Dytiscus

Taxobox
name = "Dytiscus"


image_caption = "Dytiscus latissimus"
regnum = Animalia
phylum = Arthropoda
classis = Insecta
ordo = Coleoptera
familia = Dytiscidae
genus = "Dytiscus"
genus_authority = Linnaeus, 1758
subdivision_ranks = Species
subdivision = "26 species"

"Dytiscus" (based on Greek "δυτικός", "able to dive") is a genus of predacious diving beetles that usually live in wetlands and ponds. They are predators that can reduce mosquito larvae.They are slim, usually around two inches long and have six legs.

Life history

Adult beetles and their larvae are aquatic but the pupae spend their life in the ground. Females lay eggs inside the tissue of aquatic plants such as reeds. The eggs hatch in about three weeks and the larvae are elongate with a round and flat head and strong mandibles. The larvae are predatory and their mandible have grooves on their inner edge through which they are able to suck the body fluids of their prey. The larvae take air from the surface of the water using hairs at the end of their abdomen. These lead to spiracles into which the air is taken.

Once the larvae grow to some size, they move to soil at the edge of water and burrow into a cell and pupate.

The adults breathe by going to the surface and upending. They collect air under their elytra and are able to breathe this collected air using spiracles hidden under the elytra.

In "Dytiscus marginalis" and other species the tarsus of the fore legs is modified in males to form a circular sucker. A reduced sucker is also seen in the mid leg of the male. [Miall, L. C. (1912) The natural history of Aquatic Insects. Macmillan and Co. Ltd.]

Parasitoids

Eggs of Dytiscus are sometimes parasitized by wasps of the families Eulophidae, Mymaridae and other Chalcidoidea. [Jackson D.J. (1958) A further note on a Chrysocharis (Hymenoptera, Eulophidae) parasitizing the eggs of Dytiscus marginalis L., and a comparison of its larva with that of "Caraphractus cinctus" Walk. (Hym., Mymaridae) J.Soc.Brit.Entomol. 6:15-22.] [Jackson D.J. (1961) Observations on the biology of "Caraphractus cinctus" Walker (Hymenoptera, Mymaridae), a parasitoid of the eggs of Dytiscidae. II. Immature stages and seasonal history with a review of mymarid larvae. Parasitology. 51:269-294.]

References

External links

* [http://www.entomology.ualberta.ca/searching_species_details.php?s=4258 Dytiscus dauricus]
* [http://delta-intkey.com/britin/ord/www/colvers.htm Poem describing Dytiscus]