The paper states that sex differences in energetic costs are strongly shaped by body size dimorphism. It also says that in highly sexually dimorphic species, the energetic costs of gestation and lactation in females can be matched by the energetic costs to males of maintaining a large body size.

This study on the frog Xenopus tropicalis reports that "Warming attenuates sexual dimorphism" and that a 5 °C increase in ambient temperature "can establish a new metabolic state, resulting in elevated oxidative stress and a shift in energy allocation towards immune defense at the expense of sexual development." The authors frame this as a temperature-dependent trade-off: "To maintain whole-body homeostasis and adapt to external conditions, the limited energy resources of organisms must be flexibly invested in growth, development, immunity, and reproduction according to external cues, requiring trade-offs among these life-history traits." They conclude that warm temperature accelerates metabolic rates and induces new energy requirements, which can challenge sexual development and dimorphic traits under thermally stressful conditions.

The article explicitly notes that sexual dimorphism is often associated with costly behaviours and that increased sexual dimorphism is often inferred to correlate with increased energy costs of the larger sex. It concludes that the costs of sexual dimorphism are primarily the maintenance of a large body size.

The authors state that the "increased-energy" hypothesis predicts that in species in which males are larger, males incur disproportionately higher rates of metabolism than females. They report that in Damaraland mole-rats, "the larger-bodied males had higher resting metabolic rates than females," and conclude that "sexual dimorphism in body size and composition carries significant energetic costs for males." This paper directly examines how sexual dimorphism translates into elevated energetic expenditure.

The article says that heat dissipation is mediated by body size and that sexual dimorphism can influence heat loss. It also states that thermoregulation is energetically costly, linking dimorphism to energetic constraints under thermal stress.

This study investigates "sex-specific metabolic signatures associated with stress exposure in the hypothalamus and pituitary" of mice. The authors show that stress exposure produces different metabolic profiles in males and females, indicating sexually dimorphic regulation of energy metabolism in key neuroendocrine centers. These sex differences in metabolic response under stress conditions suggest that the energetic costs of maintaining sex-specific phenotypes and physiology are modulated by stress, including potentially thermal stress, and may differ between males and females.

The review details that above the upper critical temperature of the thermoneutral zone (TNZ), "there is an increase of the metabolic rate because of the energy cost of the mechanisms for cooling" such as cutaneous vasodilation and sweating, with sweating described as "a more energetically expensive mechanism." It also notes that "mammals dedicate 40–50% of their total energy expenditure to sustain a constant" core temperature around 37 °C, and that most mammals spend time at ambient temperatures below their TNZ, which "implies that they activate energy-costly thermoregulatory mechanisms" to maintain homeostasis, with sex differences in basal metabolic rate and thermoregulatory responses highlighted.

The study notes that "Sex and reproductive status may fundamentally alter thermal sensitivity because they influence production and dissipation of body heat. Individuals with larger bodies (typically males if dimorphic) or greater energetic demands (reproductive females) produce more metabolic heat." It further states that "Heat dissipation is mediated by body size and shape meaning sexual dimorphism can influence heat loss" and that "Elevated heat load comes at an energetic cost and harms fitness because the capacity of an endotherm to dissipate heat constrains allocation to reproduction." The authors frame sex-specific thermoregulatory trade‑offs as a key mechanism through which climate warming imposes disproportionate energetic and fitness costs.

The paper states that in sexually size-dimorphic species living in hot environments, larger males have more difficulty dissipating body heat and reducing evaporative water loss. It also says that sexual differences in heat sensitivity can lead to different patterns of shelter use in males and females.

This research on human skeletal traits notes that "Human sexual dimorphism is frequently assessed through skull and pelvic size and shape" and that climatic variation and associated stress "may be significant factors in sexual dimorphism's etiology." The authors report that "This research highlights a reduction in sexual dimorphism in populations under greater climatic stress," comparing a Terry collection sample to Native Alaskans. They find that Native Alaskans, living under more climatic stress, show a more 'male' morphotype but reduced dimorphism in pelvic features, reinforcing "the complex and multifaceted relationship between climate and sexual dimorphism."

The paper states that "Climate warming can induce a cost-of-living ‘squeeze’ in ectotherms by increasing energetic expenditures while reducing foraging gains." Using biophysical models, the authors show that rising temperatures increase energy requirements for desert lizards while simultaneously constraining their opportunities to acquire food. They conclude that species-specific behavior and ecology can mediate this energetic squeeze, highlighting that climate warming generally raises the energetic cost of living under thermally stressful conditions for ectotherms.

The study reports a significant interaction between sex and temperature, with males having lower standard metabolic rate below 16 °C but increasing to about 16% higher than females at warmer temperatures. This provides direct evidence that sex-specific energetic costs can change with temperature.

The article says that a comparison of variation in physiology and developmental response to thermal stress found important differences between species and sexes. This is relevant evidence that thermal stress responses can be sex-dependent.

This highlight discusses a preprint by Shetty et al. showing that "females and males appear to respond differently to changes in stress levels and diet." After foot shocks and high-fat diet, the authors report that "foot shocks after HFD or chow diet increased energy expenditure of both male and female mice," but behavioral and metabolic responses differed between sexes. The work indicates sexually dimorphic effects of stress and diet on energy metabolism, supporting the idea that the energetic costs of stress and maintaining sex-specific traits and behaviors can differ between males and females.

The study finds that "males have a higher metabolic rate than females," with differences being statistically significant at lower ambient temperatures of 14, 16, and 18 °C, and male mean metabolic values consistently higher across all tested temperatures. It also reports that metabolic rate increases as ambient conditions deviate from thermal comfort, linking thermoregulation to increased energy expenditure and documenting sex-related differences in these energetic responses.

