Prey selectivity and the effect of diet on growth and development of a dragonfly, Sympetrum sanguineum
- Published
- Accepted
- Subject Areas
- Ecology, Entomology
- Keywords
- predation, prey selection, switching, optimal foraging theory, ecological stoichiometry, survival, aquatic insects
- Copyright
- © 2019 Dudová et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Prey selectivity and the effect of diet on growth and development of a dragonfly, Sympetrum sanguineum. PeerJ Preprints 7:e27721v1 https://doi.org/10.7287/peerj.preprints.27721v1
Abstract
Despite a long tradition of research, our understanding of mechanisms driving prey selectivity in predatory insects is limited. According to optimal foraging theory, predators should prefer prey which provides the highest amount of energy per unit time. However, prey selectivity may also depend on previous experience and nutritional demands driven by stoichiometry. From the long-term perspective, diet composition affects predator fitness. An open question is whether short-term selectivity of predators provides a diet which is optimal in the long-term. To shed more light on these issues, we conducted laboratory experiments on prey selectivity and its long-term consequences in larvae of the dragonfly Sympetrum sanguineum. We conditioned the larvae to one of two prey types, the cladoceran Daphnia magna and Chironomus larvae, and then exposed them to various combinations of the two prey types. We found that dragonfly larvae conditioned to Chironomus larvae consumed the same amount of D. magna, but significantly less Chironomus larvae compared to dragonfly larvae conditioned to D. magna. However, there was no effect of experience on their success of capture and handling time, suggesting a limited role of learning in their ability to process prey. We then tested the long-term effects of diets with different proportions of both prey for survival and growth of the dragonfly larvae. Individuals fed Chironomus-only diet performed significantly worse than dragonflies fed D. magna, while larvae fed a mixed diet performed the best in terms of growth and survival until adulthood. In conclusion, we show that dragonfly larvae fed by Chironomus larvae performed poorly and compensated by preferring D. magna when both prey types were available. The superiority of the mixed diet suggests that a diverse diet may be needed to satisfy nutritional demands in S. sanguineum larvae. We demonstrate that merging short-term predation experiments with relevant data on predator fitness may provide better understanding of predator-prey interactions and conclude that detailed information on the (mis)matches between prey stoichiometry and predator nutritional demands is needed for further progress.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Data on selective predation from the short term experiment
Each observation contains information about the number of Daphnia magna and Chironomous larvae offered as prey and the number of approaches towards each prey type, the number of attacks, and the number of succesfully captured prey.
Handling times of the larvae of Sympetrum sanguineum processing their prey during the short-term experiment on prey selectivity
Information about the number of Daphnia magna and Chironomus larvae available and handling time for individual predation events are provided for each dragonfly larva identified by a unique ID.
Data from the long-term experiment on the effect of diet on growth and development of Sympetrum sanguineum
Each line contains information about the survival, body weight, body length, and head width of individual larvae of S. sanguineum, and the same data on the adults in individuals which successfully completed their development.