Ref ID : 755
John J. Gilbert, Richard S. Stemberger, and Hanover, N.H.; The costs and benefits of gigantism in polymorphic species of the rotifer Asplanchna. Arch.Hydrobiol.Beih. 21:185-192, 1985
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An analysis of the small, saccate and giant, campanulate morphs of Asplanchna silvestrii supports the hypothesis that the potential for gigantism in polymorphic species of Asplanchna evolved to permit the exploitation of larger-bodied prey. For a given level of reproduction, campanulates must eat about 5 times as much prey biomass per day as saccates. However, calculations suggest that campanulates, with their much greater coronal surface area and similar swimming speed, should swim through about 13 times as much water/day and require 2-4 times lower concentrations of prey biomass for reproduction. Additional calculations, using a 2 prey-species model, suggest that campanulates should have a reproductive advantage over saccates whenever the large prey (Asplanchna brightwelli) that they eat are no more than 28-40 times less abundant than the small prey (Synchaeta oblonga) that saccates eat. The absolute and relative abundances of large prey are likely to be highest in the very eutrophic environments inhabited by polymorphic Asplanchna.