Hojun Song

Department of Entomology, Texas A&M University, College Station, Texas, U.S.A.

From cricket songs to swarming locusts: elucidating patterns and processes of orthopteran evolution

Orthoptera is the most diverse order within Polyneoptera with more than 28,000 species known worldwide, and includes familiar insects, such as grasshoppers, crickets, katydids, and wetas.  Throughout 350 million years of evolution, orthopteran insects have diversified into numerous lineages that occupy every conceivable terrestrial habitat outside the polar regions and play integral roles in their ecosystems. Such diversity in form and function has attracted researchers who use these insects as model systems for studying anatomy, bioacoustics, chemical ecology, evolutionary ecology, life‐history traits, neurobiology, physiology, and speciation. My research program has focused on understanding the evolutionary relationships among major orthopteran lineages to gain deeper understanding of orthopteran evolution. In this presentation, I provide two fascinating examples of how orthopteran insects can be used as model systems for elucidating patterns and processes of evolution. In the first example, I explore the evolution of acoustic communication in Orthoptera based on a new phylogenomic analysis and ancestral character reconstruction, and discuss about the evolution of hearing and sound producing organs and propose a new evolutionary scenario on how hearing and singing evolved in this group. In the second example, I explore the evolution of density-dependent phenotypic plasticity in grasshoppers and locusts by integrating phylogenetics, transcriptomics, and manipulative behavioral experiments, and discuss about what makes locusts different from grasshoppers.

Central American locust (Schistocerca piceifrons) (Orthoptera: Acrididae) swarm. Image taken by H. Song on Socorro Island in Mexico.