The female spider then constructs an egg sac within her bell, laying between 30 and 70 eggs. It is thought that prior to mating, the male constructs a diving bell adjacent to the female's then spins a tunnel from his bell, breaking into hers to gain entrance. The bells built by males are typically smaller than females' and are replenished less often. Females spend most of their time within their bells, darting out to catch prey animals that touch the bell or the silk threads that anchor it and occasionally surfacing to replenish the air within the web. Both sexes build diving bell webs which are used for digesting prey, although only the female's larger bell is used for mating and raising offspring. The appearance of the diving bell gave rise to the genus name Argyroneta, from the Greek "argyros" (ἄργυρος), meaning "silver", and "neta", a neologism (perhaps for *νητής) derived from the verb "neo" (νέω) "spin", intended to mean "spinner of silver". The spiders themselves fall prey to frogs and fish. The spiders prey on aquatic insects and crustaceans such as mosquito larvae and Daphnia. This larger body size is also associated with longer front legs, shown to affect diving ability and giving the males superiority in diving over the more sessile females. Theories suggest that the male's more active hunting style requires greater strength to overcome water resistance and counteract the buoyancy of their mobile air supplies. This size differential favoring males is unusual for spiders, where sexual dimorphism is usually in favour of larger females. ![]() Males are more active and on average almost 30% larger than females, measuring 10–15 mm (0.39–0.59 in) in head-and-body length compared to 8–12 mm (0.31–0.47 in). The species range in size, although the size of females may be limited as they put more energy into building and maintaining their larger bells. aquatica is able to remain submerged for prolonged periods of time due to the silk-based structure it constructs in order to retain an oxygen supply, named after the diving bell structure it resembles. The spider lives for about two years in captivity. Ecology Īs with other spiders it breathes air when submerged in water, an air bubble is trapped by a dense layer of hydrophobic hairs on its abdomen and legs, giving the abdomen a silvery appearance. Most of the range is inhabited by the nominate subspecies, but Japan has its own subspecies, the very similar A. It ranges through much of mainland Europe (no records from Portugal, Greece and Albania), the British Isles and central to northern Asia ranging as far south as Iran and as far north as Siberia, up to latitude 62°N. aquatica is found in clean freshwater habitats with aquatic vegetation, such as lakes, ponds, canals, marshes and slow-moving streams. ![]() Several of these, as well as a few others, may dive into water to avoid larger predators. Numerous species, including some Ancylometes, Dolomedes, Megadolomedes, Pardosa, Pirata, Thalassius and others, live above water at the surface, but may actively submerge for a prolonged period of time, are strong swimmers and will catch underwater prey. Some spiders living in periodically flooded habitats can survive for an extended period of time underwater by entering a coma-like state, up to 16–36 hours in Arctosa fulvolineata. For example, certain Desis species spend the high tide in an air-filled underwater retreat made from silk and forage on land in the intertidal zone during low tide. ![]() There are several other spiders that are semiaquatic, either periodically living underwater or willing to dive. It only briefly surfaces to replenish its oxygen supply and occasionally will bring prey to the surface. aquatica is the only known species of spider that spends almost all its life underwater, including resting, catching and eating prey, mating, egg laying, and overwintering. Although prey is usually consumed underwater in the diving bell, it is occasionally brought to the surface.Ī.
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