Genome-wide analysis reveals transcriptional and translational changes during diapause of the Asian corn borer (Ostrinia furnacalis).

BACKGROUND: Diapause, a pivotal phase in the insect life cycle, enables survival during harsh environmental conditions. Unraveling the gene expression profiles of the diapause process helps uncover the molecular mechanisms that underlying diapause, which is crucial for understanding physiological adaptations. In this study, we utilize RNA-seq and Ribo-seq data to examine differentially expressed genes (DEGs) and translational efficiency during diapause of Asian corn borer (Ostrinia furnacalis, ACB). RESULTS: Our results unveil genes classified as "forwarded", "exclusive", "intensified", or "buffered" during diapause, shedding light on their transcription and translation regulation patterns. Furthermore, we explore the landscape of lncRNAs (long non-coding RNAs) during diapause and identify differentially expressed lncRNAs, suggesting their roles in diapause regulation. Comparative analysis of different types of diapause in insects uncovers shared and unique KEGG pathways. While shared pathways highlight energy balance, exclusive pathways in the ACB larvae indicate insect-specific adaptations related to nutrient utilization and stress response. Interestingly, our study also reveals dynamic changes in the HSP70 gene family and proteasome pathway during diapause. Manipulating HSP protein levels and proteasome pathway by HSP activator or inhibitor and proteasome inhibitor affects diapause, indicating their vital role in the process. CONCLUSIONS: In summary, these findings enhance our knowledge of how insects navigate challenging conditions through intricate molecular mechanisms.

Evaluation of the effect of clonazepam and its metabolites on the life cycle of Megaselia scalaris (Loew) (Diptera: Phoridae).

Fly colonization patterns and development are crucial in estimating the post-mortem interval (PMI) of decomposing corpses. Understanding the potential effects of xenobiotics on species development in cadaveric entomofauna is essential for accurate PMI estimation, given their presence in decomposing bodies. Benzodiazepines, commonly prescribed for their anxiolytic, hypnotic, and muscle relaxant effects, are of forensic interest due to their potential for abuse, dependence, intoxication, and overdose-related deaths. This study aimed to explore the effect of clonazepam and its metabolites on Megaselia scalaris, a species commonly used to estimate PMI, the alteration of which could impact the accuracy of said estimation. The S9 biotransformation fraction, an in vitro model consisting of an array of metabolic enzymes, was used to generate phase I and II metabolites for evaluating their effect on M. scalaris development, representing an innovative approach to this type of study. Megaselia scalaris larvae were reared in synthetic growth media under controlled conditions. The study compared different groups: control, clonazepam, and clonazepam with S9 fraction. Larvae were measured daily to determine growth rate, and clonazepam concentrations were analyzed using HPLC-DAD. Results showed that larvae grown in media containing clonazepam or clonazepam with S9 fraction developed faster than control larvae, reaching their pupal stage earlier. Growth rates were also altered in treated groups. In conclusion, the presence of clonazepam and its metabolites accelerated the life cycle of M. scalaris, potentially impacting the accuracy of PMI estimation. These findings underscore the importance of considering xenobiotics in forensic entomological studies for precise post-mortem interval determination.

The irregular developmental duration mainly caused by the broad-complex in Chilo suppressalis.

Chilo suppressalis, a critical rice stem borer pest, poses significant challenges to rice production due to its overlapping generations and irregular developmental duration. These characteristics complicate pest management strategies. According to the dynamic analysis of the overwintering adults of C. suppressalis in fields, it indicates that the phenomenon of irregular development of C. suppressalis exists widely and continuously. This study delves into the potential role of the Broad-Complex (Br-C) gene in the developmental duration of C. suppressalis. Four isoforms of Br-C, named CsBr-C Z1, CsBr-C Z2, CsBr-C Z4, and CsBr-C Z7, were identified. After CsBr-Cs RNAi, the duration of larva development spans extended obviously. And, the average developmental duration of dsCsBr-Cs feeding individuals increased obviously. Meanwhile, the average developmental duration of the dsCsBr-C Z2 feeding group was the longest among all the RNAi groups. After dsCsBr-Cs feeding continuously, individuals pupated at different instars changed obviously: the proportion of individuals pupated at the 5th instar decreased and pupated at the 7th instar or higher increased significantly. Moreover, the pupation rate of dsCsBr-Cs (except dsCsBr-C Z7) were significantly lower than that of dsGFP. The same results were obtained from the mutagenesis in CsBr-C genes mediated by CRISPR/Cas9. The average developmental duration of CsBr-Cs knockout individuals was significantly prolonged. And, the instar of pupation in knockout individuals was also delayed significantly. In conclusion, this work showed that CsBr-Cs played a crucial role in pupal commitment and affected the developmental duration of C. suppressalis significantly.

