Multiple convergent evolution of arboreal life in oribatid mites indicates the primacy of ecology

Abstract

Frequent convergent evolution in phylogenetically unrelated taxa points to the importance of ecological factors during evolution, whereas convergent evolution in closely related taxa indicates the importance of favourable pre-existing characters (pre-adaptations). We investigated the transitions to arboreal life in oribatid mites (Oribatida, Acari), a group of mostly soil-living arthropods. We evaluated which general force-ecological factors, historical constraints or chance-was dominant in the evolution of arboreal life in oribatid mites. A phylogenetic study of 51 oribatid mite species and four outgroup taxa, using the ribosomal 18S rDNA region, indicates that arboreal life evolved at least 15 times independently. Arboreal oribatid mite species are not randomly distributed in the phylogenetic tree, but are concentrated among strongly sclerotized, sexual and evolutionary younger taxa. They convergently evolved a capitate sensillus, an anemoreceptor that either precludes overstimulation in the exposed bark habitat or functions as a gravity receptor. Sexual reproduction and strong sclerotization were important pre-adaptations for colonizing the bark of trees that facilitated the exploitation of living resources (e.g. lichens) and served as predator defence, respectively. Overall, our results indicate that ecological factors are most important for the observed pattern of convergent evolution of arboreal life in oribatid mites, supporting an adaptationist view of evolution.

Community structure of soil oribatida (acari) two years after windthrow in the high tatra mountains

“…On the other hand, species from the family Eremaeidae were present only in EXT stand. The occurrence of Eremaeus hepaticus, Eueremaeus oblongus and Eueremaeus silvestris is often associated with surface residues (tree bark, branches, decaying wood) left after forest harvesting (Maraun et al 2009;Fischer et al 2010). Maraun & Scheu (2000) observed that Oppiidae are generally abundant in forest soils whereas in strongly disturbed habitats their density is lower, which is in agreement with the distribution of this family in the present study.…”

Arthropod colonization of land – Linking molecules and fossils in oribatid mites (Acari, Oribatida)

“…Our analysis included all major oribatid mite groups and the phylogenetic tree is widely consistent with phylogenies based on morphological and other molecular markers (Grandjean, 1969;Haumann, 1991;Norton et al, 1993;Maraun et al, 2004Maraun et al, , 2009Domes et al, 2007a,b). Most nodes are strongly supported by high bootstrap support and posterior probabilities (Table 1) but the phylogenetic resolution was not strong at nodes connecting basal oribatid mites (e.g.…”

Can phylogenetic signal, character displacement, or random phenotypic drift explain the morphological variation in the genus Geonoma (Arecaceae)?

“…A scatterplot with no relationship between phylogenetic history and morphology would result. This pattern would also arise under convergent evolution, in which different evolutionary trajectories result in similar solutions to the same ecological problem (Wake, 1991; Maraun et al ., 2009).…”