SHORT COMMUNICATION Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera) Glenda Dias & Karla S. C. Yotoko & Luiz F. Gomes & José Lino-Neto Received: 13 March 2012 / Revised: 11 June 2012 / Accepted: 11 July 2012 / Published online: 22 July 2012 # Springer-Verlag 2012 Abstract Several species of Tenebrionidae are stored- grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the sper- matogenetic process in these organisms, the cells origi- nating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orienta- tion. This paper details the spermiogenesis of the tene- brionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae. Keywords Spermatozoa . Spermatodesmata . Tenebrionidae . Spermatogenesis Introduction The Tenebrionidae family is one of the largest families of Coleoptera. It is considered important as it has sev- eral species that are stored-grain pests (Booth et al. 1990). Its high number of species makes it difficult to establish limits and, consequently, taxonomic composi- tion. Although there are studies using morphological, molecular and behavioural data, many doubts remain about the systematics of the Tenebrionidae (Doyen and Tschinkel 1982; Levkaničová 2009). Spermatogenesis and the spermatozoa show variations among different groups of animals. These variations are due to small mutations accumulated during the evolu- tionary process, possibly related to the life history of these organisms (Triplehorn and Johnson 2005). In fact, spermatogenesis and especially the morphology of the spermatozoids have been particularly important in help- ing to resolve the systematics of various groups of animals, including insects (e.g. Baccetti and Dallai 1978; Jamieson et al. 1999). In insects, each spermatogonium entering spermato- genesis undergoes successive mitotic divisions, forming a group of type II spermatocytes denominated as cysts. These spermatocytes undergo two meiotic divisions to produce haploid cells, the spermatids. The cysts Communicated by: Sven Thatje Electronic supplementary material The online version of this article (doi:10.1007/s00114-012-0949-6) contains supplementary material, which is available to authorized users. G. Dias : J. Lino-Neto Laboratórios de Biologia Estrutural, Departamento de Biologia Geral, UFV, 36570-000 Viçosa, Minas Gerais, Brazil K. S. C. Yotoko Laboratórios de Bioinformática e Evolução, Departamento de Biologia Geral, UFV, 36570-000 Viçosa, Minas Gerais, Brazil L. F. Gomes Departmento de Biologia, IFMA, 65025-001 São Luís, Maranhão, Brazil J. Lino-Neto (*) Department of General Biology, Federal University of Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil e-mail: jslinoneto@gmail.com Naturwissenschaften (2012) 99:773–777 DOI 10.1007/s00114-012-0949-6