Chao Du

Cantharides, a medicinal insect listed in the Chinese Pharmacopoeia for its anticancer efficacies, faces increasing demand, leading to depletion of wild resources. The larvae's exclusive feeding on locust eggs hindered their large‐scale rearing. This study compared the nutritional profiles and feeding effects of an artificial diet of yellow‐black small cantharides ( Hycleus cichorii Linnaeus 1758) and its natural food, locust eggs, to inform improvements in diet formulation. The analyses revealed that the artificial diet contained significantly higher total sugar but lower crude protein and fat compared to locust eggs. Larvae fed with the artificial diet exhibited reduced survival rates, consumed more food, yet achieved lower body weights at maturity. Although the digestion rate was higher in larvae fed with the artificial diets, their conversion efficiency was notably poorer than that of larvae fed with locust eggs. Mass spectrometry identified 6689 distinct compounds, with 2739 showing significantly lower abundance in the artificial diet than in locust eggs. These diminished compounds were predominantly enriched in metabolism pathways such as sugar and amino acid metabolisms, riboflavin metabolism, and insect hormone synthesis, potentially impacting larval survival, growth, and nutrient utilization. These findings not only provide scientific insights into understanding the specialized feeding mechanisms of cantharides larvae but also offer crucial theoretical guidance for optimizing artificial diet formulations for medicinal cantharides.

Background/Objectives: Pyrrhalta aenescens, a major pest of elm trees, causes extensive ecological and economic damage through rapid population growth and defoliation. Existing research mainly focuses on its biological traits and chemical control, with little knowledge about its reproductive development mechanisms, a key factor in population expansion. In other insects, the steroid hormone 20-hydroxyecdysone (20E) regulates development and reproduction via microRNA (miRNA)-mediated pathways, but this has not been studied in P. aenescens. This study aimed to systematically identify miRNAs responsive to 20E in P. aenescens and unravel their roles in regulating reproduction and metabolic pathways, providing foundational insights into hormone–miRNA crosstalk in this ecologically significant pest. Methods: Adult beetles (collected from Baotou, Inner Mongolia) were injected with 1.0 μg/μL 20E or control. Total RNA from three biological replicates (10 adults each) was sequenced, followed by miRNA identification, differential expression analysis, target prediction, and functional enrichment. Results: Small RNA sequencing identified 205 miRNAs (162 conserved, 43 novel), with 12 DEMs post-20E treatment. Target prediction linked these miRNAs to 7270 genes, including key regulators of the FoxO signaling pathway and MAPK signaling pathway. KEGG analysis highlighted lipid metabolism and stress response pathways. Conclusions: This study revealed that 20E modulates miRNA networks to regulate FoxO and MAPK pathways in P. aenescens, suggesting hormonal control of lipid metabolism and developmental processes. As the first miRNA resource for this pest, our findings provide mechanistic insights into 20E–miRNA crosstalk and identify potential molecular targets for disrupting its reproductive biology, laying a foundation for eco-friendly pest control.

Gut microbiota crucially affects metabolism and health. Hycleus cichorii Linnaeus has been listed as a medicinal insect in the Pharmacopeia of the People's Republic of China due to the presence of cantharidin, which has a curative effect on many cancers and skin diseases. In order to analyze the effects of dietary habits and gender on the diversity and composition of gut microbiota in H. cichorii and provide a basis for an artificial diet, in this study, the full‐length 16S rRNA sequencing technology was used to analyze the gut microbiota of 35 H. cichorii adults, including wild female adults (WFA), wild male adults (WMA), female adults fed with luffa flowers (LFA), male adults fed with luffa flowers (LMA), female adults fed with artificial diet (AFA), and male adults fed with artificial diet (AMA). The results displayed that the major bacterial phyla present in the gut microbiota of the H. cichorii were Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, Teneriicutes, and Actinobacteria. The major bacterial genera were Lactococcus , Lactobacillus , Enterococcus , Ralstonia , Sebaldella , Dysgonomonas , Spiroplasma , Weissella , Klebsiella , and Serratia . Food habits had a significant effect on the diversity and composition of gut microbiota in H. cichorii , whereas gender did not exhibit a remarkable impact on the diversity and composition of gut microbiota. The artificially fed group of H. cichorii had more beneficial microorganisms in the intestine and higher food utilization efficiency. These results provide a basis for subsequent examination of gut microbiota in H. cichorii or other Coleoptera insects, as well as the artificial rearing of blister beetles.