The adult shell matrix protein repertoire of the marine snail Crepidula is dominated by conserved genes that are also expressed in larvae.

Mollusca is a morphologically diverse phylum, exhibiting an immense variety of calcium carbonate structures. Proteomic studies of adult shells often report high levels of rapidly-evolving, 'novel' shell matrix proteins (SMPs), which are hypothesized to drive shell diversification. However, relatively little is known about the phylogenetic distribution of SMPs, or about the function of individual SMPs in shell construction. To understand how SMPs contribute to shell diversification a thorough characterization of SMPs is required. Here, we build tools and a foundational understanding of SMPs in the marine gastropod species Crepidula fornicata and Crepidula atrasolea because they are genetically-enabled mollusc model organisms. First, we established a staging system of shell development in C. atrasolea for the first time. Next, we leveraged previous findings in C. fornicata combined with phylogenomic analyses of 95 metazoan species to determine the evolutionary lineage of its adult SMP repertoire. We found that 55% of C. fornicata's SMPs belong to molluscan orthogroups, with 27% restricted to Gastropoda, and only 5% restricted at the species level. The low percentage of species-restricted SMPs underscores the importance of broad-taxon sampling and orthology inference approaches when determining homology of SMPs. From our transcriptome analysis, we found that the majority of C. fornicata SMPs that were found conserved in C. atrasolea were expressed in both larval and adult stages. We then selected a subset of SMPs of varying evolutionary ages for spatial-temporal analysis using in situ hybridization chain reaction (HCR) during larval shell development in C. atrasolea. Out of the 18 SMPs analyzed, 12 were detected in the larval shell field. These results suggest overlapping larval vs. adult SMP repertoires. Using multiplexed HCR, we observed five SMP expression patterns and three distinct cell populations within the shell field. These patterns support the idea that modular expression of SMPs could facilitate divergence of shell morphological characteristics. Collectively, these data establish an evolutionary and developmental framework in Crepidula that enables future comparisons of molluscan biomineralization to reveal mechanisms of shell diversification.

Mesocosm Studies Suggest Climate Change May Release Aedes aegypti (Diptera: Culicidae) Larvae from Cold Inhibition and Enable Year-Round Development in a Desert City.

AbstractGlobal warming trends, human-assisted transport, and urbanization have allowed poleward expansion of many tropical vector species, but the specific mechanisms responsible for thermal mediation of range changes and ecological success of invaders remain poorly understood. Aedes aegypti (Diptera: Culicidae) is a tropical mosquito currently expanding into many higher-latitude regions, including the urban desert region of Maricopa County, Arizona. Here, adult populations virtually disappear in winter and spring and then increase exponentially through summer and fall, indicating that winter conditions remain a barrier to the development of some life stages of A. aegypti. To determine whether cold limits the winter development of A. aegypti larvae in Maricopa County, we surveyed for larval abundance and tested their capacity to develop in ambient and warmed conditions. Aedes aegypti larvae were not observed in artificial aquatic habitats in winter and spring but were abundant in summer and fall, suggesting winter suppression of adults, larvae, or both. Water temperatures in winter months fluctuated strongly; larvae were usually cold paralyzed at night but active during the day. Despite daytime temperatures that allowed activity and achieving similar degree-days as warmed mesocosms, larvae reared under ambient winter conditions were unable to develop to adulthood, perhaps due to repetitive cold damage. However, warming average temperature by 1.7°C allowed many larvae to successfully develop to adults. Because daytime highs in winter will often allow adult flight, it is likely that relatively minor additional winter warming may allow A. aegypti populations to develop and reproduce year-round in Maricopa County.

