#587. INTRODUCTION. ABSTRACT. METHODS. RESULTS. DISCUSSION. FUTURE PLANS. LIFE HISTORY VARIATION IN INVADING APPLESNAILS (“ POMACEA CANALICULATA” ) MAY POSE ECOLOGICAL THREAT TO WETLANDS.
LIFE HISTORY VARIATION IN INVADING APPLESNAILS (“POMACEA CANALICULATA”) MAY POSE ECOLOGICAL THREAT TO WETLANDS
We would like to thank Bob Howells (TPWD), Mark Kramer and Ann Brinley (Armand Bayou), and Southwestern University for supporting this research. Ecology students Kim Boyd, Matthew Garcia and Cody Freas provided the intraspecific competition data.
Rebecca K. Marfurt, Brandon B.Boland and Dr. Romi L. Burks
Department of Biology, Southwestern University, Georgetown, TX 78626
For more information about applesnail research, please contact [email protected]
Each Results figure refers to
Experiment # in Methods
In native habitats, channeled applesnails (Pomacea canaliculata) graze periphyton. However, casual observations from introduced populations suggest these invaders show variation in feeding ecology, predator response and life history strategies. Attempts to predict this consumer influence on ecosystem function suffer from a lack of basic data. We tested how salinity affected snail mortality. Both adults and hatchlings tolerated salinity levels up to 8 ppt. Adult feeding on lettuce increased significantly at 8 ppt compared to 0 ppt (p = 0.002), while hatchling consumption of algae did not vary (p = 0.284). To see how these consumers responded to predators from the invaded ecosystem, we tested behavioural responses to predatory cues from fish, turtles, crayfish and adult applesnails. Results indicated that fish and crayfish prompted similar predator-avoidance behaviors in hatchlings (p’s < 0.05) and that hatchling response changed over time. Consumption rates of juvenile and redear sunfish did not vary (Χ2, p > 0.05) between native (ramshorn) and exotic applesnails. We recently found that the presence of sunfish enhanced consumption by adult snails when presented alone, but depressed consumption in combination with conspecific cues. Juveniles did show signs of intraspecific competition. Research providing insight into the basic ecology of applesnails can foster management efforts at the ecosystem scale.
Control: No cue
Background picture shows students conducting field surveys of applesnails at Horsepen Bayou near Houston.