Pesticide-induced surface XXXX by lumbricid earthworms in grassland: life-stage and species differences.

@entity6405 @entity4222 @entity6404 @entity1129 @entity13642
Pesticide-induced changes in surface @entity4222 by earthworms in grassland were investigated using trapping and the fungicide @entity13642 . Traps were tended daily for 15 days after spraying, resulting in 2152 earthworms, five species, and juvenile predominance which reflected species/life-stage composition in the soil. Significant increases in @entity4222 (all worms) occurred already by day 2 due to spraying, final treatment level being 2.8 x control. Life-stage composition indicated an increased juvenile proportion from 55% to 75% due to treatment. Spraying caused surfacing juveniles to increase significantly by day 2, reaching a final level 3.8 x control, whereas for mature worms a significant increase did not occur until day 4. Species rank-order was Aporrectodea longa>A. rosea> @entity6404 >A. caliginosa in control areas, but A. longa> @entity6405 >A. rosea>A. caliginosa in sprayed areas; spraying altered the rank-order such that the anecic A. longa and @entity6405 dominated, jointly increasing from 59% to 78%. At species level, @entity6405 and A. longa exhibited significant increases of 4.6 x and 3.6 x in final @entity4222 levels in treated areas, the @entity1129 having trends for increase. Species-specific differences for reaction time occurred, with significantly elevated @entity4222 already by day 1 for @entity6405 , and day 2 for @entity1129 . For each species, juveniles consistently showed greater increases than mature worms due to spraying, significantly so for juvenile @entity6405 , A. longa, and A. caliginosa, the two anecics reaching as high as 5.3 x and 4.7 x. The response of mature worms differed: A. longa and A. rosea increased surfacing due to treatment, @entity6405 showed a delayed reaction, whereas A. caliginosa exhibited suppressed @entity4222 . Results are discussed relative to behavior, ecological category, and risk of toxic exposure.