Effects of the El Niño-Southern Oscillation and seasonal weather conditions on Aedes aegypti infestation in the State of São Paulo (Brazil): A Bayesian spatio-temporal study.

BACKGROUND: Seasonal fluctuations in weather are recognized as factors that affect both Aedes (Ae.) aegypti mosquitoes and the diseases they carry, such as dengue fever. The El Niño-Southern Oscillation (ENSO) is widely regarded as one of the most impactful atmospheric phenomena on Earth, characterized by the interplay of shifting ocean temperatures, trade wind intensity, and atmospheric pressure, resulting in extensive alterations in climate conditions. In this study, we investigate the influence of ENSO and local weather conditions on the spatio-temporal variability of Ae. aegypti infestation index. METHODS: We collected seasonal entomological survey data of immature forms of Ae. aegypti mosquitoes (Breteau index), as well as data on temperature, rainfall and the Oceanic Niño Index (ONI) for the period 2008-2018 over the 645 municipalities of the subtropical State of São Paulo (Brazil). We grounded our analytical approach on a Bayesian framework and we used a hierarchical spatio-temporal model to study the relationship between ENSO tracked by ONI, seasonal weather fluctuations and the larval index, while adjusting for population density and wealth inequalities. RESULTS: Our results showed a relevant positive effect for El Niño on the Ae. aegypti larval index. In particular, we found that the number of positive containers would be expected to increase by 1.30-unit (95% Credible Intervals (CI): 1.23 to 1.37) with El Niño events (i.e., ≥ 1°C, moderate to strong) respect to neutral (and weak) events. We also found that seasonal rainfall exceeding 153.12 mm appears to have a notable impact on vector index, leading potentially to the accumulation of ample water in outdoor discarded receptacles, supporting the aquatic phase of mosquito development. Additionally, seasonal temperature above 23.30°C was found positively associated to the larval index. Although the State of São Paulo as a whole has characteristics favourable to proliferation of the vector, there were specific areas with a greater tendency for mosquito infestation, since the most vulnerable areas are predominantly situated in the central and northern regions of the state, with hot spots of abundance in the south, especially during El Niño events. Our findings also indicate that social disparities present in the municipalities contributes to Ae. aegypti proliferation. CONCLUSIONS: Considering the anticipated rise in both the frequency and intensity of El Niño events in the forthcoming decades as a consequence of climate change, the urgency to enhance our ability to track and diminish arbovirus outbreaks is crucial.

Gut fungal diversity across different life stages of the onion fly Delia antiqua.

A significant number of microorganisms inhabit the intestinal tract or the body surface of insects. While the majority of research on insect microbiome interaction has mainly focused on bacteria, of late multiple studies have been acknowledging the importance of fungi and have started reporting the fungal communities as well. In this study, high-throughput sequencing was used to compare the diversity of intestinal fungi in Delia antiqua (Diptera: Anthomyiidae) at different growth stages, and effect of differential fungi between adjacent life stages on the growth and development of D. antiqua was investigated. The results showed that there were significant differences in the α and ß diversity of gut fungal communities between two adjacent growth stages. Among the dominant fungi, genera Penicillium and Meyerozyma and family Cordycipitaceae had higher abundances. Cordycipitaceae was mainly enriched in the pupal and adult (male and female) stages, Penicillium was mainly enriched in the pupal, 2nd instar and 3rd instar larval stages, and Meyerozyma was enriched in the pupal stage. Only three fungal species were found to differ between two adjacent growth stages. These three fungal species including Fusarium oxysporum, Meyerozyma guilliermondii and Penicillium roqueforti generally inhibited the growth and development of D. antiqua, with only P. roqueforti promoting the growth and development of female insects. This study will provide theoretical support for the search for new pathogenic microorganisms for other fly pests control and the development of new biological control strategies for fly pests.

Slc4a7 Regulates Retina Development in Zebrafish.

