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Size-dependent aggression towards kin in a cannibalistic species
Chloe A Fouilloux1, Lutz Fromhage1, Janne K Valkonen1
1Department of Biology and Environmental Science, University of Jyvaskyla, P.O. Box 35, 40014 Jyväskylä, Finland.
Summary
Cannibalistic tadpoles show less aggression towards siblings, especially when size differences are minimal. However, large tadpoles attack smaller relatives faster, balancing fitness costs and benefits.
Area of Science:
- Behavioral Ecology
- Animal Behavior
- Evolutionary Biology
Background:
- Intraspecies aggression in juveniles can jeopardize survival to reproduction.
- Factors influencing aggression, such as genetics and environment, vary across species.
- Cannibalism of relatives can reduce inclusive fitness, leading some species to evolve kin discrimination.
Purpose of the Study:
- To investigate how physical traits (relative size) and genetic relatedness influence aggression in cannibalistic tadpoles.
- To understand the trade-offs between individual fitness and relatedness in mediating aggressive behavior.
Main Methods:
- Experimental pairing of tadpoles (full-sibling, half-sibling, non-sibling) with varying sizes.
- Recording aggression and activity levels in controlled arena settings.
- Utilizing a theoretical model to complement empirical findings on larval aggression.
Main Results:
- Aggression is predicted by the interaction between relative size and genetic relatedness.
- Large tadpoles in non-sibling dyads exhibit significantly higher aggression than in sibling dyads.
- Siblings attacked faster in size-mismatched pairs compared to non-sibling pairs, despite lower overall aggression.
Conclusions:
- Larval aggression in *Dendrobates tinctorius* reflects a balance between relatedness and size.
- Individuals may trade-off personal fitness gains against the fitness of their relatives.
- Kin recognition and size asymmetry play crucial roles in modulating cannibalistic aggression.
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