Pub Date : 2025-11-13DOI: 10.1016/j.jinsphys.2025.104907
Erinç Çelik Biçer, Olga Sak, Aylin Er
Extreme temperatures, the most evident indicator of climate change, threaten the delicate balance among parasitoids, key components of the ecosystem, and their agricultural pest hosts. Understanding the effects of thermal stress on parasitoids is essential for improving the mass production of Bracon hebetor (Hymenoptera: Braconidae), and predicting how the climate change will affect host-parasitoid relationship. The immune system of the host Galleria mellonella (Lepidoptera: Pyralidae) varied with both temperature and duration of exposure. Total hemocyte count peaked at 40 °C after 24 h due to elevated granulocyte, plasmatocyte, spherulocyte, and other cell types. The mitotic index peaked at 38 °C (24 h) before dropping sharply at 40 °C. Strong encapsulation responses rose significantly at 40 °C compared to 38 °C. Re-exposing adult females of B. hebetor to thermal stress, along with its previously heat-stressed hosts, altered biological traits in both adult females and F1 offspring, especially the reduced egg fecundity. Rising temperatures initially reduced the female sex ratio, but ultimately it nearly balanced out. At 36 °C, 95 % of the 24 eggs per female developed into adults, and prolonged adult longevity increased parasitoid numbers and extended their active period, a key finding. Overall, B. hebetor displayed high thermal tolerance, yet temperature-driven changes in host immunity and parasitoid traits may reshape their interactions under future climates.
{"title":"Influence of thermal stress on the cellular immunity of Galleria mellonella F. (Lepidoptera: Pyralidae), and the biological traits of Bracon hebetor (Hymenoptera: Braconidae) in a host–parasitoid interaction: implications under climate change","authors":"Erinç Çelik Biçer, Olga Sak, Aylin Er","doi":"10.1016/j.jinsphys.2025.104907","DOIUrl":"10.1016/j.jinsphys.2025.104907","url":null,"abstract":"<div><div>Extreme temperatures, the most evident indicator of climate change, threaten the delicate balance among parasitoids, key components of the ecosystem, and their agricultural pest hosts. Understanding the effects of thermal stress on parasitoids is essential for improving the mass production of <em>Bracon hebetor</em> (Hymenoptera: Braconidae), and predicting how the climate change will affect host-parasitoid relationship. The immune system of the host <em>Galleria mellonella</em> (Lepidoptera: Pyralidae) varied with both temperature and duration of exposure. Total hemocyte count peaked at 40 °C after 24 h due to elevated granulocyte, plasmatocyte, spherulocyte, and other cell types. The mitotic index peaked at 38 °C (24 h) before dropping sharply at 40 °C. Strong encapsulation responses rose significantly at 40 °C compared to 38 °C. Re-exposing adult females of <em>B. hebetor</em> to thermal stress, along with its previously heat-stressed hosts, altered biological traits in both adult females and F<sub>1</sub> offspring, especially the reduced egg fecundity. Rising temperatures initially reduced the female sex ratio, but ultimately it nearly balanced out. At 36 °C, 95 % of the 24 eggs per female developed into adults, and prolonged adult longevity increased parasitoid numbers and extended their active period, a key finding. Overall, <em>B. hebetor</em> displayed high thermal tolerance, yet temperature-driven changes in host immunity and parasitoid traits may reshape their interactions under future climates.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104907"},"PeriodicalIF":2.3,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526425","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}
Pub Date : 2025-11-12DOI: 10.1016/j.jinsphys.2025.104905
Cassidy Orange, Biana Qiu, Susan Villarreal
Seminal fluid proteins (SFPs), produced in the male accessory glands (MAGs) and transferred during mating, induce key post-mating changes in females, including altered feeding, reduced receptivity, and shifts in reproductive investment. In mosquitoes, these effects are well characterized in some Aedes and Anopheles species, whereas their role in Culex remains poorly understood. We tested whether MAG products alone reduce female receptivity in Culex pipiens. MAGs were dissected from virgin males, proteins extracted, and homogenates injected into virgin females, alongside saline and non-injected controls. Insemination rates were assessed under two contexts: no choice trials, where males encountered females from a single treatment group and choice trials, where all treatment types were presented simultaneously. To evaluate male mating attempts independent of sperm transfer, we also applied a fluorescent dye-transfer assay in which dye applied to male abdomens marked females during attempted copulation. MAG-injected females were significantly less likely to be inseminated than controls, implicating SFPs in inducing refractoriness. This effect was stronger in no choice trials, suggesting reduced mating reflects female rejection rather than male discrimination among female types. Dye-transfer data revealed few attempted copulations without insemination and no evidence that males preferentially courted non-injected virgin controls. Our findings confirm the conserved role of SFPs for female receptivity from an understudied species and establishes a foundation for identifying the molecular drivers of refractoriness in Culex, a key step for reproductive-based vector control strategies.
