Neotropical Species Research Articles

Sequencing and Description of the Mitochondrial Genome of Orthopodomyia fascipes (Diptera: Culicidae).

The genus Orthopodomyia Theobald, 1904 (Diptera: Culicidae) comprises 36 wild mosquito species, with distribution largely restricted to tropical and temperate areas, most of which are not recognized as vectors of epidemiological importance due to the lack of information related to their bionomy and involvement in the cycle transmission of infectious agents. Furthermore, their evolutionary relationships are not completely understood, reflecting the scarcity of genetic information about the genus. Therefore, in this study, we report the first complete description of the mitochondrial genome of a Neotropical species representing the genus, Orthopodomyia fascipes Coquillet, 1906, collected in the Brazilian Amazon region. Using High Throughput Sequencing, we obtained a mitochondrial sequence of 15,598 bp, with an average coverage of 418.5×, comprising 37 functional subunits and a final portion rich in A + T, corresponding to the control region. The phylogenetic analysis, using Maximum Likelihood and Bayesian Inference based on the 13 protein-coding genes, corroborated the monophyly of Culicidae and its two subfamilies, supporting the proximity between the tribes Orthopodomyiini and Mansoniini, partially disagreeing with previous studies based on the use of molecular and morphological markers. The information generated in this study contributes to a better understanding of the taxonomy and evolutionary history of the genus and other groups of Culicidae.

Breeding records of 325 bird species from Peru over 21 years based on citizen science data

AbstractBreeding is a key component of the life history of birds. Documenting diverse aspects of their breeding biology provides valuable natural history data that can be used to address questions of evolutionary, ecological, or conservation significance. Despite its importance, this information is scarce for most Neotropical species. We compiled 1180 breeding records corresponding to 325 bird species for the period 2000–2021, through an in‐depth review of photo or video records from Peru, sourced from Macaulay Library and iNaturalist platforms. We determined the geographical distribution of the breeding records, described patterns of activity and nesting behavior (i.e., host plant preference and clutch size), and explored the timing of breeding. Our study represents one of the few efforts to provide nationwide data on breeding birds in the Neotropical region. We also offer broad taxonomic coverage for further studies interested in testing hypotheses on the variation of reproductive traits and timing at both local and regional scales. The complete data set for this abstract published in the Data Article section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2024-07.1/jalter-en.

Prevalence and Risk Factors of Bone and Dental Lesions in Neotropical Deer.

Bone and dental lesions have been documented in various deer species globally, affecting the efficiency of ingestion and digestion, consequently influencing their general health and leading to a decline in survival and reproductive performance. The present study aimed to characterize bone and dental lesions in the dry skulls of individual deer, estimate the prevalence of these lesions, and assess potential risk factors associated with the development of bone and dental alterations. This study assessed bone and dental lesions in 180 dry skulls of eleven neotropical deer species, originating from both captivity and wildlife conditions, through direct visual inspection. A high prevalence of bone and dental lesions was observed in all analyzed species. Dental calculus was the most common alteration (96.7%), followed by dental wear (71.1%). Animal age positively correlated with most bone and dental alterations, indicating that older animals showed more lesions. Additionally, the prevalence of these alterations was similar between sexes. Moreover, all lesions were more common in captive-bred animals, likely attributed to their older age and a less diverse diet. Blastocerus dichotomus and Mazama americana were most affected by bone resorption and dental trauma and had the highest dental calculus prevalence, along with Subulo gouazoubira and Passalites nemorivagus. All eleven species evaluated in the present study were susceptible to the occurrence of bone and dental lesions. Therefore, monitoring oral health and diet in captivity are fundamental practices for the conservation of these species.

