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INSECT‐CYCAD SYMBIOSIS AND ITS RELATION TO THE POLLINATION OF ZAMIA FURFURACEA (ZAMIACEAE) BY RHOPALOTRIA MOLLIS (CURCULIONIDAE)
Author(s) -
Norstog Knut J.,
Fawcett Priscilla K. S.
Publication year - 1989
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1989.tb15117.x
Subject(s) - cycad , biology , weevil , curculionidae , botany , pollen , diapause , cabbage looper , gracillariidae , larva , trichoplusia , noctuidae
Zamia furfuracea , a cycad of Mexican origin, in cultivation is pollinated by the snout weevil, Rhopalotria mollis , also of Mexican origin. This weevil apparently is host specific, swarming upon male cones of the cycad, where mating, feeding, and oviposition occur. Sporophylls of male cones are rich in starch; those of female cones are poor in starch, and weevils feed upon male cones and are visitors to but not feeders upon or within female cones. Pollen transport to female cones occurs during such visitation. All stages of metamorphosis of R. mollis occur within male cones; larvae feed exclusively on parenchyma of microsporophylls, pupate within stalks of microsporophylls, and emerge as adults from the outer ends of microsporophylls. They do not feed on pollen and do not damage microsporangia or pollen. Toward the end of the breeding season of the weevil (and the cycad), some larvae enter diapause in thick‐walled pupal cases within microsporangial stalks of pollen‐spent cones. These remain in diapause until the next reproductive season of the cycad.