{"title":"The effect of male accessory gland extracts on female receptivity in Culex pipiens mosquitoes","authors":"Cassidy Orange, Biana Qiu, Susan Villarreal","doi":"10.1016/j.jinsphys.2025.104905","DOIUrl":"10.1016/j.jinsphys.2025.104905","url":null,"abstract":"<div><div>Seminal fluid proteins (SFPs), produced in the male accessory glands (MAGs) and transferred during mating, induce key post-mating changes in females, including altered feeding, reduced receptivity, and shifts in reproductive investment. In mosquitoes, these effects are well characterized in some <em>Aedes</em> and <em>Anopheles</em> species, whereas their role in <em>Culex</em> remains poorly understood. We tested whether MAG products alone reduce female receptivity in <em>Culex pipiens</em>. MAGs were dissected from virgin males, proteins extracted, and homogenates injected into virgin females, alongside saline and non-injected controls. Insemination rates were assessed under two contexts: no choice trials, where males encountered females from a single treatment group and choice trials, where all treatment types were presented simultaneously. To evaluate male mating attempts independent of sperm transfer, we also applied a fluorescent dye-transfer assay in which dye applied to male abdomens marked females during attempted copulation. MAG-injected females were significantly less likely to be inseminated than controls, implicating SFPs in inducing refractoriness. This effect was stronger in no choice trials, suggesting reduced mating reflects female rejection rather than male discrimination among female types. Dye-transfer data revealed few attempted copulations without insemination and no evidence that males preferentially courted non-injected virgin controls. Our findings confirm the conserved role of SFPs for female receptivity from an understudied species and establishes a foundation for identifying the molecular drivers of refractoriness in <em>Culex</em>, a key step for reproductive-based vector control strategies.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104905"},"PeriodicalIF":2.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145523632","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}
Pub Date : 2025-11-05DOI: 10.1016/j.jinsphys.2025.104903
Xiankun Shang , Jili Wei , Wei Liu , Chenghua Huang , Xuehong Pan
Exolontha castanea (Coleoptera: Melolonthinae) larvae are a major subterranean pest of sugarcane in China. The adults exhibit strong flight capacity and positive phototaxis. This study investigated the external morphology, internal microstructure, and light-induced adaptations of the compound eyes in both female and male E. castanea using light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The compound eyes feature a peninsula-shaped canthus that extends deeply into the basement membrane region. A marked sexual size dimorphism of the eye was observed, with females having significantly larger eyes and a greater number of facets (10,780.92 in females vs. 9,901.30 in males). The eyes were identified as being of the optical superposition type. The ommatidial length is approximately 800 μm. Moreover, the cornea was significantly thicker in female adults than in males. The crystalline cone is eucone and bullet-shaped, consisting of three to four Semper cells. Each ommatidium contains eight retinula cells (R1-R8). The cell bodies of R1-R7 form a retinular tract that traverses the clear zone, with their nuclei located in a distally swollen region. R8 is a basal cell situated beneath the rhabdom near the basement membrane. The retina was classified as the scotopic type. The proximal ends of R1-R7 extend inward to form a rhabdomere, which collectively constitute an open, seven-lobed rhabdom. The inter-rhabdom spaces are densely filled with tracheoles. Under different light conditions, including darkness, ultraviolet, violet, blue, red, and white light, the eyes demonstrate dynamic adaptations by modulating the length of the primary pigment cells (PPCs) and the migration of pigment granules. Under dark adaptation, the retinula cells are closely apposed to the crystalline cone, and pigment granules accumulate around it. Upon light exposure, the PPCs surrounding the cone elongated, the retinula cells shortened radially, and the pigment granules migrated into the elongated PPCs region beneath the cone, thereby reducing light entry. Furthermore, the degree of PPCs elongation is positively correlated with light intensity.
