| Summary: | 碩士 === 國立臺灣大學 === 生態學與演化生物學研究所 === 102 === Agonistic behavior is commonly adopted by animals for competing resources. Resource defense theory points out that the aggressiveness of animals is affected by competitor numbers and resource value. As these factors increase, the aggressiveness might increases, decreases, or has a quadratic change. Individuals of Hemidactylus frenatus often aggregate around the lights and compete on insect prey. Results of previous studies on the intraspecific aggressiveness of this species were contradictory, and whether its aggressiveness is affected by abovementioned factors is also unknown. An indoor experiment, manipulating 2 levels of competitor numbers and 3 levels of food abundance, were thus conducted to clarify their effects on the aggressiveness of foraging H. frenatus. The results indicated that the aggressiveness was generally lower when there were more competitors, i.e., lower long-distance agonistic ratio, overall hostility ratio, median intensity ratio, and interaction time. However, dominant geckos tended to show a higher ratio of high intensity behavior at the same time. This ratio was also affected by food abundance and showed a quadratic response along with the increasing food abundance. A quadratic response was also found in the interaction time of encounters between subordinates. The study confirmed that both competitor numbers and food abundance have effects but may act differently on intraspecific agonistic behavior of H. frenatus, and the importance of social status was also revealed. This study provides a rare example of applying resource defense theory on agonistic interaction of reptiles.
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