New cave species of Cyphoderus Nicolet and Pararrhopalites Bonet & Tellez (Hexapoda, Collembola) from Caatinga biome, Brazil

In recent years, surveys have revealed a high diversity of troglophilic and troglobitic species of Brazilian Collembola, mainly represented by the Entomobryidae and Sminthuridae, which hold some representative genera in Brazilian caves such as Cyphoderus Nicolet and Pararrhopalites Bonet & Tellez. Here we describe in detail two new species of these genera sampled from caves of the semiarid region of Rio Grande do Norte state, Brazil. Cyphoderus caatinguensis sp. nov. is similar to other Neotropical species of the tridenticulati group, but it is unique by the combination of labial chaetotaxy, ungues with a filamentous apical tooth and number of feathered chaetae on the dorsal face of the dens. Pararrhopalites iataganii sp. nov. differs from other Neotropical species of the genus especially by the number of subsegments of the fourth antennomere, number of cephalic spines, manubrium chaetotaxy and ventral dens formula. Recognition of these species enhances our understanding of the subterranean fauna in the Neotropics, and their identification may support future conservation policies for caves of the Rio Grande do Norte state, Brazil.

First record of the genus Tetradonia Wasmann, 1894 (Coleoptera: Staphylinidae: Aleocharinae) in Colombia, with description of two new species

This paper describes and illustrates two new species of the genus Tetradonia Wasmann, 1894 (Staphylinidae: Aleocharinae), discovered in the Eastern Andes of Colombia: T. vonbeerensis Gualdrón-Diaz & Chani-Posse sp. n. and T. ramirezi Gualdrón-Diaz & Chani-Posse sp. n. This report marks the first documented presence of the genus in Colombia. Furthermore, our findings contribute to an increased understanding of Neotropical Tetradonia species, bringing the total known species count to forty-one.

A conversion proposal for biomass estimates in termites

AbstractTermites (Isoptera) constitute a considerable fraction of the global animal biomass. Conventionally, termite dry biomass estimates (g) range between 1:3 and 1:6 of fresh biomass (g). But estimates are often based on a few species or coarse taxonomic resolution. In this study, we (1) calculated the fresh and dry mass of 15 widely distributed Neotropical termite species (three families) and (2) established the conversion ratio for dry mass, which is indispensable for biomass estimates. Workers and soldiers were sampled in their colonies and quickly weighed in the laboratory to obtain the fresh mass. Then, the individuals were placed in 80% alcohol for 5 days and weighed. Finally, the samples were dried at 60°C for 24 h and weighed again. Our results suggest an average ratio of 1:4.2 (dry‐to‐fresh mass), with a mean (±SE) conversion ratio of 0.24 ± 0.06, for estimating termite biomass at local, regional, and global scales. Moreover, our results demonstrate that values from termites preserved in alcohol could still be used to estimate biomass. Specifically, after insertion in alcohol, the termites lost 16.9%–56% of their water content, with an average of 26.5%. While this represents a source of bias in estimates using samples from biological collections, dry mass was significantly related to fresh mass ( = 0.99; dry mass = 0.000055 + 0.22 × fresh mass), and to the mass of termites in alcohol ( = 0.97; dry mass = 0.00014 + 0.26 × mass in alcohol). Applying our results to data from the literature indicates that global termite dry biomass ranges from 89 to 106 Mt.

Primordial germ cells of Astyanax altiparanae, isolated and recovered intact after vitrification: A preliminary study for potential cryopreservation of Neotropical fish germplasm

Primordial germ cells (PGCs) constitute an important cell lineage that directly impacts genetic dissemination and species conservation through the creation of cryobanks. In order to advance the field of animal genetic cryopreservation, this work aimed to recover intact PGCs cryopreserved in embryonic tissues during the segmentation phase for subsequent in vitro maintenance, using the yellow-tailed tetra (Astyanax altiparanae) as a model organism. For this, a total of 202 embryos were distributed in two experiments. In the first experiment, embryos in the segmentation phase were dissociated, and isolated PGCs were maintained in vitro. They were visualized using gfp-Pm-ddx4 3′UTR labeling. The second experiment aimed to vitrify PGCs using 3 cryoprotective agents or CPAs (dimethyl sulfoxide, ethylene glycol, and 1,2 propanediol) at 3 molarities (2, 3, and 4 M). The toxicity, somatic cell viability, and recovery of intact PGCs were evaluated. After cryopreservation and thawing, 2 M ethylene glycol produced intact PGCs and somatic cells (44 ± 11.52 % and 42.35 ± 0.33 %, respectively) post-thaw. The recovery of PGCs from frozen embryonic tissues was not possible without the use of CPAs. Thus, the vitrification of PGCs from an important developmental model and Neotropical species such as A. altiparanae was achieved, and the process of isolating and maintaining PGCs in a culture medium was successful. Therefore, to ensure the maintenance of genetic diversity, PGCs obtained during embryonic development in the segmentation phase between 25 and 28 somites were stored through vitrification for future applications in the reconstitution of species through germinal chimerism.