{"title":"Microstructural characteristics and mechanisms underlying dynamic light adaptation in the compound eyes of Exolontha castanea (Coleoptera: Melolonthinae)","authors":"Xiankun Shang , Jili Wei , Wei Liu , Chenghua Huang , Xuehong Pan","doi":"10.1016/j.jinsphys.2025.104903","DOIUrl":"10.1016/j.jinsphys.2025.104903","url":null,"abstract":"<div><div><em>Exolontha castanea</em> (Coleoptera: Melolonthinae) larvae are a major subterranean pest of sugarcane in China. The adults exhibit strong flight capacity and positive phototaxis. This study investigated the external morphology, internal microstructure, and light-induced adaptations of the compound eyes in both female and male <em>E. castanea</em> using light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The compound eyes feature a peninsula-shaped canthus that extends deeply into the basement membrane region. A marked sexual size dimorphism of the eye was observed, with females having significantly larger eyes and a greater number of facets (10,780.92 in females vs. 9,901.30 in males). The eyes were identified as being of the optical superposition type. The ommatidial length is approximately 800 μm. Moreover, the cornea was significantly thicker in female adults than in males. The crystalline cone is eucone and bullet-shaped, consisting of three to four Semper cells. Each ommatidium contains eight retinula cells (R1-R8). The cell bodies of R1-R7 form a retinular tract that traverses the clear zone, with their nuclei located in a distally swollen region. R8 is a basal cell situated beneath the rhabdom near the basement membrane. The retina was classified as the scotopic type. The proximal ends of R1-R7 extend inward to form a rhabdomere, which collectively constitute an open, seven-lobed rhabdom. The inter-rhabdom spaces are densely filled with tracheoles. Under different light conditions, including darkness, ultraviolet, violet, blue, red, and white light, the eyes demonstrate dynamic adaptations by modulating the length of the primary pigment cells (PPCs) and the migration of pigment granules. Under dark adaptation, the retinula cells are closely apposed to the crystalline cone, and pigment granules accumulate around it. Upon light exposure, the PPCs surrounding the cone elongated, the retinula cells shortened radially, and the pigment granules migrated into the elongated PPCs region beneath the cone, thereby reducing light entry. Furthermore, the degree of PPCs elongation is positively correlated with light intensity.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104903"},"PeriodicalIF":2.3,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467777","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}
Pub Date : 2025-11-04DOI: 10.1016/j.jinsphys.2025.104902
Tzvi S. Goldberg , Yuval Shalem , Daiki Fujinaga , Kerry E. Mauck , S.Hollis Woodard , Naoki Yamanaka , Guy Bloch
Juvenile hormones (JHs) are key insect endocrine signals regulating pre-adult development and adult life history strategies, physiology, and behavior. The importance of this endocrine signal has led to the development of insecticides targeting JH signaling pathways. While effective against target pests, they can also affect beneficial insects, such as pollinators and natural pest enemies, many of which are hymenopterans. Research on JH, which is crucial for understanding the physiology, behavior, and organization of social insects, requires effective means to manipulate JH signaling pathways. A common method for reducing JH titers includes applying the phytotoxin precocene-I (P-I), which abolishes JH biosynthesis in the corpora allata (CA). However, achieving consistently effective topical treatments has proven challenging. Here, we investigated the dynamics of the effect of P-I manipulations on JH titers and reproductive development in orphan worker groups of a key pollinator bumble bee. A single P-I treatment effectively reduced circulating JH levels in newly emerged workers, even after 12 days. The treatment delayed but did not prevent ovarian activation. Multiple treatments failed to further reduce JH titers or ovarian activity, and were overall less effective than surgically removing the CA. Finally, we suggest guidelines for developing P-I manipulation studies, and more generally, compare methods for reducing circulating JH levels in insects.
