{"title":"外部寄主越冬寄生虫在成虫阶段如何应对寒冷?","authors":"","doi":"10.1016/j.jtherbio.2024.103940","DOIUrl":null,"url":null,"abstract":"<div><h3>Introduction</h3><p>When overwintering, most endoparasitoids are protected from the cold inside their hosts. However, some endoparasitoids, along with ectoparasitoids, fall into the category called outside-hosts-overwintering parasitoids (OHOP) at immature or adult stages. We compared the cold-hardiness capacity and strategy between adult OHOP and their hosts (HOST) by examining their supercooling points (SCP), with acclimation periods and acclimation temperatures, and their lower lethal temperatures at 50% mortality (LLT50). We hypothesized that OHOP are more cold-hardy than their HOST, with lower SCP and LLT50.</p></div><div><h3>Materials and methods</h3><p>Throughout the summers of 2020, 2021, and 2022, adult cabbage seedpod weevils (HOST) were sampled with a sweep net at the canola pod stage, and thousands of pods were collected and placed in emergence boxes to retrieve the adult OHOP <em>Trichomalus perfectus</em>. Regarding SCP measures, OHOP and HOST were separated according to various treatments. Each treatment considered a target exposure temperature (5, 10, or 20 °C) or a target exposure period (5, 15 or 25 days) at 5 °C. Regarding LLT measures, OHOP and HOST were categorized into five treatments, each corresponding to a specific exposure temperature (−5, −10, −15, −20 or −25 °C).</p></div><div><h3>Results and conclusion</h3><p>Acclimations to a lower temperature (5 °C) and a longer period (25 days) led to a significantly lower SCP of OHOP than HOST. Regarding OHOP, the average SCP was −19.71 °C when the acclimation temperature was 20 °C and significantly decreased to −23.20 °C when it was 5 °C. The average SCP was −18.82 °C when the acclimation period was five days and significantly decreased to −23.20 °C when it was 25 days. Conversely, the average SCP for HOST was never below −20 °C. At 20 °C acclimation temperature, HOST exhibited a significantly higher SCP of −14.64 °C compared to acclimations at 5 °C (−19.19 °C) and 10 °C (−20.00 °C), but there were no significant differences between 5 and 10 °C nor between acclimation periods. Therefore, the adult OHOP is more cold-hardy than its HOST. OHOP also exhibited a lower LLT50 than HOST, with −19.20 °C <em>versus</em> −17.59 °C. Finally, OHOP and HOST employ the same freeze-avoidance strategy, as evidenced by their SCP values (−19.57 °C <em>versus</em> −16.80 °C) which closely align with their respective LLT50. Adult OHOP better survive winter than their HOST in cold environments.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S030645652400158X/pdfft?md5=6a447b7695cd0399fc9443f484cfbeb5&pid=1-s2.0-S030645652400158X-main.pdf","citationCount":"0","resultStr":"{\"title\":\"How do outside-hosts-overwintering parasitoids, at the adult stage, cope with cold?\",\"authors\":\"\",\"doi\":\"10.1016/j.jtherbio.2024.103940\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Introduction</h3><p>When overwintering, most endoparasitoids are protected from the cold inside their hosts. However, some endoparasitoids, along with ectoparasitoids, fall into the category called outside-hosts-overwintering parasitoids (OHOP) at immature or adult stages. We compared the cold-hardiness capacity and strategy between adult OHOP and their hosts (HOST) by examining their supercooling points (SCP), with acclimation periods and acclimation temperatures, and their lower lethal temperatures at 50% mortality (LLT50). We hypothesized that OHOP are more cold-hardy than their HOST, with lower SCP and LLT50.</p></div><div><h3>Materials and methods</h3><p>Throughout the summers of 2020, 2021, and 2022, adult cabbage seedpod weevils (HOST) were sampled with a sweep net at the canola pod stage, and thousands of pods were collected and placed in emergence boxes to retrieve the adult OHOP <em>Trichomalus perfectus</em>. Regarding SCP measures, OHOP and HOST were separated according to various treatments. Each treatment considered a target exposure temperature (5, 10, or 20 °C) or a target exposure period (5, 15 or 25 days) at 5 °C. Regarding LLT measures, OHOP and HOST were categorized into five treatments, each corresponding to a specific exposure temperature (−5, −10, −15, −20 or −25 °C).