Climate change impacts on ectotherms will be a consequence of an interplay between species-specific evolutionary effects, population-level local adaptation, and developmental or plastic effects in individuals. While variation in thermal tolerance resulting from species physiological differences and local adaptation are well researched, how variation in plasticity across habitats might impact vulnerability to climate change remains poorly understood. We studied microhabitat (understory vs. open) distributions and the plasticity in thermal tolerance of four Bicyclus butterfly species across forest and ecotone (savanna-forest transition zone) habitats in Cameroon. For each species, we performed common garden experiments at two stable temperature regimes (20 and 30 °C) and quantified larval and adult thermal tolerance. We found clear differences in distributions across species such that two species were more associated with open microhabitats (B. dorothea and B. vulgaris) while two others were more understory associated (B. sanaos and B. sandace), with variation across seasons and habitats (forest vs. ecotone). Three species exhibited higher plasticity in critical thermal maximum (CTmax) in the ecotone relative to the forest indicating the importance of the interaction between habitat and developmental temperatures in influencing thermal tolerance. Microhabitat distributions were also consistent with trends in thermal tolerance; the most understory-associated species had both the lowest average CTmax and lowest plasticity in CTmax in the ecotone. Our findings suggest that microclimate and thermal adaptation shape plastic responses to thermal tolerance, and these factors will likely result in heterogenous responses to climatic change for tropical insects.

Stronger and more frequent El Niño events are contributing to a decline in arthropod diversity and population, as well as to a reduction in the ecological services the animals provide.

I assessed whether non-native insect colonisation altered the population distribution of one case study island-endemic insect: Discophallus ascension of volcanic Ascension Island in the South Atlant...

Nature - Time-series data from tropical forests tracking weather and declines in arthropod diversity and function show that fluctuations in species were largely dependent on their El Niño...

Invasive animals threaten island-native arthropods with predation. We found that introduced ants and rats conducted 77% of experimental arthropod live bait predations on Ascension Island. Predation w....

Nature Reviews Biodiversity, Published online: 04 April 2025; doi:10.1038/s44358-025-00038-9Insect biodiversity in tropical forests is poorly understood but is probably facing declines, with serious consequences for ecosystem functions and services. This Review describes the major threats to insect biodiversity, which include the effects of a burgeoning human population and of climate change. The authors further highlight the urgent need for greater efforts to measure and monitor insect biodiversity in the tropics and discuss emerging approaches to facilitate such studies.

Tiny habitats of tiny species: the importance of micro-refugia for threatened island-endemic arthropods

Moths are the most taxonomically and ecologically diverse insect taxon for which there exist considerable time-series abundance data. There is an a...