{"title":"Precocene-I mediated reduction of juvenile hormone titers and ovarian activity is ephemeral in a bumble bee","authors":"Tzvi S. Goldberg , Yuval Shalem , Daiki Fujinaga , Kerry E. Mauck , S.Hollis Woodard , Naoki Yamanaka , Guy Bloch","doi":"10.1016/j.jinsphys.2025.104902","DOIUrl":"10.1016/j.jinsphys.2025.104902","url":null,"abstract":"<div><div>Juvenile hormones (JHs) are key insect endocrine signals regulating pre-adult development and adult life history strategies, physiology, and behavior. The importance of this endocrine signal has led to the development of insecticides targeting JH signaling pathways. While effective against target pests, they can also affect beneficial insects, such as pollinators and natural pest enemies, many of which are hymenopterans. Research on JH, which is crucial for understanding the physiology, behavior, and organization of social insects, requires effective means to manipulate JH signaling pathways. A common method for reducing JH titers includes applying the phytotoxin precocene-I (P-I), which abolishes JH biosynthesis in the corpora allata (CA). However, achieving consistently effective topical treatments has proven challenging. Here, we investigated the dynamics of the effect of P-I manipulations on JH titers and reproductive development in orphan worker groups of a key pollinator bumble bee. A single P-I treatment effectively reduced circulating JH levels in newly emerged workers, even after 12 days. The treatment delayed but did not prevent ovarian activation. Multiple treatments failed to further reduce JH titers or ovarian activity, and were overall less effective than surgically removing the CA. Finally, we suggest guidelines for developing P-I manipulation studies, and more generally, compare methods for reducing circulating JH levels in insects.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104902"},"PeriodicalIF":2.3,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145458975","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}
Pub Date : 2025-10-26DOI: 10.1016/j.jinsphys.2025.104901
Takashi Kuriwada
Many insects regulate diapause—a dormant physiological state—in response to photoperiod, with short day length typically signaling approach of winter and inducing diapause. However, artificial light at night (ALAN), often associated with urbanization, can disrupt these photoperiodic cues and inhibit diapause induction. This review examines the disruption of diapause induction by ALAN, a topic that has only recently attracted considerable attention. First, it summarizes recent empirical studies on ALAN-induced diapause inhibition. Then, it outlines the physiological and molecular genetic mechanisms involved, which remain only partially understood. Next, it discusses potential factors limiting adaptation to ALAN-induced diapause disruption. Finally, this review presents key perspectives from physiological, evolutionary, and applied entomological standpoints to guide future research, emphasizing the need to integrate existing knowledge of diapause regulation with field and laboratory studies to better understand the effects of ALAN and guide mitigation efforts.
{"title":"The age of bright nights: Photoperiodic disruption of insect diapause by artificial light at night","authors":"Takashi Kuriwada","doi":"10.1016/j.jinsphys.2025.104901","DOIUrl":"10.1016/j.jinsphys.2025.104901","url":null,"abstract":"<div><div>Many insects regulate diapause—a dormant physiological state—in response to photoperiod, with short day length typically signaling approach of winter and inducing diapause. However, artificial light at night (ALAN), often associated with urbanization, can disrupt these photoperiodic cues and inhibit diapause induction. This review examines the disruption of diapause induction by ALAN, a topic that has only recently attracted considerable attention. First, it summarizes recent empirical studies on ALAN-induced diapause inhibition. Then, it outlines the physiological and molecular genetic mechanisms involved, which remain only partially understood. Next, it discusses potential factors limiting adaptation to ALAN-induced diapause disruption. Finally, this review presents key perspectives from physiological, evolutionary, and applied entomological standpoints to guide future research, emphasizing the need to integrate existing knowledge of diapause regulation with field and laboratory studies to better understand the effects of ALAN and guide mitigation efforts.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104901"},"PeriodicalIF":2.3,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145390368","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}
Pub Date : 2025-10-20DOI: 10.1016/j.jinsphys.2025.104893
Samuel M. Stratton, Delbert A. Green II
Diapause is an environmentally induced, transcriptionally driven alternative developmental program that enables organisms to withstand adverse environmental conditions. The lasting consequences of diapause experience once development is resumed in permissible conditions have not been extensively explored. The monarch butterfly provides an interesting system to address this question as reproductive diapause is a critical component of their annual North American migration. Post-diapause female monarchs remigrate to the southern US after mating at overwintering sites in Mexico yet show evidence of potentially increased robustness (greater reproductive capacity and longevity) compared to summer non-migratory monarchs. Here we further investigate the phenotypic effects of diapause experience on monarch butterflies. Monarchs reared under different pre-adult conditions, either natural fall (diapause inducing) or laboratory summer-like (non-diapause development), were shifted to identical natural fall conditions upon eclosion and then assayed for adult brain transcription under identical controlled conditions. We find that fall conditions during pre-adult development are necessary to induce diapause. Diapause history is a strong predictor of adult brain transcription. Post-diapause individuals retained signatures of diapause maintenance-like processes, such as altered protein production, mitochondrial metabolism, and lipid regulation. However, the post-diapause response is transcriptionally distinct. Genes related to translation, with particular emphasis on mitochondrial ribosomal proteins, have increased expression post-diapause, while genes enriched for phospholipid metabolism and neurodevelopmental function have decreased expression in post-diapause individuals. Post-diapause individuals also show evidence of enhanced stress response and mechanisms that promote longevity. Overall, diapause history has lasting consequences on environmental response that may impact monarchs’ remigratory flights.
