title: Sperm Cells of a Primitive Strepsipteran.
abstract: The unusual life style of Strepsiptera has presented a long-standing puzzle in establishing its affinity to other insects. Although Strepsiptera share few structural similarities with other insect orders, all members of this order share a parasitic life style with members of two distinctive families in the Coleoptera-the order now considered the most closely related to Strepsiptera based on recent genomic evidence. Among the structural features of several strepsipteran families and other insect families that have been surveyed are the organization of testes and ultrastructure of sperm cells. For comparison with existing information on insect sperm structure, this manuscript presents a description of testes and sperm of a representative of the most primitive extant strepsipteran family Mengenillidae, Eoxenos laboulbenei. We compare sperm structure of E. laboulbenei from this family with that of the three other families of Strepsiptera in the other strepsipteran suborder Stylopidia that have been studied as well as with members of the beetle families Meloidae and Rhipiphoridae that share similar life histories with Strepsiptera. Meloids, Rhipiphorids and Strepsipterans all begin larval life as active and viviparous first instar larvae. This study examines global features of these insects' sperm cells along with specific ultrastructural features of their organelles.
authors.affiliation: Department of Entomology, University of Illinois, 320 Morrill Hall, 505 S. Goodwin Avenue, Urbana, IL 61801, USA. j-nardi@uiuc.edu.
authors.forename: James B
authors.initials: JB
authors.lastname: Nardi
authors.affiliation: Department of Zoology and Physical Anthropology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. jdelgado@um.es.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Delgado
authors.affiliation: Department of Zoology and Physical Anthropology, Faculty of Biology, University of Murcia, Murcia 30100, Spain. fcollant@um.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Collantes
authors.affiliation: Biological Electron Microscopy, Frederick Seitz Materials Research Laboratory, Room 125, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, USA. lamiller@illinois.edu.
authors.forename: Lou Ann
authors.initials: LA
authors.lastname: Miller
authors.affiliation: Imaging Technology Group, Beckman Institute for Advanced Science and Technology, University of Illinois, 405 N. Mathews Avenue, Urbana, IL 61801, USA. c-bee1@illinois.edu.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Bee
authors.affiliation: Department of Zoology, South Parks Road, Oxford OX1 3PS, UK. jeyaraney.kathirithamby@zoo.ox.ac.uk.
authors.forename: Jeyaraney
authors.initials: J
authors.lastname: Kathirithamby
keywords: Meloidae; Rhipiphoridae; Strepsiptera; sperm structure; testis