Integrative and Comparative Biology最新文献

Wind can significantly influence heat and water exchange between organisms and their environment, yet microclimatic variation in wind is often overlooked in models forecasting the effects of environmental change on organismal performance. Accounting for the effects of wind may become even more critical given the anticipated changes in wind speed across the planet as climates continue to warm. In this study, we first assessed how wind speed varies across the planet and how wind speed may change under climate warming at macroclimatic scales. We also used microclimatic data to assess how wind speed changes temporally throughout the day and year as well as the relationship between wind speed, temperature, and standard deviation in each environmental variable using data from weather stations in North America. Finally, we used a suite of biophysical simulations to understand how wind speed (and its interactions with other environmental variables and organismal traits) affects the temperatures and rates of water loss that plants and animals experience at a microclimatic scale. We found substantial latitudinal variation in wind speed and the change in wind speed under climate change, demonstrating that temperate regions are predicted to experience simultaneous warming and reductions in wind speed. From the microclimatic data, we also found that wind speed is positively associated with temperature and temperature variability, indicating that the effects of wind speed may become more challenging to predict under future warming scenarios. The biophysical simulations demonstrated that convective and evaporative cooling from wind interacts strongly with organismal traits (such as body size, solar absorptance, and conductance) and the heating effects of solar radiation to shape heat and water fluxes in terrestrial plants and animals. In many cases, the effect of wind (or its interaction with other variables) was comparable to the effects of air temperature or solar radiation. Understanding these effects will be important for predicting the ecological impacts of climate change and for explaining clinal variation in traits that have evolved across a range of thermal environments.

Climate change is leading to higher and more variable temperatures worldwide, and these changes are likely to have consequences on the incubation stage of egg-laying organisms. Artificial incubation can be used to address a variety of mechanistic, ecological, and conservation questions related to the development of egg-laying animals in a warming climate. Artificial incubation of passerine eggs remains rare because their eggs can be highly sensitive to incubation conditions, causing it to be challenging to successfully incubate their eggs to hatch in captivity. The goal of this study was to describe a protocol to artificially incubate eggs of house sparrows (Passer domesticus), a widespread model species, and to provide a framework that can be used to develop protocols for artificial incubation of other passerine species. Since sufficient egg mass loss is necessary for proper development and can be related to hatching success, we monitored mass loss of eggs in natural nests in the field and used this information to inform and modify artificial incubation conditions. We found that eggs in our study population lost an average of 11.34% of their original mass across the incubation period, and that mass loss was greater later in incubation. To identify conditions promoting high hatching success, we tested incubation conditions of 36.9-37.4°C, 40-50% relative humidity (RH), and automatic and hand egg turning. We achieved 100% hatching success of artificially incubated eggs using a rocking incubator with automatic turning (90°/h) and three 180°C hand turns per day, incubation conditions of 37.36°C and 42.6% RH, and hatching conditions of 36.73°C and 57.9% RH. These conditions and the framework we provide to develop incubation protocols for other passerine species can be applied to better understand how changing environmental conditions are affecting the development of egg-laying organisms.

Changing climatic conditions can lead to diminished overlap in the timing of flowering and pollinator foraging, potentially resulting in the weakening or loss of plant-pollinator interactions and reducing the fitness of both partners. However, several complexities of phenological shifts limit our ability to predict their consequences for plant-pollinator mutualisms. First, phenological shifts reflect the responses of individuals but are often summarized at the community, species, or population level, potentially obscuring variation that has important implications for interactions within and between species. Second, metrics of phenological asynchrony in pollination, such as temporal overlap between flowering and pollinator foraging, may not accurately characterize changes in interaction strength or fitness costs and benefits and thus are not true metrics of mismatch. Third, our focus has been on shifts in individual life-history events, such as flowering, rather than entire life cycles, despite the physiological integration of seasonal life-history stages (phenophases) that may be under different selection pressures. We suggest that we can advance our understanding of phenological shifts and their consequences for plants and pollinators by studying individual phenological variation in both partners across natural or experimental environmental gradients, measuring interaction rates and their fitness implications in addition to synchrony or overlap, and taking an integrated life cycle approach that can reveal trade-offs. Together, these approaches can yield temporally explicit fitness landscapes for plant and pollinator phenologies and improve our understanding of the consequences of climate change-induced phenological shifts.