Inherited retinal degenerations (IRDs) are a group of genetic disorders characterized by the progressive degeneration of retinal cells, leading to irreversible vision loss. SLC4A7 has emerged as a candidate gene associated with IRDs, yet its mechanisms remain largely unknown. This study aims to investigate the role of slc4a7 in retinal development and its associated molecular pathogenesis in zebrafish. Morpholino oligonucleotide knockdown, CRISPR/Cas9 genome editing, quantitative RT-PCR, eye morphometric measurements, immunofluorescent staining, TUNEL assays, visual motor responses, optokinetic responses, rescue experiments, and bulk RNA sequencing were used to assess the impact of slc4a7 deficiency on retinal development. Our results demonstrated that the knockdown of slc4a7 resulted in a dose-dependent reduction in eye axial length, ocular area, and eye-to-body-length ratio. The fluorescence observations showed a significant decrease in immunofluorescence signals from photoreceptors and in mCherry fluorescence from RPE in slc4a7-silenced morphants. TUNEL staining uncovered the extensive apoptosis of retinal cells induced by slc4a7 knockdown. Visual behaviors were significantly impaired in the slc4a7-deficient larvae. GO and KEGG pathway analyses reveal that differentially expressed genes are predominantly linked to aspects of vision, ion channels, and phototransduction. This study demonstrates that the loss of slc4a7 in larvae led to profound visual impairments, providing additional insights into the genetic mechanisms predisposing individuals to IRDs caused by SLC4A7 deficiency.

Development of germline progenitors in larval queen honeybee ovaries.

Honeybees (Apis mellifera) are a keystone species for managed pollination and the production of hive products. Eusociality in honeybees leads to much of the reproduction in a hive driven by the queen. Queen bees have two large active ovaries that can produce large numbers of eggs if conditions are appropriate. These ovaries are also active throughout the long lives of these insects, up to 5 years in some cases. Recent studies have indicated that the germline precursors of the adult honeybee queen ovary are organized into 8-cell clusters, joined together by a polyfusome; a cytoplasmic bridge. To understand the origin of these clusters, and trace the development of the honeybee queen ovary, we examined the cell types and regionalization of the developing larval and pupal queen ovaries. We used established (nanos and castor), and novel (odd skipped) gene expression markers to determine regions of the developing ovary. Primordial germline cells develop in the honeybee embryo and are organized into ovary structures before the embryo hatches. The ovary is regionalized by larval stage 3 into terminal filaments and germaria. At this stage, clusters of germline cells in the germaria are joined by fusomes and are dividing synchronously. The origin of the 8-cell clusters in the adult germarium is therefore during larval stages. On emergence, the queen ovary has terminal filaments and germaria but has not yet developed any vitellaria, which are produced after the queen embarks on a nuptial flight. The lack of germaria, and the storing of germline progenitors as clusters, may be adaptions for queen bees to endure the metabolic demands of a nuptial flight, as well as rapidly lay large numbers of eggs to establish a hive.

Selenium Treatment Ameliorates the Adverse Effects Caused by Dynamin Gene Knockdown in Bombyx mori.

Our previous research reported the influence of 50 µM selenium (Se) on the cytosolization (endocytosis) pathway, which in turn stimulates the growth and development of Bombyx mori. Lately, dynamin is recognized as one of the key proteins in endocytosis. To explore the underlying mechanisms of Se impact, the dynamin gene was knocked down by injecting siRNAs (Dynamin-1, Dynamin-2, and Dynamin-3). This was followed by an analysis of the target gene and levels of silk protein genes, as well as growth and developmental indices, Se-enrichment capacity, degree of oxidative damage, and antioxidant capacity of B. mori. Our findings showed a considerable decrease in the relative expression of the dynamin gene in all tissues 24 h after the interference and a dramatic decrease in the silkworm body after 48 h. RNAi dynamin gene decreased the silkworm body weight, cocoon shell weight, and the ratio of cocoon. In the meantime, malondialdehyde level increased and glutathione level and superoxide dismutase/catalase activities decreased. 50 µM Se markedly ameliorated these growth and physiological deficits as well as decreases in dynamin gene expression. On the other hand, there were no significant effects on fertility (including produced eggs and laid eggs) between the interference and Se treatments. Additionally, the Se content in the B. mori increased after the dynamin gene interference. The dynamin gene was highly expressed in the silk gland and declined significantly after interference. Among the three siRNAs (Dynamin-1, Dynamin-2, and Dynamin-3), the dynamin-2 displayed the highest interference effects to target gene expression. Our results demonstrated that 50 µM Se was effective to prevent any adverse effects caused by dynamin knockdown in silkworms. This provides practical implications for B. mori breeding industry.

