The early toad gets the worm: cane toads at an invasion front benefit from higher prey availability
Article first published online: 29 JAN 2013
© 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society
Journal of Animal Ecology
Volume 82, Issue 4, pages 854–862, July 2013
How to Cite
Brown, G. P., Kelehear, C., Shine, R. (2013), The early toad gets the worm: cane toads at an invasion front benefit from higher prey availability. Journal of Animal Ecology, 82: 854–862. doi: 10.1111/1365-2656.12048
- Issue published online: 13 JUN 2013
- Article first published online: 29 JAN 2013
- Manuscript Accepted: 4 DEC 2012
- Manuscript Received: 8 JUL 2012
- alien species;
- Bufo marinus ;
- introduced species;
- invasion rate
- In biological invasions, rates of range expansion tend to accelerate through time. What kind of benefits to more rapidly dispersing organisms might impose natural selection for faster rates of dispersal, and hence the evolution of range-edge acceleration? We can answer that question by comparing fitness-relevant ecological traits of individuals at the invasion front compared with conspecifics in the same area a few years post-invasion.
- In tropical Australia, the rate of invasion by cane toads (Rhinella marina) has increased substantially over recent decades, due to shifts in heritable traits. Our data on field-collected cane toads at a recently invaded site in the Australian wet–dry tropics span a 5-year period beginning with toad arrival.
- Compared with conspecifics that we monitored in the same sites post-invasion, toads in the invasion vanguard exhibited higher feeding rates, larger energy stores, better body condition and faster growth.
- Three processes may have contributed to this pattern: (i) higher prey availability at the front (perhaps due to reduced competition from conspecifics); (ii) the lack of viability-reducing parasites and pathogens in invasion-front toads; and (iii) distinctive (active, fast-growing) phenotypes of the invasion-front toads.
- Nutritional benefits to individuals in the invasion vanguard (whether because of higher prey availability, or lower pathogen levels) thus may have conferred a selective advantage to accelerated dispersal in this system.