NRE 516 - Aquatic Entomology

Course Description and Readings | Collection Information | Class Supplies and Equipment
Winter 2005 | Winter 2003 | Winter 2001 | Winter 1999
Winter 2005 | Winter 2003 | Winter 2001


Notes on Morphology and Taxonomy / References Cited and Additional Taxonomic Sources / List of Taxa Presented

Lab Notes for Odonata - “Dragonflies and Damselflies”

A collection of aquatic insects and a field notebook will be required as a part of this course. The collection will represent 30% of your final grade. Collections will be preserved in ethyl alcohol and stored (usually) in 4 dram glass screw-top vials: The following equipment is either required (denoted in bold) or suggested.

Readings in required texts:

  • Westfall and Tennessen, 1996, pp. 164-211 in Merritt and Cummins. (Larvae and Adults - genera)
  • Hilsenhoff, 1995, pp. 11-17. (Larvae - genera)

There will be additional useful keys made available, which will be available in lab or provided by your lab instructor. These include:

  • Gloyd and Wright, 1959 (Odonata nymph genera)
  • Needham, Westfall, and May. 2000. Dragonflies of North America. (This update to the Needham and Westfall (1955) classic provides keys (a few of which contain errors) for anisopteran larvae and adult species, but unfortunately no diagnoses for larval taxonomy).
  • Smith and Pritchard. 1956, pp. 106-153 in Usinger. (Odonata nymphs and adult genera).
  • Walker, 1953 (for Zygoptera larvae and adult species)
  • Walker, 1958 (for Anisoptera larvae and adult species excluding Macromiidae, Corduliidae, and Libellulidae)
  • Walker and Corbet, 1975 (for Anisoptera larvae and adult species of Macromiidae, Corduliidae, and Libellulidae only)
  • Westfall and May. 1996. (for Zygoptera adults and larvae - recent, but no diagnoses for larval taxonomy - a second edition is scheduled to be in print by the end of 2005)

These and additional references are given at the end of this handout.

Notes on Morphology and Taxonomy / References Cited and Additional Taxonomic Sources / List of Taxa Presented

Notes on Morphology and Taxonomy

If you are working with Michigan larval Odonata, you will have an easier time keying them through Hilsenhoff (1995) due to the more limited geographical representation of species. However, if you cannot make a conclusive identification with this, consult the other keys available as some characters used in Hilsenhoff are not entirely reliable for some genera. This appears especially so for some of the Gomphidae (Arigomphus, Stylurus and Gomphus) and Coenagrionidae (especially the Ischnura, Coenagrion and Enallagma couplet). Because the keys are based on larval characters of the last instar, identification of earlier instars may become problematic, and therefore caution should be exercised in making taxonomic determinations.

You will encounter differences in terminology in some older texts. For example, in Needham and Westfall (1955), the caudal appendages are named differently than in your more current text. The epiproct thus may be called the superior appendage and the paraprocts are called the inferior appendages. The cerci are the lateral caudal appendages. Fortunately, terminology appears to have stabilized and remains consistent for texts since the last 30 years or so. Westfall and Tennessen (1996) or Rowe (1987) serve as good references for morphological terminology.

The larval labium of many genera is critical in identification. In particular you may be asked to count the number of lateral setae on each lateral lobe and the number of mental setae on each side of a median line of that structure. Note that some mental setae may be poorly developed as seen in Figure 17 from Needham et al. (2000). Mental setae counts may be frequently used to separate species within a genus. Species-level identification of larvae for certain taxa (e.g., Stylurus, Ophiogomphus, Gomphus, Macromia, Cordulegaster, etc.) requires making precise length/width ratio estimations of certain body features with a calibrated microscope graticule.

Wing venation in most references cited in this handout are that of Tillyard (1917) and the same as described by Westfall and Tennessen (1996). A variation of the venation designations is found in Walker and Corbet (1975, pp. 6-7). Adult characters for many genera rely on color of the thorax and/or abdomen which do not remain with preservation in alcohol. Therefore, you may have to rely heavily on other characters. This may require checking species characters within several possible genera for a correct identification. For example, Amphiagrion in the Coenagrionidae (couplet 3, page 181 of Merritt and Cummins, 1996) mentions the adult is red or is reddish brown and black. In addition, the couplet notes the intersternum has a mound-like tubercle bearing numerous stiff setae. The only species in Michigan has only a low tubercle, and our preserved specimen has no color. However, this species short legs (hind femur is 2 mm long) which can help confirm the genus.

The taxonomic resolution of several groups of odonates remains difficult and await a thorough analysis.

