Stream Macroinvertebrates, EPT Taxa, and Lab Techniques in Freshwater Ecology

Why are stream macroinvertebrates important?

They recycle nutrients and provide food for other organisms.

What does the presence of EPT taxa indicate?

Indicates the stream is healthy.

Which group is not part of the EPT taxa?

Dragonflies.

What adaptation helps insects resist being washed away by current?

Dorsoventral flattening (flat body shape).

Which group has three tails and feathery abdominal gills?

Mayflies. (Ephemeroptera)

 Which group has two tails and lacks plate-like abdominal gills?

Stoneflies. (Plecoptera)

Which group builds cases from sand, sticks, or rocks?

Caddisflies. (Trichoptera)

Mayfly nymphs feed as:

Collectors (detritus) or scrapers (algae/diatoms).

Caddisfly larvae can be identified by:

Six legs at the front and prolegs with claws at the rear.

What type of microscope is used in this lab?

Dissecting (stereo) microscope.

What magnification range does the dissecting microscope provide?

0.5x - 4.5x.

Why do we use a dissecting microscope instead of a compound microscope?

It's better for large, whole specimens like insects.

 Which group is considered “Most Wanted” when assessing stream health?

EPT taxa.

If your stream has mostly “Most Wanted” species, it is:

Very healthy.

What does % EPT taxa measure?

The % of all organisms that are EPT taxa.

If you calculate % EPT taxa as (Total Most Wanted ÷ Total Observed) × 100, what does a higher % mean?

A higher % means better health.

When handling specimens in lab, you should:

Keep them in their vials and use the microscope.

What tool should you use to move specimens gently?

Forceps.

One lab task is to draw a specimen. What must you include?

Labels of features, magnification used, and measured length.

 After finishing, microscopes should be put away with:

Eyepieces facing into the cabinet.