Phylogeography of the white-nest swiftlet Aerodramus fuciphagus (Thunberg, 1812) in Thailand

Abstract

Originally the white-nest swiftlet, Aerodramus fuciphagus, lived in large colonies in natural caves on coastal islands, but now it also occurs in man-made buildings such as sacred buildings and swiftlet houses. The observations in this study found that colonies of A. fuciphagus in swiftlet houses have been widely expanded along the coastlines, ranging from the East through the South of the Gulf of Thailand and Andaman Sea. The majority of swiftlet houses are located on the mainland opposite the natural cave habitats on islands, at the river mouth areas and in urban areas. Due to the fact that the number of swiftlet buildings has been enormously increased in the past several years and that to date there is no official regulation or law for controlling the construction of swiftlet houses, negative impacts to human and natural ecosystems could occur in the future. Therefore, the studies on ecological impact and health risk assessment for setting the proper management plan are urgently needed. The genetic relationship of A. fuciphagus colonies was investigated using two mitochondrial DNA genes (cyt-b and ND2) and eight microsatellite loci among and within swiftlet colonies from across recently established man-made colonies in Thailand. Ten white-nest swiftlet colonies were sampled along the coast of the Gulf of Thailand and the Andaman Sea in Thailand. Genetic diversity of mtDNA was very low whereas that of microsatellite loci was high. Estimates of genetic differentiation, [phi][subscript st] (mtDNA) and F[subscript st] (microsatellites) values were very low and some negative values were found, indicating that genetic variability within colonies was higher than between colonies. Analyses of mtDNA haplotype relationships and microsatellite data did not detect genetic structure across the sampled distribution. Microsatellites were also analyzed using STRUCTURE and it was found that the number of subpopulations of white-nest swiftlets in sampled colonies was one (K = 1). The lack of genetic differentiation among swiftlet house colonies could be a result of high gene flow between colonies and large population sizes. The results suggest that A. fuciphagus living in recently established man-made houses in Thailand should be considered members of a single panmictic population.