Labidura riparia

Labidura riparia is a species of earwig in the family Labiduridae characterized by their modified cerci as forceps, and light tan color. They are commonly known as the shore earwig, tawny earwig, riparian earwig, or the striped earwig due to two dark longitudinal stripes down the length of the pronotum. They are sometimes wrongly referred to as Labidura japonica, although said species is actually a subspecies, Labidura riparia japonica, found only in Japan. L. riparia are a cosmopolitan species primarily in tropical to subtropical regions. Body size varies greatly, ranging from 16 mm to 30 mm, with 10 abdominal segments. Males and females differ in forcep size, with males having much larger and stronger curve, while females have smaller, straighter forceps with a slight curve at the end. Earwigs use these forceps to assist in predation, defense, sexual selection, courtship and mating, and wing folding.

L. riparia are a subsocial earwig with complex maternal habits. They are voracious predators, and highly regarded as efficient for pest control in many situations. Repugnitory glands in the earwigs cause them to secrete a foul smelling pheromone to deter predators, which is said to smell like decomposition.

Males of this species have two penises in which they can use interchangeably. Individuals have a preference on which they dominantly use though. Just like humans’ limb dexterity, L. riparia have a 90% prevalence of “right-handed” penises. This unequal proportion is unique to this species compared to all other earwigs, and may have a relationship with the spermatheca location on females.