No consistently reliable morphological feature appears to separate larvae of Corduliidae and Libellulidae, and all recent attempts (Walker and Corbet 1975, Westfall 1984, Hilsenhoff 1995, Westfall and Tennessen’s 1996, Needham et al. 2000) devise synthetic keys. Indeed, this is one of several arguments against recognizing their familial ranking. (They - and Macromiidae - are retained as subfamilies of Libellulidae in Needham et al. 2000, i.e., Macromiinae, Corduliinae and Libellulinae, although most authors have accepted their elevation based on adult features). Thus, attempts to separate the Corduliidae and Libellulidae are often given with cautionary notes (e.g., Westfall and Tennessen (1996, footnote on p. 174 for couplet #5). You may find it easier with Hilsenhoff (1995) and other keys where no attempt is made to separate these two families. Rather you should key to the genus directly to derive the appropriate associated family.

The proposal to combine the older taxa in Corduliidae of Epicordulia and Tetragoneuria into the genus Epitheca (Walker 1966) has generally been largely followed (e.g., Hilsenhoff 1995, Westfall and Tennessen 1996), but not universally accepted (e.g., Rosser 1991, Needham et al. 2000). Thus, be consistent with your terminology if you use the older taxonomy. Hilsenhoff (1995) at couplet 36 uses the genus Epitheca. This also occurs in Walker and Corbet (1975). Westfall and Tennessen (1996) at couplet 7 (page 197) splits Epitheca into the subgenera Epicordulia or Tetragoneuria, which Needham et al. (2000) still recognize as genera. Many other keys, and all literature before 1966, recognize the latter two genera instead of Epitheca.

The status of the Gomphus-complex remains rather messy, and frankly reflects less a lumper/splitter dispute and more a problem of poor taxonomy. Earlier workers usually grouped (as subgenera) species of Gomphus, Gomphurus and Hylogomphus as well as Stylurus and Arigomphus into a taxonomic "basket" called Gomphus (Needham and Westfall 1955). Currently, the generic elevation of Arigomphus and Stylurus has been accepted. You will see that many authors (Walker 1957, Rosser 1991, Westfall and Tennessen 1996) follow a conservative approach in recognizing Arigomphus and Stylurus as valid genera, but do not recognize the generic elevation proposed by Carle (1982, 1986) and Carle and May (1996) for Gomphus (=Hylogomphus), Phanogomphus (=Gomphus sensu str.) and Gomphurus, which is followed in Hilsenhoff (1995). The table below summarizes the various placements of Michigan species of Gomphus. The issue will only be resolved with a comprehensive morphological, ecological, behavioral and molecular review of all known species in Asia, Europe and North America.

Gomphus species Needham and Westfall 1955, Walker 1957, 1958  - subgenera Carle (1982, 1986), Hilsenhoff 1995
G. adelphus Hylogomphus Gomphus
G. exilis Gomphus Phanogomphus
G. fraternus Gomphurus Gomphurus
G. graslinellus Gomphus Phanogomphus
G. lineatifrons Gomphurus Gomphurus
G. lividus Gomphus Phanogomphus
G. quadricolor Gomphus Phanogomphus
G. spicatus Gomphus Phanogomphus
G. vastus Gomphurus Gomphurus
G. ventricosus Gomphurus Gomphurus
G. viridifrons Hylogomphus Gomphus

Cordulegaster as a group is currently under considerable dispute, despite several attempts over the past two decades (e.g., Carle 1983, Lohmann 1992) to construct monophyletic groupings among species traditionally placed in this genus. The table below summarizes various placement of Cordulegaster species. Many researchers - especially in North America - are reluctant to accept these proposals (but see May and Carle 1996), and we will follow the conservative practice of relegating Taeniogaster, Thecophora and Zoraena as subgenera of Cordulegaster (as in Westfall and Tennessen 1996).

North American Distribution
Westfall and Tennessen 1996 - subgenera
Carle 1983 - genera
Lohmann 1992 - genera
C. obliqua
C. bilineata
C. diastatops
C. sayi
C. diadema
West, C. Am.
C. dorsalis
C. erronea
C. maculata

The traditional separation of Ladona and Plathemis from Libellula has not been universally accepted, largely due to the similarity of adult features of species of the former two genera to a Palearctic species of Libellula. However, most workers presently follow the generic ranking of Ladona and Plathemis because of, among other reasons, distinct features in larval morphology that clearly differentiate these taxa. Further, recent molecular work analyzing proteins and DNA tends to strongly support the argument for separating these taxa.

Older literature (e.g., Walker 1953) uses Agriidae for Calopterygidae, and Agrion for Calopteryx.

Finally, the recent publication by Corbet (1999) marks a tremendous synthesis regarding our knowledge about odonate biology and ecology. Any serious student of Odonata will need to consult this tome.

