INNATE AND LEARNED CUES - SCALE COVER SELECTION BY APHYTIS-MELINUS (HYMENOPTERA, APHELINIDAE)

Citation
Djw. Morgan et Jd. Hare, INNATE AND LEARNED CUES - SCALE COVER SELECTION BY APHYTIS-MELINUS (HYMENOPTERA, APHELINIDAE), Journal of insect behavior, 11(4), 1998, pp. 463-479
Citations number
35
Categorie Soggetti
Entomology
Journal title
ISSN journal
08927553
Volume
11
Issue
4
Year of publication
1998
Pages
463 - 479
Database
ISI
SICI code
0892-7553(1998)11:4<463:IALC-S>2.0.ZU;2-X
Abstract
Aphytis melinus recognizes and accepts covers of its host, California red scale, Aonidiella aurantii (Maskell) (Homoptera: Diaspididae), bef ore assessing the size or quality of the scale body beneath. We evalua ted the role of a non-volatile kairomone, O-caffeoyltyrosine, and prio r experience with hosts on the recognition (antennal drumming) and acc eptance (ovipositor probing) of scale covers differing in age and, the refore, size. We tested several hypotheses concerning the role of expe rience with hosts on host recognition and acceptance. The first predic ts that experience with a particular host size leads to increased sele ction of that host size in the future. The second predicts that the '' quality'' of the experience with hosts sets a threshold of quality for future acceptance. We manipulated the quality of wasp experience with hosts by exposing some wasps to high-quality hosts (large scale insec ts under large covers) and other wasps to low-quality hosts (small sca le insects under small covers and small scale insects under large cove rs). Control (naive) wasps were held without experience with hosts. Wa sps were then offered five size classes of covers directly after remov al from the scale insects (unmanipulated) or after removing the kairom one from the covers (kairomone-free). For covers with natural levels o f kairomone, no effect of experience with hosts on host recognition wa s observed. When the kairomone was removed, however, any experience wi th hosts increased recognition compared to naive wasps. Moreover, expe rienced wasps preferentially recognized covers of the size to which th ey had experience. Results for host acceptance differed from those for host recognition. Wasps given experience with large hosts accepted mo re covers with kairomone than wasps in other treatments, but the size preference did not vary among treatments. When the kairomone war; remo ved, however, wasps given experience with large hosts under large cove rs preferred larger covers. Host recognition and acceptance are contro lled by different behavioral mechanisms. Prior experience with hosts d oes not alter host recognition but does affect the rate of acceptance. The quality of the experience does not affect the acceptance of cover s containing natural levels of kairomone but does affect host acceptan ce when the kairomone is removed. Experience with hosts alters the mot ivation of wasps to accept covers, and the direction of this effect is determined by the size (quality) of body the wasps were given during the experience.