The complete mitochondrial genome of Mylabris sibirica Fischer von Waldheim, 1823 was sequenced and characterized. The mitogenome is 15,794 bp long with 37 annotated genes, comprising 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. The phylogenetic analysis based on the mitochondrial genome sequences revealed that M. sibirica clustered with M. quadripunctata. This study presents the complete mitochondrial genome of M. sibirica for the first time, which could be beneficial for systematic studies on Mylabrini.

Insect gut microbiota and their metabolites play a significant role in the shaping of hosts' diets and feeding habits. We conducted 16S rDNA amplicon sequencing on the gut microbiota of specialist blister beetle larvae that feed on locust eggs and artificial food at different instars, to explore the relationship between gut microbiota and the specialized feeding habit of the blister beetle larvae. There is no significant difference in the gut microbial structure among the second to the fourth instar larvae under the same rearing conditions, but the gut microbial structure of the first instar larvae was significantly different from the second to the fourth instar larvae fed by different diets. Bacteria associated with polysaccharide utilization are relatively barren in first instar larvae. Compared to the carbohydrate content between the artificial diet and locust eggs, we speculate that an excessive amount of polysaccharides in the artificial diet may be detrimental to the growth and development of first instar larvae. Gut microbiota of the second to the fourth instar larvae fed with different diets significantly differ in microbial community structure. The different bacteria, especially the metabolism‐related intestinal bacteria in locust eggs‐fed larvae, may help the hosts adapt to the environment and contribute to the production of active ingredients. The relative abundance of polysaccharide utilization‐related bacteria was significantly higher in the artificial diet‐fed larvae compared to the locust eggs‐fed larvae, which showed the same result when compared to the first instar larvae. Changes in gut microbes of blister beetle larvae and their metabolic inferences could enrich our understanding of the nutritional requirements of the specialist and help optimize the artificial diet of medicinal cantharides.

The giant panda (Ailuropoda melanoleuca) is the epitome of a flagship species for wildlife conservation and also an ideal model of adaptive evolution. As an obligate bamboo feeder, the giant panda relies on the olfaction for food recognition. The number of olfactory receptor (OR) genes and the rate of pseudogenes are the main factors affecting the olfactory ability of animals. In this study, we used the chromosome-level genome of the giant panda to identify OR genes and compared the genome sequences of OR genes with five other Ursidae species (spectacled bear (Tremarctos ornatus), American black bear (Ursus americanus), brown bear (Ursus arctos), polar bear (Ursus maritimus) and Asian black bear (Ursus thibetanus)). The giant panda had 639 OR genes, including 408 functional genes, 94 partial OR genes and 137 pseudogenes. Among them, 222 OR genes were detected and distributed on 18 chromosomes, and chromosome 8 had the most OR genes. A total of 448, 617, 582, 521 and 792 OR genes were identified in the spectacled bear, American black bear, brown bear, polar bear and Asian black bear, respectively. Clustering analysis based on the OR protein sequences of the six species showed that the OR genes distributed in 69 families and 438 subfamilies based on sequence similarity, and the six mammals shared 72 OR gene subfamilies, while the giant panda had 31 unique OR gene subfamilies (containing 35 genes). Among the 35 genes, there are 10 genes clustered into 8 clusters with 10 known human OR genes (OR8J3, OR51I1, OR10AC1, OR1S2, OR1S1, OR51S1, OR4M1, OR4M2, OR51T1 and OR5W2). However, the kind of odor molecules can be recognized by the 10 known human OR genes separately, which needs further research. The phylogenetic tree showed that 345 (about 84.56%) functional OR genes were clustered as Class-II, while only 63 (about 15.44%) functional OR genes were clustered as Class-I, which required further and more in-depth research. The potential odor specificity of some giant panda OR genes was identified through the similarity to human protein sequences. Sequences similar to OR2B1, OR10G3, OR11H6 and OR11H7P were giant panda-specific lacking, which may be related to the transformation and specialization from carnivore to herbivore of the giant panda. Since our reference to flavoring agents comes from human research, the possible flavoring agents from giant panda-specific OR genes need further investigation. Moreover, the conserved motifs of OR genes were highly conserved in Ursidae species. This systematic study of OR genes in the giant panda will provide a solid foundation for further research on the olfactory function and variation of the giant panda.

