Meeting Abstract
The cane toad (Rhinella marina) is an invasive species introduced to southern Florida, and populations expanding northward are predicted to have higher locomotive capacity. To assess endurance of toads from Florida, toads from a northern (New Port Richey (NPR)) (n = 24) and southern (Miami (n = 20)) population were placed into a 1.83m long track and tapped to encourage movement. A principal component analysis was performed on the number of taps, hops, and time it took for the toads to stop moving. The first component, “unwillingness to move”, (fewer taps and hops, and shorter time until movement stopped) characterized 91.65% of the data variation. Track dispersal decreased with increasing leg : SVL ratio (p = 0.05), and NPR toads traveled less far than Miami toads (p = 0.01). Unwillingness to move increased with increasing leg : SVL ratio (p = 0.04), and NPR cane toads were more unwilling to move compared to Miami cane toads (p = 0.005). Another toad subset (n = 38 (Miami) and n = 34 (NPR)) was placed inside of a mechanical locomotion setup, where they were forced to move until reaching exhaustion. Each toad was immediately removed, bled to obtain lactate levels, and then allowed to rest. Toads that traveled further had higher lactate (p = 0.05). When forced to move, NPR toads traveled 5.12 (+/- 1.78)m further than Miami toads (p < 0.01), and NPR individuals had lower lactate at exhaustion than those from Miami (p = 0.03). Lactate levels decreased with increasing toad mass (p = 0.01), and decreased more in Miami compared NPR cane toads (p = 0.04). Lactate decreased over time in resting toads (p < 0.01), although the rate of which was the same for both populations (p = 0.78). These results indicate behavioral and endurance changes have occurred in these toads from northward dispersal.
