Responses of brambles, Rubus vestitus, to herbivory.
We investigated the effect of fertilisation and multiple episodes of simulated herbivory on the prickliness of bramble, Rubus vestitus. The prickliness of fertilised, uncut plants was significantly greater than that of plants in all other treatments. Our results indicate that prickle production is constrained by resource availability, with brambles allocating resources to growth under intense herbivory. Isozyme electrophoresis of plants collected from Wytham Woods, Oxford, UK, failed to detect any variation, suggesting that observed variation in prickliness may be primarily the result of phenotypic plasticity. In our experiments, however, we observed significant variation in prickliness among putative genotypes.
Department of Biology, York University, 4700 Keele Street, M3J 1P3, North York, Ontario, Canada.
Debra
D
Gibson
Department of Biology, York University, 4700 Keele Street, M3J 1P3, North York, Ontario, Canada.
Dawn R
DR
Bazely
Department of Biology, York University, 4700 Keele Street, M3J 1P3, North York, Ontario, Canada.
Joel S
JS
Shore
Herbivory; Physical defence; Prickles; Rubus vestitus; Trade-off