Termite dispersal is influenced by their diet

Abstract

Termites feed on vegetal matter at various stages of decomposition. Lineages of wood- and soil-feeding termites are distributed across terrestrial ecosystems located between 45°N and 45°S of latitude, a distribution they acquired through many transoceanic dispersal events. While wood-feeding termites often live in the wood on which they feed and are efficient at dispersing across oceans by rafting, soil-feeders are believed to be poor dispersers. Therefore, their distribution across multiple continents requires an explanation. Here, we reconstructed the historical biogeography and the ancestral diet of termites using mitochondrial genomes and δ 13 C and δ 15 N stable isotope measurements obtained from 324 termite samples collected in five biogeographic realms. Our biogeographic models showed that wood-feeders are better at dispersing across oceans than soil-feeders, further corroborated by the presence of wood-feeders on remote islands devoid of soil-feeders. However, our ancestral range reconstructions identified 33 dispersal events among biogeographic realms, 18 of which were performed by soil-feeders. Therefore, despite their lower dispersal ability, soil-feeders performed several transoceanic dispersals that shaped the distribution of modern termites.

Resource adaptation drives the size–complexity rule in termites

“…First, the analysable sample did not include species with clearly defined trimorphic soldiers or workers [25], but such species are relatively uncommon and are unlikely to change the conclusions. Second, soil-feeders comprise species feeding on a much wider decomposition range than wood-feeders, as revealed by stable isotope ratios [21,49]. Hence, using stable isotope data may reveal more subtle patterns.…”

“…Colony size was obtained from published data compilations [34,[37][38][39][40] and references therein, complemented with several specific references not in the compilations [41][42][43][44][45][46][47]. Then, the remaining variables of interest were obtained from those same references if they provided such variables, or from other published data compilations on the respective subjects: sterile caste number [25], nest-food separation [48] and soilfeeding [21,49]. In the few cases in which data were not found in those compilations, they were searched for in Google Scholar (see below).…”

“…However, mound-building Coptotermes were treated as separate nesters [53]. Also, species were classified as wood-feeders or soil-feeders based on the morphology of their mandibles [21,49]. Ideally, one would use a quantitative measure of degree of soil-feeding such as nitrogen stable isotope ratios, but those were not available for over half the analysable species.…”

“…Phylogenetic relations among the analysed species were determined based on recent dated phylogenies informative of family- and subfamily-level relations of termites [49,54] and relations within the Termitidae [49,55], complemented with specific phylogenies for Kalotermitidae [56], Macrotermitinae [57,58], Apicotermitinae [59] and Cubitermitinae [60]. The few clades that could not be resolved were considered polytomies, and the tree was coded in Newick format.…”

Mitochondrial phylogenetics position a new Afrotropical termite species into its own subfamily, the Engelitermitinae (Blattodea: Termitidae)

“…Taxa assigned to the Termitinae feed on diverse substrates, including wood, soil, humus and litter (Donovan et al, 2001; Hellemans, Šobotník, et al, 2022; Hellemans, Wang, et al, 2022), and have soldiers with various defence strategies combining chemical and/or physical weapons (Šobotník et al, 2010). Despite the huge diversity of Termitidae in the Afrotropics (Krishna et al, 2013), only six genera with soldiers having non‐snapping mandibles ( Amitermes Silvestri, Cephalotermes Silvestri, Eremotermes Silvestri, Forficulitermes Emerson, Microcerotermes Silvestri and Tuberculitermes Holmgren) and six genera with soldiers having snapping mandibles ( Angulitermes Sjöstedt, Capritermes Wasmann, Pericapritermes Silvestri, Promirotermes Silvestri, Quasitermes Emerson and Termes Linnaeus) are assigned to Termitinae (Constantino, 2020).…”