Second is the pre-parasitic larva that hatches from the egg the fully developed larva remains in the egg 7–10 days before hatching. The life cycle of nematomorphs has 4 stages: First is the egg, which takes about 10–12 days to complete its larval development after being laid. Around the same time the gonads probably start to differentiate between the sexes. After 25 days of infection differences between males and females can be seen. In the definitive host, development takes approximately 30 days. As cysts they can survive the host's metamorphosis and wait for the host to be consumed by a definitive host. The larvae infect larvae of aquatic insects and snails that serve as paratenic hosts. Eggs are released into the water where they hatch into larvae. Up to as six million eggs are produced by a single female. varius lays a long, white, string of eggs and dies. Once the sperm lands, a large circular glob forms which passes into the seminal receptacle of the female within twenty four hours of mating. However, if the sperm does not land on the appropriate posterior area of the female, conception will fail. No penetration occurs during copulation and the male releases his sperm immediately. Upon encounter, the female signals to the male that she is ready and willing to mate. They swim in the shallow waters in search for a mate. Adults worms emerge from their insect hosts late spring or summer. varius includes a terrestrial and an aquatic stage. This parasite is a pseudocoelomate whose body consists of an areole containing cuticle layer, monolayer hypoderm, muscular layer, ventral nerve cord and a digestive tract. Male worms can grow to be 12–29 cm in length whereas females are generally longer and can grow to be 12–31 cm in length. Paragordius varius have a slightly off-center mouth and distinct grooves running along its cylindrical body. The definitive hosts are mainly terrestrial arthropods, most often carabid beetles, crickets and praying mantids. varius is usually found in water or wet areas. Adults are over 10 cm long and 400 μm in diameter. They cycle between terrestrial and aquatic habitats and are most commonly known for their ability to manipulate their definitive host to jump into a pool of water, which allows them to complete their life cycle. Paragordius varius is a parasite species in the horsehair worm group (Nematomorpha).
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