{"title":"Central role of squid gene during oocyte development in the Hemiptera Rhodnius prolixus.","authors":"Agustina Pascual, Catalina Taibo, Rolando Rivera-Pomar","doi":"10.1016/j.jinsphys.2024.104719","DOIUrl":"https://doi.org/10.1016/j.jinsphys.2024.104719","url":null,"abstract":"<p><p>Oocyte polarity establishment is a conserved and crucial phenomenon for embryonic development. It relies on the precise spatial localization of maternal factors deposited during oocyte development, which is essential for establishing and maintaining cell polarity and subsequently specifying embryonic axes. The heterogeneous nuclear ribonucleoprotein (hnRNP) encoded by the squid (sqd) gene has been implicated in mRNA localization and embryonic axis establishment in Drosophila melanogaster. Comparative genomics allowed for the identification of a homologue in Rhodnius prolixus. In this study, we investigated the function of Rp-sqd during oogenesis and early embryonic development. We observed persistent expression of Rp-sqd during oocyte development, with localization in the cytoplasm of ovary germarium and growing oocytes in previtellogenic and vitellogenic stages. A Parental RNA interference (RNAi) experiment targeting Rp-sqd resulted in female sterility. The ovaries showed disrupted oocyte development, disarray of follicular epithelium, and affected nurse cells integrity. Immunostaining and microscopic techniques revealed microtubule disarray and a reduction in the presence of organelles in the trophic cords that connect the germarium with the oocytes. The Rp-sqd depletion impacted the transcript expression of maternal mRNAs involved in apoptosis, axis formation, oogenesis, and cytoskeleton maintenance, indicating a pleiotropic function of Rp-sqd during oogenesis. This study provides new insights into the genetic basis of R. prolixus oogenesis, highlighting the crucial role of Rp-sqd in oocyte development, fertility, and germarium integrity. These findings contribute to our understanding of insect developmental processes, provide a foundation for future investigations into reproduction, and reveal the regulatory mechanisms governing the process.</p>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142568748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Aversive sexual learning in the kissing bug Rhodnius prolixus: Modulation of different sexual responses in males and females","authors":"","doi":"10.1016/j.jinsphys.2024.104717","DOIUrl":"10.1016/j.jinsphys.2024.104717","url":null,"abstract":"<div><div>Although sexual learning can be a key process in the reproductive success of animals, research focused on the experience-dependent modulation of courtship in insects is scarce. In kissing bugs, the behavioural steps implicated in mating have been exhaustively studied, but not the involvement of learning in them. Our objective was to determine whether the sexual behaviour of <em>Rhodnius prolixus</em> could be modulated by experience. During training, couples were submitted to eight assays, in which they received a vibration (negative reinforcement) when the male attempted to copulate the female. Immediately after, they were separated, not allowing the occurrence of copulation. We found that along training, males’ latency to perform a copulatory attempt increased, male’s copulatory attempts were less frequent, and females’ locomotor activity did not change. These results suggest that males, and not females, learned to avoid the vibration by reducing their intention to copulate. In post-training tests, conditioned males presented with new naïve females reverted to low copulatory attempt latencies, suggesting that the modulation was partner-specific. Besides, conditioned females increased their rejection frequencies to males’ copulatory attempts, suggesting that a second type of learning occurred in females. These results constitute the first evidence of sexual learning in hematophagous insects. Males and females seem to change their selectivity according to their previous sexual experience. We discuss the relevance that this plasticity might have in the fitness of this epidemiologically relevant insect.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142568805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The effects of diet and semiochemical exposure on male Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) metabolic rate at a range of temperatures","authors":"","doi":"10.1016/j.jinsphys.2024.104718","DOIUrl":"10.1016/j.jinsphys.2024.104718","url":null,"abstract":"<div><div>The oriental fruit fly, <em>Bactrocera dorsalis</em> (Hendel) (Diptera: Tephritidae), is an invasive species that has rapidly spread across the African continent, endangering the security of agricultural industries. The sterile insect technique (SIT) is being investigated as a viable additional pest management tool to suppress <em>B. dorsalis</em> populations after its successful implementation in other parts of the world. There is evidence to suggest that pre-release nutritional and semiochemical treatments for sterilised males can enhance their competitive performance against wild type males in SIT programs. This study examined how sterilisation, a diet rich in protein (addition of yeast hydrolysate) or containing semiochemicals (methyl eugenol or eugenol) affected the resting metabolic (RMR) of male <em>B. dorsalis</em> at different temperatures (15 – 30 °C), measured using flow-through respirometry. Our results indicated that the negative effect of sterilisation on RMR decreased as temperature increased and that duration of exposure to semiochemicals for 1 to 4 days was not a significant influencing factor on male <em>B. dorsalis</em> RMR. Protein-rich diet increased average RMR, but the difference in RMR between dietary groups decreased as temperature increased. Semiochemical feeding reduced the average RMR in male <em>B. dorsalis</em>. The difference in RMR between males that consumed semiochemical and those that did not increased with as temperature increased.