Sperm structure of some Neuroptera and phylogenetic considerations

Male vitellogenin regulates gametogenesis through a testis-enriched big protein in Chrysopa pallens

In insects, vitellogenin (Vg) is generally viewed as a female-specific protein. Its primary function is to supply nutrition to developing embryos. Here, we reported Vg from the male adults of a natural predator, Chrysopa pallens. The male Vg was depleted by RNAi. Mating with Vg-deficient male downregulated female Vg expression, suppressed ovarian development and decreased reproductive output. Whole-organism transcriptome analysis after male Vg knockdown showed no differential expression of the known spermatogenesis-related regulators and seminal fluid protein genes, but a sharp downregulation of an unknown gene, which encodes a testis-enriched big protein (Vcsoo). Separate knockdown of male Vg and Vcsoo disturbed the assembly of spermatid cytoplasmic organelles in males and suppressed the expansion of ovary germarium in mated females. These results demonstrated that C. pallens male Vg signals through the downstream Vcsoo and regulates male and female reproduction.

Morphology of the male reproductive system and sperm ultrastructure of the green lacewing, Chrysopa pallens (Rambur, 1838) (Neuroptera: Chrysopidae)

BACKGROUND

Chrysopa pallens is one of the most beneficial and effective natural predators, and is famous for its extensive distribution, wide prey spectrum, and excellent reproductive performance. This study examined the anatomy and fine structure of the C. pallens reproductive system and spermatogenesis.

RESULTS

The male reproductive system of C. pallens comprises a pair of testes, a vas deferens, seminal vesicles, accessory glands, and short ejaculatory ducts. The testes were already mature on the day of emergence, but the accessory glands did not mature until 5 days post-emergence. In early spermatids, the flagellum had an axoneme on one side of the two mitochondrial derivatives. The nucleus was surrounded by parallel crystalline and paracrystalline materials. The spermatid envelope extends towards the paracrystalline material in a tail-shaped wing. In mature spermatids, the axoneme is located between the two accessory bodies and mitochondrial derivative sets. The parallel-crystalline and paracrystalline materials disappeared. In the testes, the wall of seminal cysts consists of a layer of epithelium, a muscular-connective sheath, and several vesicles of different sizes. The mature seminal cysts contained 128 spermatozoa. The accessory gland is composed of six parts: ventral papilla-like protuberance, anterior glandular lobe, lateral glandular lobe, seminal cyst, posterior kidney-shaped lobe, and posterior papilla-like protuberance. Muscle fibers and secretory granules are extensive.

CONCLUSIONS

This study provides information on the reproductive system of C. pallens and offers a resource for taxonomy and reproductive biology.

Phylogeny and Evolution of Neuropterida: Where Have Wings of Lace Taken Us?

The last 25 years of phylogenetic investigation into the three orders constituting the superorder Neuropterida-Raphidioptera, Megaloptera, and Neuroptera-have brought about a dramatic revision in our understanding of the evolution of lacewings, snakeflies, dobsonflies, and their diverse relatives. Phylogenetic estimations based on combined analyses of diverse data sources, ranging from adult and larval morphology to full mitochondrial genomic DNA, have begun to converge on similar patterns, many times in accordance with hypotheses put forth by Cyril Withycombe nearly a century ago. These data, in combination with information from the fossil record, have given a revised perspective on the historical evolution and classification of Neuropterida, necessitating an overhaul of their organization and providing focus and insight on fruitful future efforts for neuropterology.

Los coniopterígidos de la Península Ibérica e Islas Baleares (Insecta: Neuropterida, Neuroptera: Coniopterygidae)

Se revisan las especies de coniopterígidos presentes en la fauna de la Península Ibérica e Islas Baleares donde, hasta la fecha, están representadas por 39 especies pertenecientes a 8 géneros. Partiendo de los datos generales conocidos, damos una diagnosis de la familia y citamos algunos elementos sobre su historial paleontológico y su distribución, y algunos datos sobre su morfología, su biología, sus estadios juveniles y comportamiento, y se comenta una breve introducción sobre el historial en el conocimiento de la familia, y en particular en la Península Ibérica y Baleares. Se propone revalidar a Coniopteryx (Holoconiopteryx) tullgreni Tjeder, 1930 sp. reval. como especie válida, se describe Helicoconis bachi n. sp. como nueva especie, y se mantiene, se discute y se argumenta nuestro criterio sobre la validez de Coniopteryx parthenia (Nav.s & Marcet, 1910) (sensu Meinander, 1972a) frente a Coniopteryx hoelzeli (sensu Günter, 1993). Se incluye una lista de las especies pertenecientes a la fauna de la Península Ibérica y Baleares, una clave de identificación de los imagos de las subfamilias, géneros y especies citadas, y una clave de sus larvas conocidas a nivel genérico. De cada una de estas especies se recopilan y se anotan todas las referencias bibliográficas existentes relativas a las especies de la zona estudiada, tanto con la denominación actualmente aceptada, como de sus sinonimias y/o cualquier otra combinación nomenclatural bajo las cuales hayan sido citadas. También de cada una de las especies se anotan los datos conocidos y los ahora aportados (1.800 nuevos ejemplares de 32 especies) sobre su distribución general, aspectos de su morfología externa y/o genital, as. como de su variabilidad, estadios juveniles, biolog.a, fenolog.a y distribuci.n altitudinal y geogr.fica en la Península y archipi.lago balear, en base a un total de 12.215 ejemplares estudiados.

Structure and Evolution of Insect Sperm: New Interpretations in the Age of Phylogenomics

This comprehensive review of the structure of sperm in all orders of insects evaluates phylogenetic implications, with the background of a phylogeny based on transcriptomes. Sperm characters strongly support several major branches of the phylogeny of insects-for instance, Cercophora, Dicondylia, and Psocodea-and also different infraordinal groups. Some closely related taxa, such as Trichoptera and Lepidoptera (Amphiesmenoptera), differ greatly in sperm structure. Sperm characters are very conservative in some groups (Heteroptera, Odonata) but highly variable in others, including Zoraptera, a small and morphologically uniform group with a tremendously accelerated rate of sperm evolution. Unusual patterns such as sperm dimorphism, the formation of bundles, or aflagellate and immotile sperm have evolved independently in several groups.

Overview on spermatogenesis and sperm structure of Hexapoda

The main characteristics of the sperm structure of Hexapoda are reported in the review. Data are dealing with the process of spermatogenesis, including the aberrant models giving rise to a reduced number of sperm cells. The sperm heteromorphism and the giant sperm exceeding the usual sperm size for length and width are considered. The characteristics of several components of a typical insect sperm are described: the plasma membrane and its glycocalyx, the nucleus, the centriole region and the centriole adjunct, the accessory bodies, the mitochondrial derivatives and the flagellar axoneme. Finally, a detailed description of the main sperm features of each hexapodan group is given with emphasis on the flagellar components considered to have great importance in phylogenetic considerations. This study may be also useful to those requiring an introduction to hexapod reproduction.