The roles of chemoreception and vision in the foraging of brown bullheads and banded killifish.

Abstract

In terms of foraging habits and morphology, brown bullheads (Ameiurus nebulosus) and banded killifish (Fundulus diaphanus) have a number of contrasting characteristics. Brown bullheads are benthic and feed on detritus, whereas banded killifish school just below the surface and feed on floating insect larvae. In light of these differences I hypothesized that brown bullheads find food faster than the banded killifish when allowed the use of chemoreception. When deprived of chemoreception, I predicted that the banded killifish find food more quickly. In the absence of light, I predicted the time for the brown bullheads to find a food item would not be affected while the banded killifish would take longer to find a food item. I tested these hypotheses using 15 brown bullheads and 15 banded killifish in 5 cm of water in Tupperware contianers measuring 43 cm by 12 cm. I placed a food item in the corner opposite the fish and recorded the time to uptake in light and odor, light only, and odor only treatments. I found significant differences between the three treatments for both species (F=15.0357 for banded killifish, F=22.2296 for brown bullheads). The brown bullheads found the food significantly quicker than the banded killifish under the vision and odor treatment (t=2.1805, df=16, P<0.05). Contrary to my hypothesis, the brown bullheads did take signfiicantly longer to find the food when deprived of vision (t=4.1927, df=14, P<0.05).