Indian Brook
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 Indian Brook | |
|---|---|
| Stream code: | LCD_IndBrk_323 |
| Basin: | Lake Champlain Direct |
| State or Province: | Vermont |
| Country: | USA |
| Latitude: | 44.494762 |
| Longitude: | -73.106422 |
| School: | Colchester High School |
The following are the most common invertebrates collected from this stream site.
Contents
- 1 Elmidae
- 2 Aeshnidae
- 3 Athericidae
- 4 Physidae
- 5 Dicranota
- 6 Belostomatidae
- 7 Tipulidae
- 8 Hydropsychidae
- 9 Chironomidae
- 10 Leuctra
- 11 Oligochaeta
- 12 Psephenus
- 13 Ancylidae
- 14 Antocha
- 15 Limnephilidae
- 16 Nigronia
- 17 Cambaridae
- 18 Simuliidae
- 19 Uenoidae
- 20 Veliidae
- 21 Baetidae
- 22 Cheumatopsyche
- 23 Philopotamidae
Elmidae
- Order
- Coleoptera
- Family
- Elmidae
- Common name
- riffle beetle
We very commonly find 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, Macroychu, Optioservus, Phanocerus, Promoresia, and Stenelmis.
Images of the adult and larval riffle beetles.
More information on Dubiraphia, Macronychus, Optioservus, Phanocerus, Promoresia, and Stenelmis.
Aeshnidae
- Order
- Odonata
- Family
- Anisoptera
- Common name
- Darner
- Tied fly
- Carey Special
All dragonflies have five points sticking out from the back end. Members of this family of dragonflies are distinctly long as can be seen in the photograph. Other common families tend to be a wider and flatter. If you pull out on the mouthparts under the head you'll see that they look flat in side view. If they look spoon-shaped then it is from a different family. Like other Odonata, members of this family have four wingpads. Like members of the sub-order Anisoptera, the abdomen terminates in five points. The prementum and palpal lobes of this dragonfly are flat when viewed from side.
Images of the four wingpads, the abdomen, the prementum and palpal lobes, and a view from the the side.
Athericidae
- Order
- Diptera
- Family
- Athericidae
- Common name
- water snipe flies
Members of the family Athericidae have wrinkled bodies with prolegs on the ventral side. Their mandibles- which can be seen by carefully cutting the head open- move parallel to each other. On the end of their abdomen there are two lobes fringed with setae. Our collections include just the single genus Atherix.
Image of the two lobes of the abdomen.
Physidae
- Family
- Physidae
Members of the family Physidae belong in the class of Gastropoda. Members contain a single, coiled shell with a left handed spiral going counterclockwise. Belonging to the family of aquatic pulmonates, members breathe air using a structure similar to a lung.
Images of the family Physidae, the class of Gastropodaand a shell with a left-handed spiral.
Dicranota
- 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.
Image of the prolegs.
Belostomatidae
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- Order
- Hemiptera
- Family
- Belostomatidae
- Common name
- Giant water bug; toe biter
These spectacular insects are among the largest we collect and so the first common name is appropriate. The second common name we list is also unfortunately true; wading barefoot in a pond may confirm this. There are 2 parallel structures coming off the back end that distinguish this family from most other true bugs; these become more obvious in older individuals. Larger individuals also become more pointed at the back end. We used a photograph of a younger specimen because those are most commonly sampled and are easily confused with naucorids. Click to see an example of a larger specimen.
Tipulidae
- Order
- Diptera
- Family
- Tipulidae
- Common name
- The Crane Fly
- Tied fly
- Gangle Legs
Like other larvae from the order Diptera, members of the family Tipulidae (crane flies) lack legs. Tipulidae have retracted, difficult-to-see head capsules at one end, and a spiracular disk at the other end. The spiracular disk can sometimes look like a face leading to some confusion about which end is which. Upon gently cutting the head open, one can see that the mandibles are not parallel to each other, but rather move against each other.
The genera we've encountered include Antocha, Dicranota, Hexatoma, Limnophila, Molophilus, Pedecia and Tipula.
