Correlation between Larger Body Mass, Smaller Wing and Alternative Reproductive Tactics in Psolodesmus mandarinus Damselflies

• Main Authors: Yang, I-Hsiu, 楊佾修
• Other Authors: Lin, Chung-Ping
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/hp2878

碩士 === 國立臺灣師範大學 === 生命科學系 === 106 === Males of the many animal species use alternative reproductive tactics (ARTs) to obtain mating opportunity and reproductive success. In odonate species, adult males employ various genetically or conditionally based mating tactics (territoriality, non-territoriality/wandering/sneaking, or switching between the two). The evolution of different ARTs via sexual selection in recently diverged odonate species may have facilitated their speciation process. However, the relative effects of the ARTs between closely related but phenotypically divergent odonate species is poorly known. This study investigated the causes and consequences of the ARTs in two parapatrically distributed subspecies of Taiwanese Psolodesmus mandarinus damselflies, P. m. mandarinus and P. m. dorothea. The observations indicate that the males of both subspecies employ the same three mating tactics, including territorial, switching, and non-territorial. In P. m. mandarinus population of Fusan, an increase in body mass and decrease in hindwing area is associated with an increase in territoriality. Compared to non-territorial males, territorial and switching P. m. mandarnus males have higher mating opportunity (i.e. to engage in at least one mating). However, only switching but not territorial P. m. mandarnus males have higher mating success than non-territorial males. In contrast, none of the body size indicators are associated with territoriality in P. m. dorothea population of Lianhuachi. Only the switching but not territorial P. m. dorothea males had higher mating opportunity than non-territorial males. The mating tactics of P. m. dorothea males had no significant effect on their mating success. In both P. mandarinus subspecies, the switching males instead of territorial males, appear to have the highest fitness. These results suggest that the ARTs of the two P. mandarinus subspecies were different in their associations of morphological traits and fitness consequences, which may be due to habitat differences or observer effects.