Endocrine Disruption Trends in Frogs

Researchers who examined specimens of cricket frogs in museum collections from Illinois over past 150 years observed an increase in sexual abnormalities in animals collected during the 1950s, when chlorinated pesticide and PCB uses were beginning to peak.

The proportion of individuals with abnormalities was highest in the heavily industrialized and urbanized portions of the state, intermediate in the intensively farmed areas, and lowest in the less intensively managed and ecologically more diverse portions of the state. A declining trend in abnormalities over time was observed from specimens collected in the urbanized/industrialized areas of the state. The investigators concluded that these findings are consistent with the hypothesis that endocrine disruption contributed to the decline of cricket frogs in Illinois.