{"title":"Diapause history has lasting effects on adult brain gene expression in monarch butterflies","authors":"Samuel M. Stratton, Delbert A. Green II","doi":"10.1016/j.jinsphys.2025.104893","DOIUrl":"10.1016/j.jinsphys.2025.104893","url":null,"abstract":"<div><div>Diapause is an environmentally induced, transcriptionally driven alternative developmental program that enables organisms to withstand adverse environmental conditions. The lasting consequences of diapause experience once development is resumed in permissible conditions have not been extensively explored. The monarch butterfly provides an interesting system to address this question as reproductive diapause is a critical component of their annual North American migration. Post-diapause female monarchs remigrate to the southern US after mating at overwintering sites in Mexico yet show evidence of potentially increased robustness (greater reproductive capacity and longevity) compared to summer non-migratory monarchs. Here we further investigate the phenotypic effects of diapause experience on monarch butterflies. Monarchs reared under different pre-adult conditions, either natural fall (diapause inducing) or laboratory summer-like (non-diapause development), were shifted to identical natural fall conditions upon eclosion and then assayed for adult brain transcription under identical controlled conditions. We find that fall conditions during pre-adult development are necessary to induce diapause. Diapause history is a strong predictor of adult brain transcription. Post-diapause individuals retained signatures of diapause maintenance-like processes, such as altered protein production, mitochondrial metabolism, and lipid regulation. However, the post-diapause response is transcriptionally distinct. Genes related to translation, with particular emphasis on mitochondrial ribosomal proteins, have increased expression post-diapause, while genes enriched for phospholipid metabolism and neurodevelopmental function have decreased expression in post-diapause individuals. Post-diapause individuals also show evidence of enhanced stress response and mechanisms that promote longevity. Overall, diapause history has lasting consequences on environmental response that may impact monarchs’ remigratory flights.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"167 ","pages":"Article 104893"},"PeriodicalIF":2.3,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145337116","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}
Pub Date : 2025-10-03DOI: 10.1016/j.jinsphys.2025.104892
Rory Lockett , Milena Figueiredo de Sousa , Katherine A Nicoluzakis , Arianne Cease , Karen L Sweazea
Although mealworms (Tenebrio molitor) typically consume grains, studies reveal they also consume decaying plant matter, animal waste, and even plastics. The goal of this work was to study mealworms as an emerging model organism to understand how feeding in an urban environment impacts the nutritional composition of insects. We evenly divided 3500 mealworms among each of the following seven substrates designed to model potential food sources in urban versus more natural areas: wheat germ (control); Styrofoam (STY); mixture of soil, grasses, and leaves from urban (UL) or rural lawns (RL); wheat germ with carrot slices (WG + CAR); and organic potting soil in the absence (PS) or presence of Turf Builder (PS + TB). Mealworms were fed for three weeks, after which we measured whole body mass, protein, crude fat, total sugars, glucose, water, and oxidized lipoproteins. No significant differences in nutrient composition were found between mealworms fed soil or lawn substrates. Mealworms fed PS, PS + TB or WG + CAR had lower oxidized lipoproteins compared to the WG diet, likely attributed to antioxidants present in PS and carrots. Mealworms consuming soils or lawns were relatively deficient in proteins, fats, and sugar nutrients compared to WG or WG + CAR, although they maintained higher water content. In contrast, mealworms consuming Styrofoam contained less dietary fat and total sugars than WG or WG + CAR, and less water, but more crude fat, than either soil substrate. These findings demonstrate that mealworms consuming urban-associated substrates (i.e. potting soil, lawns, Styrofoam) are nutritionally deficient compared to those consuming wheat germ with or without carrots.
