Biology subjects

da Silva, C. R. B.

Publications and source records attributed to da Silva, C. R. B..

6 recordsLinked to original sources

bioRxiv2025

Nesting behaviour drives the evolution of heat tolerance and climate vulnerability in bees

Species vulnerability to climate change depends in part on their capacity to evolve in response to increasing heat1. Within terrestrial ectotherms, heat tolerance generally corresponds weakly to current climates, which has led many to conclude that this trait is evolutionarily constrained2-4. However, most studies have not accounted for the role of microclimates, potentially obscuring signals of local adaptation. We examined heat tolerance in 95 species of wild bees that varied in nesting behaviour across the latitudinal extent of Australia. Species nest (ground, wooden cavities, or plant stems) micro-climate temperatures predicted heat tolerance evolution, where stem nesters evolved the highest heat tolerances, and ground nesters evolved the lowest heat tolerances due to their ability to evade extreme heat. A moderate level of phylogenetic inertia in heat tolerance was explained by patterns of related species sharing nesting behaviours. This indicated repeated adaptive evolution of similar heat tolerances, rather than strong evolutionary constraints on heat tolerance. Finally, incorporating nesting behaviour into assessments of climate change vulnerability changed the rank order of which species were most at risk. This underscores the need to understand what drives the evolution of heat tolerance across species to better identify the taxa most at risk to climate change.

ecology↗

bioRxiv2024

Before the brink: sublethal impacts of climate change on stingless bee flight performance

AimWe aimed to understand the sublethal impacts of climate change on native bee ecology. We evaluated how flight performance, a key trait for predator escape, dispersal, and pollination, is impacted by temperature. We aimed to understand how species geographic ranges shape species thermal performance curves (TPCs) and determine species vulnerability to further warming. LocationAustralia Time periodPresent Major taxa studiedStingless bees MethodsWe tested the flight speed and acceleration of two species of stingless bees, Austroplebeia australis and Tetragonula carbonaria at seven test temperatures. We examined how the climate experienced by species throughout their ranges shapes their TPCs. Inferences were made on how sublethal increases in temperature will likely impact key ecological activities associated with flight by estimating the proportion of species geographic ranges that experience temperatures that exceed their thermal optima. ResultsSpecies TPCs reflected the thermal environments they inhabit. A. australis, which experiences greater thermal variation and hotter temperatures throughout their range, had a broader TPC and higher thermal optima. However, A. australis also had faster flight performance than T. carbonaria, rejecting the jack-of-all-trades master-of-none hypothesis. Further increases in temperature will reduce flight performance of T. carbonaria at a faster rate (due to their narrower TPCs) than A. australis, however, a larger proportion of the A. australis range is currently exposed to temperatures above their thermal optima. Main conclusionsClimates will impact species ecology before they reach their lethal limits. Our study supports the idea that species fundamental niche breadths are linked to their geographic ranges, but that trade-offs are not associated with flight performance and ability to perform across a broad range of temperatures. When assessing vulnerability to climate change, it is important to consider how temperature impacts species traits, but also the climates that species experience throughout their unique geographic ranges.

physiology↗

bioRxiv2024

Species richness patterns in Fijian bees are explained by constraints in physiological traits

Determining the ecological and evolutionary mechanisms that underpin patterns of species richness across elevational gradients is a key question in evolutionary ecology, and can help to understand species extinction risk under changing climates. In the tropical montane islands of Fiji, there are 28 species of endemic bee in the subgenus Lasioglossum (Homalictus), where species richness increases with elevation despite decreasing land surface (habitat) areas. We used a combination of spatially explicit phylogenetic diversity analyses and phylogenetic trait analyses to examine the factors shaping species distributions in these bees. We found that species at higher elevations had lower heat tolerance and desiccation resistance than those at lower elevations, consistent with these traits constraining species elevational ranges. We also found high species phylogenetic diversity within mountains, and high phylogenetic signal in species heat tolerance and minimum elevational ranges, consistent with these traits being evolutionarily conserved among mountain-top taxa following vicariant (allopatric) speciation. We found no evidence to suggest that interspecific competition is shaping species elevational ranges. In all, our findings indicate that phylogenetic conservatism in physiological traits related to climatic niche, such as heat tolerance, can explain why species richness is highest at mountain tops in this system, with species having tracked their climatic niches over time towards ever higher (cooler and wetter) elevations. Because high elevations in this archipelago are extremely limited ([~]2.3% of total land area), only miniscule elevational islands in the sky remain into which this diverse, but climate-restricted fauna, can retreat as climates warm.

evolutionary biology↗

bioRxiv2023

Local climate change velocities explain multidirectional range shifts in a North American butterfly assemblage