Notes on Morphology and Taxonomy / References Cited and Additional Taxonomic Sources / List of Taxa Presented

References Cited and Recent Additional Taxonomic References

Carle, F. L. 1983. A new Zoraena (Odonata: Cordulegastridae) from Eastern North America, with a key to the
adult Cordulegastridae of America. Annals of the Entomological Society of America 76(1):61-68.
_________. 1986. The classification, phylogeny and biogeography of the Gomphidae (Anisoptera). I. Classification. Odonatologica 15(3):275-326.
Charlton, R. E., and R. A. Cannings. 1993. The larvae of Williamsonia fletcheri Williamson (Anisoptera: Corduliidae). Odonatologica 22(3): 335-343
Cook, C. and J. J. Daigle. 1985. Ophiogomphus westfalli spec. nov. from the Ozark region of Arkansas and Missouri, with a key to the Ophiogomphus species of eastern North America (Anisoptera:Gomphidae). Odonatologica 14(2):89-99.
Corbet, P.S. 1980. Biology of Odonata. Ann. Rev. Ent. 25:189-217.
__________. 1999. Dragonflies: behavior and ecology of Odonata. Comstock Publishing Associates, Ithaca, New York.
Corbet, P. S., C. Longfield, and N. W. Moore. 1985. Dragonflies. Collins, London. xiv + 260 pp. (reprint)
Davies, D.A.L. and P. Tobin. 1984. The dragonflies of the World. A systematic list of the extant species of Odonata. Vol. 1. Zygoptera and Anisozygoptera. Soc. Int. Odonat. Rapid Comm. (Suppl.) 3:x + 128 pp.
Davis D.A.L. and P. Tobin. 1985. The dragonflies of the World. A systematic list of the extant species of Odonata. Vol. 2. Anisoptera. Soc. Int. Odonat. Rapid Comm. (Suppl.) 5:xii + 152 pp.
Dunkle, S.W. 1985. The taxonomy of the Libellula vibrans group (Odonata:Libellulidae). Trans. Am. Ent. Soc. 111(3):399-405.
_________. 1989. Dragonflies of the Florida peninsula, Bermuda, and the Bahamas. Scientific Publishers, Gainesville, Florida.154 pp.
Garrison, R. W. 1991. A synonymic list of the New World Odonata. Argia 3(2):1-30.
Glotzhober, R.C. 1986. Ohio dragonflies and damselflies. Ohio Historical Soc., Columbus, Ohio.
Gloyd, L.K. and M. Wright. 1959. Odonata, pp. 917-940. In Freshwater biology. 2nd ed. W.T. Edmondson (ed.). John Wiley & Sons, N.Y. 1248 pp.
Hilsenhoff, W. L. 1995. Aquatic insects of Wisconsin, 3rd Ed. Natural History Museums Council, University of Wisconsin-Madison. Madison, Wisconsin. 79 pp.
Lohmann, H. 1992. Revision der Cordulegastridae. 1. Entwurf einer neuen Klassifizierung der Familie (Odonata: Anisoptera). Opuscula Zoologica Fluminen 96:1-18.
Munz, P.A. 1919. A venational study of the suborder Zygoptera. Mem. Ent. Soc. Am. 3:1-307.
Needham, J. G. and H. B. Heywood. 1929. A handbook of the dragonflies of North America. C.C. Thomas, Springfield, Illinois. 378 pp.
Needham, J.G. and M. J. Westfall, Jr. 1955. A manual of the dragonflies of North America (Anisoptera) including the Greater Antilles and the provinces of the Mexican border. Univ. Calif. Press, Berkeley. 615 pp.
Needham, G. E., M. J. Westfall, Jr., and M. L. May. 2000. Manual to the Dragonflies of North America, 2nd Edition. Scientific Publishers: Gainesville, FL.
Pennack, R.W. 1978. Freshwater invertebrates of the United States. 2nd ed. J. Wiley & Sons, NY. 803 pp.
Rowe, R.  1987. The dragonflies of New Zealand. Auckland University Press, New Zealand. 260 pp.
Smith, W. A. unpublished. Larval key to the species of the genus Ophiogomphus (Odonata: Gomphidae) of the upper Midwestern United States.
Smith, R.F. and A.E. Pritchard. 1956. Odonata, pp. 106-153. In Aquatic insects of California. R. L. Usinger (ed.). Univ. Calif. Press, Berkeley. 508 pp.
Snodgrass, R. E. 1954. The dragonfly larva. Smithsonian Misc. Coll. 123:4175.
Tillyard, R. J. 1917. The biology of dragonflies. Cambridge University Press, Cambridge, UK. 396 pp.
Vogt, T.E. and J.E. McPherson. 1985. State records and confirmations of Odonata from Illinois and Missouri. Great Lakes Ent. 18(1):7-13.
Walker, E.M. 1953. The Odonata of Canada and Alaska. Part I. General, Part II. The Zygoptera-damselflies. Vol. I. Univ. Toronto Press, Toronto. 292 pp.
___________. 1957. The affinities of the North American species of Gomphus as revealed by the genitalia (Odonata, Gomphidae). Contributions of the Royal Ontario Museum, Division of Zoology and Palaeontology, No. 46, 24 pp.
___________. 1958. The Odonata of Canada and Alaska. Anisoptera. Vol. 2. Univ. Toronto Press, Toronto. 318 pp.
___________. 1966. On the generic status of Tetragoneuria and Epicordulia (Odonata: Corduliidae). The Canadian Entomologist 98(9):897-902.
Walker, E.M. and P.S. Corbet. 1975. The Odonata of Canada and Alaska. Anisoptera, Macromiidae, Corduliidae, Libellulidae. Vol. 3. Univ. Toronto Press, Toronto. 307 pp.
Westfall, Jr., M.J. 1984. Odonata, pp. 126-176. In An introduction to the aquatic insects of North America. 2nd edition. R.W. Merritt and K.W. Cummins (ed.). Kendall/Hunt Publishing Co., Dubuque, IA.
Westfall, M. J., Jr. and K. J. Tennessen. 1996. Odonata, pp. 164-211, in An Introduction to the Aquatic Insects of North America, 3rd Ed. R. W. Merritt and K. W. Cummins (eds.). Kendell/ Hunt Publishing Company: Dubuque, Iowa.
Westfall, Jr. M. J., and M. L. May, 1996. Damselflies of North America. Scientific Publishers: Gainesville, Florida. 650pp.
Wright, M. and A. Peterson. 1944. A key to the genera of anisopterous dragonfly nymphs of the United States and Canada (Odonata, suborder Anisoptera). Ohio J. Sci. 44:151-166.

