Chelisoches morio, commonly known as the black earwig, is a cosmopolitan earwig in the family Chelisochidae. Black earwigs are active at all times of the day, and prefer wet habitats. Adults can grow up to 36 millimetres (1.4 in).
Female C. morio lay eggs in clusters, known as egg masses. The eggs are laid via an ovipositor in an irregularly shaped nest. The nests are about body length in size and are lined with soil and coir particles. The female digs out and builds the nest in moist substrates. After the eggs are laid, the females remains beside the egg cluster and protects, whisks, rearranges and maintains moisture of the eggs with her mouthparts until they hatch.[7] By guarding the cluster, the female ensures the viability of the eggs. If the female is separated from the eggs immediately after laying, they become void and will not hatch.[8]
Once the eggs hatch into the first instar, the nymphs aggregate next to their mother. For the next day, the mother feeds the nymphs and tends to them with her mouthparts. Before molting into their second instar, the nymphs stop feeding. The mother continues to protect them throughout the molting process (10-20 minutes). After the nymphs have finished molting to the second instar, they disperse and maternal care is concluded.[8]
Courtship is initiated by the male. He begins by tapping his antennae back and forth until he reaches the female. A receptive female then begins tapping her antennae back and forth before touching the male's antennae.[9] If the female is not receptive, the male will pursue until the female is receptive, or the female will use her own cerci to repel the male.
The touching of a female's antennae to the male's is the receptive signal that cues the male to move to the side of the female and curve his abdomen. In this position, the male pushes his cerci beneath the subgenital plate of the female, and their genitalia come into contact. A pair of C. morio can mate 2-8 times and copulation can last from minutes to an hour. Additionally, a male can mate with up to 6 females, each of which will produce fertilized eggs.
Mating occurs several times throughout an adults lifetime, and can occur at any time of day. Multiple matings is beneficial to the female as it leads to higher brood counts and increases the proportion of viable eggs.[9]