Reporting on a study in Nature Climate Change, the article explains that "an increase in body temperature increases the rate at which animals use energy" and that "human-induced climate warming is expected to increase the energetic cost of living for ectotherms." It describes results showing that when fruit flies develop with another species at warmer temperatures "their energy expenditure increases" and model simulations indicate we may "underestimate the energy needs of ectotherms in a warming world" if behavioral interactions are not considered. This provides empirical support that thermal stress from climate warming increases energetic costs.

The authors note that "Temperature and thermal variability are increasing worldwide, with well-known survival consequences" and investigated male reproductive performance under different thermal regimes. They report that "mating success improved under fluctuating benign temperature conditions and declined as temperature stress increased," and that "fertility and productivity were severely reduced at fluctuating mean high temperature for all genotypes." They conclude that while thermal stress can increase genetic variation, "this is unlikely to compensate for the overall severe negative effect on reproductive performance as mean temperature and variance increase." This work shows that increasing thermal stress imposes reproductive and thus energetic or fitness costs.

The paper argues that heatwaves can impose hidden fitness costs by altering reproductive traits. It states that "By increasing variance in reproductive traits, heatwaves can influence both intra- and inter-sexual selection processes and affect pre- and post-copulatory episodes of sexual selection." The authors suggest that repeated heatwaves may modify mating success, sperm performance, and offspring viability, thereby changing the strength and direction of sexual selection. This implies that more thermally stressful environments can alter the costs and dynamics of sexual dimorphism through impacts on reproductive investment and sexual selection.

The paper states that when the sexes have very different roles during the breeding season, their energetic optima will be different and sexual size dimorphism is predicted. This supports the idea that dimorphism is tied to energetics.

Britannica defines sexual dimorphism as "the differences in appearance between males and females of the same species, such as in color, shape, size, and structure." It notes that these differences arise from inherited sex-specific patterns in the genetic material and often include traits like larger body size, elaborate ornamentation, or specialized structures. While the entry does not quantify energetic costs, it implies that sexually dimorphic traits such as larger size or complex structures are maintained by biological processes that require energy, and that these traits reflect underlying differences in physiology and life history between the sexes.

Reporting on a theoretical study of cellular energetics, the article explains that living cells pay a "hidden energy price" not only to run chemical reactions but "to keep them on track and block all the alternatives," introducing concepts of maintenance cost and restriction cost. It notes that "the more improbable the behavior, the higher its cost," meaning more constrained or specialized physiological processes require higher energetic expenditure to maintain, which conceptually applies to maintaining complex traits such as sexual dimorphism under varying environmental conditions.

This review discusses how sex differences in morphology and physiology, including sexual dimorphism, are underpinned by divergent endocrine systems that carry maintenance and regulatory costs. It notes that sexually dimorphic traits often require sex-specific hormone production and receptor expression, and that these endocrine mechanisms must remain robust across environmental stressors, which can increase energetic and regulatory demands to preserve dimorphic phenotypes under changing thermal or ecological conditions.

This experimental article examines how sexual dimorphism affects thermal tolerance and reports that differences in body size and morphology between sexes can lead to distinct thermal performance curves and stress responses. It shows that in some species, one sex exhibits higher tolerance to heat or cold, suggesting that maintaining dimorphism involves sex-specific physiological adjustments and energy use when environments become thermally challenging.

This paper describes sex-specific physiological and metabolic responses to thermal stress in ectothermic animals, showing that males and females can differ in their metabolic rate increases and survival under heat stress. It highlights that these differences are often linked to sexually dimorphic body size, reproductive roles, or hormone profiles, implying that the energetic costs of coping with thermal extremes are modulated by sexual dimorphism and can become more pronounced as temperatures approach species' tolerance limits.

The project description notes that sexually dimorphic traits such as male ornaments "represent some of the most remarkable within-species variation and arise from a genome that is largely shared between males and females." It emphasizes that the evolution and maintenance of these traits involve sexual selection and sexual conflict, which can impose fitness costs. Although not focused on energetics, the text highlights that exaggerated ornaments and other dimorphic traits are often condition-dependent and costly to produce and maintain, implying associated metabolic and energetic burdens that may be influenced by environmental conditions.

The study aims "to describe population variability in body composition dimorphism, and to test whether annual temperature and proxies for population energy supply accounted for this variability" across 96 human populations. The authors note that worldwide variation in stature and limb proportions reflects thermal adaptation and that body composition dimorphism varies with mean annual temperature and energy supply. They argue that ecogeographic patterns of sexual dimorphism may be shaped not only by temperature-based selection but also by environmental stressors linked to energy availability, indicating that climate and energetic context influence the expression and potential costs of dimorphism.

The PDF discusses the cost of secondary sexual characters and links sexual dimorphism with energy use. It is useful as background on how sexually selected traits can impose energetic costs, though it is less direct on thermal stress than the other sources.

In evolutionary biology, sexually dimorphic traits such as larger male body size, weapons (horns, antlers), and ornaments (plumage, coloration) are widely understood to be energetically expensive to grow and maintain. Theoretical models of sexual selection and life-history evolution treat these traits as condition-dependent, meaning individuals must divert energy from other functions (immune defense, thermoregulation, somatic maintenance) to support dimorphic traits. Under thermally stressful environments, ectotherms in particular experience increased baseline metabolic costs, so the relative energetic burden of maintaining costly sexually dimorphic traits is expected to rise, contributing to trade-offs and potential reductions in dimorphism.