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142502164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Attractiveness versus stickiness: Behavioural preferences of Drosophila melanogaster with competing visual stimuli","authors":"","doi":"10.1016/j.jinsphys.2024.104716","DOIUrl":"10.1016/j.jinsphys.2024.104716","url":null,"abstract":"<div><div>In nature, animals often encounter various competing stimuli and must make choices among them. Although the behaviour under two identical stimuli has been extensively studied for fruit flies, <em>Drosophila melanogaster</em>, how the appeal of one stimulus for the animals is influenced by the appeal of the other is not fully understood. In the present study, we systematically investigated this equation using a modified Buridan’s paradigm. We focused on the behaviour of fruit flies under asymmetric visual stimuli, i.e., two black stripes of different widths. We characterized two behaviour modes: (1) Attractiveness: moving toward a stripe in the inner area of the platform, and (2) Stickiness: staying around the edge near a stripe. Our results reveal that while Attractiveness of a stripe is primarily influenced by its own width and remains relatively independent of the opposite stripe, Stickiness is significantly affected by the width of the competing stripe. These findings suggest that the behavioural response of fruit flies to visual stimuli involves complex decision-making processes influenced by both intrinsic and extrinsic factors. This study provides new insights into the cognitive and sensory mechanisms underlying visual preference behaviour in <em>Drosophila</em> and highlights the importance of considering multiple stimuli in behavioural assays.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142467625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gene regulation by mating depends on time, diet, and body region in female Aedes aegypti","authors":"","doi":"10.1016/j.jinsphys.2024.104715","DOIUrl":"10.1016/j.jinsphys.2024.104715","url":null,"abstract":"<div><div><em>Aedes aegypti</em> is a major vector of several arboviruses that cause human mortality and morbidity. One method for controlling the spread of these viruses is to control mosquito reproduction. During mating, seminal fluid molecules and sperm are transferred and these stimuli influence female post-mating physiology and behavior. Yet, little is known about the mechanisms underlying these post-mating responses. To fill this gap, short-read RNA sequencing was used to identify differentially expressed genes between unmated (control) and mated females in the head/thorax (HT), abdomen (Ab) and the lower reproductive tract (LRT), of mosquitoes reared with 3% and 12% sucrose. The results revealed that at 3% sucrose, four, 408 and 415 significantly differential expressed genes (DEGs) were identified in the HT, Ab and LRT, respectively, at six hours post mating (hpm). The number of DEGs dropped dramatically at 24 hpm with no DEGs in the HT, three in the Ab, and 112 in the LRT. In contrast, the number of DEGs was lower at 6 hpm than 24 hpm in the LRT at 12% sucrose. Comparing our results to a similar study which used 10% sucrose revealed evidence in support of condition-dependent regulation of gene expression by mating in this species. This study shows that mating-induced transcriptional changes depend on time point after mating, body region, and diet. Our results provide foundational knowledge for future functional analyses to identify genes and pathways involved in the post-mating behavioral and physiological changes of female mosquitoes.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142467626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Phenotypical aspects of Culex pipiens biotype pipiens during diapause: Lipid utilization, body size, insemination, and parity","authors":"","doi":"10.1016/j.jinsphys.2024.104714","DOIUrl":"10.1016/j.jinsphys.2024.104714","url":null,"abstract":"<div><div>In temperate regions, female <em>Culex pipiens</em> biotype <em>pipiens</em> mosquitoes undergo diapause in winter. Diapausing biotype <em>pipiens</em> mosquitoes are potentially important winter reservoirs for mosquito-borne viruses, such as West Nile virus (WNV), Usutu virus (USUV), and Sindbis virus (SINV). Mosquitoes in diapause have not taken a bloodmeal prior to winter. Therefore, they do not become infected by taking an infectious bloodmeal and as a consequence, vertical transmission is considered the primary mechanism of mosquito-borne virus overwintering. Prior to winter, biotype <em>pipiens</em> mosquitoes build up fat reserves, which they utilize throughout winter. Furthermore, earlier studies have indicated that larger body size is correlated with increased survival during winter. However, not much is known about lipid utilization and body size of wild biotype <em>pipiens</em> mosquitoes in diapause. Therefore, we performed monthly collections of diapausing biotype <em>pipiens</em> mosquitoes in two consecutive winters (2020/2021 and 2021/2022) in bunkers of the New Hollandic Waterline in the Netherlands. Every month, we checked the proportion of inseminated and parous females via microscopy. In addition, we measured wing length as proxy for body size, and assessed total lipid content. Furthermore, we monitored indoor temperature in the overwintering locations. We show that the overwintering sites in our study provide relatively stable environments, in which temperatures rarely drop below 0 °C. The vast majority of biotype <em>pipiens</em> females were inseminated (84.1 %) and nulliparous (97.5 %). We detected differences in body size between but not within the two years of sampling. Additionally, we detected a difference in lipid content between the sampling years. We confirm that the vast majority of diapausing biotype <em>pipiens</em> females are inseminated and nulliparous. This indicates that they did not blood feed prior to winter, which underscores the likeliness of vertical transmission being the primary mechanism behind virus overwintering. The detected difference in body size between years can most likely be attributed to differences in summer conditions the mosquitoes were exposed to as larvae, although this needs confirmation. The difference in lipid depletion could not be explained by differences in climatic conditions. To shed more light on the links between climatic conditions, body size, lipid depletion and the consequences for mosquito population dynamics and arbovirus transmission, future experimental work, for example by arbovirus exposure followed by artificially induced diapause, is desired.