The predatory behavior of male A̲ṉo̲ḻi̲s̲ c̲a̲ṟo̲ḻi̲ṉe̲ṉs̲i̲s̲ c̲a̲ṟo̲ḻi̲ṉe̲ṉs̲i̲s̲ : effects of hunger and prey distance on involvement time

Most models have several factors in common when approaching how the optimal diet (the diet which maximizes the net rate of energy or mass intake) in a fine grain situation (an area in which resources are distributed in a random manner) is obtained. One of these factors is that each food type has an associated food value measured in calories or units of weight and an associated involvement time. This does not take into consideration either distance between predator and prey or the hunger state of the animal. Previous studies have suggested that hunger may affect involvement time and that pursuit time may be a function of distance. Therefore, it is possible that either one or the other or both are capable of modifying involvement time. In light of this hypothesis, the present study was designed to determine if either distance and/or hunger state has an effect on involvement time or its components in male Anolis carolinensis carolinensis.

A 4 x 4 factorial arrangement was used with four progressive distances and four progressive hunger states. Ten replications were completed in the laboratory, each composed of the 16 combined states. In each trial a lizard in a specific hunger state was given an opportunity to pursue, capture, and consume a fly tethered at a set distance.

The results show that involvement time was influenced by both distance and hunger state. The effect of hunger was not significant at the 0.05 alpha level, but was borderline at 0.06. The subcomponent handling time was not affected by the distance traveled or the hunger state of the individual. Differences found in involvement time can be traced directly to the subcomponent pursuit time. Pursuit time is affected by both distance and hunger. Pursuit time is composed of move time and stop time. Move time is affected by the distance a predator has to travel for a prey item, but not the hunger state of the predator. Stop time is affected by both distance and hunger. Both sub-variables of stop time (wait and survey time) are affected by these sources of variation.