User:Mccannm/sandbox

Labidura riparia
A Labidura riparia specimen in Ebro Delta, Spain
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Dermaptera
Suborder:	Forficulina
Family:	Labiduridae
Genus:	Labidura
Species:	L. riparia
Binomial name
Labidura riparia Pallas, 1773

A male Labidura riparia specimen in Köpenick, Berlin

A male Labidura riparia specimen in Köpenick, Berlin, in a threatening pose

Labidura riparia is a species of earwig in the family Labiduridae, formally Forficula riparia , characterized by their modified cerci as forceps, and light tan colour (Choate 1987, Tawfik 1973). They are more commonly known as the striped earwig, due to two dark longitudinal stripes down the length of the pronotum (Choate 1987, Gross 1967). They are often referred to as Labidura japonica, although said species is a subspecies found only in Japan (Kimimura 2014). L. riparia are a cosmopolitan species primarily in tropical to subtropical regions (Choate 1987). Body size varies greatly, ranging from 16 mm to 30 mm, with 10 abdominal segments (Choate 1987, Tawfik 1973). 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 (Choate 1987). Earwigs use these forceps to assist in predation, defense, sexual selection, courting and mating, and wing folding (Jarvis 2005, Tawfik 1973).

L. riparia are a subsocial earwig with complex maternal habits (Kimimura 2014, Radl 1991). They are voracious predators, and highly regarded an efficient for of pest control in many situations (Kimimura 2014). Repugnitory glands in the earwigs cause them to secrete a foul smelling pheromone to deter predators, which is said to smell like decomposition (Choate 1987).

Males of this species have two penises in which they can use interchangeably (Kimimura 2006). Individuals have a preference on which they dominantly use though (Kimimura 2006). Just like humans’ limb dexterity, L. riparia have a 90% prevelance of “right-handed” penises (Kimimura 2006). This unequal proportion is unique to this species compared to all other earwigs, and may have a relationship with the spermatheca location on females (Kimimura 2014).

Ecology

The striped earwig prefers dark, moist environments with shelter that it can hide during the daytime (Earl 1986). They can be found in a variety of niches though, from cultured and uncultured farmlands, woodlands, and the margins of ponds and lakes (Choate 1987, Earl 1986). To save energy, the earwigs will occupy abandoned mole cricket burrows for brooding nests (Choate 1987). Individuals are known to fly after a disturbance in search of a new nest as theirs may have become waterlogged or destroyed (Gross 1967). Flight towards light has been observed due to their methods of orientation via the moon (Tawfik 1973, Ugolini 1996).

L. riparia are generalist predators whose diet consists entirely of insects, or scavenged meat (Katsuyuki 2007, Tawfik 1973). They have a preference to Lepidoptera larvae and insect eggs, but will eat any available insect (Afify 1971, Tawfik 1973). Because of their flexible eating habits, they easily adapt to any habit as long as there are insect around (Choate 1987). In absence of a ready food supply, they have been known to eat nymphs and eggs of their own species (Radl 1991, Tawfik 1973). As nocturnal insects, earwigs only hunt after sunset, but feed primarily just after sunset occurs (Earl 1986). Feeding habits of females depend more on their ovulatory cycle, and will go long periods of time without eating in preparation of egg laying (Bassal 2001).

The primary predator to L. riparia is ants, as they prey on unattended eggs (Katsuyuki 2007). Overlap of predation does occur between organisms though as the earwigs prey on the ant eggs as well, the effect of ants on earwigs seems to be greater than the reverse relationship, as populations of earwigs increase if the ant’s decrease (Gross 1967, Katsuyuki 2007).

Nesting and life cycle

Nests are essential for protection from the environment, and predators, and needed for the success of their offspring’s survival. Special nests are dug for molting, feeding, and egg laying (Tawfik 1973). A suitable nest is chosen and dug out by the female under a rock or tree bark (Jarvis 2005). Female earwigs are the primary caregivers as they become hostile to males while in their brooding chambers (Tawfik 1973). While the female is laying her eggs she grabs them and cleans them of any fungi or dirt one by one as they are laid (Tawfik 1973). They do this to 60-100 eggs, and once finished they lay over top of the eggs much like a hen (Tawfik 1973). The female continues to groom the eggs and stay guarding them for 10 days until they begin to hatch (Jarvis 2005, Radl 1991, Tawfik 1973). At this time the mother goes in search of food for her young, and continues feeding and grooming them until they leave the nest themselves 2-5 days later(Radl 1991, Tawfik 1973). Each female will do this up to three times in her life, sometimes more than one at a time (Tawfik 1973). Some females get lost returning to their brood and start caring for another individual clutch as they are not able to distinguish between their own young and another’s (Radl 1991, Tawfik 1973). The young will go on to dig their own nest for molting taking anywhere from 4 to 50 days to reach the next instar, repeating to a total of 6 instars before adulthood (Tawfik 1973). Once adults, the individuals will life for only 2-3 months, and begin courting immediately (Tawfik 1973). This is done by a feeling of antennae, and mutual grabbing of each other’s abdomens with their forceps until copulation occurs (Tawfik 1973). 2-3 generations will occur in a year, with the last generation hibernating underground through winter (Tawfik 1973).