Mr Zhuzhi Zhang1, Mr Nathan Lo1

1the University of Sydney, Sydney, Australia

Biography:

I'm a PhD candidate in biology at the University of Sydney. Current research interests are evolutionary ecology and phylogeny, focusing on the phylogeny and parallel evolution of the Australian wood-feeding cockroaches (Panesthiinae), and soil-burrowers (Geoscapheinae). I completed my master's studies at the Australian National University, focusing on the effects of environmental stress of insufficient water on the reproductive behaviour and fitness of insects. I also participated in the phylogenetic and taxonomic revision of Vitaceae for my undergraduate thesis.

Abstract:

A significant and enduring debate in biology is whether evolution is predictable. Clarifying this question will enhance our understanding of biological diversification. Studying taxa that have undergone parallel evolution at the genetic level, i.e. independent evolution of the same or similar traits in different lineages, underpinned by the same or similar genomic mechanisms, can help elucidate the predictability of evolution. Observed parallel evolution shows that genetic mutations are potentially non-random, leading to several hypotheses such as mutational bias and/or selection of pleiotropic mutations. Geoscapheinae is a group of soil-burrowing cockroaches in Australia, which appear to exhibit recurrent parallel evolution. Due to their similar morphology and behavior, until recently, it was assumed that this group shared a common ancestor; however, recent phylogenetic work showed that they evolved from their wood-feeding ancestors multiple times. To increase our understanding of this group, we analyzed Australian wood-feeding cockroaches (Panesthiinae), and soil-burrowers (Geoscapheinae) from across their distribution 1) confirmed whether most Geoscapheinae groups are sitting in two wood-feeding species, 2) confirmed the soil-burrowing lifestyle in this group has independently originated on at least six occasions, and 3) the cause of these transformations was due to changing environments, such as the expansion of arid environments and the formation and expansion of several geographical barriers for rainforest organisms on the east coast of Australia. Furthermore, we conducted whole-genome sequencing for pairs of sister groups of wood-feeding and soil-burrowing cockroaches to investigate the genomic basis of parallel evolution. Using a comparative genomic approach, we tested the extent to which parallel morphological evolution is driven by parallel molecular evolution. This work will provide new observations on the natural experiment of transitioning to a new environment and lifestyle and offering a deeper understanding of parallel evolution.