Otter Creek

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Streams logo web.jpg Otter Creek
Basin:Otter Creek
State or Province:Vermont
Country:USA
Latitude:43.24727
Longitude:-72.59495


The following are the most common invertebrates collected from this stream site.

Baetis

Baetis.jpg
Order
Ephemeroptera
Family
Baetidae
Genus
Baetis


Common name
The Little Olive
Tied fly
Sawyer Pheasant Tail Nymph
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.

Image of the long, dark wing pads.




Chironomidae

Chironomidae.jpg
Order
Diptera
Family
Chironomidae


Common name
Nonbiting midge
Tied fly
Griffith's Gnat
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 caddisfly family Philopotamidae.

More information on Philopotamidae.




Neophylax

Neophylax examples.jpg
Order
Trichoptera
Family
Uenoidae
Genus
Neophylax


Common name
Fool's Caddis
Tied fly
Peeping Caddis
Neophylax are characterized by having a sclerotized pronotum and mesonotum. They build a case of coarse sand grains often with a pair of latteral pebbles or "ballast stones". The larvae are rather stout and the head is scrunched in between the limbs. The anal hooks are attached directly to the abdomen and they rarely come out of the case when preserved. On the ventral surface of the abdominal segments, one can see darkened ovals, known as the chloride epithelia. Like the Limnephilidae, they have a prosternal horn, though it can sometimes be small. Also, they have a dorsal hump and two lateral humps on the first abdominal segment- be careful! Often times, these features can be squished down or damaged in the sampling process. A larva removed from it's case is shown here.

The feature that distinguishes Uenoidae from Limnephilidae is the mesonotum: on either side of the midline, the anterior margin is notched.

Because our samples were taken in summer, we found large numbers of Neophylax pre-pupae. We anticipate that there will be fewer present in the streams in late September and many of those sampled will be at the pupal or adult stage. Samples taken in October would tend to have more empty cases.



Ceratopsyche

Ceratopsyche.jpg
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. Biologists have gone back and forth between lumping this genus into Hydropsyche and splitting it back out. ITIS currently lists it as a genus (Feb 2013) but we are aware of a recent paper that lumped it under Hydropsyche.




Optioservus

Optioservus (Larvae).jpg
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 sutellum observable in the dorsal view.

Images of the straight definition between segments, the dorsal ridgesand the diamond-shaped scutellum.




Simuliidae

Simuliidae.jpg
Order
Diptera
Family
Simuliidae


Simuliidae appear rather like bowling pins with heads. Relatively speaking, we collect few members of this family and have we have not identified them past family at this point.

Click here for a close up image of the heads.




Ephemerella

Drunella Whole.jpg
Order
Ephemeroptera
Family
Ephemerellidae
Genus
Ephemerella


Common name
The Hendrickson; The Red Quill; The Hendrickson Spinner Fall
Tied fly
Hendrickson; Flick's Red Quill; Lunn's Particular
Mayflies in this genus have long intersegmental setae on their cerci that extend laterally and may or may not have whorls of spines at the end of each segment of their cerci. Their maxillary palps are well-developed.

Image of the intersegmental setae.



Rhyacophila

Rhyacophila.jpg
Order
Trichoptera
Family
Rhyacophilidae
Genus
Rhyacophila


Common name
Green Caddis
Tied fly
Henryville Special or Glass Bead Caddis
In our lab, Rhyacophila is known as the "Michelin Man" due to its large banded body. It has a very obviously checker-patterned head. It also has terrifying anal claws with large accessory hooks.

Links to images that may be useful if you have a magnifying glass or microscope: Checker-patterned head. Anal claws with large accessory hooks.




Drunella

Drunella Whole.jpg
Order
Ephemeroptera
Family
Ephemerellidae
Genus
Drunella


Tied fly
Bluewinged Olive Dun
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.



Cheumatopsyche

Cheumatopsyche.jpg
Order
Trichoptera
Family
Hydropsychidae
Genus
Cheumatopsyche


Cheumatopsyche has a forked foretrochantin (as does Ceratopsyche). The foretrochantin is the projection at the uppermost portion of the front leg closest to the head. The leg may need to be pulled away from the body to expose this feature. 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.