One increasingly common set of interactions occurs when native herbivorous insects encounter and utilize exotic plant species. The spread of exotic organisms results in novel species interactions that can produce evolutionary changes 1. Despite having largely switched to a novel exotic host and generally performing better on it, this population has retained breadth in preference and ability to use other hosts. hispida leaves contained the highest concentrations of iridoid glycosides, and iridoid glycoside composition varied with host species and tissue type. Diet strongly influenced secondary chemical uptake by larvae. Larvae developed successfully on all species and grew to similar size on all of them unless they ate only Castilleja leaves (rather than bracts) which limited their growth. Neonates had no preference among host species, but consistently chose bracts over leaves within both Castilleja species. Oviposition preference changed over time. Adult females readily laid eggs on all hosts but favored Plantago and tended to avoid C. We measured oviposition preference, neonate preference, larval growth, and secondary chemical uptake on all three hosts. Two of the hosts ( Castilleja hispida, Castilleja levisecta) were used ancestrally while the other, Plantago lanceolata, is exotic and was adopted more recently.
We examined relationships between an endangered subspecies of the butterfly Euphydryas editha (Taylor’s checkerspot) and three host plant species. Adoption of novel host plants by herbivorous insects can require new adaptations and may entail loss of adaptation to ancestral hosts.
0 kommentar(er)