Notes on the genus Elegansovella Hirschmann, 1989 (Acari, Mesostigmata, Urodinychidae)

The genus Elegansovella Hirschmann, 1989 (Mesostigmata: Uropodina: Urodinychidae) is resurrected for species of the Uroobovella elegans-group. This genus differs from the other taxa of Uroobovella Berlese, 1903 sensu lato based on the shape of the idiosoma and the caudal and dorsal setae. Three species from the Uroobovella elegans-group are transferred to the genus Elegansovella, as E. pectintata (Hirschmann, 1973), comb. nov., E. pectinatasimilis (Hiramatsu, 1980), comb. nov. and E. serangensis (Hiramatsu, 1980), comb. nov. The other seven species from this species group are transferred to Monstrobovellagen. nov., as M. crustosa (Vitzthum, 1926), comb. nov., M. enodis (Hiramatsu, 1985), comb. nov., M. faceta (Hiramatsu & Hirschmann, 1978), comb. nov., M. facetaoides (Hiramatsu & Hirschmann, 1978), comb. nov., M. imadatei (Hiramatsu, 1980), comb. nov., M. incerta (Hiramatsu & Hirschmann, 1978), comb. nov. and M. incertaoides (Hiramatsu & Hirschmann, 1978), comb. nov. The new genus differs from Elegansovella by the shape of the idiosoma and the shape of marginal and dorsal setae. Six Monstrobovella species occur in the Oriental Realm and only one species is known from the Neotropical region. The present paper contains the description of a second Neotropical species of Monstrobovella (M. mancocapacisp. nov.) which was found in Peru. The new species differs from its Neotropical congener in the dorsal and marginal setation.

Influence of plant growth-promoting bacteria on leaf carbon and nitrogen metabolism of two drought-stressed neotropical tree species: a metabolomic approach.

Deforestation of Atlantic Forest has caused prolonged drought events in the last decades. The need for reforestation is growing, and the development of native seedlings that are more tolerant to drought stress is necessary. A biotechnological tool that improves plant tolerance is the use of plant growth-promoting bacteria (PGPB) as inoculants. Two species of PGPB were inoculated in drought-stressed seedlings of two neotropical tree species that have been used in environmental restoration programs: Cecropia pachystachya and Cariniana estrellensis. Biometrical, physiological, and metabolomic parameters from carbon and nitrogen pathways were evaluated. We found that the PGPB positively influenced photosynthesis and growth parameters in both trees under drought. The enzymes activities, the tricarboxylic acid cycle intermediates, the amino acids, and protein contents were also influenced by the PGPB treatments. The results allowed us to find the specific composition of secondary metabolites of each plant species. This study provides evidence that there is not a single mechanism involved in drought tolerance and that the inoculation with PGPB promotes a broad-spectrum tolerance response in Neotropical trees. The inoculation with PGPB appears as an important strategy to improve drought tolerance in Atlantic Forest native trees and enhance environmental restoration programs' success. MAIN CONCLUSION: The association with plant growth-promoting bacteria improved the tolerance to drought in Neotropical trees through biochemical, physiological, and biometrical parameters. This can enhance the success of forest restoration programs.