Notes on Morphology and Taxonomy / References Cited and Additional Taxonomic Sources / List of Taxa Presented

List of Taxa Presented

You must be able to identify in a lab exam the following taxa, larvae to genus, adults to family, either by sight or using a taxonomic resource. Taxa denoted in blue are to be identified by sight, those in black are taxa to be identified using any resource you wish within a set period of time (e.g., 1 minute). Adult specimens are also provided for your information.

Suborder Family Genus Number Stage Required Identification
Zygoptera Calopterygidae Calopteryx Odo-1 L Visual
Zygoptera Calopterygidae Calopteryx Odo-2 A  
Zygoptera Calopterygidae Hetaerina Odo-3 L Visual
Zygoptera Lestidae Lestes Odo-4 L Visual
Zygoptera Coenagrionidae Argia Odo-5 L Key
Zygoptera Coenagrionidae Chromagrion Odo-6 L Key
Zygoptera Coenagrionidae Enallagma Odo-7 L Visual
Zygoptera Coenagrionidae Enallagma Odo-8 A  
Zygoptera Coenagrionidae Ischnura Odo-9 L Visual
Zygoptera Coenagrionidae Ischnura Odo-10 A  
Zygoptera Coenagrionidae Nehalennia Odo-11 L Key
Anisoptera Aeshnidae Aeshna Odo-12 L Visual
Anisoptera Aeshnidae Anax Odo-13 L Visual
Anisoptera Aeshnidae Anax? Odo-14 A  
Anisoptera Aeshnidae Boyeria Odo-15 L Visual
Anisoptera Aeshnidae Basiaeschna Odo-16 L Key
Anisoptera Gomphidae Dromogomphus Odo-17 L Key
Anisoptera Gomphidae Phanogomphus Odo-18 L Visual
Anisoptera Gomphidae Hylogomphus Odo-19 L Key
Anisoptera Gomphidae Hagenius Odo-20 L Visual
Anisoptera Gomphidae Ophiogomphus Odo-21 L Visual
Anisoptera Gomphidae Stylurus Odo-22 L Key
Anisoptera Gomphidae tba Odo-23 A  
Anisoptera Cordulegastridae Cordulegaster Odo-24 L Visual
Anisoptera Cordulegastridae Cordulegaster Odo-25 A  
Anisoptera Macromiidae Macromia Odo-26 L Visual
Anisoptera Macromiidae Didymops Odo-27 L Key
Anisoptera Corduliidae Cordulia Odo-28 L Key
Anisoptera Corduliidae Epitheca Odo-29 L Visual
Anisoptera Corduliidae Epitheca Odo-30 A  
Anisoptera Corduliidae Somatochlora Odo-31 L Key
Anisoptera Libellulidae Celithemis Odo-32 A Key
Anisoptera Libellulidae Ladona Odo-33 L Visual
Anisoptera Libellulidae Leucorrhinia Odo-34 L Visual
Anisoptera Libellulidae Libellula Odo-35 L Visual
Anisoptera Libellulidae Nannothemis Odo-36 L Key
Anisoptera Libellulidae Pantala Odo-37 L Key
Anisoptera Libellulidae Plathemis Odo-38 L Visual

Page last edited: January 24, 2005 (EB)


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