed on bees orally exposed to estimated LC₅ values for spinosad and CuSO₄. The microbiota were characterized through 16S rRNA gene target sequencing. Acute and oral sublethal exposure to spinosad and CuSO₄ did not affect the overall activity, flight take-off, and food consumption. However, CuSO₄ decreased bee respiration rate and copper accumulated in exposed bees. Exposure to spinosad increased the proportional abundance of the genus Gilliamella, but CuSO₄ did not alter the composition of the gut microbiota. In conclusion, sublethal exposure to CuSO₄ induces changes in respiration, and spinosad changes the abundance of gut microorganisms of P. helleri.

Development of the insulin secretion mechanism in fetal and neonatal rat pancreatic B-cells: response to glucose, K+, theophylline, and carbamylcholine

We studied the development of the insulin secretion mechanism in the pancreas of fetal (19- and 21-day-old), neonatal (3-day-old), and adult (90-day-old) rats in response to stimulation with 8.3 or 16.7 mM glucose, 30 mM K+, 5 mM theophylline (Theo) and 200 microM carbamylcholine (Cch). No effect of glucose or high K+ was observed on the pancreas from 19-day-old fetuses, whereas Theo and Cch significantly increased insulin secretion at this age (82 and 127% above basal levels, respectively). High K+ also failed to alter the insulin secretion in the pancreas from 21-day-old fetuses, whereas 8.3 mM and 16.7 mM glucose significantly stimulated insulin release by 41 and 54% above basal levels, respectively. Similar results were obtained with Theo and Cch. A marked effect of glucose on insulin secretion was observed in the pancreas of 3-day-old rats, reaching 84 and 179% above basal levels with 8.3 mM and 16.7 mM glucose, respectively. At this age, both Theo and Cch increased insulin secretion to close to two-times basal levels. In islets from adult rats, 8.3 mM and 16.7 mM glucose, Theo, and Cch increased the insulin release by 104, 193, 318 and 396% above basal levels, respectively. These data indicate that pancreatic B-cells from 19-day-old fetuses were already sensitive to stimuli that use either cAMP or IP3 and DAG as second messengers, but insensitive to stimuli such as glucose and high K+ that induce membrane depolarization. The greater effect of glucose on insulin secretion during the neonatal period indicates that this period is crucial for the maturation of the glucose-sensing mechanism in B-cells.