Pollination ecology of <i>Yucca elata</i>: an experimental study of a mutualistic association

TitlePollination ecology of Yucca elata: an experimental study of a mutualistic association
Publication TypeJournal Article
Year of Publication1993
AuthorsJames CD, M. Hoffman T, Lightfoot DC, Forbes GS, Whitford WG
Date Published1993
Call Number00609
Keywordsarticle, articles, invertebrate, Tegeticula, invertebrate, yucca moth, journal, journals, mutualism, plant, Yucca, pollination ecology, Tegeticula, Yucca, yucca moth, Tegeticula, Yucca, pollination ecology

The pollination biology of a population of 250 Yucca elata and the prodoxid yucca moth Tegeticula yuccasella have a mutualistic association that is essential for the successful sexual reproduction of both species. However, a wide range of other invertebrate species visit flowers during the day and at night. Our aim was to quantify the role of yucca moths and other invertebrate visitors in pollination and fruit set, using manipulative field experiments. Inflorescences were bagged during the day or night (N= 12 Inflorescences) to restrict flower visitors to either nocturnal or diuranl groups. Yucca moths were active exclusively nocturnally during the flowering period and thus did not visit Inflorescences that were unbagged during the day. None of the 4022 flowers exposed only to diurnal visitors set fruit, whereas 4.6% of the 4974 flowers exposed only to nocturnal visitors (including yucca moths) produced mature fruit. The proportion of flowers production fruit in the latter treatment was not significantly different from unbagged control Inflorescences. In a series of experimental manipulations we also determined that: (1) flowers opened at dusk and were open for tow days on average, but were only receptive to pollen on the first night of opening; (2) pollen must be pushed down the stigmatic tube to affect pollination; and (3) most plants require out-cross pollination to produce fruit. The combination of these results strongly suggests that yucca moths are the only species affecting pollination in Y. elata and that if another species was to affect pollination, it would be a rare event.