Two Cryptic Species in Brontispa longissima (Coleoptera: Chrysomelidae): Evidence from Mitochondrial DNA Analysis and Crosses between the Two Nominal Species

Abstract

The beetle Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) is a serious invasive pest of the coconut palm, Cocos nucifera I., in Southeast Asia and the Pacific region. Genetic analysis is essential to ecological and evolutionary study of such invasive species. We therefore conducted molecular analyses by using partial sequences (1044 bp) of the mitochondrial cytochrome oxidase subunit I (COI) genes of B. longissima collected from several locations. We found two monophyletic groups: one distributed over a limited area (Australia, Papua New Guinea, Samoa, and Sumba Island; referred to as the Pacific group) and the other collected from a wide area of Asia and the Pacific region (referred to as the Asian group). We compared the biological and morphological traits of the two groups. We found that insects in the Pacific group had a shorter developmental time from hatching to adult emergence, produced fewer eggs, and had a larger adult body size than insects in the Asian group. Elytral color patterns did not differ between the two groups. Our interpopulation crosses produced significantly fewer progeny than intrapopulation crosses, suggesting that B. longissima represents two cryptic species.

Unique clade of alphaproteobacterial endosymbionts induces complete cytoplasmic incompatibility in the coconut beetle

“…Our findings regarding B. longissima suggest that this may be another case in which bidirectional CI causes speciation. Although we used B. longissima obtained from East Timor alone in this study, CI between the two clades occurs in coconut beetles from different locations; individuals from Papua New Guinea belonging to the Pacific clade show complete CI when crossed with those from Japan belonging to the Asian clade (12). In the Papua New Guinea beetles, we detected the same endosymbionts as in the beetles from Lp (Fig.…”

“…Di belongs to the Asian clade, and Lp belongs to the Pacific clade (34). Insects were reared on fresh leaves of Phoenix canariensis Chabaud as described previously (12).…”

“…distributed in a limited area (12). Recent invasions and outbreaks have been reported only for the Asian clade.…”

“…Recent invasions and outbreaks have been reported only for the Asian clade. The two clades copulate with each other, and sperm are successfully delivered to the spermatheca, but hatchability is much lower than that of intraclade crosses, indicating that CI occurs between them (12); however, what induces this CI remains unknown.…”

Keragaman Fenotipe dan Genetik Kumbang Brontispa longissima (Coleoptera: Chrysomelidae) pada Tanaman Kelapa; The Genetic and Phenotypic Diversities of Brontispa longissima Beetle (Coleoptera: Chrysomelidae) on Coconut Palms

“…Pada sebelas tahun terakhir, B. longissima telah menyebar dengan cepat dan menimbulkan kerusakan berat di kawasan Asia (Cambodia, Indonesia, Jepang, Myanmar, Filipina, Taiwan, Thailand dan Vietnam) (Takano et al, 2011;Yamashita et al, 2008), Australia (Darwin, Broome, kepulauan Moa, Cooktown, Cairns, Innisfail, Marcoola dan Townsville) (Ma et al, 2011) dan Pacific (French, Polynesia, New Caledonia dan Vanuatu) (Takano et al, 2011;Takano et al, 2013), sehingga merubah status hama ini menjadi hama penting (Rethinam & Singh, 2007). B. longissima telah dimasukkan sebagai hama invasif (Anonim, 2009).…”