The oviposition preference and offspring performance of Aethina tumida (Coleoptera: Nitidulidae).

Given the rapid spread and potential harm caused by the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae) in China, it has become imperative to comprehend the developmental biology of this invasive species. Currently, there is limited knowledge regarding the impact of A. tumida female oviposition site preference on larval growth and development. To examine this, we investigated the ovipositional preference of adult female A. tumida on bee pupae, beebread, banana, and honey through a free choice test. Furthermore, we assessed the impact of these food resources on offspring performance, which included larval development time, survival, wandering larvae weight, emerged adult body mass, reproduction, and juvenile hormone titer. Our results showed that A. tumida females exhibited a strong preference for ovipositing on bee pupae compared to other diets, while showing reluctance toward honey. Moreover, A. tumida larvae that were fed on bee pupae displayed accelerated growth compared to those fed on other diets. Furthermore, A. tumida fed on bee pupae exhibited higher weights for wandering larvae, and emerged adult, increased pupation rates, enhanced fecundity and fertility, as well as a larger number of unilateral ovarioles during the larval stage when compared to those fed on other diets. Overall, the results indicate that the oviposition preferences of A. tumida females are adaptive, as their choices can enhance the fitness of their offspring. This finding aligns broadly with the hypothesis of oviposition preference and larval performance. This study can provide a foundation for the development of attractants aimed at promoting the oviposition of the A. tumida adults.

Xylocopa caerulea and Xylocopa auripennis harbor a homologous gut microbiome related to that of eusocial bees.

Background: Eusocial bees, such as bumblebees and honey bees, harbor host-specific gut microbiota through their social behaviors. Conversely, the gut microbiota of solitary bees is erratic owing to their lack of eusocial activities. Carpenter bees (genus Xylocopa) are long-lived bees that do not exhibit advanced eusociality like honey bees. However, they often compete for nests to reproduce. Xylocopa caerulea and Xylocopa auripennis are important pollinators of wild plants on Hainan Island. Whether they have host-specific bacteria in their guts similar to eusocial bees remains unknown. Methods: We targeted the bacterial 16S rRNA V3-V4 region to investigate the diversity of bacterial symbionts in the fore-midgut and hindgut of two carpenter bees, X. caerulea and X. auripennis. Results: A maximum of 4,429 unique amplicon sequence variants (ASVs) were detected from all samples, belonging to 10 different phyla. X. caerulea and X. auripennis shared similar bacterial community profiles, with Lactobacillaceae, Bifidobacteriaceae, and Orbaceae being dominant in their entire guts. X. caerulea and X. auripennis harbor a highly conserved core set of bacteria, including the genera Candidatus Schmidhempelia and Bombiscardovia. These two bacterial taxa from carpenter bees are closely related to those isolated from bumblebees. The LEfSe analysis showed that Lactobacillaceae, Bifidobacteriaceae, and the genus Bombilactobacillus were significantly enriched in the hindguts of both carpenter bees. Functional prediction suggested that the most enriched pathways were involved in carbohydrate and lipid metabolism. Conclusions: Our results revealed the structure of the gut microbiota in two carpenter bees and confirmed the presence of some core bacterial taxa that were previously only found in the guts of social bees.

Gut microbiota composition and gene expression changes induced in the Apis cerana exposed to acetamiprid and difenoconazole at environmentally realistic concentrations alone or combined.

Apis cerana is an important pollinator of agricultural crops in China. In the agricultural environment, A. cerana may be exposed to acetamiprid (neonicotinoid insecticide) and difenoconazole (triazole fungicide), alone or in combination because they are commonly applied to various crops. At present, our understanding of the toxicological effects of acetamiprid and difenoconazole on honey bee gut microbiomes is limited. The primary objective of this study was to explore whether these two pesticides affect honey bees' gut microbiota and to analyze the transcriptional effects of these two pesticides on honey bees' head and gut. In this study, adults of A. cerana were exposed to acetamiprid and/or difenoconazole by contaminated syrup at field-realistic concentrations for 10 days. Results indicated that acetamiprid and/or difenoconazole chronic exposure did not affect honey bees' survival and food consumption, whereas difenoconazole decreased the weight of honey bees. 16S rRNA sequencing suggested that difenoconazole and the mixture of difenoconazole and acetamiprid decreased the diversity index and shaped the composition of gut bacteria microbiota, whereas acetamiprid did not impact the gut bacterial community. The ITS sequence data showed that neither of the two pesticides affected the fungal community structure. Meanwhile, we also observed that acetamiprid or difenoconazole significantly altered the expression of genes related to detoxification and immunity in honey bees' tissues. Furthermore, we observed that the adverse effect of the acetamiprid and difenoconazole mixture on honey bees' health was greater than that of a single mixture. Taken together, our study demonstrates that acetamiprid and/or difenoconazole exposure at field-realistic concentrations induced changes to the honey bee gut microbiome and gene expression.

Bioactive characterization of multifloral honeys from Apis cerana cerana, Apis dorsata, and Lepidotrigona flavibasis.

