Molecular phylogeny, laboratory rearing, and karyotype of the bombycid moth, Trilocha varians

Takaaki Daimon1,2a*, Masaya Yago3b, Yu-Feng Hsu4c, Tsuguru Fujii1d, Yumiko Nakajima5e, Ryuhei Kokusho1f, Hiroaki Abe6g, Susumu Katsuma1h, and Toru Shimada1i*

1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
2National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
3The University Museum, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
4Department of Life Science, National Taiwan Normal University, 88, Ting Chou Rd., Sec 4, Taipei 116, Taiwan
5Gene Research Center, University of the Ryukyu, Chihara 1, Nishihara-cho, Okinawa 903-0213, Japan
6Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan

Abstract

This study describes the molecular phylogeny, laboratory rearing, and karyotype of a bombycid moth, Trilocha varians (F. Walker) (Lepidoptera: Bombycidae), which feeds on leaves of Ficus spp. (Rosales: Moraceae). The larvae of this species were collected in Taipei city, Taiwan, and the Ryukyu Archipelago (Ishigaki and Okinawa Islands, Japan). Molecular phylogenetic analyses revealed that T. varians belongs to the subfamily Bombycinae, thus showing a close relationship to the domesticated silkworm Bombyx mori (L.), a lepidopteran model insect. A laboratory method was developed for rearing T. varians and the time required for development from the embryo to adult was determined. From oviposition to adult emergence, the developmental zero was 10.47 °C and total effective temperature was 531.2 day–degrees, i.e., approximately 30 days for one generation when reared at 28 °C. The haploid of T. varians consisted of n = 26 chromosomes. In highly polyploid somatic nuclei, females showed a large heterochromatin body, indicating that the sex chromosome system in T. varians is WZ/ZZ (female/male). The results of the present study should facilitate the utilization of T. varians as a reference species for B. mori, thereby leading to a greater understanding of the ecology and evolution of bombycid moths.

Keywords: Bombycini, Bombyx, COI gene, DDC gene, Ernolatia, Ficus, Morus, silkworm

Correspondence: a daimontakaaki@affrc.go.jp, i shimada@ss.ab.a.u-tokyo.ac.jp, *Corresponding author

Editor: Jake Tu was Editor of this paper.

Received: 26 April 2011 | Accepted: 4 November 2011 | Published: 10 April 2012

ISSN: 1536-2442 | Volume 12, Number 49

Daimon T, Yago M, Hsu Y-F, Fujii T, Nakajima Y, Kokusho R, Abe H, Katsuma S, Shimada T. 2012. Molecular phylogeny, laboratory rearing, and karyotype of the bombycid moth, Trilocha varians. Journal of Insect Science 12:49 available online: insectscience.org/12.49


Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6