{"title":"Urban substrates alter the nutritional composition of an emerging model insect, Tenebrio molitor","authors":"Rory Lockett , Milena Figueiredo de Sousa , Katherine A Nicoluzakis , Arianne Cease , Karen L Sweazea","doi":"10.1016/j.jinsphys.2025.104892","DOIUrl":"10.1016/j.jinsphys.2025.104892","url":null,"abstract":"<div><div>Although mealworms (<em>Tenebrio molitor</em>) typically consume grains, studies reveal they also consume decaying plant matter, animal waste, and even plastics. The goal of this work was to study mealworms as an emerging model organism to understand how feeding in an urban environment impacts the nutritional composition of insects. We evenly divided 3500 mealworms among each of the following seven substrates designed to model potential food sources in urban versus more natural areas: wheat germ (control); Styrofoam (STY); mixture of soil, grasses, and leaves from urban (UL) or rural lawns (RL); wheat germ with carrot slices (WG + CAR); and organic potting soil in the absence (PS) or presence of Turf Builder (PS + TB). Mealworms were fed for three weeks, after which we measured whole body mass, protein, crude fat, total sugars, glucose, water, and oxidized lipoproteins. No significant differences in nutrient composition were found between mealworms fed soil or lawn substrates. Mealworms fed PS, PS + TB or WG + CAR had lower oxidized lipoproteins compared to the WG diet, likely attributed to antioxidants present in PS and carrots. Mealworms consuming soils or lawns were relatively deficient in proteins, fats, and sugar nutrients compared to WG or WG + CAR, although they maintained higher water content. In contrast, mealworms consuming Styrofoam contained less dietary fat and total sugars than WG or WG + CAR, and less water, but more crude fat, than either soil substrate. These findings demonstrate that mealworms consuming urban-associated substrates (i.e. potting soil, lawns, Styrofoam) are nutritionally deficient compared to those consuming wheat germ with or without carrots.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"166 ","pages":"Article 104892"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232645","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}
Pub Date : 2025-09-26DOI: 10.1016/j.jinsphys.2025.104891
Judit Gonzalvo , Nuria Farrus , Jorge Escudero , Petra Berková , Martin Moos , Marcela Nouzova , Fernando G. Noriega , David Pujal , Josep Bau , Maria-Dolors Piulachs
PIWI-interacting RNAs (piRNAs) are small non-coding RNAs, typically 26 to 31 nucleotides long, originally known for silencing transposable elements (TEs), thus maintaining genomic stability. However, recent research has revealed additional regulatory roles. In this study, we investigate piRNA-305221, which is highly expressed in the ovaries of the German cockroach, Blattella germanica, to understand its involvement in oogenesis and reproduction. piRNA-305221 is found in germinal and somatic cells during the gonadotropic cycle, and is maternally provided to the egg. Its expression correlates with critical ovarian events, such as endoreplication and follicular cell differentiation, suggesting regulatory functions beyond TE silencing. Functional knockdown using antisense oligonucleotides (ASOs) resulted in delayed oviposition, malformed oothecae, and reduced offspring viability. Gene expression analysis revealed that the reduction of piRNA-305221 decreased shade (Cyp314a1) mRNA levels, impairing the conversion of ecdysone to its active form, 20-hydroxyecdysone, and a concomitant increase in expression of upstream steroidogenic genes (spook (Cyp307a1), phantom (Cyp306a1), disembodied (Cyp302a1)). These results indicate that piRNA-305221 may regulate steroidogenesis through direct or indirect control of mRNA targets. This study highlights the broader regulatory functions of piRNAs and demonstrates the utility of ASO-mediated knockdown in functional studies of non-coding RNAs.
