Our cover shows a tropical stonefly, an aquatic insect found in many rivers and streams (photo credit: Alisha A Shah). In the paper Climate variability predicts thermal limits of aquatic insects across elevation and latitude, Shah et al tested Janzen’s extension of the climate variability hypothesis, which posits that increased seasonal variation at high latitudes should result in greater temperature overlap across elevations, and favour wider thermal breadths in temperate organisms compared to their tropical counterparts, by measuring stream temperatures and thermal breadths for 62 aquatic insect species from temperate and tropical streams spanning an elevation gradient of c. 2000 m. They found that tropical aquatic insects have narrower thermal breadths than their temperate counterparts. Their findings suggest that lowland tropical insects may be the most vulnerable to climate change compared to other populations. Read the paper here and plain language research summary here.

Also in this issue, Shorter juvenile telomere length is associated with higher survival to spawning in migratory Atlantic salmon (which was featured in this news article from New Scientist) and Suonan et al’s Asymmetric winter warming advanced plant phenology to a greater extent than symmetric warming in an alpine meadow (can read the related Insight here) and Simpson et al’s Still armed after domestication? Impacts of domestication and agronomic selection on silicon defences in cereals (read our Q&A with the author here.)

Read other papers in this issue or browse the free plain language summaries.