LONG-TERM CHANGES IN THE OVIPOSITION BEHAVIOR OF THE CABBAGE BUTTERFLY, PIERIS-RAPAE, INDUCED BY CONTACT WITH PLANTS

ABSTRACT. Contact between the tarsi and cabbage foliage was found to have important influences on the oviposition behaviour of Pieris rapae, whereas contact between the ovipositor tip and cabbage foliage showed no influence. Oviposition on a leaf disc was not influenced by the presence of previously laid eggs. Gravid female P.rapae showed an increased tendency to approach and land on host or non‐host foliage, or on yellow or green cards, after tarsal contact with cabbage foliage. This effect persisted for at least 72h. It was accompanied by an increased tendency to oviposit on non‐host plants, most obviously within seconds of contact with cabbage, but with some persistence after 72h. Contact with a non‐host leaf (lettuce) reduced the tendency of females to land on plants, but this effect was less pronounced than the one induced by contact with cabbage. These behavioural changes were immediate as well as long‐term and were not associated with changes in the ovaries, so they probably result from the direct effects of sensory input on the CNS. Such behaviour probably increased the likelihood that gravid females would locate host‐plants for oviposition in the field. For tests of host‐plant specificity, the implications are that the behaviour of gravid females towards an array of plants might differ according to the presence or absence of hosts, not only during the test, but also during the preceding several days. Copyright © 1979, Wiley Blackwell. All rights reserved