Parallel evolution of mound-building and grass-feeding in Australian nasute termites

Abstract

Termite mounds built by representatives of the family Termitidae are among the most spectacular constructions in the animal kingdom, reaching 6-8 m in height and housing millions of individuals. Although functional aspects of these structures are well studied, their evolutionary origins remain poorly understood. Australian representatives of the termitid subfamily Nasutitermitinae display a wide variety of nesting habits, making them an ideal group for investigating the evolution of mound building. Because they feed on a variety of substrates, they also provide an opportunity to illuminate the evolution of termite diets. Here, we investigate the evolution of termitid mound building and diet, through a comprehensive molecular phylogenetic analysis of Australian Nasutitermitinae. Molecular dating analysis indicates that the subfamily has colonized Australia on three occasions over the past approximately 20 Myr. Ancestral-state reconstruction showed that mound building arose on multiple occasions and from diverse ancestral nesting habits, including arboreal and wood or soil nesting. Grass feeding appears to have evolved from wood feeding via ancestors that fed on both wood and leaf litter. Our results underscore the adaptability of termites to ancient environmental change, and provide novel examples of parallel evolution of extended phenotypes.

Multiple abiotic factors correlate with parallel evolution in Australian soil burrowing cockroaches

“…Gross, Borowsky, & Tabin, ; Protas et al., ) as well as in more divergent taxa (e.g. Arab et al., ; Emerson & Koehl, ; Stearns & Fenster, ).…”

“…In each area, some individuals adapt to a novel niche created by the onset of aridity, and eventually become reproductively isolated from their parent species, which remains in the original niche. Although some studies have found evidence for an association between ancient aridification events and parallel evolution (Arab et al., ; Lo et al., ), the abiotic factors associated with these changes remain understudied.…”

Modern termites inherited the potential of collective construction from their common ancestor

“…Mound‐building has also multiple origins among higher termites, as exemplified by the Australian Nasutitermitinae in which it evolved independently in at least six lineages (Arab et al., 2017). As is the case for shelter tube construction, there is a possibility that all species of Nasutitermitinae share the same behavioral rules and that the species that do not build mounds under natural conditions are able to do so under unusual conditions.…”

Life in the “dead heart” of Australia: The geohistory of the Australian deserts and its impact on genetic diversity of arid zone lizards

“…Indeed, the crown radiation for the spinifex‐specialised phasmid geckos in the mid‐Miocene broadly overlaps with the inferred age of the spinifex radiation (Laver et al, 2017; Skipwith, et al, 2019). Recent work on Australian nasute termites inferred a transition from wood to grass and litter feeding in one major group occurred in the mid‐Miocene, with the switch to exclusive grass feeding in two sister‐pairs (including the spinifex termite Nasutitermes triodea ) inferred to have occurred ~ 5‐6 Mya (Arab, et al, 2017). Alternatively, as vegetation types would have expanded and contracted their distributions with climatic cycles, taxa may have diverged after the emergence of an associated vegetation formation, but during these contraction phases.…”