{"title":"A piRNA modulates the levels of 20-hydroxyecdysone in the ovary of the German cockroach","authors":"Judit Gonzalvo , Nuria Farrus , Jorge Escudero , Petra Berková , Martin Moos , Marcela Nouzova , Fernando G. Noriega , David Pujal , Josep Bau , Maria-Dolors Piulachs","doi":"10.1016/j.jinsphys.2025.104891","DOIUrl":"10.1016/j.jinsphys.2025.104891","url":null,"abstract":"<div><div>PIWI-interacting RNAs (piRNAs) are small non-coding RNAs, typically 26 to 31 nucleotides long, originally known for silencing transposable elements (TEs), thus maintaining genomic stability. However, recent research has revealed additional regulatory roles. In this study, we investigate piRNA-305221, which is highly expressed in the ovaries of the German cockroach, <em>Blattella germanica</em>, to understand its involvement in oogenesis and reproduction. piRNA-305221 is found in germinal and somatic cells during the gonadotropic cycle, and is maternally provided to the egg. Its expression correlates with critical ovarian events, such as endoreplication and follicular cell differentiation, suggesting regulatory functions beyond TE silencing. Functional knockdown using antisense oligonucleotides (ASOs) resulted in delayed oviposition, malformed oothecae, and reduced offspring viability. Gene expression analysis revealed that the reduction of piRNA-305221 decreased <em>shade</em> (Cyp314a1) mRNA levels, impairing the conversion of ecdysone to its active form, 20-hydroxyecdysone, and a concomitant increase in expression of upstream steroidogenic genes (<em>spook</em> (Cyp307a1), <em>phantom</em> (Cyp306a1), <em>disembodied</em> (Cyp302a1)). These results indicate that piRNA-305221 may regulate steroidogenesis through direct or indirect control of mRNA targets. This study highlights the broader regulatory functions of piRNAs and demonstrates the utility of ASO-mediated knockdown in functional studies of non-coding RNAs.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"166 ","pages":"Article 104891"},"PeriodicalIF":2.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145186165","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}
Pub Date : 2025-09-24DOI: 10.1016/j.jinsphys.2025.104890
María C. Viegas , Federico H. Gomez , Mariana Loyo Anguiano, Fabian M. Norry
Desiccation stress is one of the most critical stress forms in terrestrial environments under climate change and global warming. To search for genetic variation and any possible associations between lifespan after desiccation and two morphometric traits of head in flies, we used two sets of recombinant inbred lines (RIL) of Drosophila melanogaster. Desiccation survival was measured as lifespan at 25 °C by exposing flies to a desiccation environment for 1.5 h at 2, 4, and 6 days of age. This desiccation treatment decreased dramatically (2.5 times, in average) lifespan in treated flies as compared to control flies. There was high variation in desiccation survival across lines within each of two RIL panels, with mean survival ranging between 5 and 27 days across RIL. Composite interval mapping revealed 5 QTLs, all of them on chromosome 2 in females. The genetic basis of survival after desiccation episodes was found to be partially different from the genetic basis of survival under permanent desiccation studied previously in these RIL. Desiccation survival (lifespan after desiccation stress) was significantly correlated not to body size but rather to two parts of the head capsule that are well known to be related in a trade-off in Drosophila: frons and eye size. These associations between lifespan and head morphology appeared after non-lethal desiccation episodes rather than under permanent desiccation stress.
