The creation of a subspecies
In 200An infraspection classification is herewith proposed mainly on the basis of a slight difference in the shape of male palp recognized between specimens from Europe and Japan.ONO, H. "New and Remarkable Spiders of the Families Liphistiidae, Argyronetidae, Pisauridae, Theridiidae and Araneidae (Arachnida) from Japan." Bull Natl Sci Mus Ser A 28.1 (2002): 51-60.Ono proposed the new subspecies because the Japanese male's
Habitats in Japan
According to T. Matsumoto the Japanese water spider has been “found in …the Mizoro Pond in Kyoto Prefecture, Kiritappu, heKusiro swamp, Teshio, heSarobetu swamp in heHokkaido prefecture, Syarki village in Aomori prefecture, nd theOita prefecture.MASUMOTO, T., et al. "Water Conditions of the Habitat of the Water Spider Argyroneta Aquatica (Araneae: Argyronetidae) in Mizoro Pond." ACTA ARACHNOLOGICA 47 (1998): 121-4.” All of these habitats are “isolated geographically.”Behavior
Males and females are different in many ways. Males rove frequently, searching for prey and for mates. Females, however, spend the majority of their lives inside their diving bells; they ambush their prey. Males are better divers than females.Schuetz, D., and M. Taborsky. "Adaptations to an Aquatic Life may be Responsible for the Reversed Sexual Size Dimorphism in the Water Spider, Argyroneta Aquatica." Evolutionary Ecology Research 5.1 (2003): 105-17. Females and juveniles are active during the night, while males are active during the daytime. The young do not balloon like other spiders do, rather, they leave their nest and find their new homes by swimming.Masumoto, T., et al. "Time Budget of Activity in the Water Spider Argyroneta Aquatica (Araneae: Argyronetidae) Under Rearing Conditions." Acta Arachnologica 47.2 (1998): 125-31.Mating
The Japanese water spider is unusual in that males are almost always larger than females. This is called sexual size dimorphism (SSD). When water spiders mate the male begins by approaching the female's diving bell. He then chases her out of the diving bell and they begin “courtship swimming.” They then return to the female's diving bell to mate.Silk and construction
The Japanese water spider spins four main kinds of silk: (1) silk used for the diving bell, (2) silk to anchor the diving bell to water plants, (3) silk for “walking” so as to get prey and mate, and (4) silk for the egg-cocoon.De Bakker, D., et al. "Description of the Structure of Different Silk Threads Produced by the Water Spider Argyroneta Aquatica (Clerck, 1757)(Araneae: Cybaeidae)." Belgian Journal of Zoology 136.2 (2006): 137-43. The diving bell silk is “used for breathing,” that is it serves to oxygenate the diving bell. Females produce larger diving bells than males. Males build their diving bells less carefully than females do. Males also frequently make more walking threads than females. Females weave the egg-cocoon into the top of the diving bell. The egg-cocoon is made up of two parts. The outer is the cocoon-sac and the inner part is the egg sack.Other
Argyronetidae vs. Cybinidae
There has been some debate amongst arachnologists as to whether the water spider (''A. a. aquatica'') belongs to the family Cybinidae or Argyronetidae. In this article the Japanese water spider (''A. a. japonica'') is listed as being in the family Argyronetidae, because the subspecies authority, Hirotsugu Ono, chose to place it in this family.The Anime Short Film
In 2006References
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