Microscopic analysis of the digestive and reproductive tracts of male Silpha obscura (Coleoptera: Silphidae).

Abstract

Silpha obscura Linnaeus, 1758 (Coleoptera: Silphidae) is an omnivorous beetle species known for damaging agricultural crops, making it an important target for pest control strategies. Despite its impact, no studies have yet examined the anatomical and histological structures of the male digestive and reproductive tracts of S. obscura. Therefore, this study aimed to describe these structures in detail, which could provide insights into potential control methods. Twenty individuals were collected and histologically processed, with observations made using light microscopy. The digestive tract of S. obscura comprises 3 parts: a short foregut, a relatively long and wide midgut characterized by folds and numerous crypts of the blind intestine, and a narrow and elongated hindgut, which expands into the rectum. Malpighian tubules attach at the beginning of the hindgut, which continues with the ileum, colon, and rectum and ends at the anus. The male reproductive tract includes a pair of testes, a pair of efferent ducts (vas efferentia), a pair of deferent ducts (vas deferentia), a pair of seminal vesicles, 2 pairs of accessory glands, and the ductus ejaculatorius, which extends into the ejaculatorius bulbus. The reproductive tract terminates with the aedeagus. The testes consist of 2 lobes, each containing numerous follicles where spermatogenesis and spermiogenesis occur. This study provides detailed insights into the anatomy and histology of the digestive and male reproductive tracts of Silpha obscura. These findings may lead to new strategies for controlling this agricultural pest. Understanding these structures is crucial for further research.