issues and experts

Cracking Darwinism: natural perfumes mediate mate choice and speciation in stick insects says SFU study

February 21, 2017

A collaborative study involving SFU biological sciences researchers Bernard Crespi, Gerhard Gries, and Regine Gries, along with researchers from University of Sheffield, Royal Holloway University of London, and other institutions reveals that natural selection can drive speciation through cryptic colouration and mate choice in stick insects. The findings suggest that genetic changes associated with cryptic camouflage to different host plants could begin the process of differentiation between populations.

“However, in order for the speciation process to progress more substantially towards distinct species, more parts of the genome need to be affected,” says Crespi. “At this crucial point, the significance of mate choice based on taste and smell becomes of key importance.”

In the study, published by Nature Ecology & Evolution, the researchers analyzed data collected over 18 years of research from more than 100 populations of 11 species of plant-eating stick insects from across California.  

“The body of insects is covered with a layer of natural oils and waxes, which are produced by the insects, and protect their body from desiccation and injuries caused by abrasion. These chemical compounds, known as cuticular hydrocarbons or CHCs, play an important role as contact signals in mate choice decisions in other insects.”

The new results in this study underscore the complexity of speciation, and the difficulties that need to be overcome for initial levels of population differentiation to progress towards advanced stages of speciation.

“In other words, substantial progress towards the formation of new species might often require the alignment of several different factors, and a resulting multitude of changes across the genome.”

Bernard Crespi, Biological Sciences, 778.782.3533,
Justin Wong, University Communications, 778.782.5151/778.782.3035,