Problems with developmental stability in two rodent species from Chornobyl

¹ The University of Georgia's, Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, U.S.A.
² Institute of Ecology, The University of Georgia, Athens, GA 30602, U.S.A.
³ International Radioecology Laboratory, Slavutych 07100, Ukraine
⁴ Illinois State Museum, 1011 East Ash St., Springfield, IL 62703, U.S.A.

Abstract

Changes in developmental patterns are some of the most important effects that may be observed at radioactively contaminated sites like those at Chornobyl. Developmental instability may arise from the interactions between an organism's genotype and its environment and be manifested as deviant morphology. Fluctuating asymmetry (FA) is a measure of deviations from the expected bilateral symmetry of the body. Our objective was to test for differences in FA in two rodent species (Apodemus flavicollis and Clethrionomys glareolus) that live in habitats surrounding the failed Chornobyl reactor. Rodents were collected from four different locations (two contaminated and two reference sites), and a series of adult skulls were photographed and 24 landmarks on each skull were located on digital images from photographed skulls. FA was calculated from the differences in these landmarks on the right and left side of the skull. Significantly more asymmetry (~2X) was observed in mice and voles living around Chornobyl compared to those living at the uncontaminated reference sites. These are relatively large effects in comparison to those previously found for plants and swallows. FA can be a cheap, easily determined and sensitive indicator of radiation-induced stress in small mammals. FA can be used to prioritize environments for remediation efforts and to efficiently evaluate the effectiveness of the remediation efforts.