Journal
CANADIAN JOURNAL OF ZOOLOGY
Volume 96, Issue 11, Pages 1278-1283Publisher
CANADIAN SCIENCE PUBLISHING
DOI: 10.1139/cjz-2018-0006
Keywords
common earthworm; Lumbricus terrestris; risk-taking; foraging; life-history trade-offs; starvation
Categories
Funding
- University of Toronto at Mississauga's Biology Department
Ask authors/readers for more resources
Species should avoid risks to protect accumulated fitness. However, when faced with starvation, organisms may accept risks to enhance future reproductive opportunities. We investigated the effect of starvation on risk-taking behaviour in the common earthworm (Lumbricus terrestris Linnaeus, 1758). Lumbrictis terrestris are negatively phototactic annelids that feed on decaying plant matter at the soil surface. Feeding in high-light conditions is a potentially riskier choice, given the threats of visual predators and desiccation. We predicted that starvation in L terrestris would increase risk-taking behaviour and decrease time taken (latency) to make choices. We manipulated the starvation level of L. terrestris individuals (nonstarved, half-starved, and fully starved) and presented them with a binary foraging choice. Lumbricus terrestris could choose either a low-food and dark condition (low-risk condition) or a high-food and light condition (high-risk condition). We found that starved individuals selected the high-risk condition more often than nonstarved individuals. Starved individuals also had a decreased latency to first choice. Risk-taking did not scale with level of starvation; there was no difference in foraging choice and latency between half- and fully starved individuals. Our results indicate that L terrestris makes state-dependent foraging choices, providing insight into the importance of fundamental life-history trade-offs in this understudied species.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available