TRADE-OFFS IN LARVAL PERFORMANCE ON NORMAL AND NOVEL HOSTS

Authors
Citation
Jn. Thompson, TRADE-OFFS IN LARVAL PERFORMANCE ON NORMAL AND NOVEL HOSTS, Entomologia experimentalis et applicata, 80(1), 1996, pp. 133-139
Citations number
45
Categorie Soggetti
Entomology
ISSN journal
00138703
Volume
80
Issue
1
Year of publication
1996
Pages
133 - 139
Database
ISI
SICI code
0013-8703(1996)80:1<133:TILPON>2.0.ZU;2-Q
Abstract
The evolution of host specialization in phytophagous insects is genera lly thought to involve genetic trade-offs that prevent individuals fro m maximizing fitness simultaneously on two or more hosts. Several hypo theses, however, have suggested that trade-offs may not be evident in experiments comparing larval performance on normal and novel hosts. Te sts on survivorship, growth rate, and pupal mass among families of the swallowtail butterfly Papilio oregonius on its normal host and on a n ovel host provide support for these hypotheses, although they do not d iscriminate among them. Families differed in their relative performanc e on the hosts, but there was no evidence of a negative genetic correl ation between hosts for any of the measures of performance. In additio n, there were no correlations among the different measures, corroborat ing an earlier result suggesting that these different components of pe rformance in the P. machaon species group are under at least partially separate genetic control. These results and similar results published for other insects have now produced a body of studies indicating that genetic trade-offs in individual components of larval performance may not be a major factor preventing shifts onto novel host plants. Trade -offs leading to the evolution of host specialization are more likely to involve coordination among the various components of performance to gether with ecological factors that allow higher fitness on one host t han on others.