Ecological Role
Habitat:
Despite having an average lifespan that ranges from
mere hours to a few days, it is not difficult to come across a
colony of Isonychia bicolor mayflies, as their breeding
grounds are widespread and they are quite an abundant species
wherever they are found. Some research shows that they are very
particular to which kinds of rivers they can successfully
inhabit, but overall the population is large compared to other
insects (Neuswanger 2012). (This is not to mention they have
two generations per year, which contributes
to their puzzling high prevalence. For more on this, see our
page about
Reproduction and Life Cycle!) While the genus Isonychia is
able to thrive in habitats across the globe, with its members
scattered even throughout parts of Asia and Central America,
Isonychia bicolor is distributed primarily on the
North American continent (Kondratieff and Voshell 1984). Among
the many places where it resides, the majority of the species
inhabits the eastern region of the United States and occurs with
highest concentration in swiftly-flowing, relatively large
mountain rivers and streams (Kondratieff and Voshell 1984,
Echols et al. 2010).
Most often, Isonychia bicolor is found most often in the Benthic zone** of these water
bodies and tends to prefer areas where the vegetation is dense
and twisted, and various debris of the woods (sticks, leaves,
decaying organic matter) coats the water in a nutrient-rich
layer (Echols et al. 2010).
**The Benthic zone, for clarification, skirts the floor
all the way down to the bottom, across, and back up again on the
other side of bodies of water, including riverbeds. This
organism, in its early life stages, spends most of its time in
the uppermost part of this zone--that is, the segment that rests
closest to the land of the shoreline/river's edge.
Feeding Habits/Nutrition:
Isonychia bicolor is
one
of four Isonychiidae ("brush-legged") genera in North America that utilize the
technique called "suspension" or "filter" feeding to
gain 98% of their nutrients from "amorphous
detritus" in rivers and streams. These organic
debris particles are generally generally
ranging from 0.1-0.7 micrometers, or μm in size
(Echols et al. 2010).
- Clinging on to rocky riverbed substrates, these
"streamlined, vigorous swimmers" face the direction of the
current, using
tiny appendages called setae on their fore- (front)
legs as a kind of self-created, evolutionarily-produced, makeshift fishing net (Echols et al. 2010). It is
using this evolutionary technique that they are able
to collect the fine particles they do, creating a
mutually beneficial exchange between themselves, who
receive a hearty meal, and their neighboring
species, who enjoy cleaner water as a result of the
straining action of Isonychia bicolor setae
at work (Jacobi and Benke 1991).
-
Only the larval (nymph) forms of these
mayflies feed at all; strangely enough, once they
have developed into their adult forms, the parts of their entire
system have vanished—mouthparts and all
(Net Industries 2012)! To
see more on life cycle stages, click here.
These mayflies also obtain food by scraping
algae from rocks and sediments, and by consuming
diatoms, and decomposing plant material. In some
habitats they consume plankton and smaller aquatic
insects by way of predatory behavior, which is quite
rare among the mayfly genera (Neuswanger 2012; Net
Industries 2012).
Environment/Other Species Interactions:
Because
Isonychia bicolor cleans the water in
which they live, they can be considered the
custodians of the currents (Jacobi and Benke
1991).
Because they can consume a variety of food sources,
Isonychia bicolor allow for more different
species to live in the same habitat.
Isonychia bicolor
and Us: Scientific, Economic, Practical and
Commercial Uses:
The nymphs of Isonychia bicolor are especially
desirable for the study of ecotoxicology, a domain of ecology
concerned with protecting ecosystems and their inhabitants by
optimizing environmental conditions. Why?
- Nymphs are very sensitive to pollutants, serve as good
indicators of contamination like some types of metal, ammonia, etc.
- Researchers use these nymphs in field
studies to identify sources of pollution and identify its environmental impact (Echols et al.
2010).
Another large use of these mayflies which pertains
to many, many people, especially those who consider
themselves native to the northwoods country, is
the popular hobby/"sport" of fly-fishing. Whether
for recreation, for food, for the industry itself,
or for the simple love of harnessing nature by the
river, the Isonychia bicolor insect in all
of its forms makes a great lure for trout and more.
-For more information on commercial
fly-fishing and the species involved with it, view
the photo- and blog-filled homepages of these two
avid naturists, researchers, photographers, lovers
of the outdoors, and proclaimed fisher-people
themselves at:
Jason Neuswanger (www.Troutnut.com),
and
Nome Buckman (www.ReelNorthLLC.com).
*To
return to the website Table of Contents,
or for more information on the common names listed
just below the header of this page, go
Home.