</p></div><div><h3>Results and conclusion</h3><p>Acclimations to a lower temperature (5 °C) and a longer period (25 days) led to a significantly lower SCP of OHOP than HOST. Regarding OHOP, the average SCP was −19.71 °C when the acclimation temperature was 20 °C and significantly decreased to −23.20 °C when it was 5 °C. The average SCP was −18.82 °C when the acclimation period was five days and significantly decreased to −23.20 °C when it was 25 days. Conversely, the average SCP for HOST was never below −20 °C. At 20 °C acclimation temperature, HOST exhibited a significantly higher SCP of −14.64 °C compared to acclimations at 5 °C (−19.19 °C) and 10 °C (−20.00 °C), but there were no significant differences between 5 and 10 °C nor between acclimation periods. Therefore, the adult OHOP is more cold-hardy than its HOST. OHOP also exhibited a lower LLT50 than HOST, with −19.20 °C <em>versus</em> −17.59 °C. Finally, OHOP and HOST employ the same freeze-avoidance strategy, as evidenced by their SCP values (−19.57 °C <em>versus</em> −16.80 °C) which closely align with their respective LLT50. Adult OHOP better survive winter than their HOST in cold environments.</p></div>\",\"PeriodicalId\":17428,\"journal\":{\"name\":\"Journal of thermal biology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-08-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S030645652400158X/pdfft?md5=6a447b7695cd0399fc9443f484cfbeb5&pid=1-s2.0-S030645652400158X-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of thermal biology\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S030645652400158X\",\"RegionNum\":2,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of thermal biology","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S030645652400158X","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOLOGY","Score":null,"Total":0}
How do outside-hosts-overwintering parasitoids, at the adult stage, cope with cold?
Introduction
When overwintering, most endoparasitoids are protected from the cold inside their hosts. However, some endoparasitoids, along with ectoparasitoids, fall into the category called outside-hosts-overwintering parasitoids (OHOP) at immature or adult stages. We compared the cold-hardiness capacity and strategy between adult OHOP and their hosts (HOST) by examining their supercooling points (SCP), with acclimation periods and acclimation temperatures, and their lower lethal temperatures at 50% mortality (LLT50). We hypothesized that OHOP are more cold-hardy than their HOST, with lower SCP and LLT50.
Materials and methods
Throughout the summers of 2020, 2021, and 2022, adult cabbage seedpod weevils (HOST) were sampled with a sweep net at the canola pod stage, and thousands of pods were collected and placed in emergence boxes to retrieve the adult OHOP Trichomalus perfectus. Regarding SCP measures, OHOP and HOST were separated according to various treatments. Each treatment considered a target exposure temperature (5, 10, or 20 °C) or a target exposure period (5, 15 or 25 days) at 5 °C. Regarding LLT measures, OHOP and HOST were categorized into five treatments, each corresponding to a specific exposure temperature (−5, −10, −15, −20 or −25 °C).
Results and conclusion
Acclimations to a lower temperature (5 °C) and a longer period (25 days) led to a significantly lower SCP of OHOP than HOST. Regarding OHOP, the average SCP was −19.71 °C when the acclimation temperature was 20 °C and significantly decreased to −23.20 °C when it was 5 °C. The average SCP was −18.82 °C when the acclimation period was five days and significantly decreased to −23.20 °C when it was 25 days. Conversely, the average SCP for HOST was never below −20 °C. At 20 °C acclimation temperature, HOST exhibited a significantly higher SCP of −14.64 °C compared to acclimations at 5 °C (−19.19 °C) and 10 °C (−20.00 °C), but there were no significant differences between 5 and 10 °C nor between acclimation periods. Therefore, the adult OHOP is more cold-hardy than its HOST. OHOP also exhibited a lower LLT50 than HOST, with −19.20 °C versus −17.59 °C. Finally, OHOP and HOST employ the same freeze-avoidance strategy, as evidenced by their SCP values (−19.57 °C versus −16.80 °C) which closely align with their respective LLT50. Adult OHOP better survive winter than their HOST in cold environments.
期刊介绍:
The Journal of Thermal Biology publishes articles that advance our knowledge on the ways and mechanisms through which temperature affects man and animals. This includes studies of their responses to these effects and on the ecological consequences. Directly relevant to this theme are:
• The mechanisms of thermal limitation, heat and cold injury, and the resistance of organisms to extremes of temperature
• The mechanisms involved in acclimation, acclimatization and evolutionary adaptation to temperature
• Mechanisms underlying the patterns of hibernation, torpor, dormancy, aestivation and diapause
• Effects of temperature on reproduction and development, growth, ageing and life-span
• Studies on modelling heat transfer between organisms and their environment
• The contributions of temperature to effects of climate change on animal species and man
• Studies of conservation biology and physiology related to temperature
• Behavioural and physiological regulation of body temperature including its pathophysiology and fever
• Medical applications of hypo- and hyperthermia
Article types:
• Original articles
• Review articles