Need for shared internal mound conditions by fungus-growingMacrotermesdoes not predict their species distributions, in current or future climates

Abstract

The large, iconic nests constructed by social species are engineered to create internal conditions buffered from external climatic extremes, to allow reproduction and/or food production. Nest-inhabiting eusocial Macrotermitinae (Blattodea: Isoptera) are outstanding palaeo-tropical ecosystem engineers that evolved fungus-growing to break down plant matterca62 Mya; the termites feed on the fungus and plant matter. Fungus-growing ensures a constant food supply, but the fungi need temperature-buffered, high humidity conditions, created in architecturally complex, often tall, nest-structures (mounds). Given the need for constant and similar internal nest conditions by fungi farmed by differentMacrotermesspecies, we assessed whether current distributions of six AfricanMacrotermescorrelate with similar variables, and whether this would reflect in expected species' distribution shifts with climate change. The primary variables explaining species’ distributions were not the same for the different species. Distributionally, three of the six species are predicted to see declines in highly suitable climate. For two species, range increases should be small (less than 9%), and for a single species,M. vitrialatus,‘very suitable’ climate could increase by 64%. Mismatches in vegetation requirements and anthropogenic habitat transformation may preclude range expansion, however, presaging disruption to ecosystem patterns and processes that will cascade through systems at both landscape and continental scales.This article is part of the theme issue ‘The evolutionary ecology of nests: a cross-taxon approach’.