Reproductive biology of subterranean crustaceans is influenced by environmental conditions, hydrological dynamics and water availability. Potiberaba porakuara is a troglobitic amphipod endemic to limestone aquifers of the Brazilian semiarid Caatinga, where periodic droughts may drastically reduce or completely dry subterranean habitats. Since its first record in 2007, only ovigerous females have been observed, suggesting possible alternative reproductive mechanisms. We experimentally evaluated the effects of water-level variation on the reproductive dynamics of P. porakuara under controlled laboratory conditions. During a 30-day desiccation experiment, water volume was gradually reduced while oviposition was monitored daily. Egg deposition began shortly after water reduction and increased progressively as water availability declined, stabilising around day 25, indicating a physiological limit to reproductive output. Complementary hatching assays showed that eggs deposited on the substrate remained viable and hatched rapidly following rehydration after 30-day dry period, demonstrating resistance to desiccation. These findings indicate that hydrological fluctuations strongly influence reproduction in P. porakuara, suggesting that oviposition synchronised with drought and desiccation-resistant eggs are key adaptations for persistence in temporary subterranean habitats, mainly in semiarid conditions as in the Caatinga.
In the fruit fly, Drosophila melanogaster, a relatively uncharacterized developmental timepoint termed the mid-third instar transition (MIT) occurs during the third and final larval stage. While there are no obvious morphological changes that occur during the MIT, widespread changes in gene expression are thought to prepare the organism to enter metamorphosis. How these massive changes in gene expression are regulated and how they alter larval behaviour and physiology are unclear. Here, we examine tissue and developmental stage-specific transcriptome data generated as part of the ModEnCODE project to better understand how changes in gene expression at the MIT alter physiology in preparation for metamorphosis. Analysis of enriched binding motifs suggests that regulation of MIT genes is complex but is likely mediated, at least in part, by ecdysone. Our results also suggest that gene expression changes at the MIT likely prepare the larva for metamorphosis in numerous ways, including altering metabolism to help meet energetic demands, increasing glue protein production allowing pupae to adhere to surfaces and preparing the immune system to control the spread of microbes during histolysis of larval tissues. At the same time, changes in imaginal tissues support the proliferation and differentiation of cells characteristic of the metamorphic moult.
Studying the morphology of the male reproductive system is crucial for understanding the reproductive biology of insects, particularly pest species. This study aimed to characterize the male reproductive system of the strawberry beetle pest Coraebus elatus (Fabricius, 1787) using light and scanning electron microscopies. The results revealed that each testis contains six testis follicles, each displaying distinct stages of differentiation of germ cells. Fully developed sperm pass through the vas deferentia, lined with a single-layer cuboidal epithelium and a muscle layer. While the wall of the tubular accessory glands is lined with a single-layered cuboidal epithelium, the wall of the bean-shaped spermatophoral glands is surrounded by a pseudostratified columnar epithelium. These glands open into the ejaculatory duct which is surrounded by a single-layer cylindrical epithelium and a muscle layer. This study provides valuable data that will serve as a foundation for future research on the morphology and systematic.