Hydropsychidae
- Order
- Trichoptera (caddisfly)
- Family
- Hydropsychidae
- Common name
- net spinning caddisfly
- Tied fly
- Emergent Sparkle Pupa, Vermont Hare's Ear
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.
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.
Commonly found genera include Cheumatopsyche, Ceratopsyche, and Hydropsyche. Less commonly, we have found Arctopsyche and Potamyia.
Images of the forked trochantin and the paired sclerites.
Chironomidae
- 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.
Leuctra
- 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.
Image of the divergent wing pads.
Oligochaeta
- Common name
- aquatic earthworms; black worms
Aquatic earthworms lack legs and are characterized by having 20 or more segments. Unlike leeches, they lack a suction disk. We collect members of two or more orders in this class as small numbers of stream sites and they are rarely numerous. They are more common at pond and lake sites.
Image of the 20 or more segments.
Psephenus
- Order
- Coleoptera
- Family
- Psephenidae
- Genus
- Psephenus
The true "water penny" is commonly found in the waters sampled. Psephenus has a rounded shape with relatively smooth edge. The false water penny, whose edges are serrated, has a more oval appearance. The gills on the ventral surface are found only in the true water pennies.
Another genus encountered in this family is Ectopria.
Ancylidae
- Order
- Basommatophora
- Family
- Ancylidae
Members of the family Ancylidae belong in the class of Gastropoda. As Pulmonate snails, these members breathe using lung-like structures but can also use a gill-like structure called a pseudobranch to extract oxygen from water. Their shallow conical shells look like those of miniature limpets.
More information on the class of Gastropoda.
Antocha
- Order
- Diptera
- Family
- Tipulidae
- Genus
- Antocha
This small dipteran 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.
Limnephilidae
- Order
- Trichoptera
- Family
- Limnephilidae
- Tied fly
- Paul Young's Strawman Nymph, Grouse and Orange
This family of Trichoptera is characterized by having sclerotization on the dorsal surface of the first two thoracic segments. Also, it has a dorsal hump on the first abdominal segment, along with two lateral humps. Here, on a more mature specimen, one can see the prosternal horn characteristic of it and another family Uenoidae. More information on the Uenoidae.
Images of the dorsal hump, the two lateral humps, and theprosternal horn.
Nigronia
- Order
- Megaloptera
- Family
- Corydalidae
- Genus
- Nigronia
Members of the genus Nigronia share some superficial commonalities with Trichoptera, but on careful inspection one can see the two pair of anal claws that help place it in the order Megaloptera. The size of mature larvae is impressive; specimens from other genera exceed 8 cm in length. The abdominal segments have ribbon-like gills on the lateral portions. The mouth has mandibles that are serrated and used for biting prey. They can be confused with the more slender whirling beetle larvae; whirligig larvae also have simpler jaws.
Images of the two pairs of anal claws, whirligig beetle larvae and their simpler jaws.
Cambaridae
- Order
- Decapoda
- Family
- Cambaridae
- Common name
- crayfish
Crayfish have forward-facing claws and resemble small lobsters. It would be difficult to confuse these organisms with anything else from a Vermont stream. Seven species in two common genera (Orconectes and Cambarus) have been collected in Vermont.
Simuliidae
- 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.
Uenoidae
- Order
- Trichoptera
- Family
- Uenoidae
- 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.
Veliidae
- Order
- Hemiptera
- Family
- Veliidae
This family of Hempitera actually lives on the surface of the water, but can sometimes float into the net while taking benthic samples. Members of the family Veliidae are characterized by the claw of the foreleg; it is inserted before the apex. Also, its hind leg has a beautiful fan of hydrofuge hairs.
Click here to see the claw inserted before the apex and the fan of hydrofuge hairs.
Baetidae
- Order
- Ephemeroptera
- Family
- Baetidae
- Common name
- Small minnow mayfly
- Tied fly
- Tiny blue-winged olive
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.
More information on the genera:
Cheumatopsyche
- 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.
Philopotamidae
- Order
- Trichoptera
- Family
- Philopotamidae
- Common name
- fingernet caddisflies
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).
Image of the faint white 'T' shaped labrum. Common genera include Dolophilodes, Wormaldia, and Chimarra.
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