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nutritional quality regulates postnatal wing morph in pea aphids","authors":"","doi":"10.1016/j.jinsphys.2024.104713","DOIUrl":"10.1016/j.jinsphys.2024.104713","url":null,"abstract":"<div><div>Aphids can produce winged or wingless offspring in response to environmental changes. Host nutrition is one of the extensively studied environmental factors influencing the plasticity of wing morphs of aphids. In this study, we found that the pea aphid, <em>Acyrthosiphon pisum</em>, produced a low proportion of winged offspring when fed on plants, but a significantly higher proportion on the artificial diet. Interestingly, when newly born nymphs were transferred back to the artificial diet after feeding on plants for six hours or longer, most nymphs became wingless. These results suggest that the wing morph state of pea aphids can change postnatally, potentially determined by the nutritional quality of their food. Furthermore, aphids feeding on the artificial diet exhibited higher levels of glucose and stronger insulin signaling activity compared with aphids on plants. Conversely, the amino acid levels were lower, and TOR signaling was weaker in aphids fed on the artificial diet. Insulin and the target of rapamycin (TOR) are the primary nutrient-sensing signaling pathways involved in controlling organism growth and have been implicated in regulating aphid wing morph plasticity. We tested whether these nutrient responsive pathways were involved in postanal wing determination of aphids. However, reducing amino acid content in the diet or inhibiting TOR with rapamycin resulted in a decrease of the winged morph, suggesting that the lower amino acid levels or TOR activity was not responsible for the higher proportion of winged morph on the artificial diet. These results suggest that nutritional quality, particularly sugars like sucrose and glucose, may regulate the postnatal wing morph of the pea aphid, likely via the insulin signaling pathway.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142391102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multigenerational expression of antimicrobial peptides in Aedes aegypti exposed to Metarhizium anisopliae: Is trans-generational immune priming involved?","authors":"","doi":"10.1016/j.jinsphys.2024.104712","DOIUrl":"10.1016/j.jinsphys.2024.104712","url":null,"abstract":"<div><div>We assessed, for the first time, a multigenerational expression of antimicrobial peptides (AMPs) in <em>Aedes aegypti</em> larvae exposed to the entomopathogenic fungus, <em>Metarhizium anisopliae,</em> and correlated it with a possible involvement in <em>trans</em>-generational immune priming (TGIP). <em>Aedes aegypti</em> larvae were first exposed to blastospores or conidia of <em>M. anisopliae</em> CG 489 for 24 and 48 h, and the relative expression of AMPs were measured using quantitative Real-Time PCR. A suspension of conidia was prepared, and two different survival tests were conducted with different larval generations (F0, F1, and F2). In the first bioassay, the survival curves of the three generations were conducted separately and compared with their respective control groups. In the other bioassay, the survival curves of the F0, F1, and F2 generations were compared simultaneously against a naïve group exposed to Tween 80. In both survival tests, the F0 generation was more susceptible to <em>M. anisopliae</em> than subsequent generations. For molecular analyses related to TGIP, F0, F1, and F2 larvae were exposed to conidia, and their expression of AMPs was compared with their control groups and a naïve group. There was no differential expression of <em>cecropin</em>, <em>defensin A</em> or <em>cathepsin B</em> between generations. <em>Lysozyme C</em>, however, showed an increase in expression across generations, suggesting a role in TGIP. These discoveries may help us develop biological insecticides against mosquito larvae based on entomopathogenic fungi.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142289258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Larval stress affects adult Drosophila behavior and metabolism","authors":"","doi":"10.1016/j.jinsphys.2024.104709","DOIUrl":"10.1016/j.jinsphys.2024.104709","url":null,"abstract":"<div><div>In this study, we raised the following question: “Does metamorphosis, being a “reboot” of all systems of the organism, erase the changes that occurred at earlier stages of insect development?” To answer this question, we investigated several behavioral, metabolic and neuroendocrine parameters in <em>Drosophila melanogaster</em> imago that had undergone heat stress at the 3rd larval instar (32 °C, 48 h). We discovered that larval stress negatively affected feeding and locomotor behavior, as well as total lipid content in adult flies. At the same time, these flies demonstrated a considerable increase in carbohydrate content and expression level of insulin/insulin-like growth factor signaling (IIS) pathway genes, <em>dfoxo</em>, <em>dilp6</em> and <em>dInR</em>. The data obtained allow us to conclude that metamorphosis does not erase the effect of stress exposure at early developmental stages and causes dramatic changes in carbohydrate and lipid metabolism as well as locomotor activity of adult insects, which is at least in part due to changes in IIS activity.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142289257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}