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Macroinvertebrates home

Streams project

 

Metawee River

These are the ten most common macroinvertebrates identified from samples from the Metawee River. The samples were collected July 10th, 2008 from two different sites in Dorset, VT.

Click on images to zoom in. 

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: 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: 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: Coleoptera 
FAMILY: Elmidae
GENUS:
Optioservus

The larvae of Optioservus have open coxae, as determined by the straight definition between segments on the ventral side of the pronotum.

The adult Optioservus have a compact appearance, especially the head and thorax. There are also dorsal ridges and a characteristic diamond-shaped scutellum observable in the dorsal view.
SMC

 

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.

[Bug_templates/Arthrop/Insecta/Eph/baetidae_pseudocleon.htm]

ORDER: Plecoptera
FAMILY: Chloroperlidae
GENUS: Alloperla

Chloroperlids from this genus are characterized by a fringe of intrasegmental setae on their cerci.

ORDER: Ephemeroptera
FAM
ILY: Heptageniidae
GEN
US:
Epeorus

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

ORDER: Ephemeroptera
FAMILY: Baetidae 
GENUS: Baetis 

This mayfly has three "tails" and a unique head shape. Its gills are oval shaped and insert dorsally. More mature nymphs have long, dark wing pads. SMC

ORDER: Plecoptera
FAMILY: Perlidae
GENUS: Acroneuria

Acroneuria have postocular fringe consisting of many close-set thick spinules. They have three ocelli, and there is a yellow m-shaped mark in front of the middle ocellus. The bases of their cerci have thick, silky setae.

 

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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