amphibian malformations, Cricket frog, Acris crepitans
Reports of malformed amphibians have been increasing, including external deformities such as missing or extra arms and legs, missing eyes and mandibles, and internal abnormalities involving the bladder, digestive system, and testes. Natural phenomena such as limb amputations during predation attempts by other animals, parasitism, xenobiotic chemicals (herbicides, insecticides, fertilizers and others), and UV-B or other radiation (either directly or indirectly by triggering production of toxicants from nontoxic chemicals) have all been linked to amphibian abnormalities. From 1968-71, I studied the natural history, effective breeding size, and seasonal, annual, and geographic variation in color morph frequencies of cricket frogs (Acris crepitans) in Illinois to evaluate the potential adaptive significance of polymorphism in the species. Cricket frogs from seven different populations were marked for later identification and followed for three years. Additionally, cricket frogs from 28 other populations in Illinois were sampled at least once. A detailed review of my field notes showed that 30 years ago the frequency of abnormalities recorded throughout Illinois was 0. 39% and that most oddities involved missing arms and legs (0.32%) rather than extra limbs (0.07%). Missing limbs may reflect attempted predation by other animals while extra limbs would indicate developmental errors. Only seven confirmed deformities (extra or deformed arms, deformed digits, underdeveloped mouth) were recorded in almost 10,000 frogs examined.
Journal of the Iowa Academy of Science
© Copyright 2000 by the Iowa Academy of Science, Inc.
Gray, Robert H.
"Morphological Abnormalities in Illinois Cricket Frogs, Acris crepitans, 1968-71,"
Journal of the Iowa Academy of Science: JIAS: Vol. 107:
, Article 11.
Available at: http://scholarworks.uni.edu/jias/vol107/iss3/11