Zoological Studies

Vol. 62, 2023

(update: 2023.6.1)

Genetic Structure of the Endemic Fiddler Crab Uca (Xeruca) formosensis on the West Coast of Taiwan

Kun-Chin Hung1, Ching-Yu Liou2, Chih-Chung Wen3, and Hui-Chen Lin1,* 

1Department of Life Science, Tunghai University, Taichung 407, Taiwan. *Correspondence: E-mail: hclin@thu.edu.tw (Lin).
E-mail: x12127802@gmail.com (Hung)
2Endemic Species Research Institute, Council of Agriculture of the Executive Yuan, Jiji, Nantou 552005, Taiwan. E-mail: lcy@tesri.gov.tw (Liou)
3Department of Safety, Health and Environmental Engineering, Hungkuang University, Taichung 433, Taiwan. E-mail: wen1558@sunrise.hk.edu.tw (Wen)

(Received 20 January 2022 / Accepted 17 February 2023 / Published 1 June 2023)
Communicated by His-Te Shih

Xeruca formosensis is the only endemic species of fiddler crab on the west coast of Taiwan. However, its natural habitats and populations have been compromised by excessive anthropogenic activities and improper land use over the past four decades. In light of these changes, we sought to evaluate the genetic diversity and gene flow of the species by examining the genetic variation of X. formosensis at different sampling locations. To this end, we performed molecular analyses of three endonuclease-amplified fragment length polymorphisms (TE-AFLP) and the cytochrome oxidase subunit I (COI) marker from leg muscle samples. We found that the genetic variation within sampling locations was higher than that among sampling locations, and the expected heterozygosity of genetic diversity (Hj) was 0.152 for TE-AFLP data. Meanwhile, the COI marker showed high haplotype diversity (h = 0.976 0.008) and a low genetic differentiation level (FST = 0.021) in X. formosensis populations. Importantly, the genetic connectivity of X. formosensis may be influenced by larval-stage crabs drifting between coastal and marine habitats. As such, crab gene flow is promoted among populations by larval exchange via nearshore currents. Although X. formosensis has high gene flow, the species could undergo an extinction crisis if the population sizes continue to decline, as with most endangered species. In order to maintain the natural habitats and population size of X. formosensis, long-term monitoring and investigation will be necessary.

Key words: Xeruca formosensis, Genetic variation, Larvae drifting, Genetic diversity.

Citation: Hung KC, Liou CY, Wen CC, Lin HC. 2023. Genetic structure of the endemic fiddler crab Uca (Xeruca) formosensis on the west coast of Taiwan. Zool Stud 62:24.doi:10.6620/ZS.2023.62-24.