Estimating the evolutionary timescale for Dictyoptera — ASN Events

Estimating the evolutionary timescale for Dictyoptera (#89)

Jun Tong 1 , Nathan Lo 1 , Simon Ho
  1. The University of Sydney, The University Of Sydney, NSW, Australia

Dictyoptera is a monophyletic superorder containing cockroaches, termites and mantids (orders: Blattaria, Isoptera and Mantodea, respectively) – three related insects that seem quite distinct from each other. Dictyoptera have a wide global distribution that is reflected in the large assortment of adaptations they have evolved. Distinctive traits such as eusociality and sub-sociality, predation, maternal care, mound construction, flight, bioluminescence, and burrowing can be found within respective taxa. Thus far, the estimated origin of this fascinatingly diverse group has been largely based upon fossil evidence. The fossil record of the Carboniferous is replete with primitive cockroach-like ‘roachoids’, but these insects are different to extant Dictyoptera in several key aspects. Fossils of that are wholly Dictyoptera only appear later in the early Cretaceous, suggesting that the common ancestor of Dictyoptera emerged sometime in the late Jurassic.

 Much progress has been made recently in estimating the timescale of termite evolution, but the evolutionary timescale of Dictyoptera as a whole remains to be studied using molecular data and current methods that incorporate relaxed molecular-clocks. Using a multi-gene dataset that includes representative cockroaches, termites and mantids, we are currently in the process of estimating a timescale for Dictyoptera. We will calibrate our molecular-clock analysis using several independently dated cockroach fossils. Our work will seek to date the origin of the major Dictyoptera families, as well as important adaptive traits such as eusociality and predation.