Spilostethus

Spilostethus is a genus of true bugs in the family Lygaeidae, commonly known as seed bugs. The genus includes several species, among them Spilostethus pandurus and Spilostethus hospes, with a distribution that spans Europe, North Africa, and parts of Asia. Taxonomic placement in Lygaeidae has varied with different classifications over time, but Spilostethus is generally treated as part of the group of seed-feeding bugs known as lygaeids.

Members of Spilostethus are small to medium in size, typically about 6 to 12 millimeters long. They are often conspicuously colored in red or orange and black, a pattern that serves as a warning to potential predators. The body is oval and flattened, with wings developed in most adults and a characteristic arrangement of markings on the hemelytra and the connexivum (the lateral edges of the abdomen).

Ecology and behavior are focused on seed feeding. Spilostethus species feed on the seeds of a wide range of herbaceous plants, including many common weeds and wildflowers. They are usually found on flowering plants, hedgerows, meadows, and coastal vegetation, often in sunny, exposed spots. Reproduction involves laying eggs on host plants; nymphs pass through several instars before reaching adulthood. Some species can sequester plant-derived toxins from their diet, which provides chemical defense against predators.

Distribution and habitat vary by species, but Spilostethus bugs are commonly encountered across temperate regions of Europe and adjacent areas, where they may occur in loose aggregations on seed heads or singly on vegetation. They are generally considered harmless to humans, primarily posing a minor nuisance if disturbed.