Phototoxicity and fish predation: selective factors in color morphs
In the Toolik Lake region of arctic Alaska, Heterocope septentrionalis occurs in two distinct color morphs, dark red and pale green. The dark form tends to occur in shallow fishless ponds and the pale form in large, deep lakes with fish, Phototoxicity and fish predation experiments on the two morphs...
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| Format: | Text |
| Language: | English |
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1981
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.7782 http://www.aslo.org/lo/toc/vol_26/issue_3/0454.pdf |
| Summary: | In the Toolik Lake region of arctic Alaska, Heterocope septentrionalis occurs in two distinct color morphs, dark red and pale green. The dark form tends to occur in shallow fishless ponds and the pale form in large, deep lakes with fish, Phototoxicity and fish predation experiments on the two morphs showed that the dark red form had better suwivorship in bright sunlight and the pale green form was less susceptible to predation by visually feeding fish. ‘Ihe red color is caused by a keto-carotenoid pigment. In lakes where predation presents a greater:hreat than sunlight the keto-carot-cnoid pigment is complexed with a protein to produce green Heierocope. Intense pigmentation of zooplankton has generally been thought to be non-adaptive in the presence of visually feed-ing vertebrate planktivores, since it is well established that large, easily visible zooplankton are preferentially fed upon by planktivorous fish and salamanders |
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