Plant-pollinator interactions have persisted and evolved over millions of years. These interactions are shaped by environmental factors. However, global environmental changes are disturbing these interactions in the Anthropocene. One way both plants and pollinators can respond (and potentially adapt) to these changing environments is through phenotypic plasticity mediated by epigenetic modifications and non-genetic inheritance. Yet, research on how, and to what extent, epigenetic modifications and non-genetic inheritance shape plant-pollinator dynamics is rare. In this forward-looking perspective, we discuss different ways in which the environment mediates epigenetic marks and non-genetic inheritance into the subsequent generation. By taking a broader perspective, we discuss four mechanisms of epigenetic modification and non-genetic inheritance in both plants and pollinator systems: epigenetic modifications, inter-generational non-genetic inheritance, transgenerational non-genetic inheritance, and cultural transmission. We discuss the roles of various epigenetic marks and the transfer of molecules that cause epigenetic changes and non-genetic inheritance in plants and pollinators, which either directly or indirectly affect the outcome of plant-pollinator interactions. We provide a framework for the ecological and evolutionary implications for inheritance of acquired traits driving plant-pollinator interactions and discuss its importance in a rapidly changing environment. Lastly, we suggest ways to experimentally test the role of epigenetic marks and non-genetic inheritance, and how to integrate such mechanisms into long-term studies on plant-pollinator interactions during the Anthropocene.

Rising environmental temperatures and extreme climatic events are negatively affecting ectothermic animals, especially those with limited opportunities for behavioral thermoregulation (i.e., passive thermoregulators). Rather than rely on behavioral buffering, thermally passive ectotherms may instead adjust their thermal preferences (either lowering or increasing them) to perform their biological activities at warmer temperatures. Nevertheless, temporal comparisons of preferred temperatures in wild populations of passive thermoregulators remain scant, limiting our capacity to broadly anticipate their responses to rising temperatures. Here, we compared laboratory thermal preferences across years (2003-2004 vs. 2016-2018) in 3 thermally passive lizard species from Central Mexico: the anguimorphs Gerrhonotus liocephalus, Xenosaurus rectocollaris, and X. tzacualtipantecus. These species exhibit different habitat use and live in places where heat wave events have increased over time, allowing temporal comparisons of thermal preferences in warming habitats. We discovered that the 3 species increased their thermal preferences by ∼1°C in 12-15 years. Our results indicate that these, and likely other passive thermoregulators must adjust their thermal preferences in response to global warming, rising a profound concern about their long-term viability as they approach intrinsic limits in their thermal physiology.

The fitness implications of climate variability and change are often estimated by integrating an organism's thermal sensitivity of performance across a time series of experienced body temperatures. Although this approach is an important first step in evaluating an organism's sensitivity to climate or climate change, it ignores potential influences of recent exposure to thermal stress on current thermal sensitivity. Here, we account for recent thermal stress by estimating rates of damage, repair, and other carryover effects; and we illustrate the approach with fecundity and development rate data from experiments that exposed aphids to various stressful and fluctuating temperatures. Our analyses indicate that heat stress for these aphids starts near the upper thermal limit for performance; that heat stress intensifies with both the exposure duration and with temperature; and that there is considerable capacity for repair at temperatures near the thermal optimum for performance. Results from experiments with aphids indicate that incorporating time series of damage, recovery, and repair will be necessary to anticipate fitness outcomes of climate change and variability.

Global temperatures are shifting in complex ways due to climate change. While early research focused on rising mean temperatures and its effect on biological outcomes, recent work has emphasized understanding the influence of temperature variability. In particular, many studies investigate temperature variation by symmetrically expanding daily temperature ranges around a fixed mean or by increasing daytime maximums. Although these approaches isolate specific aspects of temperature change, they often fail to capture how climate change is actually reshaping daily temperature cycles. In this perspective paper, we use climate data across three geographic scales to illustrate a striking and consistent pattern: daily minimum temperatures are rising faster than daily maximums, effectively reducing daily temperature range. A global analysis reveals that nighttime minimum temperatures are increasing more rapidly than daytime maximums across most land areas worldwide, especially at higher latitudes and elevations. At the continental scale, North American climate data show that asymmetric warming occurs year-round, with the strongest effects in winter. Regional patterns reveal especially strong nighttime warming in mountainous regions like the Rocky and Pacific Mountain systems. Locally, hourly data from Paradise, Nevada show nighttime temperatures have risen by over 4°C since the 1950s, while daytime highs remained stable, reducing daily temperature range by more than 4°C. We then synthesize findings from 84 studies that directly investigated biological responses to nighttime warming. Nearly half (47%) of the orders studied were plants, highlighting major taxonomic gaps in animal and microbial systems. Most studies (57%) were in organismal biology, yet few were hypothesis driven. Across taxa, asymmetric warming alters energetics, increases metabolic costs, and affects both thermal performance traits (e.g., metabolism, activity) and threshold-dependent traits (e.g., phenology, sex determination). We highlight evidence that nighttime warming may enhance or inhibit cellular recovery from heat stress (Heat Stress Recovery Hypotheses), shift species interactions, disrupt pollination networks, and reshape community structure. We conclude with a call for broader research across taxa, life stages, and ecological contexts, and recommend experimental, field-based, and modeling approaches tailored to disentangle the unique effects of asymmetric warming. Understanding asymmetric warming is not just a research gap-it's a pressing ecological imperative essential for predicting and mitigating climate change impacts on biodiversity.

