Interactions among Vetches Bearing Extrafloral Nectaries, their Biotic Protective Agents, and Herbivores
1988
Koptur, Suzanne | Lawton, John H.
The stipular nectaries of the common vetch (Vicia sativa L.) are present on young plants from about the seventh node and continue to secrete nectar through flowering, until fruit are mature. The ant Myrmica ruginodis is the primary visitor to these nectaries in North Yorkshire, England. The ants are effective at removing or disturbing some of the externally feeding insect herbivores (mostly Lepidoptera, and some Coleoptera), but leaves nevertheless sustain some damage from hard—bodied beetles. More devasting are the pod—feeding larvae of Cydia spp., tortricid moths that oviposit on ovaries of flowers and whose larvae feed in the developing legumes, safe from ants. In areas where ant abundance is highest, the pod—feeding larvae are apparently well protected by ants from their natural enemies, ichneumonid parasitoid wasps (Scambus planatus and Campoplex punctulatus). Plants in such areas have greater numbers of seeds damaged and produce fewer viable seeds than plants in areas of low ant abundance. The vetches are more successful where ant abundance is low; larvae in the pods get parasitized, and fewer seeds are damaged. These data imply that pod feeders may have successfully short—circuited extrafloral nectary—mediated ant defense for their own benefit.
显示更多 [+] 显示较少 [-]