The evolution of soil-burrowing cockroaches (Blattaria: Blaberidae) from wood-burrowing ancestors following an invasion of the latter from Asia into Australia

Abstract

Morphologically similar cockroaches in the subfamilies Panesthiinae and Geoscapheinae (Blattaria: Blaberidae) display contrasting feeding habits, behaviour and biogeographical distributions. Panesthiinae, found throughout Asia and Australia, all live in and feed on decaying wood that they burrow into. Geoscapheinae are restricted to Australia and construct and live in burrows in the soil, where they feed on dry leaves taken from the surface. A lack of knowledge about phylogenetic relationships among these cockroaches hinders an understanding of the factors that have shaped the evolution of their diverse lifestyles and biogeography. To address this issue, we sequenced three genes from representatives of nine of the 10 genera in the two subfamilies, and performed phylogenetic analyses. The well-supported topology revealed the Panesthiinae to be paraphyletic with respect to the Geoscapheinae. Soil-burrowing cockroaches appear to have evolved from a lineage of wood burrowers that invaded Australia from the north some time after the merging of the Asian and Australian tectonic plates ca. 20 Myr ago. The main factor promoting the evolution of soil burrowing is likely to have been one of the periods of strong aridity that Australia has experienced since the Miocene period.

Molecular phylogeny of Blaberidae (Dictyoptera, Blattodea) with implications for taxonomy and evolutionary studies

“…These unsurprising results have been suggested several times and concern the monophyly of Blaberidae, (Geoscapheinae + Panesthiinae) and Oxyhaloinae (Maekawa et al 2003;Inward 2007;Pellens et al 2007;Djernaes et al 2012;Legendre et al 2014Legendre et al , 2015. Likewise, a strong support was found, here and in previous studies, for Gyninae, Panchlorinae and Pycnoscelinae.…”

“…Later, cockroach systematists identified several morphological synapomorphies supporting the monophyly of Blaberidae (Grandcolas 1996;Klass & Meier 2006; brood sac underneath the female genitalia, sclerite R3v small, first vein of vannus with many basal rami, tracheation very dense and tracheae vesicle-shaped, presence of a muscle connecting sclerite L2 and pouch lve). Monophyly has also repeatedly been found with molecular data as well (Maekawa et al 2003;Inward 2007;Pellens et al 2007;Djernaes et al 2012;Legendre et al 2014Legendre et al , 2015.…”

Multiple evolutionary origins of Australian soil-burrowing cockroaches driven by climate change in the Neogene

“…Our results support the hypothesis that the Australian taxa in Panesthiinae and Geoscapheinae are descendants of Asian wood feeders that invaded Australia via Wallace's Line [19]. First, Australian lineages are nested among Asian lineages in the tree (figure 2 evidence, which is almost certainly unattainable.…”

“…A molecular phylogenetic study of a limited number of taxa from Panesthiinae and Geoscapheinae (17 and 4, respectively) showed that the former evolved in Asia, later colonizing Australia and giving rise to Geoscapheinae [19]. The four species of Geoscapheinae examined formed a monophyletic group that was relatively distant from the two Australian species of Panesthiinae included in the study [19].…”

“…The four species of Geoscapheinae examined formed a monophyletic group that was relatively distant from the two Australian species of Panesthiinae included in the study [19]. The colonization of Australia by ancestral members of Panesthiinae was presumed to have occurred following the collision between the Australian and Asian tectonic plates around 20 Ma, although no formal analyses of divergence times were performed.…”