Symbiotic flagellate protists as cryptic drivers of adaptation and invasiveness of the subterranean termite Reticulitermes grassei Clément

Abstract

Changes in flagellate protist communities of subterranean termite Reticulitermes grassei across different locations were evaluated following four predictions: (i) Rural endemic (Portugal mainland) termite populations will exhibit high diversity of symbionts; (ii) invasive urban populations (Horta city, Faial island, Azores), on the contrary, will exhibit lower diversity of symbionts, showing high similarity of symbiont assemblages through environmental filtering; (iii) recent historical colonization of isolated regions—as the case of islands—will imply a loss of symbiont diversity; and (iv) island isolation will trigger a change in colony breeding structure toward a less aggressive behavior. Symbiont flagellate protist communities were morphologically identified, and species richness and relative abundances, as well as biodiversity indices, were used to compare symbiotic communities in colonies from urban and rural environments and between island invasive and mainland endemic populations. To evaluate prediction on the impact of isolation (iv), aggression tests were performed among termites comprising island invasive and mainland endemic populations. A core group of flagellates and secondary facultative symbionts was identified. Termites from rural environments showed, in the majority of observed colonies, more diverse and abundant protist communities, probably confirming prediction (i). Corroborating prediction (ii), the two least diverse communities belong to termites captured inside urban areas. The Azorean invasive termite colonies had more diverse protist communities than expected and prediction (iii) which was not verified within this study. Termites from mainland populations showed a high level of aggressiveness between neighboring colonies, in contrast to the invasive colonies from Horta city, which were not aggressive to neighbors according to prediction (iv). The symbiotic flagellate community of R. grassei showed the ability to change in a way that might be consistent with adaptation to available conditions, possibly contributing to optimization of the colonization of new habitats and spreading of its distribution area, highlighting R. grassei potential as an invasive species.

Ecological specificity of the metagenome in a set of lower termite species supports contribution of the microbiome to adaptation of the host

“…There is evidence that the gut microbiome of termites has contributed to the adaptation of different termite species to their specific ecologies [33,36,[42][43][44]. There are pronounced ecological differences between the so-called termite life types [45,46].…”

Macrobiological Degradation of Esterified Wood with Sorbitol and Citric Acid

“…Shipworms ingest wood particles produced by the grinding action of their shells, while termites manipulate lignocellulosic material with their mouth parts. Even though their attack pattern affects the macroanatomical structure of wood, both organisms rely on diverse mechanisms involving multiple complementary enzymes to degrade lignocellulose [1,2].…”

Ecological specificity of the metagenome in a set of lower termite species supports contribution of the microbiome to adaptation of the host

“…There is evidence that the gut microbiome of termites has contributed to the adaptation of different termite species to their specific ecologies [33,36,[42][43][44]. There are pronounced ecological differences between the socalled termite life types [45,46].…”