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

Pesticide-induced changes in surface migration by earthworms in grassland were investigated using trapping and the fungicide benomyl. 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 migration (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>Lumbricus terrestris>A. caliginosa in control areas, but A. longa>L. terrestris>A. rosea>A. caliginosa in sprayed areas; spraying altered the rank-order such that the anecic A. longa and L. terrestris dominated, jointly increasing from 59% to 78%. At species level, L. terrestris and A. longa exhibited significant increases of 4.6 x and 3.6 x in final migration levels in treated areas, the endogeic A. rosea and A. caliginosa having trends for increase. Species-specific differences for reaction time occurred, with significantly elevated migration already by day 1 for L. terrestris, and day 2 for A. longa and A. caliginosa. For each species, juveniles consistently showed greater increases than mature worms due to spraying, significantly so for juvenile L. terrestris, 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, L. terrestris showed a delayed reaction, whereas A. caliginosa exhibited suppressed migration. Results are discussed relative to behavior, ecological category, and risk of toxic exposure.

Magnetic bones in human sinuses.

Studies on the interaction of magnetic fields and biological organisms have centred on the influence of applied magnetic fields on the physiology and behaviour of organisms, including humans, and a search for magnetic sources within the organisms themselves. Evidence continues to accumulate that a wide range of organisms, from bacteria to vertebrates, can detect and orient to ambient magnetic fields (for examples see refs 2-4). Since the discovery that magnetic orientation by bacteria was due to the presence within the organism of magnetic particles of the ferric/ferrous oxide, magnetite, the search has begun for other biogenic deposits of inorganic magnetic material and ways in which the possession of such material might confer on the organism the ability to orient to ambient magnetic fields. Such magnetic material, often identified as magnetite, has been discovered in bees, homing pigeons, dolphins and various other organisms, including man. A variety of hypotheses for the use of magnetite in magnetic field detection have been proposed. We report here that bones from the region of the sphenoid/ethmoid sinus complex of humans are magnetic and contain deposits of ferric iron. The possible derivations and functions of these deposits are discussed.