INNATE LANDWARD ORIENTATION IN THE LITTORAL ISOPOD TYLOS-EUROPAEUS

Solar orientation experiments have shown that laboratory-born (inexper t) young of the littoral isopod Tylos europaeus are capable of using t he sun compass to assume an escape direction corresponding to the Y ax is of their mother's home shore. As in sandhoppers, the escape directi on and capacity for solar orientation appear to be innate. The hypothe sis whereby the direction of the sea-land axis is innate in littoral a rthropods with direct development, inhabiting rectilinear coastlines a nd having a limited vagility along the X axis is discussed.