Monday, April 10, 2017

Episode 363 (4-10-17): Students Make a Call for Stream Insects and Other Aquatic Invertebrates

CLICK HERE to listen to episode audio (4:17)

Transcript of audio, notes on the audio, photos, and additional information follow below.

All Web addresses mentioned were functional as of 4-7-17.


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the week of April 10, 2017.

SOUND - ~ 4 sec

That’s the sound of water flowing in the South Fork Roanoke River in Montgomery County, Va.   If you were under that flow on a rock, stick, leaf, or sediment on the stream bottom, who, or what, might be your neighbors?  This week, a group of Virginia high school students gives us a quick lesson on that subject.  Have a listen for about 20 seconds.

GUEST VOICES - ~18 sec –
Males: Black fly! Crane fly! Midge!
Females: Riffle beetle! Water Penny! Hellgrammite!
Males: Mayfly! Stonefly! Caddisfly!
Females: Dragonfly! Damselfly!
Males: Lunged snail!
Females: Gilled snail!

You’ve been listening to the names of 13 kinds of aquatic organisms found in streams, lakes, or other freshwater habitats.  The names were shouted out by students from Patrick County High School, located in Stuart, Virginia, during a visit to Virginia Tech on March 31, 2017.  Collectively, the organisms are called macroinvertebrates: “macro” because they’re large enough to be seen without a microscope; and “invertebrates” because they don’t have an internal backbone.

Over 11,000 species of macroinvertebrates are known to inhabit freshwaters in North America, and many more species are found in marine waters.   Some, like freshwater snails, are aquatic for their entire life cycle; others, like many aquatic insects, emerge from water as adults.  Aquatic macroinvertebrates are important components of biological communities, the term for interacting populations of different species within a given area and time.  Within those communities, macroinvertebrates have various ecological roles, such as, as predators, like dragonflies; prey for fish, like many mayflies; consumers of algae off surfaces, like many snails; collectors of floating organic debris, like blackflies; or parasites, like some water mites.

They also have various requirements or tolerances for different physical and chemical factors, such as temperature, the level of dissolved oxygen, and the level of pollutants.  This, along with relatively limited movement, makes macroinvertebrates valuable for biological assessments of water quality and aquatic habitat.  For example, freshwater Virginia streams without significant pollutants or other impairments typically have a diverse biological community, with many different kinds of macroinvertebrates.  In contrast, a stream with poor physical or chemical conditions will tend to have less diversity and may be dominated by the more tolerant kinds of organisms.

Thanks to Patrick County High School students and the school’s Dan River Basin Association Club for lending their voices and energy to this episode.  As those students did at Virginia Tech, bring your curiosity and observation powers next time you visit a stream or other water body, and you just might have a biological community meeting with...[GUEST VOICES] aquatic macroinvertebrates!


For more Virginia water sounds, music, and information, visit us online at, or call us at (540) 231-5463.  Virginia Water Radio is produced by the Virginia Water Resources Research Center, part of Virginia Tech’s College of Natural Resources and Environment.  Thanks to Stewart Scales for his banjo version of Cripple Creek to open and close the show.   In Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.


The guest voices in this episode were students from Patrick County High School, located in Stuart, Virginia, recorded on a visit to the Virginia Tech College of Natural Resources and Environment on March 31, 2017. Thanks to the students, the school’s Dan River Basin Association Club, school faculty Stephen Henderson and Brenda Martin, and the Dan River Basin Association’s Wayne Kirkpatrick for their visit and participation in this episode.

Thanks to Liz Sharp, Tony Timpano, and Eryn Turney, all of the Virginia Tech College of Natural Resources and Environment, for their help with this episode. 

Click here if you’d like to hear the full version (1 min./11 sec.) of the “Cripple Creek” arrangement/performance by Stewart Scales that opens and closes this episode.  More information about Mr. Scales and the group New Standard, with which Mr. Scales plays, is available online at

Special note: Careful listeners may have heard a bird in the background near the end of this episode.  That was a Tufted Titmouse, calling outside the window during the recording of this episode at Cheatham Hall on the Virginia Tech campus in Blacksburg.  It doesn’t have anything to do with aquatic macroinvertebrates, but it sounded nice, so it stayed!


Dragonfly perched above a pond on the grounds of Eyre Hall near Cheriton, Va., (Northampton County), October 6, 2007.

Stoneflies collected from the South Fork Roanoke River near Elliston, va. (Montgomery County), September 24, 2009.
Caddisfly cases on a cobble in the New River near Eggleston, Va., (Giles County), August 31, 2014.


Below are three cartoons about aquatic macroinvertebrates, which illustrate some behaviors seen in three important groups: mayflies, stoneflies, and caddisflies.  The illustrations are by George Wills of Blacksburg, Va. (  The source of the illustrations and the accompanying information is “Bottom-dwellers Tell Stories about the Water Above," written by Sarah Engel for Virginia Water Central, April-June 2002 (Virginia Water Resources Research Center newsletter), available online at online at

If water flow or the level of dissolved oxygen in water, some mayflies may use movements to increase the pass of water across the gills on their abdomen (posterior body section), where oxygen is absorbed from the water.

As a group, stoneflies are particularly sensitive to the level of dissolved.  In response to low dissolved oxygen, some stoneflies will use “push-ups” to increase movement of water across the gills on their thorax (middle body section).
Many kinds of caddisflies are known build various kinds of cases from leavers, stones, or other materials, held together by a silk-like material that the insects produce.  But net-spinner caddisflies (the family known as Hydropsychidae) don’t live in cases; instead, they use silk-like material to produce nets with which they filter food out of passing water.