Honey is a complex food product, and has been linked to a number of substantial health advantages. The aim of this study was to assess the phenolic compounds, organic acids, microbial community, antioxidant activity, and antimicrobial activity of multifloral honeys produced by Apis cerana cerana, A. dorsata, and Lepidotrigona flavibasis in Hainan province, China. Our results illustrated that chlorogenic acid was the major phenolic component in all honeys. L. flavibasis honey showed the greatest antioxidant activity (DPPH IC50 value, 7.66 mg/mL; FRAP value, 5217.06 µmol TE/kg), as well as the highest levels of proline (548.64 mg/kg), total flavonoid (11.67 mg QE/100 g), total phenolic (132.73 mg GAE/100 g), and Lactobacillus (96.28 %). Besides, all honeys were found to have a broad spectrum of antibacterial activity. Overall, our data imply that Hainan honeys, particularly stingless bee honeys, have been beneficial components of human diets.

Complete mitochondrial genome of the stingless bee Lepidotrigona terminata (Hymenoptera: Meliponinae) and phylogenetic analysis.

Lepidotrigona terminata (Smith, 1878) is a stingless bee that distributed in Eastern Asia. The complete mitogenome of L. terminata (GenBank accession number MN737481) is 15,431 bp in size, including 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs genes, and a noncoding D-loop region. The D-loop region is located between ND4L and tRNAMet, different from the other two stingless bee mitogenomes previously reported. The base composition of the whole L. terminata mitogenome is 38.18% for A, 11.67% for G, 38.32% for T, and 11.83% for C, with a high AT bias of 76.50%. The present data could contribute to a detailed phylogeographic analysis of this valuable economic insect for further study in differentiating closely related species.

Chronic toxicity and biochemical response of Apis cerana cerana (Hymenoptera: Apidae) exposed to acetamiprid and propiconazole alone or combined.

Acetamiprid and ergosterol-inhibiting fungicide (EBI) are frequently applied to many flowering plants, while honey bees are pollinating agents or pollinators of the flowers. Hence honey bees are often exposed to these pesticides. But until now, the effects of theses combinations at field-realistic doses on honey bee health have been poorly investigated. In this study, we explore the synergistic mortality and some physiological effects in surviving honey bees after chronic oral exposure to acetamiprid and/or propiconazole in the laboratory. The results indicated that chronic combined exposure to acetamiprid and propiconazole produced a significant synergistic effect on mortality both for newly emerged bees (50% mortality in 7.2 days) and forager bees (50% mortality in 4.8 days). Honey bee weight of newly emerged bees was decreased after feeding food with a field concentration of acetamiprid and propiconazole, alone or combined for 10 days. Combination of acetamiprid and propiconazole also modulated the activities of P450s, GST and CAT in newly emerged bees and forager bees than either alone, but neither pesticide affected the activity of AChE. These results show that chronic combined exposure to pesticides of relatively low toxicity may caused severely physiological disruptions that could be potentially damaging for the honey bees.

Acute toxicity and sublethal effects of myclobutanil on respiration, flight and detoxification enzymes in Apis cerana cerana.

Myclobutanil is currently used on the flowering plants. Little is known about how Apis cerana cerana respond to myclobutanil exposure. Hence, the acute toxicity of myclobutanil and its sublethal effects on respiration, flight and detoxification enzymes [7-ethoxycoumarin O-deethylase (ECOD) and glutathione S-transferases (GSTs)] in A. cerana cerana were investigated. The results indicated that formulation grade myclobutanil showed moderate toxicity to A. cerana cerana either contact (LD50=4.697µg/bee) or oral (LD50=2.154µg/bee) exposure. Sublethal dose of myclobutanil significantly reduced the respiration rate of workers at 24h and 48h regardless of the exposure method. However, myclobutanil didn't significantly affect the take-off flight. After nurse bees exposure to the dose (LD5) of formulation-grade myclobutanil, ECOD activity was significantly induced when compared with control, but GST activity didn't change. In the forager bees, no enzyme markers response was obtained in this test. From the present study we can infer that myclobutanil disturb respiration and P450-mediated detoxification of the individual bees of A. cerana cerana. Thus, myclobutanil may has risk for A. cerana cerana, it should be cautiously used.

Six new Chinese species of the Pachyprotasis melanosoma group (Hymenoptera: Tenthredinidae) with a key to the species.

The Pachyprotasis melanosoma group is defined as a part of the former P. rapae group, and a key to this species of this group from China is provided. Six new species from China are described in this paper: P. coximaculata Zhong & Wei, sp. n.; P. coxipunctata Zhong & Wei, sp. n.; P. hengshani Zhong & Wei, sp. n.; P. maculoscutellata Zhong & Wei, sp. n.; P. pailongensis Zhong & Wei, sp. n. and P. qilianica Zhong & Wei, sp. n. 

[Effects of temperature on Brontispa longissima population growth].

The study on the development, survival and reproduction of Brontispa longissima at 5 different temperature (16, 20, 24, 28, 32 degrees C) showed that the threshold temperature and effective accumulative temperature for the whole generations of Brontispa longissima were 11.08 degrees C and 966.22 degrees C, respectively, and 4-5 generations could occur in a year in Danzhou, Hainan Province. One generation had the highest survival rate (92.5%) at 28 degrees C, but failed to survive at 32 degrees C. Brontispa longissimna reared at 28 degrees C had the greatest intrinsic increasing rate (r(m) = 0.0260), finite increasing capacity (lamda = 1.0263), and population trend index (I = 50.8). The shortest mean generation time (123.1 d) and population doubling time (26.7 d) were obtained at 20 degrees C and 28 degrees C, respectively. The temperature from 24 degrees C to 28 degrees C was suitable for the development and reproduction of Brontispa longissima.