Dytiscus

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Subclassis: Pterygota
Cladus: Metapterygota
Infraclassis: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Coleopterida
Ordo: Coleoptera
Subordo: Adephaga

Familia: Dytiscidae
Subfamilia: Dytiscinae
Tribus: Dytiscini
Genus: Dytiscus
Species (29): D. alaskanus – D. anxius – D. carolinus – D. circumcinctus – D. circumflexus – D. cordieri – D. dauricus – D. delictus – D. dimidiatus – D. dinutus – D. fasciventris – D. habilis – D. harrisii – D. hatchi – D. hyalinus – D. hybridus – D. lapponicus – D. latissimus – D. latro – D. mutinensis – D. marginalis – D. marginicollis – D. ooligbucki – D. persicus – D. pisanus – D. semisulcatus – D. sharpi – D. thianschanicus – D. venticalis – D. vexatus
Name

Dytiscus Carolus Linnaeus, 1758

Type species: Dytiscus marginalis Linnaeus, 1758; fixation: subsequent designation by Latreille 1810

References
Primary references

Linnaeus, C. 1758. Systema Naturae per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Tomus I. Editio decima, reformata. Holmiæ: impensis direct. Laurentii Salvii. i–ii, 1–824 pp DOI: 10.5962/bhl.title.542: 411. Reference page.

Additional references

Latreille, P.A. 1810. Considérations générales sur l'ordre naturel des animaux composant les classes des crustacés, des arachnides, et des insectes : avec un tableau méthodique de leurs genres, disposés en familles. Paris: Schoell, 444 pp. BHL Reference page. [p. 426]
Roughley, R.E. 1990: A systematic revision of species of Dytiscus Linnaeus (Coleoptera: Dytiscidae). Part 1. Classification based on adult stage. Quaestiones entomologicae 26(3): 383-557. PDF Reference page.

Links

Dytiscus Taxon details on Fauna Europaea
ZooBank: 99DAFD81-0C57-4642-8F8C-48D34FC2B71F

Dytiscus ("little diver" based on Greek δυτικός, "able to dive" and the diminutive suffix -ίσκος) is a Holarctic genus of predaceous diving beetles that usually live in wetlands and ponds. There are 26 species in this genus distributed in Europe, Asia, North Africa and North and Central America. They are predators that can reduce mosquito larvae.

Dytiscus are large water beetles with a robust, rounded shape and they measure 2.2–4.4 cm (0.9–1.7 in) long depending on the exact species involved.[1] The largest, D. latissimus, is among the largest species in the family and its size is only matched by certain Megadytes.[1] The tarsi of the males are modified into suckers which are used to grip the female in mating. Females are usually larger than the males and come in two forms, with grooved (sulcate) or smooth elytra. Males only ever have smooth elytra. The adults of most species can fly.
Contents

1 Life history
2 Parasitoids
3 Species
4 References
5 External links

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.

The larvae (known as "water tigers") are elongate with a round and flat head and strong mandibles. They 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 forelegs is modified in males to form a circular sucker. A reduced sucker is also seen in the midleg of the male.[2]
Parasitoids

Eggs of Dytiscus are sometimes parasitized by wasps of the families Eulophidae, Mymaridae and other Chalcidoidea.[3][4]
Species

Dysticus contains the following species:[5]

Dytiscus alaskanus J.Balfour-Browne, 1944
Dytiscus avunculus C.Heyden, 1862
Dytiscus caraboides Linnaeus, 1758
Dytiscus carolinus Aubé, 1838
Dytiscus circumcinctus (Ahrens, 1811)
Dytiscus circumflexus Fabricius, 1801
Dytiscus cordieri Aubé, 1838
Dytiscus dauricus Gebler, 1832
Dytiscus delictus (Zaitzev, 1906)
Dytiscus dimidiatus Bergsträsser, 1778
Dytiscus distantus Feng, 1936
Dytiscus fasciventris Say, 1824
Dytiscus habilis Say, 1830
Dytiscus harrisii Kirby, 1837
Dytiscus hatchi Wallis, 1950
Dytiscus hybridus Aubé, 1838
Dytiscus krausei H.J.Kolbe, 1931
Dytiscus lapponicus Gyllenhal, 1808
Dytiscus latahensis Wickham, 1931
Dytiscus latissimus Linnaeus, 1758
Dytiscus latro Sharp, 1882
Dytiscus lavateri Heer, 1847
Dytiscus marginalis Linnaeus, 1758
Dytiscus marginicollis LeConte, 1845
Dytiscus miocenicus Lewis & Gundersen, 1987
Dytiscus mutinensis Branden, 1885
Dytiscus persicus Wehncke, 1876
Dytiscus pisanus Laporte, 1835
Dytiscus semisulcatus (O.F.Müller, 1776)
Dytiscus sharpi Wehncke, 1875
Dytiscus sinensis Feng, 1935
Dytiscus thianschanicus (Gschwendtner, 1923)
Dytiscus verticalis Say, 1823
Dytiscus zersii Sordelli, 1882

References

Miller, K.B.; J. Bergsten (2016). Diving Beetles of the World: Systematics and Biology of the Dytiscidae. pp. 115–116. ISBN 978-1-4214-2054-7.
Miall, L. C. (1912) The natural history of Aquatic Insects. Macmillan and Co. Ltd.
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.
Dytiscidae Species List at Joel Hallan's Biology Catalog. Texas A&M University. Retrieved on 7 May 2012.