Academics Admission Student Life Athletics About Saint Michael's News & Events

Site codes explained and mapped  (under mapping resources tab)

Macroinvertebrates home

Streams project

 

Unnamed tributary (LR_TribA_374)

These are the most common macroinvertebrates identified from samples from an unnamed tributary on Route 7 in Milton that empties into the Lamoille.

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.

PHYLUM: Annelida
CLASS: Oligochaeta

Aquatic earthworms lack legs and are characterized by having 20 or more segments. Unlike leeches, they lack a suction disk.

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: 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: Trichoptera
FAMILY:
Hydropsychidae
GENUS: Ceratopsyche

Ceratopsyche has a forked foretrochantin. The foretrochantin is the projection at the uppermost portion of the foreleg. The leg may need to be pulled away from the body to expose this feature.

Ceratopsyche have a large pair of sclerites underneath the prosternum. Note: the large single sclerite is the prosternal plate. SMC

 

 


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: Trichoptera (pupae)

Frequently pupae cannot easily be keyed down to family, so we leave them at order. Trichopteran pupae have prominent mandibles moving against each other.


CLASS: Entognatha
ORDER: Collembola
FAMILY: Isotomidae
 

This family is characterized by the third and fourth abdominal segments being of equal length.

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: Diptera
FAmily: Tipulidae
Genus: Tipula
 

This genus of Tipulidae is rather large as compared with other genera. Tipula larvae are generally dark brown and have creeping welts.

CLASS: Gastropoda
FAMILIES: Physidae, Lymnaeidae, and Planorbidae
 

Three families from this class are commonly found here. Members of the family Planorbidae are found in flattened shells. Those belonging to Lymnaeidae are found in "right-handed" shells, in which the spiral goes clockwise. Members of Physidae  are called "left-handed" as the spiral of the shell goes counterclockwise. Remember, these only count if there is an individual in the shell; don't count empty shells in your data!

Photo Source:

http://commons.wikimedia.org/wiki/File:Leech_blutegel.jpg

Phylum: Annelida
CLASS: Hirudinea
 

Leeches have bodies with 20 or more segments and a ventral suction disk on at least one end, though sometimes on both ends.

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).
2008 Saint Michael's College
One Winooski Park, Colchester, Vermont, USA 05439 | 802.654.2000 |
Privacy Policy