The effect of experience and rearing environment on the behaviour of crab spiderlings during their first weeks of life

To examine (1) the effect of experience and rearing environment on learning and behaviour over time, and (2) when (or if) newly-emerged young begin to incorporate experience into their choices, we compared the activity levels and hunting-site preferences of newly-emerged laboratory and field-reared crab spiders (Misumena vatia (Clerck, 1757)). We split spiderlings from eight broods into cohorts (1) released on goldenrod (Solidago canadensis) in the field and (2) retained individually in the laboratory, but provisioned with Drosophila melanogaster. We then tested both field-retrieved and laboratory-reared individuals at clays 3, 7, 14 and 21 for their (1) rate of activity in cages over 15 min and (2) choice of either goldenrod or wild carrot (Daucus carota), two frequent hunting sites in he field. The rearing environment clearly influenced the spiderlings' activity levels: field-reared spiderlings became more active than laboratory-reared spiders over time; however, their choice of flowers did not change, even though their experience differed. Thus, innate mechanisms dominated the spiders' early hunting-site choices, and experience only informed their decisions at later stages in ontogeny. The spiders may, therefore, have multiple mechanisms for learning that begin to operate at different times, since spiderlings improve their locomotor performance through experience, while failing to use early experience in choosing hunting sites at this early point in ontogeny.