The conservation biology of Troides aeacus formosanus (Rothschild) (Lepidoptera: Papilionidae) in Taiwan
Date Issued
2011
Date
2011
Author(s)
Wu, I-Hsin
Abstract
Troides aeacus is distributed throughout the eastern and southern Asia, which consists of five subspecies, including T. a. aeacus Felder, szechwanus Okano & Okano., malaiianus Furhsorfer, insularis Ney, and formosanus (Rothschild). Common name of T. a. formosanus (Rothschild, 1899) found in Taiwan is “small birdwing”, T. a. formosanus is an endemic subspecies restricted its distribution in Taiwan; and is protected by CITES; and is one of the five Troides aeacus subspecies. The wingspan of T. a. formosanus could reach 150 mm. It also is one of the two representative birdwing butterflies of Taiwan. The black forewings and golden hind wings of the small birdwing are decorated with black dots and grayish stripes, and there are red hair on the either side of its head.
The small birdwing is fairly large in size, elegant and precious, so it is very popular to collectors, and has been severely threatened by commercial collection since 1950s. In 1974, the Entomological Supplier Association of Great Britain agreed not to trade the endemic Taiwan subspecies T. a. formosanus, and Council of Agriculture has listed it on Appendix II of Wildlife Conservation Law in Taiwan in 1989. In addition to the captured threat, the population decline is also associated with habitat loss of the host plant of Aristolochia spp., which are climbing vines. It is known that large numbers of plants are required to sustain a healthy small birdwing population.
In this study, the life cycle and the development time of the T. a. formosanus under different temperatures were tested. The results showed that the egg stage took 7.93±072 days (n=29), the larvae stage from 1st to 5th took 4.46±0.79 days (n =28), 5.52±1.45 days (n=27), 5.33±1.41 days (n=27), 6.19±1.49 days (n=26), 9.80±1.36 days (n=28) respectively. The pupae stage was 30.21±1.42 days (n =19). I also found that as the rearing temperature increased, the development rate increased at the same time. The lower developmental threshold temperatures for the development of eggs, larvae, pupae, were estimated to be 7.66, 7.81, 12.71℃, respectively. The 4 temperature of accumulative effective temperatures of eggs were 145.42, 136.87, 137.51 and 143.62 degree-days；the larvae were 514.09,490.27, 504.87 and 471.27 degree-days；and pupae were 325.10, 412.92, 326.55 and 362.78 degree-days。The area of leaf consumption from 1st to 5th larvae stage were 5.35 ± 2.30 c㎡(n =10)、15.92 ± 4.14 c㎡(n =10)、122.43 ± 36.75 c㎡(n =10)、250.67 ± 57.48 c㎡(n =10)、1338.9 ± 148.93 c㎡(n =10), respectively. The results provide information for the conservation management of the T. a. formosanus population.
Troides aeacus formosanus is one of the five T. aeacus subspecies regions and endemic to Taiwan. In this study, partial DNA sequences of cytochrome oxidase I (CO I) and amplified fragment length of polymorphism (AFLP) markers were analyzed to delineate the differentiation and possible dispersal history of this birdwing butterfly. Phylogenetic relationship analyses have shown that T. a. formosanus could be divided into lineages I and II with limited CO I variations; and AFLP patterns have also shown two divergent clusters A and B. In populations collected from southern Taiwan, there was a significant relationship between lineage II and cluster B. Parsimonious network of CO I indicated haplotype HI, the nearest to the other subspecies, should be the basal in T. a. formosanus. Both CO I sequences and AFLP patterns indicated that haplotype diversity was high in all populations, whereas low levels of genetic differentiation were found among populations. Analysis of molecular variance suggested that most of the total variance was due to differences within populations. These results together with the divergent estimation and the specific geological topology in southern Taiwan indicated that T. a. formosanus might have moved in during recent glaciations (about 150,000 years ago) and become adapted to the tropical environments. The observed differentiation of T. a. formosanus might have resulted from the geographic barriers of the Central Range in the island of Taiwan. Moreover, genetic exchanges caused by transportation and translocation of individuals among butterfly farms or gardens in the past two decades have possibly led to the less diversification among current populations of T. a. formosanus.
Subjects
Troides aeacus formosanus
birdwing
conservation biology
genetic diversity
haplotype
conservation strategy
SDGs
Type
thesis
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