Munroe BrookThese are the ten most common macroinvertebrates identified from samples from Munroe Brook. |
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ORDER: Diptera
Midge larvae tend to be the most common macroinvertebrate at our sites. As with other Diptera, there are no true jointed legs. Chironomids 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 the philopotamids. |
ORDER: Trichoptera Cheumatopsyche have a small or inconspicuous pair of sclerites under the prosternal plate that are difficult to see. Contrast that with the larger pair of sclerites found on Ceratopsyche. To access sclerites, it's best to gently pull the pronotum and mesonotum in opposite directions. Note: the large single sclerite is the prosternal plate. Cheumatopsyche have only 2 types of hair on the abdomen: long thin plain hairs and thicker club hairs, which are narrow close to the body and widen out at the distal end. Paired sclerites on the ninth abdominal segment are notched. SMC |
ORDER: Trichoptera 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; however, not all Trichopterans have forked foretrochantins. Ceratopsyche have a large pair of sclerites underneath the prosternum. Note: the large single sclerite is the prosternal plate. SMC
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ORDER: Trichoptera Chimarra are distinguished from the other Philopotamidae by a prominent asymmetrical notch in the frontoclypeus as well as a prominent process on the femora which bears a single hair, called setae. SMC |
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ORDER: Diptera
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ORDER: Coleoptera Riffle beetles appear in the streams as adults and larvae. The larvae of Stenelmis have a sternum on the ventral side of the pronotum. The adult Stenelmis has a clear separation between the thorax and abdomen as well as a more distinctly separate head as compared to other genera. SMC |
ORDER: Ephemeroptera
This mayfly has three "tails" and a unique head shape. Its gills are oval shaped and insert dorsally. The wing pad shape is an obvious characteristic. More mature nymphs have long, dark wing pads. SMC |
ORDER:
Coleoptera
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ORDER: Diptera What's not to like about blackflies? Our
second most common dipteran. Rather like a bowling pin with hands
attached at the head end. We have not identified them past family
at this point, but it is in the long-term plan.
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PHYLUM:
Annelida Aquatic earthworms lack legs and are characterized by having 20 or more segments. Unlike leeches, they lack a suction disk.
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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 |
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