The transcription factor RUNT-like regulates pupal cuticle development via promoting a pupal cuticle protein transcription.

Holometabolous insects undergo morphological remodeling from larvae to pupae and to adults with typical changes in the cuticle; however, the mechanism is unclear. Using the lepidopteran agricultural insect Helicoverpa armigera, cotton bollworm, as a model, we revealed that the transcription factor RUNT-like (encoded by Runt-like) regulates the development of the pupal cuticle via promoting a pupal cuticle protein gene (HaPcp) expression. The HaPcp was highly expressed in the epidermis and wing during metamorphosis and was found being involved in pupal cuticle development by RNA interference (RNAi) analysis in larvae. Runt-like was also strongly upregulated in the epidermis and wing during metamorphosis. Knockdown of Runt-like produced similar phenomena, a failure of abdomen yellow envelope and wing formation, to those following HaPcp knockdown. The insect molting hormone 20-hydroxyecdysonen (20E) upregulated HaPcp transcription via RUNT-like. 20E upregulated Runt-like transcription via nuclear receptor EcR and the transcription factor FOXO. Together, RUNT-like and HaPCP are involved in pupal cuticle development during metamorphosis under 20E regulation.

BeetleAtlas: An Ontogenetic and Tissue-specific Transcriptomic Atlas of the Red Flour Beetle Tribolium castaneum.

The red flour beetle Tribolium castaneum has emerged as a powerful model in insect functional genomics. However, a major limitation in the field is the lack of a detailed spatio-temporal view of the genetic signatures underpinning the function of distinct tissues and life stages. Here, we present an ontogenetic and tissue-specific web-based resource for Tribolium transcriptomics: BeetleAtlas (https://www.beetleatlas.org). This web application provides access to a database populated with quantitative expression data for nine adult and seven larval tissues, as well as for four embryonic stages of Tribolium. BeetleAtlas allows one to search for individual Tribolium genes to obtain values of both total gene expression and enrichment in different tissues, together with data for individual isoforms. To facilitate cross-species studies, one can also use Drosophila melanogaster gene identifiers to search for related Tribolium genes. For retrieved genes there are options to identify and display the tissue expression of related Tribolium genes or homologous Drosophila genes. Five additional search modes are available to find genes conforming to any of the following criteria: exhibiting high expression in a particular tissue; showing significant differences in expression between larva and adult; having a peak of expression at a specific stage of embryonic development; belonging to a particular functional category; and displaying a pattern of tissue expression similar to that of a query gene. We illustrate how the different feaures of BeetleAtlas can be used to illuminate our understanding of the genetic mechanisms underpinning the biology of what is the largest animal group on earth.

Rapid growth and the evolution of complete metamorphosis in insects.

More than 50% of all animal species are insects that undergo complete metamorphosis. The key innovation of these holometabolous insects is a pupal stage between the larva and adult when most structures are completely rebuilt. Why this extreme lifestyle evolved is unclear. Here, we test the hypothesis that a trade-off between growth and differentiation explains the evolution of this novelty. Using a comparative approach, we find that holometabolous insects grow much faster than hemimetabolous insects. Using a theoretical model, we then show how holometaboly evolves under a growth-differentiation trade-off and identify conditions under which such temporal decoupling of growth and differentiation is favored. Our work supports the notion that the holometabolous life history evolved to remove developmental constraints on fast growth, primarily under high mortality.

The venom of Habrobracon hebetor induces alterations in host metabolism.

The ability of parasitic wasps to manipulate a host's metabolism is under active investigation. Components of venom play a major role in this process. In the present work, we studied the effect of the venom of the ectoparasitic wasp Habrobracon hebetor on the metabolism of the greater wax moth host (Galleria mellonella). We identified and quantified 45 metabolites in the lymph (cell-free hemolymph) of wax moth larvae on the second day after H. hebetor venom injection, using NMR spectroscopy and liquid chromatography coupled with mass spectrometry. These metabolites included 22 amino acids, nine products of lipid metabolism (sugars, amines and alcohols) and four metabolic intermediates related to nitrogenous bases, nucleotides and nucleosides. An analysis of the larvae metabolome suggested that the venom causes suppression of the tricarboxylic acid cycle, an increase in the number of free amino acids in the lymph, an increase in the concentration of trehalose in the lymph simultaneously with a decrease in the amount of glucose, and destructive processes in the fat body tissue. Thus, this parasitoid venom not only immobilizes the prey but also modulates its metabolism, thereby providing optimal conditions for the development of larvae.

