Sex-specific stress tolerance, proteolysis, and lifespan in the invertebrate Tigriopus californicus

Abstract

Because stress tolerance and longevity are mechanistically and phenotypically linked, the sex with higher acute stress tolerance might be expected to also live longer. On the other hand, the association between stress tolerance and lifespan may be complicated by tradeoffs between acute tolerance and long-term survival. Here we use the copepod Tigriopus californicus to test for sex differences in stress resistance, proteolytic activity and longevity. Unlike many model organisms, this species does not have sex chromosomes. However, substantial sex differences were still observed. Females were found to have superior tolerance to a range of acute stressors (high temperature, high salinity, low salinity, copper and bisphenol A (BPA)) across a variety of treatments including different populations, pure vs. hybrid crosses, and different shading environments. Upregulation of proteolytic capacity-one molecular mechanism for responding to acute stress-was also found to be sexually dimorphic. In the combined stress treatment of chronic copper exposure followed by acute heat exposure, proteolytic capacity was suppressed for males. Females, however, maintained a robust proteolytic stress response. While females *

Variation in developmental temperature alters adulthood plasticity of thermal tolerance in Tigriopus californicus

“…This suggests that at least a portion of the genetic differentiation among populations is likely adaptive. Moreover, several common-garden studies in laboratoryraised individuals have demonstrated differences in upper and lower thermal tolerance limits that are consistent with local thermal adaptation in response to the latitudinal temperature gradient across the species range (Willett, 2010;Kelly et al, 2012;Wallace et al, 2014;Pereira et al, 2014Pereira et al, , 2017Leong et al, 2018;Willett and Son, 2018;Foley et al, 2019). This variation among populations has also been associated with genetically based differences in the function and regulation of heat shock protein genes (Schoville et al, 2012;Barreto et al, 2015;Tangwancharoen et al, 2018) and in the maintenance of mitochondrial ATP synthesis rates at high temperatures (Harada et al, 2019).…”

Molecular physiology of copepods - from biomarkers to transcriptomes and back again

“…Sex is an additional consideration in studies of adult copepods. Female copepods usually have longer lifespans and higher stress resistances than males (e.g., Foley et al, 2019;Parrish and Wilson, 1978). This difference in resistance, and other physiological differences associated with reproduction may result in different transcriptional responses to stressors.…”

Patterns of Thermal Sensitivity and Sex-Specificity of Courtship Behavior Differs Between Two Sympatric Species of Enchenopa Treehopper

“…Additionally, sex-specific thermal effects may also generate breakdowns in sexual communication in the wake of global warming. While males and females within a species are often assumed to react similarly to environmental stressors like temperature (Shreve et al, 2004), sex-specific thermal responses in courtship activity could arise through sex differences in body size and thermoregulatory behavior during reproduction (Brown and Weatherhead, 2000;Matzkin et al, 2009;Darnell et al, 2013;Baudier et al, 2015;Foley et al, 2019). If reproductive activity levels across temperatures are sex-specific, shifts in temperatures could accentuate mismatches in male and female activity levels and reduce overlap when both sexes are actively seeking mates.…”

“…In addition to species-specific responses to temperature, we might predict that males and females respond differently to temperature due to underlying sex-specific physiology (Brown and Weatherhead, 2000;Matzkin et al, 2009;Darnell et al, 2013;Baudier et al, 2015;Foley et al, 2019). However, courtship activity results from a complex interaction between physiology and behavioral decisions, and we currently lack a complete framework for making an informed prediction about sex-specific responses to temperature.…”

“…However, courtship activity results from a complex interaction between physiology and behavioral decisions, and we currently lack a complete framework for making an informed prediction about sex-specific responses to temperature. The larger sex of a species-females in the case of Enchenopa (Hamilton and Cocroft, 2009)-is likely to have a higher thermal tolerance (Baudier et al, 2015;Foley et al, 2019). However, relative size does not always predict thermal preference.…”