Intra-cohort cannibalism and size bimodality: a balance between hatching synchrony and resource feedbacks
2010 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 119, no 12, 2000-2011 p.Article in journal (Refereed) Published
Cannibalistic interactions generally depend on the size relationship between cannibals and victims. In many populations, alarge enough size variation to allow for cannibalism may not only develop among age-cohorts but also within cohorts. Westudied the implications of variation in hatching period length and initial cohort size for the emergence of cannibalism andbimodal size distributions within animal cohorts using a physiologically structured population model. We found that thedevelopment of size bimodality was critically dependent on hatching period length, victim density and the presence of afeedback via shared resources. Cannibals only gained enough energy from cannibalism to accelerate in growth when victimdensity was high relative to cannibal density at the onset of cannibalism. Furthermore, we found that the opportunity forearly hatchers to initially feed on an unexploited resource increases the likelihood both for cannibalism to occur and sizebimodality to develop. Once cannibals accelerated in growth relative to victims size bimodality, reduced victim numbersand relaxed resource competition resulted. Th us, in addition to that cannibals profi ted from cannibalism through energyextraction, their potential victims also benefi ted as the resource recovered due to cannibal thinning. To ensure recruitmentsuccess, it can be critical that a few individuals can accelerate in growth and reach a size large enough to escape sizedependentpredation and winter starvation. Hence, within-cohort cannibalism may be a potentially important mechanismto explain recruitment variation especially for cannibalistic species in temperate climates with strong seasonality. However,the scope for size bimodality to develop as a result of cannibalism may be limited by low victim densities and size andfood-dependent growth rates.
Place, publisher, year, edition, pages
2010. Vol. 119, no 12, 2000-2011 p.
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:umu:diva-25769DOI: 10.1111/j.1600-0706.2010.18454.xISI: 000284371000018OAI: oai:DiVA.org:umu-25769DiVA: diva2:233728