{"title":"Lifespan after desiccation stress is genetically variable and partially associated to head traits in a set of recombinant lines in Drosophila melanogaster","authors":"María C. Viegas , Federico H. Gomez , Mariana Loyo Anguiano, Fabian M. Norry","doi":"10.1016/j.jinsphys.2025.104890","DOIUrl":"10.1016/j.jinsphys.2025.104890","url":null,"abstract":"<div><div>Desiccation stress is one of the most critical stress forms in terrestrial environments under climate change and global warming. To search for genetic variation and any possible associations between lifespan after desiccation and two morphometric traits of head in flies, we used two sets of recombinant inbred lines (RIL) of <em>Drosophila melanogaster</em>. Desiccation survival was measured as lifespan at 25 °C by exposing flies to a desiccation environment for 1.5 h at 2, 4, and 6 days of age. This desiccation treatment decreased dramatically (2.5 times, in average) lifespan in treated flies as compared to control flies. There was high variation in desiccation survival across lines within each of two RIL panels, with mean survival ranging between 5 and 27 days across RIL. Composite interval mapping revealed 5 QTLs, all of them on chromosome 2 in females. The genetic basis of survival after desiccation episodes was found to be partially different from the genetic basis of survival under permanent desiccation studied previously in these RIL. Desiccation survival (lifespan after desiccation stress) was significantly correlated not to body size but rather to two parts of the head capsule that are well known to be related in a trade-off in Drosophila: frons and eye size. These associations between lifespan and head morphology appeared after non-lethal desiccation episodes rather than under permanent desiccation stress.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"166 ","pages":"Article 104890"},"PeriodicalIF":2.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155602","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}
Pub Date : 2025-09-20DOI: 10.1016/j.jinsphys.2025.104888
Zi-Jing Zheng , Shen-Lei Li , Shu-Ting Fan , Ze-Yuan Zhang , Shang-Huan Huang , Xi-Yu Ye , Guan-Heng Zhu
The fall armyworm, Spodoptera frugiperda, is a key lepidopteran pest of numerous agricultural and industrial crops worldwide. The effects of environmental factors, such as light, on the behavior of the fall armyworm have been poorly studied. Here, in this study, CRISPR/Cas9 was employed to generate a germline knockout of the eye color genes, cinnabar and cardinal. The homozygous cinnabar mutants (cin−/−) initially exhibited a pale-yellow eye phenotype, which gradually deepened to red over time, while wild-type with black compound eyes. The cin−/− were used for behavioral observations, indicating that adult mutants exhibited abnormal rhythmic patterns in eclosion, mating, and oviposition behaviors, suggesting that rhythmicity was significantly disrupted due to the loss of eye pigmentation. At two days post-eclosion observation of paraffin sections revealed that the pigment in the compound eye almost completely disappeared. Further, real-time quantitative PCR revealed that the expression of photosensitive and rhythm genes was completely disordered. These findings showed that the presence of cinnabar is essential for the color of the compound eye and is necessary for the fall armyworm to adjust the rhythms by sensing light through compound eye pigmentation, providing new insights into the relationship between eye and circadian rhythms in insects.
{"title":"Cinnabar-dependent eye pigmentation mediates light input for circadian behavior synchronization in Spodoptera frugiperda","authors":"Zi-Jing Zheng , Shen-Lei Li , Shu-Ting Fan , Ze-Yuan Zhang , Shang-Huan Huang , Xi-Yu Ye , Guan-Heng Zhu","doi":"10.1016/j.jinsphys.2025.104888","DOIUrl":"10.1016/j.jinsphys.2025.104888","url":null,"abstract":"<div><div>The fall armyworm, <em>Spodoptera frugiperda</em>, is a key lepidopteran pest of numerous agricultural and industrial crops worldwide. The effects of environmental factors, such as light, on the behavior of the fall armyworm have been poorly studied. Here, in this study, CRISPR/Cas9 was employed to generate a germline knockout of the eye color genes, <em>cinnabar</em> and <em>cardinal</em>. The homozygous <em>cinnabar</em> mutants (<em>cin<sup>−/−</sup></em>) initially exhibited a pale-yellow eye phenotype, which gradually deepened to red over time, while wild-type with black compound eyes. The <em>cin<sup>−/−</sup></em> were used for behavioral observations, indicating that adult mutants exhibited abnormal rhythmic patterns in eclosion, mating, and oviposition behaviors, suggesting that rhythmicity was significantly disrupted due to the loss of eye pigmentation. At two days post-eclosion observation of paraffin sections revealed that the pigment in the compound eye almost completely disappeared. Further, real-time quantitative PCR revealed that the expression of photosensitive and rhythm genes was completely disordered. These findings showed that the presence of <em>cinnabar</em> is essential for the color of the compound eye and is necessary for the fall armyworm to adjust the rhythms by sensing light through compound eye pigmentation, providing new insights into the relationship between eye and circadian rhythms in insects.</div></div>","PeriodicalId":16189,"journal":{"name":"Journal of insect physiology","volume":"166 ","pages":"Article 104888"},"PeriodicalIF":2.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119352","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}
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