Fast adaptive responses in the oral jaw of Lake Victoria cichlids.
Rapid morphological changes in response to fluctuating natural environments are a common phenomenon in species that undergo adaptive radiation. The dramatic ecological changes in Lake Victoria provide a unique opportunity to study environmental effects on cichlid morphology. This study shows how four haplochromine cichlids adapted their premaxilla to a changed diet over the past 30 years. Directly after the diet change toward larger and faster prey in the late 1980s, the premaxilla (upper jaw) changed in a way that is in agreement with a more food manipulating feeding style. During the 2000s, two zooplanktivorous species showed a reversal of morphological changes after returning to their original diet, whereas two other species showed no reversal of diet and morphology. These rapid changes indicate a potential for extremely fast adaptive responses to environmental fluctuations, which are likely inflicted by competition release and increase, and might have a bearing on the ability of haplochromines to cope with environmental changes. These responses could be due to rapid genetic change or phenotypic plasticity, for which there is ample evidence in cichlid fish structures associated with food capture and processing. These versatile adaptive responses are likely to have contributed to the fast adaptive radiation of haplochromines.
Department of Integrative Zoology, Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300, RA, Leiden, The Netherlands; Naturalis Biodiversity Center, P.O. Box 9517, 2300, RA, Leiden, The Netherlands; Current Address: Fish Ecology and Evolution, EAWAG Center of Ecology, Evolution and Biogeochemistry, 6047, Kastanienbaum, Switzerland; Current Address: Institute of Ecology and Evolution, University of Bern, CH-3012, Bern, Switzerland. jacco.vanrijssel@eawag.ch.
Jacco C
JC
van Rijssel
Ellen S
ES
Hoogwater
Mary A
MA
Kishe-Machumu
Elize
E
van Reenen
Kevin V
KV
Spits
Ronald C
RC
van der Stelt
Jan H
JH
Wanink
Frans
F
Witte
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D023681:Cichlids / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D004032:Diet; D019143:Evolution, Molecular; D008437:Maxilla / Q000033:anatomy & histology*; D015048:Zooplankton
Diet change; microevolution; morphological response; phenotypic plasticity; premaxilla; selection