An overview of the drivers of performance in nonbreeding Nearctic–Neotropical migratory songbirds

ABSTRACT Developing conservation and recovery strategies for Nearctic–Neotropical migratory songbirds requires key research because population-limiting factors remain unknown for many species. In particular, the stationary nonbreeding period (sometimes referred to as overwintering) encompasses 6–8 months of the full annual cycle. We conducted a systematic review to assess what is known about the factors that influence individual-level performance (i.e., fitness proxies or indicators of self-maintenance) of Nearctic–Neotropical migratory songbirds during the stationary nonbreeding period. We focused on the metrics of apparent survival, persistence, and body condition (mass-related) indices. We found that 51 of 125 migratory Passeriformes species’ performance has been studied in 57 studies during the nonbreeding period. However, most species appear in only one study; thus, knowledge is skewed toward 3 species appearing in ≥ 10 studies. Body condition indices were the most studied group of metrics and apparent survival was the least studied. Habitat type, food availability, and precipitation were studied much more than other drivers, such as disease and predation. The most studied driver of nonbreeding performance was habitat type. Evidence was found among these studies that suggest that natural habitat types, wetter habitats or precipitation, and high availability of food may positively influence body condition, apparent survival, and persistence. Significant knowledge gaps remain that, if filled, could inform conservation strategies, especially for 59.2% of Passeriformes that are Nearctic–Neotropical migratory species and for areas of the nonbreeding range.

Revisiting the Darwin wasp genus Epelaspis Townes, 1970 (Hymenoptera: Ichneumonidae: Phygadeuontinae): five new species, new records and a key to Neotropical species

The Darwin wasp genus Epelaspis Townes, 1970 (Hymenoptera: Ichneumonidae: Phygadeuontinae) is studied in some countries of South America. We recorded the genus for the first time in Colombia, and five new species are described: Epelaspis boteroi Lima & Fernandes, sp. nov., Epelaspis constantinoi Lima & Fernandes, sp. nov., Epelaspis lulo Lima & Fernandes, sp. nov., Epelaspis tavoi Lima & Fernandes, sp. nov., and Epelaspis wagneri Lima & Fernandes, sp. nov.. Furthermore, E. anorus Townes, 1970 is newly documented for Brazil, while the geographic ranges of E. renatoi Graf & Kumagai, 1996 and E. ketiae Graf & Kumagai, 1996 are extended within the country. Digital images, maps, and a key to Neotropical Epelaspis species are provided.

Genomic Gigantism is not Associated with Reduced Selection Efficiency in Neotropical Salamanders

Genome size variation in eukaryotes has myriad effects on organismal biology from the genomic to whole-organism level. Large genome size may be associated with lower selection efficiency because lower effective population sizes allow fixation of deleterious mutations via genetic drift, increasing genome size and decreasing selection efficiency. Because of a hypothesized negative relationship between genome size and recombination rate per base pair, increased genome size could also increase the effect of linked selection in the genome, decreasing the efficiency with which natural selection can fix or remove mutations. We used a transcriptomic dataset of 15 and a subset of six Neotropical salamander species ranging in genome size from 12 to 87 pg to study the relationship between genome size and efficiency of selection. We estimated dN/dS of salamanders with small and large genomes and tested for relaxation of selection in the larger genomes. Contrary to our expectations, we did not find a significant relationship between genome size and selection efficiency or strong evidence for higher dN/dS values in species with larger genomes for either species set. We also found little evidence for relaxation of selection in species with larger genomes. A positive correlation between genome size and range size (a proxy of population size) in this group disagrees with predictions of stronger drift in species with larger genomes. Our results highlight the complex interactions between the many forces shaping genomic variation in organisms with genomic gigantism.

Humidity and temperature preference in two Neotropical species of sand flies

BackgroundArthropods vector a multitude of human disease-causing organisms, and their geographic ranges are shifting rapidly in response to changing climatic conditions. This is, in turn, altering the landscape of disease risk for human populations that are brought into novel contact with the vectors and the diseases they carry. Sand flies in the genera Lutzomyia and Pintomyia are vectors of serious disease-causing agents such as Leishmania (the etiological agent of leishmaniasis) and may be expanding their range in the face of climate change. Understanding the climatic conditions that vector species both tolerate physiologically and prefer behaviorally is critical to predicting the direction and magnitude of range expansions and the resulting impacts on human health. Temperature and humidity are key factors that determine the geographic extent of many arthropods, including vector species.MethodsWe characterized the habitat of two species of sand flies, Lutzomyia longipalpis and Pintomyia evansi. Additionally, we studied two behavioral factors of thermal fitness–thermal and humidity preference in two species of sand flies alongside a key aspect of physiological tolerance–desiccation resistance.ResultsWe found that Lu. longipalpis is found at cooler and drier conditions than Pi. evansi. Our results also show significant interspecific differences in both behavioral traits, with Pi. evansi preferring warmer, more humid conditions than Lu. longipalpis. Finally, we found that Lu. longipalpis shows greater tolerance to extreme low humidity, and that this is especially pronounced in males of the species.ConclusionsTaken together, our results suggest that temperature and humidity conditions are key aspects of the climatic niche of Lutzomyia and Pintomyia sand flies and underscore the value of integrative studies of climatic tolerance and preference in vector biology.Graphical

