Traumatic insemination is not the case in three Orius species (Heteroptera: Anthocoridae).

Abstract

Traumatic insemination (TI) is an extraordinary style of mating behavior wherein the female integument is pierced by the male extragenital structure to transfer the spermatozoa into the female’s body through wounding. Flower bugs of the genus Orius belong to the family Anthocoridae (Heteroptera), which is referred to as the “TI family”. Males possess sharp shaped extragenitalia, and females receive the extragenitalia using the copulatory tubes, which are specialized extragenital structures in Orius species. Since TI is not well studied in insects possessing the copulatory tube, we examined the genital structures and copulatory processes of three species, Orius strigicollis, O. sauteri, and O. minutus. Scanning electron microscopic observations revealed the positions of male extragenital structures during copulation. A needle-like flagellum was deeply inserted into the female intersegment between the abdominal VII and VIII segments, while the curved part of a sickle-like cone forced the intersegment to expand. No scars were detected around the copulation region after copulation. The copulatory tube adhered to the interior of segment VII, and the interior integument around the copulatory tube remained intact after copulation. On the basis of these results, TI does not occur in these Orius species. A pair of seminal conceptacles, which exists in typical TI insects, was found at the base of the oviducts in O. strigicollis. The distal end of the copulatory tube connected to a closed bag with a double-membrane, termed the sperm pouch. The sperm pouch was filled with filamentous structures after copulation and structures with equivalent forms were observed in adult male testis. These structures, considered to be spermatozoa, persisted in the pouch for at least two weeks after copulation, suggesting that the pouch is a long-term spermatozoa storage organ.