The function of juvenile-adult transition axis in female sexual receptivity of Drosophila melanogaster.

Female sexual receptivity is essential for reproduction of a species. Neuropeptides play the main role in regulating female receptivity. However, whether neuropeptides regulate female sexual receptivity during the neurodevelopment is unknown. Here, we found the peptide hormone prothoracicotropic hormone (PTTH), which belongs to the insect PG (prothoracic gland) axis, negatively regulated virgin female receptivity through ecdysone during neurodevelopment in Drosophila melanogaster. We identified PTTH neurons as doublesex-positive neurons, they regulated virgin female receptivity before the metamorphosis during the third-instar larval stage. PTTH deletion resulted in the increased EcR-A expression in the whole newly formed prepupae. Furthermore, the ecdysone receptor EcR-A in pC1 neurons positively regulated virgin female receptivity during metamorphosis. The decreased EcR-A in pC1 neurons induced abnormal morphological development of pC1 neurons without changing neural activity. Among all subtypes of pC1 neurons, the function of EcR-A in pC1b neurons was necessary for virgin female copulation rate. These suggested that the changes of synaptic connections between pC1b and other neurons decreased female copulation rate. Moreover, female receptivity significantly decreased when the expression of PTTH receptor Torso was reduced in pC1 neurons. This suggested that PTTH not only regulates female receptivity through ecdysone but also through affecting female receptivity associated neurons directly. The PG axis has similar functional strategy as the hypothalamic-pituitary-gonadal axis in mammals to trigger the juvenile-adult transition. Our work suggests a general mechanism underlying which the neurodevelopment during maturation regulates female sexual receptivity.

A transcriptome-wide analysis provides novel insights into how Metabacillus indicus promotes coral larvae metamorphosis and settlement.

BACKGROUND: Coral reefs experience frequent and severe disturbances that can overwhelm their natural resilience. In such cases, ecological restoration is essential for coral reef recovery. Sexual reproduction has been reported to present the simplest and most cost-effective means for coral reef restoration. However, larval settlement and post-settlement survival represent bottlenecks for coral recruitment in sexual reproduction. While bacteria play a significant role in triggering coral metamorphosis and settlement in many coral species, the underlying molecular mechanisms remain largely unknown. In this study, we employed a transcriptome-level analysis to elucidate the intricate interactions between bacteria and coral larvae that are crucial for the settlement process. RESULTS: High Metabacillus indicus strain cB07 inoculation densities resulted in the successful induction of metamorphosis and settlement of coral Pocillopora damicoris larvae. Compared with controls, inoculated coral larvae exhibited a pronounced increase in the abundance of strain cB07 during metamorphosis and settlement, followed by a significant decrease in total lipid contents during the settled stage. The differentially expressed genes (DEGs) during metamorphosis were significantly enriched in amino acid, protein, fatty acid, and glucose related metabolic pathways. In settled coral larvae induced by strain cB07, there was a significant enrichment of DEGs with essential roles in the establishment of a symbiotic relationship between coral larvae and their symbiotic partners. The photosynthetic efficiency of strain cB07 induced primary polyp holobionts was improved compared to those of the negative controls. In addition, coral primary polyps induced by strain cB07 showed significant improvements in energy storage and survival. CONCLUSIONS: Our findings revealed that strain cB07 can promote coral larval settlement and enhance post-settlement survival and fitness. Manipulating coral sexual reproduction with strain cB07 can overcome the current recruitment bottleneck. This innovative approach holds promise for future coral reef restoration efforts.

Natural modulation of redox status throughout the ontogeny of Amazon frog Physalaemus ephippifer (Anura, Leptodactylidae).