Sperm whales are a marine mammal famous for the aromatic substance, the ambergris, produced from its colon. Little is known about the biological processes of ambergris production, and this study aims to investigate the genetic mechanism of ambergris production in the sperm whale based on its chromosome-level genome. Comparative genomics analyses found 1207 expanded gene families and 321 positive selected genes (PSGs) in the sperm whale, and functional enrichment analyses suggested revelatory pathways and terms related to the metabolism of steroids, terpenoids, and aldosterone, as well as microbiota interaction and immune network in the intestine. Furthermore, two sperm-whale-specific missense mutations (Tyr393His and Leu567Val) were detected in the PSG LIPE, which has been reported to play vital roles in lipid and cholesterol metabolism. In total, 46 CYP genes and 22 HSD genes were annotated, and then mapped to sperm whale chromosomes. Furthermore, phylogenetic analysis of CYP genes in six mammals found that CYP2E1, CYP51A and CYP8 subfamilies exhibited relative expansion in the sperm whale. Our results could help understand the genetic mechanism of ambergris production, and further reveal the convergent evolution pattern among animals that produce similar odorants.

Lepidoptera (moths and butterflies) are widely distributed in the world, but high-level phylogeny in Lepidoptera remains uncertain. More mitochondrial genome (mitogenome) data can help to conduct comprehensive analysis and construct a robust phylogenetic tree. Here, we sequenced and annotated 17 complete moth mitogenomes and made comparative analysis with other moths. The gene order of trnM-trnI-trnQ in 17 moths was different from trnI-trnQ-trnM of ancestral insects. The number, type, and order of genes were consistent with reported moths. The length of newly sequenced complete mitogenomes ranged from 14,231 bp of Rhagastis albomarginatus to 15,756 bp of Numenes albofascia. These moth mitogenomes were typically with high A+T contents varied from 76.0% to 81.7% and exhibited negative GC skews. Among 13 protein coding genes (PCGs), some unusual initiations and terminations were found in part of newly sequenced moth mitogenomes. Three conserved gene-overlapping regions and one conserved intergenic region were detected among 17 mitogenomes. The phylogenetic relationship of major superfamilies in Macroheterocera was as follows: (Bombycoidea + Lasiocampoidea) + ((Drepanoidea + Geometroidea) + Noctuoidea)), which was different from previous studies. Moreover, the topology of Noctuoidea as (Notodontidae + (Erebidae + Noctuidae)) was supported by high Bayesian posterior probabilities (BPP = 1.0) and bootstrapping values (BSV = 100). This study greatly enriched the mitogenome database of moth and strengthened the high-level phylogenetic relationships of Lepidoptera.

Interspecific competition is an important mechanism of ecological community construction, which potentially contributes to resource differentiation and promotes the coexistence of sympatric species. Determining the food composition and resource differentiation of the whooper swans (Cygnus cygnus) and tundra swans (C. columbianus), can facilitate efforts to protect them. In this study, fecal microscopic analysis was conducted to analyze the feeding habits of whooper swans and tundra swans migrating to the Baotou Yellow River Wetland from February to May 2020; their food niche width and overlap were calculated, and the following results were obtained. The whooper swan’s diet consisted of nine species from four families of plants, mainly corn (Zea mays), reed (Phragmites australis), and halophytes (Suaeda glauca). The diet of the tundra swan comprised eleven species from five families of plants, mainly corn, quinoa (Chenopodium album) and millet (Panicum miliaceum). The food niche widths of the whooper swan and tundra swan in the Yellow River Wetland in Baotou were 2.75 and 5.18, respectively. There were five main species of food plants in total, and the index of niche overlap was 0.65. The food diversity of the tundra swan was greater than that of the whooper swan, indicating that the Yellow River wetland provides relatively diverse food resources for the tundra swans and whooper swans, thereby reducing competition and facilitating coexistence.