Rapid expansion of the distributional range and the population genetic structure of the freshwater amphipod Crangonyx floridanus in Japan

Abstract

ABSTRACT:The freshwater amphipod Crangonyx floridanus (Amphipoda: Crangonyctidae) has considered to be recently introduced from North America to Japan, and now the recorded sites of collection cover nearly all over Japan excluding the northern part. In this study, we surveyed further areas outside the known distribution ranges and also examined the population genetic structure and the phylogenetic relationships between Japanese and North American populations based on nuclear (18S rRNA) and mitochondrial (COI) DNA sequences. We found that this amphipod already reached to Hokkaido, the northernmost Japan, and suggested the rapid expansion in a pattern of concentric circles from the central part of Japan. The genetic analysis showed the genetic homogeneity of Japanese population in contrast to the genetic diversification in North American Crangonyx populations. The process of introduction, establishment, and expansion of this amphipod in Japan may be explained as follows. A limited number of individuals from a North American native population were probably inadvertently introduced and established somewhere within the Kanto region. After that the local population size increased and the range of its distribution was rapidly expanded over Japan.

Cryptic diversity and mtDNA phylogeography of the invasive demon shrimp, Dikerogammarus haemobaphes (Eichwald, 1841), in Europe

“…Some of the studied invasions were associated with a loss of genetic diversity. That is the case of the freshwater amphipod Crangonyx floridanus Bousfield, 1963 in Japan and in the United Kingdom (Nagakubo et al 2011;Mauvisseau et al 2019) or the spiny-cheek crayfish F. limosus in Europe (Filipová et al 2011). In contrast, in other aquatic organisms no loss in diversity was observed (Roman and Darling 2007;Wattier et al 2007;Brown and Stepien 2010;Rewicz et al 2015).…”

First detection of a highly invasive freshwater amphipod (Crangonyx floridanus) in the United Kingdom

“…A closely related species Crangonyx floridanus (Bousfield 1963) is also originally from the same region of North East America. Similar to C. pseudogracilis, C. floridanus has a high invasion potential and since 1989 has colonised large regions of the main island of Japan (Nagakubo et al, 2011;Tojo et al, 2010). Its rapid dispersal and high population growth (Nagakubo et al, 2011;Tojo et al, 2010) have highlighted the urgent requirement to contain the spread of C. floridanus and protect local species (Nagakubo et al, 2011).…”

“…Similar to C. pseudogracilis, C. floridanus has a high invasion potential and since 1989 has colonised large regions of the main island of Japan (Nagakubo et al, 2011;Tojo et al, 2010). Its rapid dispersal and high population growth (Nagakubo et al, 2011;Tojo et al, 2010) have highlighted the urgent requirement to contain the spread of C. floridanus and protect local species (Nagakubo et al, 2011). Both species are almost identical with field and microscope-based differentiation between the two often resulting in misidentification (Nagakubo et al, 2011).…”

“…Its rapid dispersal and high population growth (Nagakubo et al, 2011;Tojo et al, 2010) have highlighted the urgent requirement to contain the spread of C. floridanus and protect local species (Nagakubo et al, 2011). Both species are almost identical with field and microscope-based differentiation between the two often resulting in misidentification (Nagakubo et al, 2011). However, to date, there are no records of C. floridanus present within Europe (Dunn, 2013).…”

“…Differentiation of both species is also possible using comparison of cytochrome C oxidase subunit I (COI) sequences (Nagakubo et al, 2011), which is commonly used in studies of biological invasion of amphipods (Slothouber Galbreath et al, 2010) and in environmental DNA (eDNA) based surveys (Blackman et al, 2017).…”