Solitary Living Brings a Decreased Weight and an Increased Agility to the Domestic Silkworm, Bombyx mori

Regulation of insect behavior by non-coding RNAs

The adaptation of insects to environments relies on a sophisticated set of behaviors controlled by molecular and physiological processes. Over the past several decades, accumulating studies have unveiled the roles of non-coding RNAs (ncRNAs) in regulating insect behaviors. ncRNAs assume particularly pivotal roles in the behavioral plasticity of insects by rapidly responding to environmental stimuli. ncRNAs also contribute to the maintenance of homeostasis of insects by fine-tuning the expression of target genes. However, a comprehensive review of ncRNAs' roles in regulating insect behaviors has yet to be conducted. Here, we present the recent progress in our understanding of how ncRNAs regulate various insect behaviors, including flight and movement, social behavior, reproduction, learning and memory, and feeding. We refine the intricate mechanisms by which ncRNAs modulate the function of neural, motor, reproductive, and other physiological systems, as well as gene expression in insects like fruit flies, social insects, locusts, and mosquitos. Furthermore, we discuss potential avenues for future studies in ncRNA-mediated insect behaviors.

A theoretical approach to improving interspecies welfare comparisons

The number of animals bred, raised, and slaughtered each year is on the rise, resulting in increasing impacts to welfare. Farmed animals are also becoming more diverse, ranging from pigs to bees. The diversity and number of species farmed invite questions about how best to allocate currently limited resources towards safeguarding and improving welfare. This is of the utmost concern to animal welfare funders and effective altruism advocates, who are responsible for targeting the areas most likely to cause harm. For example, is tail docking worse for pigs than beak trimming is for chickens in terms of their pain, suffering, and general experience? Or are the welfare impacts equal? Answering these questions requires making an interspecies welfare comparison; a judgment about how good or bad different species fare relative to one another. Here, we outline and discuss an empirical methodology that aims to improve our ability to make interspecies welfare comparisons by investigating welfare range, which refers to how good or bad animals can fare. Beginning with a theory of welfare, we operationalize that theory by identifying metrics that are defensible proxies for measuring welfare, including cognitive, affective, behavioral, and neuro-biological measures. Differential weights are assigned to those proxies that reflect their evidential value for the determinants of welfare, such as the Delphi structured deliberation method with a panel of experts. The evidence should then be reviewed and its quality scored to ascertain whether particular taxa may possess the proxies in question to construct a taxon-level welfare range profile. Finally, using a Monte Carlo simulation, an overall estimate of comparative welfare range relative to a hypothetical index species can be generated. Interspecies welfare comparisons will help facilitate empirically informed decision-making to streamline the allocation of resources and ultimately better prioritize and improve animal welfare.

Transcriptome Analysis Reveals the Gene Expression Changes in the Silkworm (Bombyx mori) in Response to Hydrogen Sulfide Exposure

Simple Summary

The fat body is one of the most important tissues in the body of insects due to its number of functions. Nowadays the new physiological function of H₂S has gained attention as a novel signaling molecule. H₂S performs crucial regulatory functions involving growth, the cardiovascular system, oxidative stress, and inflammation in many organisms. In this study, RNA-seq technology was used to investigate the fat body of the silkworm at the transcriptional level after H₂S exposure during the 5th larvae stage. A total of 1200 (DEGs) was identified after 7.5 µM H₂S treatment, of which 977 DEGs were up-regulated and 223 DEGs were down-regulated. DEGs were mainly involved in the transport pathway, cellular community, carbohydrate metabolism, and immune-associated signal transduction. Present research provides new insights on the gene expression changes in the fat body of silkworms after H₂S exposure.

Abstract

Hydrogen sulfide (H₂S) has been recognized for its beneficial influence on physiological alterations. The development (body weight) and economic characteristics (cocoon weight, cocoon shell ratio, and cocoon shell weight) of silkworms were increased after continuous 7.5 µM H₂S treatment. In the present study, gene expression changes in the fat body of silkworms at the 5th instar larvae in response to the H₂S were investigated through comparative transcriptome analysis. Moreover, the expression pattern of significant differentially expressed genes (DEGs) at the 5th instar larvae was confirmed by quantitative real-time PCR (qRT-PCR) after H₂S exposure. A total of 1200 (DEGs) was identified, of which 977 DEGs were up-regulated and 223 DEGs were down-regulated. Most of the DEGs were involved in the transport pathway, cellular community, carbohydrate metabolism, and immune-associated signal transduction. The up regulated genes under H₂S exposure were involved in endocytosis, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), and the synthesis of fibroin, while genes related to inflammation were down-regulated, indicating that H₂S could promote energy metabolism, the transport pathway, silk synthesis, and inhibit inflammation in the silkworm. In addition, the expression levels of these genes were increased or decreased in a time-dependent manner during the 5th instar larvae. These results provided insight into the effects of H₂S on silkworms at the transcriptional level and a substantial foundation for understanding H₂S function.