PARENT SESSION
Poster Session 34: Herbivory
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Effects of plant cultivar and fungal endophyte isolate on performance and preference of bird cherry-oat aphid.
Bultman, Thomas, Sullivan, Terrence*,, Pulas, Christina, Bell, Gregory,
ABSTRACT- Neotyphodium coenophialum (Ascomycota: Clavicipitaceae) is an endophytic fungus of grasses that produces alkaloids which can have detrimental effects on some insect herbivores. We tested if variation in plant cultivar and fungal isolate affected the performance and preference of the bird cherry-oat aphids. We found that aphid populations grew faster on E- plants in both Jesup and Georgia cultivars (F3,96 = 6.7, p < 0.001; F2,72 = 12.7, p < 0.001, respectively). In the Georgia cultivar, there was no difference between the reproduction of aphids on plants infected with Wild or 542 isolates; however, in the Jesup cultivar, aphids reproduced faster on plants infected with 502 and 542 cultivars, compared to the wildtype isolate. Aphid preferences mirrored performance, for the most part. In all comparisons involving E- plants, aphids preferred the uninfected plants over those infected with N. coenophialum . In comparing just the fungal isolates, aphids showed no preference among them in both the Georgia and Jesup cultivars. Our data clearly show that R. padi is deterred by N. coenophialum and when given a choice, prefers to feed on plants lacking infection by the endophyte. Our results also show that both fungal isolates in the Georgia cultivar depressed aphid reproduction, while only the wildtype isolate did so in the Jesup cultivar. However, aphids tended to avoid all fungal isolates equally. Thus, all fungal isolates we tested in the Georgia and Jesup cultivars provide some protection from R. padi.
Key words: fungal endophyte, aphid, fescue