Species are often expected to shift their distributions poleward to evade warming climates. However, from 18 years of fixed transect monitoring data on 88 species of butterfly in the midwestern United States, we show that butterflies are shifting their centroids in all directions, except towards the region that is warming the fastest (southeast). Butterflies shifted their centroids at a mean rate of 4.87 km yr-1. The rate of centroid shift was significantly associated with local climate change velocity (temperature and precipitation), but not with mean climate change velocity throughout the species ranges. Surprisingly, the centroid shift was also unrelated to species traits expected to mediate the shift response including thermal niche breadth (range of climates butterflies experience throughout their distribution) and wingspan (often used as metric for dispersal capability). Contrasting with a number of previous studies, we observed relatively high phylogenetic signal in the rate and direction species shifted their centroids, suggesting that evolutionary history helps to explain multidirectional range shift responses and that some groups of species will be better able to shift their ranges than others. This research shows important signatures of multidirectional range shifts (latitudinal and longitudinal) and uniquely shows that local climate change velocities are more important in driving range shifts than the mean climate change velocity throughout a species entire range.

ecology↗

bioRxiv2022

Physiological traits and their relationships vary along an aridity gradient within and among Fijian bee species

O_LITemperature and water availability are hypothesised to be important abiotic drivers of the evolution of metabolic rates and gas exchange patterns, respectively. Specifically, the metabolic cold adaptation hypothesis (MCA) predicts that cold environments select for faster metabolic rates to counter the thermodynamics of biochemical reactions while the hygric hypothesis predicts that dry environments select for discontinuous gas exchange to reduce water loss. C_LIO_LIAlthough these two hypotheses consider different physiological traits and how they vary along different abiotic gradients, metabolic rate drives frequency of gas exchange patterns in insects meaning these two traits are inherently linked. Despite this link, the MCA and hygric hypotheses are rarely considered together and the extent to which metabolic rates and frequency of gas exchange vary and co-vary across climatic gradients remains unclear. C_LIO_LIWe tested the MCA and hygric hypotheses within a species of endemic Fijian bee, Homalictus fijiensis, across an altitudinal gradient of 1100 m, and among four Fijian bee species, including H. fijiensis, that inhabit different altitudinal bands. In Fiji, environmental temperature is [~]5{degrees}C lower in the central highlands than in the coastal lowlands with the highlands receiving [~]100 mm of additional precipitation than the lowlands each month. C_LIO_LIWe found an MCA-like pattern within H. fijiensis and among Fijian bee species, where metabolic rate decreased with increasing temperature, but precipitation also explained variation in metabolic rate. However, we did not find support for the hygric hypothesis within H. fijiensis or among species (frequency of gas exchange was not negatively correlated with precipitation). C_LIO_LIThe relationship between metabolic rate and frequency of gas exchange was steeper for species that occupied lower elevations on average, suggesting it is possible that these two traits can evolve independently of each other despite being positively correlated. C_LI

evolutionary biology↗

bioRxiv2022

Linking physiology to ecosystem function: how vulnerable are different functional groups to climate change?

O_LIThe resilience of ecosystem function under global climate change is governed by individual species vulnerabilities and the functional groups they contribute to (e.g. decomposition, primary production, pollination, primary, secondary and tertiary consumption). Yet it remains unclear whether species that contribute to different functional groups, which underpin ecosystem function, differ in their vulnerability to climate change. C_LIO_LIIt is important to examine if functional group vulnerability differs across space (e.g. tropical vs temperate latitudes) to determine if some regions will be more vulnerable to loss of ecosystem function than others, and to examine whether localized effects of particular community compositions override global patterns of functional group vulnerability. C_LIO_LIWe used existing upper thermal limit data across a range of terrestrial species (N = 1,743) to calculate species warming margins (degrees distance between a species upper thermal limit and the maximum environmental temperature they inhabit), as a metric of climate change vulnerability, to determine whether species that comprise different functional groups exhibit differential vulnerability to climate change, and if vulnerability trends change across geographic space. C_LIO_LIWe found that primary producers had the broadest warming margins across the globe ( = 21.85 {degrees}C) and that tertiary consumers had the narrowest warming margins ( = 4.37 {degrees}C), where vulnerability tended to increase with trophic level. C_LIO_LISpecies that contribute towards primary production were more vulnerable in low-latitude than mid-latitude regions, but warming margins across all other functional groups did not differ across regions when evolutionary history was considered. However, when evolutionary history was excluded from the analyses (as closely related species often play similar functional roles within ecosystems demonstrating true variation in functional group warming margins) we found that pollinators are more vulnerable in mid-latitude regions and that primary producers are more vulnerable in low-latitude environments. C_LIO_LIThis study provides a critical first step in linking individual species vulnerabilities with whole ecosystem responses to climate change. C_LI

ecology↗