{"title":"Stingless bee foragers experience more thermally stressful microclimates and have wider thermal tolerance breadths than other worker subcastes","authors":"Kristin M. Robinson, Kaitlin M. Baudier","doi":"10.3389/fevo.2024.1405459","DOIUrl":null,"url":null,"abstract":"IntroductionThe current state of anthropogenic climate change is particularly concerning for tropical insects, species predicted to be the most negatively affected. Researching climatic tolerance in social insects is challenging because adaptations exist at both individual and societal levels. Division of labor research helps to bridge the gap between our understanding of these adaptations at different scales, which is important because social insects comprise a tremendous portion of global animal biomass, biodiversity, and ecosystem services. Considering how individual physiologies construct group-level adaptations can improve climate change impact assessments for social species. <jats:italic>Tetragonisca angustula</jats:italic> is a neotropical stingless bee species that exhibits high worker subcaste specialization with a morphologically distinct soldier caste.MethodsWe used this species to investigate 1) whether age- and size-differentiated subcastes differ in thermal tolerance, 2) which worker subcaste operates closest to their thermal limits, and 3) the extent to which this species selects active foraging times to offset thermal stress. We measured the thermal tolerance (CT<jats:sub>max</jats:sub> and CT<jats:sub>min</jats:sub>) of small-bodied foragers and two soldier subcastes (hovering guards and standing guards) in <jats:italic>T. angustula</jats:italic>.Results and discussionDespite body size differences between foragers and guards, no differences in the upper or lower thermal limits were observed. However, the average thermal tolerance breadth of foragers was significantly larger than that of guards, and foraging sites were more thermally variable than nest sites, supporting the Climatic Variability Hypothesis at a microclimate scale and in the context of division of labor. Warming tolerance was significantly lower among small-bodied foragers compared to hovering and standing guards. The magnitude of warming tolerances indicated low risk of imminent climate change impacts in this environment but suggests that increasing temperatures and heatwave prevalence may cause foragers to meet their upper thermal limits before other subcastes. Foraging occurred at a narrower range of temperatures than would challenge critical temperatures, with higher morning activity. Directionally increasing temperatures will likely confine these preferred foraging temperatures to a narrower time window. Further study is needed to elucidate how foragers may shift times of activity in response to anthropogenic warming, but changing climates may impact plant pollination rates in natural and agricultural systems.","PeriodicalId":12367,"journal":{"name":"Frontiers in Ecology and Evolution","volume":"42 1","pages":""},"PeriodicalIF":2.4000,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Ecology and Evolution","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.3389/fevo.2024.1405459","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
IntroductionThe current state of anthropogenic climate change is particularly concerning for tropical insects, species predicted to be the most negatively affected. Researching climatic tolerance in social insects is challenging because adaptations exist at both individual and societal levels. Division of labor research helps to bridge the gap between our understanding of these adaptations at different scales, which is important because social insects comprise a tremendous portion of global animal biomass, biodiversity, and ecosystem services. Considering how individual physiologies construct group-level adaptations can improve climate change impact assessments for social species. Tetragonisca angustula is a neotropical stingless bee species that exhibits high worker subcaste specialization with a morphologically distinct soldier caste.MethodsWe used this species to investigate 1) whether age- and size-differentiated subcastes differ in thermal tolerance, 2) which worker subcaste operates closest to their thermal limits, and 3) the extent to which this species selects active foraging times to offset thermal stress. We measured the thermal tolerance (CTmax and CTmin) of small-bodied foragers and two soldier subcastes (hovering guards and standing guards) in T. angustula.Results and discussionDespite body size differences between foragers and guards, no differences in the upper or lower thermal limits were observed. However, the average thermal tolerance breadth of foragers was significantly larger than that of guards, and foraging sites were more thermally variable than nest sites, supporting the Climatic Variability Hypothesis at a microclimate scale and in the context of division of labor. Warming tolerance was significantly lower among small-bodied foragers compared to hovering and standing guards. The magnitude of warming tolerances indicated low risk of imminent climate change impacts in this environment but suggests that increasing temperatures and heatwave prevalence may cause foragers to meet their upper thermal limits before other subcastes. Foraging occurred at a narrower range of temperatures than would challenge critical temperatures, with higher morning activity. Directionally increasing temperatures will likely confine these preferred foraging temperatures to a narrower time window. Further study is needed to elucidate how foragers may shift times of activity in response to anthropogenic warming, but changing climates may impact plant pollination rates in natural and agricultural systems.
期刊介绍:
Frontiers in Ecology and Evolution publishes rigorously peer-reviewed research across fundamental and applied sciences, to provide ecological and evolutionary insights into our natural and anthropogenic world, and how it should best be managed. Field Chief Editor Mark A. Elgar at the University of Melbourne is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics and the public worldwide.
Eminent biologist and theist Theodosius Dobzhansky’s astute observation that “Nothing in biology makes sense except in the light of evolution” has arguably even broader relevance now than when it was first penned in The American Biology Teacher in 1973. One could similarly argue that not much in evolution makes sense without recourse to ecological concepts: understanding diversity — from microbial adaptations to species assemblages — requires insights from both ecological and evolutionary disciplines. Nowadays, technological developments from other fields allow us to address unprecedented ecological and evolutionary questions of astonishing detail, impressive breadth and compelling inference.
The specialty sections of Frontiers in Ecology and Evolution will publish, under a single platform, contemporary, rigorous research, reviews, opinions, and commentaries that cover the spectrum of ecological and evolutionary inquiry, both fundamental and applied. Articles are peer-reviewed according to the Frontiers review guidelines, which evaluate manuscripts on objective editorial criteria. Through this unique, Frontiers platform for open-access publishing and research networking, Frontiers in Ecology and Evolution aims to provide colleagues and the broader community with ecological and evolutionary insights into our natural and anthropogenic world, and how it might best be managed.