Larval ground plan of Platynectes Régimbart, 1879 reconsidered: description of the larvae of three species with phylogenetic considerations (Coleoptera: Adephaga, Dytiscidae)

In this contribution we describe and illustrate for the first time the larvae of three species of Platynectes Régimbart, 1879 (P. agallithoplotes Gustafson, Short & Miller, 2016, P. bakewelli (Clark, 1863), and P. reticulosus (Clark, 1863)) including detailed morphometric and chaetotaxic analyses of selected body structures in order to discover useful characters for distinguishing Platynectes larvae from those of other known Agabinae (Coleoptera: Dytiscidae). A parsimony analysis based on larval characteristics of 19 Agabinae species in six genera (Agabus Leach, 1817, Agabinus Crotch, 1873, Hydrotrupes Sharp, 1882, Ilybiosoma Crotch, 1873, Platynectes, and Platambus Thomson, 1859) was conducted using the program TNT. The results support Platynectes as a natural group whilst the six species studied split into two well supported clades: P. agallithoplotes + P. decemnotatus (Aubé, 1838) and P. curtulus (Régimbart, 1899) + P. davidorum Hájek, Alarie, Šťastný & Vondráček, 2019 + P. reticulosus + P. bakewelli. Larvae of P. agallithoplotes have proven to be characterized by a large number of unique character states, several of which were never observed until now in the Agabinae. Evidence is provided to the effect that the Neotropical species of Platynectes s. str. evolved as a unique lineage within Platynectes.

Molecular differentiation analysis of ten putative species of Fannia (Diptera: Fanniidae) collected in carrion-baited traps from Colombia.

The genus Fannia is the most representative of the Fannidae family of true flies with worldwide distribution. Some species are attracted to decomposing materials and live vertebrate animals, which makes them important in forensics, medical and veterinary fields. However, identifying Fannia species can be difficult due to the high similarity in the external morphology of females and limited descriptions and morphological keys. Herein, molecular markers could provide a complementary tool for species identification. However, molecular identification has still limited application since databases contain few data for neotropical species of Fannia. This study assessed the potential of two molecular markers, the COI-3' region and internal transcribed spacer 2 (ITS2), to differentiate 10 putative species of the genus Fannia from Colombia using distance-based and tree-based approaches. The partial ITS2 and/or COI-3' regions allowed molecular diagnosis of six species, while pairs of species Fannia colazorrensis + F. dodgei and F. laclara + F. aburrae are conflicting. Although these results might suggest that conflicting pair species are conspecific, consistent morphological differences between males do not support this hypothesis. The lack of differentiation at the nuclear and mitochondrial molecular markers for the conflicting species may be due to incomplete evolutionary lineage separation, hybridization, or introgression events. In addition, sexual selection on male morphological traits before species-specific differences in molecular markers emerge may partially explain the results. Our study provides a valuable dataset to identify and confirm some Fannia species molecularly. Further, they could be used to associate females and immature stages with their conspecifics as a baseline to deep into their biology, ecology, distribution and potential applications in forensic and medico-veterinary entomology.