During their development, amphibians undergo various physiological processes that may affect their susceptibility to environmental pollutants. Naturally occurring fluctuations caused by developmental events are often overlooked in ecotoxicological studies. Our aim is to investigate how biomarkers of oxidative stress are modulated at different stages of larval development in the Amazonian amphibian species, Physalaemus ephippifer. The premetamorphosis, prometamorphosis and metamorphic climax stages were used to analyze total antioxidant capacity (ACAP), glutathione S-transferase (GST) activity, lipid peroxidation (LPO) levels and the expression of genes nrf2, gst, gsr (glutathione reductase) and gclc (glycine-cysteine ligase, catalytic subunit). Although there was no difference in ACAP and the genes expression among the studied stages, individuals from the premetamorphosis and prometamorphosis showed higher GST activity than ones under the climax. LPO levels were highest in individuals from the metamorphic climax. The present study suggests that the oxidative status changes during ontogeny of P. ephippifer tadpoles, especially during the metamorphic climax, the most demanding developmental phase. Variations in the redox balance at different developmental stages may lead to a divergent response to pollution. Therefore, we recommend that studies using anuran larvae as biomonitors consider possible physiological differences during ontogeny in their respective analyses.

Transgenic poplar (Populus davidiana×P. bolleana Loucne) expressing dsRNA of insect chitinase gene: lines identification and resistance assay.

Poplar is a valuable tree species that is distributed all over the world. However, many insect pests infest poplar trees and have caused significant damage. To control poplar pests, we transformed a poplar species, Populus davidiana × P. bolleana Loucne, with the dsRNA of the chitinase gene of a poplar defoliator, Clostera anastomosis (Linnaeus) (Lepidoptera: Notodontidae), employing an Agrobaterium-mediated approach. The transgenic plant has been identified by cloning the T-DNA flanking sequences using TAIL-PCR and quantifying the expression of the dsRNA using qPCR. The toxicity assay of the transgenic poplar lines was carried out by feeding the target insect species (C. anastomosis). The results showed that, in C. anastomosis, the activity of chitinase was significantly decreased, consistent with the expression on mRNA levels, and the larval mortality was significantly increased. These results suggested that the transgenic poplar of dsRNA could be used for pest control.

No evidence for an up-regulation of female immune function in response to elevated risk of sexual conflict.

Sexual conflict is widespread among sexually reproducing organisms. Phenotypic plasticity in female resistance traits has the potential to moderate the harm imposed by males during mating, yet female plasticity has rarely been explored. In this experiment, we investigated whether female seed beetles invest more in immunocompetence, measured as phenoloxidase (PO) capacity, when exposed to cues signalling a greater risk of sexual conflict. Risk perception was manipulated by housing focal individuals alone or with a companion as developing larvae, followed by exposure to a mating-free male- or female-biased social environment when adults. We predicted that females exposed to cues of increased sexual conflict would have increased PO capacity. However, PO capacity did not differ between either larval or adult social treatments. Our results suggest that females may not perceive a risk to their fitness on the basis of increased male presence or are unable to adjust this aspect of their phenotype in response to that risk.

Apoptosis-dependent head development during metamorphosis of the cnidarian Hydractinia symbiolongicarpus.

Apoptosis is a regulated cell death that depends on caspases. It has mainly been studied as a mechanism for the removal of unwanted cells. However, apoptotic cells can induce fate or behavior changes of their neighbors and thereby participate in development. Here, we address the functions of apoptosis during metamorphosis of the cnidarian Hydractinia symbiolongicarpus. We describe the apoptotic profile during metamorphosis of the larva and identify Caspase3/7a, but no other executioner caspases, as essential for apoptosis in this context. Using pharmacological and genetic approaches, we find that apoptosis is required for normal head development. Inhibition of apoptosis resulted in defects in head morphogenesis. Neurogenesis was compromised in the body column of apoptosis-inhibited animals but there was no effect on the survival or proliferation of stem cells, suggesting that apoptosis is required for cellular commitment rather than for the maintenance of their progenitors. Differential transcriptomic analysis identifies TRAF genes as downregulated in apoptosis-inhibited larvae and functional experiments provide evidence that they are essential for head development. Finally, we find no major role for apoptosis in head regeneration in this animal, in contrast to the significance of apoptosis in Hydra head regeneration.