Checklist of - Entomological Society of Canada

Dytiscidae
be omnivorous. A detailed study of the life history
of any North American species is needed.
Taxonomically, Nearctic noterids are well
known bet:ause all genera have been revised. No
additional species are expected for the Canadian
fauna. TlLe classification of noterids is fairly well
known (Beutel and Roughley 1987), and ther systematic
position of the family near Dytiscidae is well
supported (Beutel and Roughley 1988, Kavanaugh
1986).
oN (2);PQ (1)
Genus HYDFi,OCANTHUS Say
Key to Nevr World species: Young (1985)
(Subgenus IIIDROCANTHUS s. str.)
H. iricolor Say
similato- Zimmermann
Genus SUPIJISELLUS Crotch
Key to North American species: Young (1979a)
S. puncticolli; (Crotch r -
ON PQ
ON
Family DYTISCIDAE predaceous diving beetles
D.J. Larson and. R.E. Roughley
In Car'ada and Alaska 262 species of Dytiscidae
are known, making this the largest family of
aquatic beetles in the region. These beetles occur in
a wide valiety of shallow-water habitats. The richest
fauna is in the emergent vegetation zone along
the edges of pools, small ponds, and small, slow
streams. .t\. number of species are characteristic of
cold-wate: habitats, such as small seepages and
springs, as weII as bog, forest, alpine, and arctic
pools. Clear, gravelly streams and saline ponds
each contain distinctive groups ofspecies.
Adults are predators or scavengers, and all larvae
are apparently predaceous. The range of prey
taken probably is determined by what prey of suitable
size , s available, but some hydroporines feed
largely olL microcrustacea, whereas some colymbetines
prey mainly on culicid larvae. As far as is
known or can be inferred, aII species in the fauna
are univo itine or semivoltine. Most species overwinter
as adults, but time of breeding and occurrence
of larval stages vary greatly among species.
Represenuative larvae of most genera have been
described, but larvae are known for only a small
percentagr: of species.
The feLmily is relatively well known taxonomically.
The principal taxonomic problems include
relating the northern Nearctic fauna with that of
the Palaezrrctic; analyzing and interpreting patterns
of geogral,hical variation, which in many species is
complex; aind developing suprasp ecifrc classifrcation,
especially within the larger genera. Identifrcation
of species may be difficult, as differences between
species are often subtle. There is therefore a need
for additional analysis to provide better species definitions
and characters for their recognition.
Reviews and revisions of many genera hirrve been
prepared or are in progress, but no single publicaiion
treats the entire fauna. The regional works of
Hatch (1953) and Larson (1975) together ccver most
of the western and boreal species. Wallis (1973)
and Larson and Colbo (1983) have publisled fairly
complete faunal lists for Manito ba and
Newfoundland, respectively. Leech and Chandler
(1956) and D.S. White et al. (1984) provide good
keys to adults and larvae of most North l\merican
genera. A number of works treating the fauna of
various states have been published in the United
States. Some of these works are especially valuable
in interpreting the Canadian fauna: California
(Leech and Chandler 1956), Florida (Young 1954),
Maine (Malcolm 1971), Nevada (La Rivers 1951),
North Dakota (Gordon and Post 1965), North and
South Carolina (Brigham 1982), and Utah (R.D.
Anderson 7962). Zaitzev (1953) outlijned the
Palaearctic distribution of Holarctic species.
AK (92); YK (111); NT (118); BC (167); AB {153); SK
(r24); MB (145); ON (155); pQ (147); NB (82); NS
(77):PE (31);LB (7a); NF (78) ' H (45)
Genus COPELATUS Erichson
Key to No:r'th American species: Young (1963o)
Subfamily COPELATINAE
TYibe Copelatini
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