Intercolony Avoidance Optimizes Foraging in Eciton burchellii Army Ants

Foraging individuals optimize spatial movement to maximize resource use in heterogeneous environments. Colonies of Eciton burchellii, a neotropical species of army ant, forage as an army, consuming broad arrays of arthropod and social insect prey. Prey depletion in foraging paths exacerbates resource heterogeneity for E. burchellii and may encourage colonies to avoid contact with recently raided areas. Colonies are known to turn in opposite directions more often than random from previous days’ foraging paths, which increases distances between recently raided areas. However, no evidence of colony avoidance of areas recently foraged by a conspecific colony has been presented. In this study, we analyze data collected in the Peruvian Amazon between 1998 and 2008 to examine colony spatial distribution using nearest-neighbor distance data. We found that colonies optimize movement by choosing foraging angles that deflect away from areas recently raided by conspecific colonies. In addition, we found that the observed nearest neighbor distance between E. burchellii colonies was more significant than expected if colonies were dispersed randomly. This dispersion pattern increases the distance between colonies and contributes to a spatial movement that optimizes foraging and decreases colony interactions at recently raided areas.

Liver damage in two neotropical fish species from a polluted estuarine area

A multi-biomarker approach was used to evaluate the liver health of two Neotropical fish species (Cathorops spixii and Atherinella brasiliensis) that inhabit two different sites of the Paranaguá bay (Paraná – Brazil) and a reference site in the Garatuba bay. Fish were sampled during summer and winter, so the variation of the responses can reflect the actual conditions of sampling sites. Data showed that fish from both sites of the Paranaguá bay are affected by the presence of pollutants from different sources. Both fish species presented adverse biomarker responses mainly in the summer, probably due to the increased human population during the period. Chronic effects in the liver related with the contamination. Thus, the results demonstrated that pollution in Paranaguá bay induce liver damage in fish that inhabit this area.

How to count bird calls? Vocal activity indices may provide different insights into bird abundance and behaviour depending on species traits

Abstract Passive acoustic monitoring (PAM) has become an important tool for surveying birds, and there is a growing demand for approaches to obtain abundance and behavioural information from PAM recordings. Changes in bird populations have been assessed by counting recorded calls and calculating the vocal activity rate (VAR, i.e. the number of calls per recording time). However, bird calls could be counted in various ways and depending on species traits, these call counts could give us different insights on bird abundance, vocal behaviour and/or habitat use. Our study had two goals: (1) to present and evaluate two new indices based on call counts, the detection rate (DR, i.e. the number of 1‐min recordings in which the presence of a target vocalization is detected) and the maximum count per minute (MAX, i.e. the maximum number of calls found in a 1‐min recording); and (2) to present a conceptual framework showing how the interpretations of VAR, DR and MAX could depend on the index and on species traits. For three Neotropical bird species with distinct traits, we calculated VAR, DR and MAX based on PAM data from 25 sites in the Yucatan Peninsula (Mexico) that varied in their degree of anthropogenic habitat disturbance. We found moderate to high correlations between the indices and higher temporal variability in VAR compared to DR and MAX. We also found different effect sizes of habitat disturbance on the three species and indices. We suggest that DR might be a more reliable index of relative abundance than VAR for species whose calling behaviour exhibits a high cue rate and that MAX may be suitable for estimating family or flock size in gregarious birds. Our findings show the potential usefulness of developing new indices based on call counts to generate ecological hypotheses and assess changes in bird abundance and behaviour.

Seed permeability: an essential trait for classifying seed dormancy type

Abstract Seed dormancy in plants can have a significant impact on their ecology. Recent work by Rojas-Villa and Quijano-Abril (2023) classified the seed dormancy class in 14 plant species from the Andean forests of Colombia by using germination trials and several microscopy techniques to describe seed anatomy and morphology. The authors conclude that Cecropia species have both physical and physiological dormancy (of which they call physiophysical dormancy) based on seed morphology and mean germination times of over 30 days. Here, we present seed permeability and germination data from neotropical pioneer tree species: Ochroma pyramidale, Cecropia longipes, and Cecropia insignis, as well as Cecropia peltata (present in Rojas-Villa and Quijano-Abril, 2023), to demonstrate that Cecropia species do not exhibit dormancy and also have high levels of seed permeability. We find that the mean germination time for all three Cecropia species in our study was less than 30 days. This suggests a need for reporting the conditions in which germination trials take place to allow for comparability among studies and using seed permeability tests to accurately identify the physical dormancy class of seeds. Further, we present data from the literature that suggests that dormancy is not a requirement for seed persistence in the seed bank.

Stingless bee foragers experience more thermally stressful microclimates and have wider thermal tolerance breadths than other worker subcastes

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.