8 September 2021 | By James Baxter-Gilbert
Many of us are now familiar with urban commensal species – those that have adapted to life in towns and cities and can be seen to adapt their behaviour to exploit their new surroundings. Some of these urbanised species are then introduced to novel systems, and go on to become invasive. This raises the question, does their ability to shift their behaviour in urban populations give these city-dwellers an advantage within an invasive range?
In a recent study published in Behavioural Ecology and Sociobiology, C∙I∙B Postdoc Dr James Baxter-Gilbert, collected toads from urban and rural areas in their native (Durban, South Africa) and invasive (Reunion & Mauritius) ranges (see news articles about previous research here and here). He and his team then examined differences in boldness and exploration in toads from each site. Because the invasion route of these toads is already known (see news article here), James was able to reconstruct whether trends in these behavioural traits changed along the invasion route.
Have invasive toads become bolder than their native counterparts?
What he found was that populations in the native range became bolder in urban populations, and that these increased boldness levels were maintained once toads were moved from urbanised populations in the native range and introduced to urban areas in novel regions.
Overall, urban toads were consistently more bold than those in rural situations.
Interestingly, along the invasion route there has also been a reversal from bolder toads to shyer toads once they left the urban areas in the invaded ranges and colonised more natural and rural settings – returning to the normal baseline levels of their rural native populations.
This tells us that benefits gained by these bold traits are sufficient to repeatedly manifest themselves when toads invade urban settings, but that rural toads gain consistent benefits from being less bold. Moreover, this study was able to show that these toads are able to switch between these different behavioural phenotypes no matter where they are introduced.
“This finding shows us more of the flexibility of these toads as invaders,” said Dr Baxter-Gilbert. “If they are moved from native or invasive ranges, they seem to be able to adaptively shift their behaviour to suit both urban and rural living.”
Read the article in full here
Baxter-Gilbert, J., Riley, J.L. & Measey, J. Fortune favors the bold toad: urban-derived behavioral traits may provide advantages for invasive amphibian populations. Behavioural Ecology and Sociobiology 75, 130 (2021). https://doi.org/10.1007/s00265-021-03061-w pdf
For more information, contact James at j.h.baxtergilbert@gmail.com
