PARENT SESSION
Oral Session #81: Pollination and Dispersal.
Presiding: T. Ricketts
Thursday, August 8. 9:00 AM to 11:30 AM. Grand Ballroom Central, Radisson.
A test of ethological isolation among entomophilous fungal species sharing common insect visitors.
BULTMAN, THOMAS*,1, LEUCHTMANN, ADRIAN2, PECK, THOMAS1, 1 Biology Department, Holland, MI2 2Geobotanisches Institut ETH, Zürich, Switzerland
ABSTRACT- Epichloe species are self incompatible fungi that need to be fertilized by spermatia of opposite mating type. Female flies of the genus Botanophila act as vectors of spermatia by ingesting and defecating spermatia onto the fungal stroma after oviposition. Larvae feed and develop on the stromata and thus maintain a symbiotic relationship with Epichloe fungi. Sole dependence on fertilized stromata as a food source should promote specialization of flies to single compatible host species. Observations made in experimental field plots and ascospore progeny analysis indicated prevalence of specific matings between stromata of the same host suggesting that flies are species-specific in their visitation behavior. However, genetic analyses of spermatia contained in the feces of individual flies did not strongly support this hypothesis. Rather, Botanophila flies appear to visit hosts that are available and defecate spermatia from a mixture of fungal species. Nonetheless, flies tend to carry spermatia of one numerically dominant species, with other species being much less frequent. Differences in competitiveness of spermatia from different species deposited on the same stroma may favor intraspecific matings.
KEY WORDS: Epichloe endophytes, mutualism, pollination, reproductive isolation