Macrophysiological Traits in Thermoregulation of Tropical Butterflies

  • 俞 佑錚

Student thesis: Master's Thesis


Species color has multiple ecological functions such as camouflage signaling UV protection and thermoregulation Color patterns are crucial to understanding macrophysiological adaptation Ectotherms require heat source from the environment to keep body temperature high enough for locomotion so the rate of heat transfer is important for ectotherms’ survival Several hypotheses related to macrophysiological adaptation has been proposed to explain the variation of ectotherms’ color lightness Thermal melanism hypothesis suggests that darker ectotherms are favored in the cold area due to higher solar absorbing rate In addition to thermoregulation ectotherms having dark color also provide a better protection against ultraviolet radiation pathogen and desiccation Body size also proposed to be related to ectotherms heat transfer large body size has a lower surface-volume ratio and thus have lower heating and cooling rate Although the thermal melanism hypothesis obtained widely empirical supports body size which also important for ectotherms’ thermoregulation was seldom considered simultaneously We investigated the direct and indirect effect of temperature radiation precipitation and ectotherms body size on the variation of color lightness by applying Taiwanese butterfly surveys from 1993 to 2014 We further conducted a heating experiment to investigate the relationship between body size color and thermal properties (maximum excess temperature; heating (cooling) rate Results show body size is the dominant factor in explaining the color lightness variation of butterflies Radiation affects butterflies color lightness variation indirectly through body size The result of the heating experiment shows that butterflies color lightness and body size affect thermoregulation ability simultaneously When body size is small having darker color has little difference in heating (cooling) rate but reaching higher maximum excess temperature than light color When body size is large having darker color has little difference in maximum excess temperature but having faster heating (cooling) rate than light color The result gives explanations of why temperate butterflies normally with small body size with dark color would be favored in cold environment and tropical ectotherms normally have larger body size can also have dark color We suggest that body size should be considered simultaneously in explaining ectotherms’ color lightness to give a more comprehensive prediction
Date of Award2018 Aug 30
Original languageEnglish
SupervisorI-Ching Chen (Supervisor)

Cite this