Darkling beetle Eleodes sp. raises its abdomen in a defensive posture as it threatens to spray a noxious chemical at a scientist who has just pinched its leg. Nearly all insects and arthropods use a variety of defensive postures to frighten predators. Darkling beetles are a family of beetles with more than 20,000 species found worldwide. They eat both fresh and decaying vegetation. They have numerous predators including birds, rodents and reptiles.