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Macroinvertebrates home

Streams project

Most common macroinvertebrates found during the Vermont EPSCoR Streams Project - This page is being reconstructed to reflect recent the field season and will be back up shortly.

Images tagged with the abbreviation NABS are from the North American Benthological Society.  Other images are photographed at Saint Michael's College.  The images are chosen with two things in mind: 1. They are presented in order of rank abundance in the samples we took, or were taken by our partners in Vermont and New York high schools; 2. The images are for the most part of preserved insects, because that is how the investigators at Saint Michael's College and in our partner schools will view specimens.  In cases where initial available images are small or of live insects, we will replace them as we take additional photographs.

Click on images to zoom in. 

ORDER: Diptera
FAMILY: Chironomidae

 Midge larvae tend to be the most common macroinvertebrate at our sites.  As with other Diptera, there are no true jointed legs.  Chironomidae do have a pair of prolegs at each end and preserved individuals tend to curl into a 'C'.  Identification past family requires slide-mounted heads.  We have seen philopotamid caddisflies misidentified with the chironomids and we suspect that that happens when samples are being sorted from trays.  Under a microscope, six prominent legs can be seen on members of the family Philopotamidae.


ORDER: Trichoptera
FAMILY: Hydropsychidae

This family of net-spinning caddisflies is very abundant at several sites.  They are important filtering collectors and are quite common at urban and agricultural sites where particles of organic material can be important food resources.  Genus-level identification is possible for mature specimens and we will include the genera we found at your site if possible. Commonly found genera include Cheumatopsyche, Ceratopsyche, and Hydropsyche. Less commonly, we have found Arctopsyche and Potamyia.

When using the key, some features that are challenging to see are the forked trochantin and the paired sclerites in the folds between segments.  Other, more easily seen key features include filamentous gills on the abdominal segments and the sclerotization of the dorsal surfaces of all three thoracic segments. Keep in mind that with smaller or more immature specimens, genus-level ID may not be possible.


ORDER: Ephemeroptera
FAMILY: Baetidae
 

This mayfly has either two or three cerci ("tails") and a unique head shape. Its gills are oval shaped and insert dorsally.

Commonly encountered genera include Acerpenna, Baetis, and Pseudocloeon.

ORDER: Coleoptera
FAMILY:
Elmidae

We have found adult and larval riffle beetles. The adults are clearly beetles, but the larvae can be confused with other orders. The forward pointing tooth on the front end of the larvae as described in the key can be a challenge to see, particularly in small individuals.

Larvae are characterized by having a single tarsal claw at the end of their legs, which have 4 segments. Adults, on the other hand, have two tarsal claws at the end of each leg.

Commonly encountered genera include Dubiraphia, Macronychus, Optioservus, Phanocerus, Promoresia, and Stenelmis.

ORDER: Diptera
FAMILY: Simuliidae

Simuliidae appear  rather like bowling pins with heads.  We have not identified them past family at this point, but it is in the long-term plan.

 

ORDER: Trichoptera
FAMILY: Philopotamidae

Philopotomidae are net-spinning filtering collectors.  A casual observer might sort them with Chironomidae, but a close look reveals six jointed legs.  The faint white 'T' shaped labrum extending from the front of the head past the mandibles is diagnostic for the family (it is sometimes withdrawn and hard to see). The asymmetrical notch gets us to genus; common genera include Dolophilodes, Wormaldia, and Chimarra. SMC

ORDER: Diptera
FAMILY: Tipulidae
GENUS: Dicranota

Dicranota can be distinguished by the two tails and their comb feet. There are usually 5 pairs of prolegs on the abdomen with combs on them. In addition, the posterior portion of the abdomen often has a slight swelling. SMC

 

 

ORDER: Ephemeroptera
FAMILY: Ephemerellidae
GENUS:
Drunella

The mayfly Drunella is distinguished by its large femoral “biceps;” these femora have tubercles on the leading margins. Gills are present on segments 3-7.

 

 

ORDER: Plecoptera
FAMILY: Leuctridae
GENUS: Leuctra

This family of stonefly is fairly slender by stonefly standards.  The divergent wing pads are a helpful characteristic. Leuctridae  are similar in overall shape to the Capniidae; however, Leuctridae often do not have pleural folds. If they are present, they only extend from abdominal segments 1-7.  Leuctra  are recognized by abdominal terga with posterior fringes of short hairs and last few segments with longer hairs. NABS

 

ORDER: Diptera
FAMILY: Tipulidae
GENUS: Antocha

This small Diptera in the cranefly family is quite common.  It is distinguished from most other dipterans we found by the 'creeping welts' that appear as prominent dark stripes along the abdomen.  The dark head is usually partly exposed; however, it can be pulled back into the thoracic cavity during preservation.
NABS

 

ORDER: Coleoptera
FAMILY: Dytiscidae
GENUS: Dytiscus

Top picture (adult): Adult Dytiscidae have streamlined bodies and hind-legs modified for swimming. They are characterized by the division of the first abdominal segment by the hind coxae, seen here.

Bottom picture (larva): Don't let the paired claws and prominent 'tails' tempt you to think 'stonefly'; these tails are far less segmented than Plecoptera tails. The head and jaws are also unlike those of stoneflies. SMC

 

ORDER: Ephemeroptera
FAM
ILY: Heptageniidae
GEN
US:
Epeorus

This is the only Heptageniidae genus present in this area with two tails!

 

The images are not a substitute for keying, but should serve as an aid in identifying common macroinvertebrates in samples.

Feedback - Partner schools: send us specimens not included above.  Taxonomists: click to email: Declan McCabe
This site is supported by Vermont EPSCoR grant from the National Science Foundation (EPS #0701410).
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