Biology subjects

Cockerell, F.

Publications and source records attributed to Cockerell, F..

3 recordsLinked to original sources

bioRxiv2025

Local adaptation in climate tolerance at a small geographic scale contrasts with broad latitudinal patterns

While climate adaptation is typically quantified across broad gradients, the potential for adaptation to the same environmental variables at small scales is rarely tested. If local-scale environmental heterogeneity can generate patterns of adaptation similar to broad gradients, then we currently underestimate adaptive capacity to global change. We quantified population variation in climate tolerance traits and their plasticity for five populations of Drosophila melanogaster from a 3000-km latitudinal gradient, which we contrasted with eight local populations from an environmentally heterogeneous 600x300km area. Population variation in stress tolerance at the local scale was comparable to that across latitude. Consistent with local adaptation, populations from warmer and drier environments showed greater heat and desiccation tolerance, and populations from more predictable environments showed greater plasticity. Climate adaptation at smaller geographic scales can therefore be comparable to adaptation across broad geographic scales. However, patterns of adaptation often changed across geography, which makes predicting responses to global change challenging.

evolutionary biology↗

bioRxiv2025

Variation in temperature but not diet determines the stability of latitudinal clines in tolerance traits and their plasticity

Latitudinal clines are routinely used as evidence of adaptation across broad climatic gradients. However, if environmental variation influences the strength of latitudinal clines, then clinal patterns will be unstable, and using patterns of adaptation to predict population responses to global change will be difficult. To test whether environmental variation influences latitudinal clines, we sampled five populations of Drosophila melanogaster spanning 3000-km of east coast Australia, and measured stress tolerance (heat, cold and desiccation) and body size on flies that developed in six combinations of temperature (13{degrees}C, 25{degrees}C and 29{degrees}C) and diet (standard and low-calorie) treatments. We found latitudinal clines where populations further from the equator had larger wings, higher cold tolerance and lower heat tolerance. For all traits, temperature determined the strength of latitudinal clines, whereas diet had little influence. Steeper clines often emerged in warmer treatments, created by latitudinal clines in plasticity. In the warmest temperature, higher latitude populations showed larger increases in heat tolerance, larger reductions in desiccation tolerance but smaller decreases in cold tolerance. Heat tolerance was the only trait that supported the climate variability hypothesis and a trade-off between plasticity and tolerance. Environment-dependent latitudinal clines are therefore likely to determine variation in population responses to global change.

evolutionary biology↗

bioRxiv2023

Fluctuating temperatures exacerbate nutritional stress during development in Drosophila melanogaster

Recent studies suggest that elevated temperatures interact with nutrition to exacerbate the negative effects of poor nutrition. Furthermore, populations adapted to distinct environments differ in their sensitivity to combined thermal and nutritional stress. However, most studies have tested these effects using constant temperatures, even though animals in the wild experience daily and seasonal thermal fluctuations. Here, we used two locally-adapted populations of D. melanogaster from the east coast of Australia (a tropical and a temperate population) to ask whether temperature fluctuations interact with nutrition in the same manner as constant temperature conditions to shape life history traits, and how this differs across populations. We found that fluctuating temperatures exacerbate the negative effects of a poor diet when compared to constant temperatures. Moreover, the negative effects of nutritional stress were significantly greater in the tropical population. In contrast, we found that the temperate population was able to utilize nutrition in unique ways to maintain optimal viability under warmer temperatures. Our findings reveal the ways in which temperature and nutrition interact to impact key life history traits in geographically distinct populations, while also highlighting the importance of using temperature assays representative of natural diel cycles when examining insect responses to climate change.

evolutionary biology↗