Life-history trade-offs of Paronychiurus kimi (Lee) (Collembola: Onychiuridae) populations exposed to paraquat.

The demography of Paronychiurus kimi, a dominant collembolan in paddy fields of Korea, was quantified for four treatments of the herbicide paraquat (0, 1.6, 16, 160 and 1600 microg/cm(2)) in a controlled environment using plaster-of-Paris as the test substrate. The survival rate of adults and the reproductive fitness of P. kimi were not affected by paraquat except at the highest dosage (1600 microg/cm(2)), when fed baker's yeast and reared on plaster-charcoal substrate. However, results of life-history experiments suggest that fitness was maintained by a tradeoff between fecundity and reproductive period. It is suggested that these are potential life-history tradeoffs of Collembola that were exposed to the manufacturer's recommended concentration of paraquat (16 microg/cm(2)).