Peter Beeck
Donald L. DeAngelis
Werner R. Scharf
Jost Borcherding
2010
<p><span>1. In gape-limited predators, body size asymmetries determine the outcome of predator-prey interactions. Due to ontogenetic changes in body size, the intensity of intra- and interspecific interactions may change rapidly between the </span><span class="ScopusTermHighlight">match</span><span> situation of a predator-prey system and the </span><span class="ScopusTermHighlight">mismatch</span><span> situation in which competition, including competition with the prey, dominates. 2. Based on a physiologically structured population model using the European perch (Perca fluviatilis), analysis was performed on how prey density (bream, Abramis brama), initial size differences in the young-of-the-year (YOY) age cohort of the predator, and </span><span class="ScopusTermHighlight">phenology</span><span> (time-gap in hatching of predator and prey) </span><span class="ScopusTermHighlight">influence</span><span> the size structure of the predator cohort. 3. In relation to the seasonality of reproduction, the </span><span class="ScopusTermHighlight">match</span><span> situation of the predator-prey system occurred when perch hatched earlier than bream and when no gape-size limitations existed, leading to decreased size divergence in the predator age cohort. Decreased size divergence was also found when bream hatched much earlier than perch, preventing perch predation on bream occurring, which, in turn, increased the competitive interaction of the perch with bream for the common prey, zooplankton; i.e. the </span><span class="ScopusTermHighlight">mismatch</span><span> situation in which also the mean size of the age cohort of the predator decreased. 4. In between the total </span><span class="ScopusTermHighlight">match</span><span> and the </span><span class="ScopusTermHighlight">mismatch</span><span>, however, only the largest individuals of the perch age cohort were able to prey on the bream, while smaller conspecifics got trapped in competition with each other and with bream for zooplankton, leading to enlarged differences in growth that increased size divergence. 5. The modelling results were combined with 7 years of field data in a lake, where large differences in the length-frequency distribution of YOY perch were observed after their first summer. These field data corroborate that </span><span class="ScopusTermHighlight">phenology</span><span> and prey density per predator are important mechanisms in determining size differences within theYOYage cohort of the predator. 6. The results demonstrate that the switch between competitive interactions and a predator-prey relationship depended on </span><span class="ScopusTermHighlight">phenology</span><span>. This resulted in pronounced size differences in the YOY age cohort, which had far-reaching consequences for the entire predator population.</span></p>
application/pdf
10.1111/j.1365-2656.2010.01704.x
en
Wiley
Match or mismatch: The influence of phenology on size-dependent life history and divergence in population structure
article