Understanding the mechanisms by which organisms adapt to variation in temperature is key to explaining their distribution across environments and to predicting their persistence to changing climate. The cellular response to heat shock, heat shock response (HSR), is a highly conserved mechanism for coping with elevated temperatures which functions through the upregulation of molecular chaperones like heat shock proteins (HSPs). Recent studies have also shown cellular response to heat shock can be quantitative (changing the magnitude of expression) or qualitative (differential usage of exons originating from the same gene). However, few studies have explored the time course of these two mechanisms in response to heat shock. We conducted a time-course experiment to examine the gene expression and exon usage changes in response to heat shock at four post-stress timepoints (30 min, 1 h, 2 h, 24 h) in a splash pool copepod, Tigriopus californicus. We detected signatures of both gene expression and exon usage changes across all timepoints. The magnitude of this response was higher at timepoints closer to heat shock and decreased with time post-heat shock. We observed that heat shock predominantly induced changes in gene expression in genes coding for chitin, HSPs, cellular growth, and differentiation. In contrast, we found that genes coding for peptidases showed both altered expression levels and exon usage. Genes associated with cellular metabolism and cytoskeletal elements primarily showed changes in exon usage. These ontology-specific response mechanisms provide new insights into the temporal landscape of HSR in Tigriopus and highlight the need to integrate qualitative and quantitative changes in gene expression to fully understand organismal responses to heat shock.

The majority of flowering plants depend on insect pollination for reproduction and declining pollinator populations pose a threat to biodiversity as well as critical crop pollination services globally. Widespread insecticide use negatively impacts pollinator physiology and behavior even at environmentally realistic concentrations below lethal toxicity, leading to reduced fitness and long-term population declines. However, significant gaps remain in our understanding of how insecticides affect diverse aspects of behavior and ultimately influence pollinator populations and pollination services. These gaps partly stem from the challenge of quantifying sublethal effects of pesticides on the complex behavioral repertoires of insects. Current methods often focus on a narrow set of behaviors at a time, limiting our ability to capture the comprehensive range of impacts within management-relevant timescales. The emergence of low-cost techniques for high-throughput behavioral quantification, or "ethomics," holds enormous potential to address this knowledge gap. Here, we used automated, computer vision-based tracking implemented on open-source hardware (Raspberry Pis) to investigate the sublethal effects of an emerging "bee-safe" butenolide insecticide (flupyradifurone), as well as a neonicotinoid insecticide (imidacloprid), on bumble bee (Bombus impatiens) behavior. We simultaneously quantified the behavior of uniquely tagged individual workers both within the nest, and during foraging in a semi-field environment, to assess the holistic effects of insecticides under naturalistic conditions. Both insecticides increased mortality risk and altered behavior, but in distinct ways across behavioral contexts. Imidacloprid modified nest behavior by decreasing activity, while flupyradifurone altered spatial behavior within the nest (shifting bees toward the brood). Imidacloprid-but not flupyradifurone-reduced overall foraging activity, while both affected floral preference. Overall, our results highlight the complex potential mechanistic links between sublethal insecticide exposure, behavior, and pollinator health. This work emphasizes the need-and possibility-for rapid and holistic pesticide risk assessment under realistic environmental conditions using high-throughput ethomics, and could inform the development of sustainable agricultural practices and conservation strategies.

Climate change will continue to increase mean global temperatures, with daily minima increasing more than daily maxima temperatures on average. In addition, altered rainfall patterns due to climate change will disrupt water availability. Such changes are likely to influence thermo-hydroregulation and reproduction strategies in terrestrial ectotherms. We manipulated access to preferred diurnal temperature (9 h vs. 4 h at preferred temperature), nocturnal temperature at rest (22 vs. 17°C) as well as water availability during gestation (± ad libitum access to water) in female common lizards (Zootoca vivipara), a cold- and wet-adapted species. We previously reported that hot conditions (day and night) accelerated gestation but high nighttime temperatures increased the burden on females already constrained by heavy resource and water investment during gestation. We expanded the understanding of this relationship by examining the effects of maternal hydration and temperature on offspring (neonates and juveniles; N = 625) physiology (water loss rates and respiratory activity), morphology, performance (endurance capacity and growth), and survival. On average, longer access to preferred temperature during the day conferred benefits on offspring growth and survival, despite a negative effect on body condition at birth. High nighttime temperatures during gestation reduced offspring postnatal growth during early life and, together with high daytime temperatures, reduced tail width and endurance capacity at birth as well as offspring survival. Additionally, water deprivation poses a challenge to homeostasis, but offspring demonstrate resilience in coping with this potential stressor and these effects were not stronger in hot climates. Notably, the benefits of hotter environments are not always additive, highlighting the complexity of temperature-mediated effects on maternal and offspring outcomes.