Genetic diversity and colony structure of Tapinoma melanocephalum on the islands and mainland of South China

Abstract

Aim Tapinoma melanocephalum is listed as one of the most important invasive pest species in China. Information regarding the patterns of invasion and effects of geographic isolation on the population genetics of this species is largely lacking.LocationSouth China.MethodsTo address this problem, we genotyped 39 colonies (two colonies were collapsed due to genetic similarity) using microsatellite markers and mitochondrial DNA sequencing to compare colony genetic structure of T. melanocephalum on the mainland and islands of South China.ResultsAn analysis of the colony genotypes showed that the genetic diversity of the mainland population was slightly higher than that of the island populations but not significantly so. However, the observed heterozygosity on Shangchuan Island (SCD) was significantly lower than that of the other colonies. We also found six haplotypes in 111 mitochondrial DNA COI sequences. The relatedness (r) value between colonies of SCD was 0.410, higher than that of the other populations. The genetic clusters among colonies were not related to geographic locations and exhibited admixture likely due to frequent human‐mediated dispersal associated with trade between the mainland population and the islands. Pairwise F STs between populations showed differentiation among mainland populations, while SCD displayed high levels of divergence (FST > 0.15) from most mainland populations. There was no significant isolation by distance among colonies. Most populations showed signs of a bottleneck effect.Main conclusionsOur study suggests that there was no significant difference in the genetic diversity among the islands and the mainland; however, the lower genetic diversity, the higher degree of genetic divergence from other colonies, and the higher relatedness among nestmates made the SCD population stand out from all the others.

Peer Review #2 of "Historical connections among river basins and climatic changes explain the biogeographic history of a water rat (v0.1)"

“…The small number of microsatellite loci used and their capability of detecting the true population structure is another plausible explanation for the discrepancy between this marker and mtDNA. Other recent studies using a similar number of microsatellite markers in other organisms (Pérez-Alquicira et al, 2018;Villamor et al, 2018;Zheng et al, 2018) also found significant genetic structure in some cases. Another study using the same microsatellite loci found significant genetic differentiation in N. squamipes samples from a very small geographic area (maximum distance among sites = 6 km).…”

Historical connections among river basins and climatic changes explain the biogeographic history of a water rat

“…The small number of microsatellite loci used and their capability of detecting the true population structure is another plausible explanation for the discrepancy between this marker and mtDNA. Other recent studies using a similar number of microsatellite markers in other organisms ( Pérez-Alquicira et al, in press ; Villamor, Costantini & Abbiati, in press ; Zheng et al, in press ) also found significant genetic structure in some cases. Another study using the same microsatellite loci ( Maroja, Almeida & Seuánez, 2003 ) found significant genetic differentiation in N. squamipes samples from a very small geographic area (maximum distance among sites = 6 km).…”

The underdog invader: Breeding system and colony genetic structure of the dark rover ant (Brachymyrmex patagonicus Mayr)

“…In the Argentine ant Linepithema humile, the size and the number of supercolonies differ among its various invasive populations, which consist of one to five supercolonies ranging from 1 to 6,000 km long (Björkman-Chiswell, Wilgenburg, Thomas, Swearer, & Elgar, 2008;Buczkowski, Vargo, & Silverman, 2004;Corin, Abbott, Ritchie, & Lester, 2007;Giraud, Pedersen, & Keller, 2002;Hirata, Hasegawa, Toita, & Higashi, 2008;Suhr, McKechnie, & O'Dowd, 2009;Suhr, O'Dowd, McKechnie, & Mackay, 2011;Thomas, Payne-Makrisâ, Suarez, Tsutsui, & Holway, 2006;Vogel, Pedersen, Giraud, Krieger, & Keller, 2010). To date, the combination of polygyny, colony budding dispersal, and unicolonial structure has been described in many invasive ants species, including the most widespread and destructive ones (reviewed in Holway et al, 2002), such as L. humile (Giraud et al, 2002), Lasius neglectus (Cremer, Ugelvig, & Drijfhout, 2008), Wasmannia auropunctata (Fournier et al, 2005), P. megacephala (Fournier et al, 2009), Monomorium pharaonis (Buczkowski & Bennett, 2009;Schmidt, d'Ettorre, & Pedersen, 2010), M. floricola (Wetterer, 2010), A. gracilipes (Thomas et al, 2010), N. fulva (Eyer, McDowell, et al, 2018), Tapinoma melanocephalum (Zheng, Yang, Zeng, Vargo, & Xu, 2018), and the polygyne form of Solenopsis invicta (Fletcher, Blum, Whitt, & Temple, 1980). Interestingly, these strategies have also been reported in a lesser extend in the invasive ant Brachyponera chinensis (Eyer, Matsuura, et al, 2018), in the tramp ant species of the genus Cardiocondyla (Heinze, Cremer, Eckl, & Schrempf, 2006) and in introduced populations of the termite Reticulitermes urbis (Leniaud, Pichon, Uva, & Bagnères, 2009).…”