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Lobopodians represent a key step in the early history of ecdysozoans since they were the first animals to evolve legs within this clade. Their Cambrian representatives share a similar body plan with a typically cylindrical annulated trunk and a series of non-jointed legs. However, they do not form a monophyletic group and likely include ancestors of the three extant panarthropod lineages (Tardigrada, Onychophora, Euarthropoda). Some species display astonishing protective devices such as cuticular plates and spines. We describe here the armor and molting process of Microdictyon from the early Cambrian of China. Microdictyon secreted ovoid paired cuticular sclerites that were duplicated in a non-synchronous way along the animal's body. The reticulated pattern and cuticular architecture of these sclerites have similarities to extant armored tardigrades that recently served in hypothesizing that tardigrades are possibly miniaturized lobopodians. Ecdysis and hard cuticular protection are now well documented in the whole spectrum of early Cambrian ecdysozoans such as soft-bodied scalidophorans, lobopodians and fully articulated euarthropods. We hypothesize that the secretion of sclerotized cuticular elements periodically renewed via ecdysis was a key innovation that opened large-scale evolutionary opportunities to invertebrate animal life, specifically ecdysozoans, both in terms of anatomical functionalities and ecological success., (© 2024. The Author(s).)

Feather moulting is a crucial process in the avian life cycle, which evolved to maintain plumage functionality. However, moulting involves both energetic and functional costs. During moulting, plumage function temporarily decreases between the shedding of old feathers and the full growth of new ones. In flying taxa, a gradual and sequential replacement of flight feathers evolved to maintain aerodynamic capabilities during the moulting period. Little is known about the moult strategies of non-avian pennaraptoran dinosaurs and stem birds, before the emergence of crown lineage. Here, we report on two Early Cretaceous pygostylian birds from the Yixian Formation (125 mya), probably referable to Confuciusornithiformes, exhibiting morphological characteristics that suggest a gradual and sequential moult of wing flight feathers. Short primary feathers interpreted as immature are symmetrically present on both wings, as is typical among extant flying birds. Our survey of the enormous collection of the Tianyu Museum confirms previous findings that evidence of active moult in non-neornithine pennaraptorans is rare and likely indicates a moult cycle greater than one year. Documenting moult in Mesozoic feathered dinosaurs is critical for understanding their ecology, locomotor ability and the evolution of this important life-history process in birds.

Since January 2019, abnormal molting has been observed frequently in approximately 40-day-old Pekin ducks in China. To investigate the possible involvement of a virus, we tested the prevalence of duck circovirus (DuCV), goose hemorrhagic polyomavirus (GHPyV), and goose parvovirus (GPV) in 11 molt cases in two provinces. GPV was detected in all cases, particularly in all samples collected from the feather area. The complete genome sequences of three GPV strains were determined and found to have 52 nucleotide changes relative to GPVs associated with short beak and dwarfism syndrome of Pekin ducks. These data will enhance our understanding of GPV diversity and outcomes of GPV infection in Pekin ducks.

Background: Molting is a critical developmental process for crustaceans, during which the claw muscles undergo periodic atrophy and restoration. But the mechanism underlying this special muscle reshuffle around ecdysis is not yet thoroughly understood., Objective: To investigate the molecular mechanism underlying the muscle's reshuffle over the molting cycle of Chinese mitten crab Eriocheir sinensis., Methods: The Illumina high-throughput sequencing technique were used to sequence the transcriptome of the whole claw muscles from Chinese mitten crab Eriocheir sinensis in three molting stages (inter-molt C stage, pre-molt D 3-4 and post-molt A-B stage); the de novo assembly, annotation and functional evaluation of the contigs were performed with bioinformatics tools., Results: Totally 129,149 unigenes, 128,190 CDS, 33,770 SSRs and a large number of SNP sites were obtained, and 3700 and 12,771 differentially expressed genes (DEGs) were identified respectively in A-B and D 3-4 stage compared with that in C stage. The identified DEGs were enriched to 746 and 1 408 GO terms respectively in A-B and D 3-4 stage compared with C stage (p ≤ 0.05). KEGG pathway analysis showed that the DEGs were significantly enriched in 14 and 11 pathways in A-B vs C comparison and D 3-4 vs C comparison (p ≤ 0.05), respectively. These DEGs are involved in several biological processes critical for the animal's growth and development, such as gene expression, protein synthesis, muscle development, new cuticle reconstruction, oxidation-reduction process and glycolytic process., Conclusion: The data generated in this study is the first transcriptomic resource from the muscles of Chinese mitten crab, which would facilitate to characterize key molecular processes underlying crab muscle's growth and development during the molting cycles.

Daily distributions of eclosion and mating activities of Pseudopidorus fasciata Walker (Lepidoptera: Zygaenidae) were recorded under natural and various laboratory conditions. Eclosion of this insect exhibited circadian gating in constant darkness (DD) but not in constant light (LL) at 28°C. Under natural conditions, the majority of adults emerged in midmorning with an eclosion peak around 1000 hours. The eclosion distribution was significantly affected by ambient temperature but not by photoperiod under laboratory conditions. Eclosion was more spread out at 22°C than at higher temperatures, and peak eclosion times were advanced at higher temperatures up to 30°C. Under natural and laboratory diurnal cycles, adults of P. fasciata preferred to mate at dusk, within a few hours before the start of the scotophase. Photoperiod and ambient temperature interacted in regulating the mating distribution in P. fasciata. Mating rhythmicity disappeared under DD and LL, under which the insect either mated arrhythmically (DD) or barely mated (LL). Overall, eclosion rhythm in this insect was predominantly regulated by temperature rather than photoperiod, whereas photoperiod appeared to be more influential than temperature in rhythmic gate of mating patterns.

Previous studies indicate most free-living avian species in both extreme and temperate environments seasonally modulate the adrenocortical responses to acute stress, and those breeding in harsh environments always express reduced adrenocortical responses, which may allow them to obtain maximal reproductive success. However, recent investigations showing a human commensal species, house sparrows (Passer domesticus), expressed similar corticosterone (CORT) responses in both benign and harsh environments. In this study, focusing on another human commensal species, Eurasian tree sparrows (P. montanus), we examined the adrenocortical response to acute stress in lowland populations, among the early and late breeding, the prebasic molt, and the wintering stages, and compared them with previously published data from populations on the Tibetan Plateau. Our results show: (1) similar to highland Eurasian tree sparrows, lowland populations show no differences in baseline CORT levels among life history stages, and the stress-induced CORT (maximal CORT, total and corrected integrated CORT) levels are lower during the early breeding and the prebasic molt stages than those in the late breeding and the wintering stages; (2) highland Eurasian tree sparrows show stronger adrenocortical responses during the prebasic molt stage than lowland populations, whereas there are no differences between the early and the breeding stages (except for maximal CORT). Our results suggest that Eurasian tree sparrows from both harsh and benign environments have similar patterns of adrenocortical responses in the breeding stage, whereas they are different in the prebasic molt stage. In highland birds, the increased maximal CORT levels during the late breeding and the small increases in adrenocortical responses during the prebasic molt are interesting but remain unexplained., (© 2011 Wiley Periodicals, Inc.)