Patterns of species assemblages and geographical distributions associated with mandible size differences in coastal tiger beetles in Japan

Abstract

Nine species of tiger beetle (Cicindelidae) occur in coastal habitats in Japan, with two to four species co‐occurring at each locality. To examine the patterns of coexistence and geographical distribution, the mandible size of co‐occurring species at 17 localities in Japan was examined, based on the assumption that competition for food is an important factor in determining these patterns. The interspecific overlap of mandible length was absent or very low in localities with two or three species, whereas it was more or less evident in localities with four species. For four large coastal species, the geographical distributions of two species with similar mandible lengths are either allopatric or parapatric, whereas those of two species with different mandible lengths largely overlap. These results strongly suggest that size‐assortment in mandible length is important in determining species assemblage and distribution in coastal tiger beetles in Japan.

Evolutionary history of coastal tiger beetles in Japan based on a comparative phylogeography of four species

“…We previously speculated on a historical process that could have led to the current distribution patterns in Japan (Satoh et al . 2003), based on the relationship between the extent of overlap in mandible size and the distribution patterns, and the present geographical distributions of the four species (continuous or isolated from continental Asia).…”

“…These nine species have different body sizes and show different geographical patterns in Japan; only two to four species are found in any one locality. Previously, we reported that co‐occurring species exhibited interspecific size differences in mandible length, regardless of the combination of co‐occurring species (Satoh et al . 2003).…”

“…Lophyridia angulata and A. anchoralis have similar disjunct distributions. They are found mainly along the Japan Sea coast of Honshu, the Pacific coast of eastern to southern Kyushu, and on Tanega‐shima, an island south of Kyushu (Momoshita 2003; Satoh et al . 2003).…”

“…In contrast, C. lewisii and Ch. laetescripta are continuously distributed through continental Asia (Tanaka 1960; Ashida 1998; Satoh et al . 2003).…”

“…Mean length is shown by a horizontal bar, the standard deviation by a rectangular box, and the maximum and minimum values by vertical bars. Data are derived from Satoh et al . (2003).…”