Used in Audio

Michael T. Barbour et al., Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers (Second Edition), EPA 841-B-99-002, July 1999.

Sarah Engel, “Bottom-dwellers Tell Stories about the Water Above,” Virginia Water Central, April-June 2002, pages 11-17, Virginia Water Resources Research Center, Blacksburg, online at

R. W. Merritt and K. W. Cummins, An Introduction to the Aquatic Insects of North America, 2nd Edition, Kendall/Hunt, Dubuque, Ia., 1984.

Oxford Dictionary and Thesaurus (American Edition), Oxford University Press, New York, 1996.

J. Reese Voshell, Jr., A Guide to Common Freshwater Invertebrates of North America, McDonald and Woodward, Blacksburg, Va., 2002.

R. G. Wetzel, Limnology—Lake and River Ecosystems (Third Edition), Academic Press, San Diego, Calif., 2001.

U.S. Environmental Protection Agency, Terms of Environment, EPA 175-B-97-001, 1997. This source give the following definition of “community”: “In ecology, an assemblage of populations of different species within a specified location in space and time. Sometimes, a particular subgrouping may be specified, such as the fish community in a lake or the soil arthropod community in a forest.”

For More Information about Aquatic Insects or Other Aquatic Macroinvertebrates

Iowa State University Department of Entomology, “BugGuide,” online at

W. Patrick McCafferty, Aquatic Entomology: The Fishermen's and Ecologists' Illustrated Guide to Insects and Their Relatives, Jones and Bartlett Publishers, Toronto, 1998; available online at

Alan Raflo, David Gaines, and Eric Day, “Mosquitoes and Water,” Virginia Water Central, June 2009, pages 6-15, Virginia Water Resources Research Center, Blacksburg, online at

University of Florida Department of Entomology, “Featured Creatures” Web site,


All Water Radio episodes are listed by category at the Index link above ( See particularly the “Insects” and “Invertebrates Other Than Insects” subject categories.

A previous episode on stream assessment with aquatic macroinvertebrates is Episode 81, 9/26/11.

Other previous episodes on aquatic macroinvertebrates include the following:
Episode 78, 9/5/11 – on mosquitoes;
Episode 119 (revisited), 8/3/15 – on dragonflies and damselflies;
Episode 262, 4/20/15 – on freshwater snails;
Episode 268, 6/1/15 – on chironomids (non-biting midges).

For a previous episode featuring Virginia high school students, please see
Episode 325, 7/18/16 – on Chesapeake Bay submerged aquatic vegetation.


This episode may help with the following Virginia 2010 Science SOLs:

Grades K-6 Earth Patterns, Cycles, and Change Theme
3.8 – Basic patterns and cycles in nature.
3.9 – Water cycle, including sources of water, energy driving water cycle, water essential for living things, and water limitations and conservation.

Grades K-6 Earth Resources Theme
3.10- impacts on survival of species.
4.9 - Va. natural resources, including watersheds, water resources, and organisms.

Grades K-6 Life Processes Theme
K.7 – basic needs and processes of plants and animals.
1.5 - animals’ basic needs and distinguishing characteristics.
2.4 - life cycles.
3.4 - behavioral and physiological adaptations.

Grades K-6 Living Systems Theme
2.5 - living things as part of a system, including habitats.
3.5 - food webs.
3.6 - ecosystems, communities, populations, shared resources.
4.5 - ecosystem interactions and human influences on ecosystem.
6.7 - natural processes and human interactions that affect watershed systems; Va. watersheds, water bodies, and wetlands; and water monitoring.

Life Science Course
LS.4 - organisms’ classification based on features.
LS.8 - community and population interactions, including food webs, niches, symbiotic relationships.
LS.9 - adaptations for particular ecosystems’ biotic and abiotic factors, including characteristics of land, marine, and freshwater environments.
LS.10 - changes over time in ecosystems, communities, and populations, and factors affecting those changes, including climate changes and catastrophic disturbances.
LS.11 - relationships between ecosystem dynamics and human activity.

Earth Science Course
ES.8 - influences by geologic processes and the activities of humans on freshwater resources, including identification of groundwater and major watershed systems in Virginia.

Biology Course
BIO.2 – water chemistry and its impact on life processes.
BIO.4 – life functions (including metabolism and homeostasis) in different organism groups, including human health, anatomy, and body systems.
BIO.6 - bases for modern classification systems, including structures, biochemistry, and developmental stages.
BIO.8 - dynamic equilibria and interactions within populations, communities, and ecosystems; including nutrient cycling, succession, effects of natural events and human activities, and analysis of the flora, fauna, and microorganisms of Virginia ecosystems.

The episode may also help with the following Virginia 2008 Social Studies SOLs:

World Geography Course
WG.2 - how selected physical and ecological processes shape the Earth’s surface, including climate, weather, and how humans influence their environment and are influenced by it.

The episode may also help with the following Virginia 2015 Social Studies SOLs, which become effective in the 2017-18 school year:

World Geography Course
WG.2 - how selected physical and ecological processes shape the Earth’s surface, including climate, weather, and how humans influence their environment and are influenced by it.

Virginia’s SOLs are available from the Virginia Department of Education, online at