(Underlined words link to glossary terms, words that are red link to photos or graphics,
words that are red and underlined have a photo and a glossary definition. The other
documents on the CD are activities teachers can do with their students. The Leaf Litter
Sifter Instructions also contains a classroom activity for doing a soil invertebrate
inventory – the PDF’s titled order guide and insect data go along with that. The PDF’s
titled spider datasheet and “Key to Common Spiders…” are an extension activity to the
Leaf litter activity)
Bugs, spiders, creepy-crawlies- these words can make your spine tingle. Slimy
earthworms, dirty cockroaches, black widow spiders with deathly bites- all creatures
folks often try to avoid. These animals, that can make the hairs on your arms stand up, are
actually invaluable members of the earth’s ecosystems. As disturbing as they are to some
of us, these creatures are responsible for sustaining most life on this planet, directly or
indirectly. They also make up the largest group of living things, more numerous than all
other species of plants and animals combined- the invertebrates.
What are invertebrates?
Invertebrates are, simply enough, animals without backbones. This group is very diverse
and includes aquatic animals like jellyfish and sponges as well as terrestrial animals such
as all insects, worms, and snails. Scientists continuously attempt to count and describe all
of the living species on earth. So far, 1,110,000 arthropod species alone have been
described in science. Phylum Arthropoda consists of insects, arachnids, crustaceans, and
many other groups. Some scientists believe that if we are able to count all of the
arthropods just in the tropical rainforests, the number of species would swell to 10
million! (source: Tree of Life Web Project)
How do we know there are so many invertebrates?
Great Smoky Mountains National Park is trying to count all of their arthropods along
with all other living things in an enormous project called the All Taxa Biodiversity
Inventory (ATBI). This attempt to find and describe all species in the park has revealed
3901 new species to the park as of fall 2005 (check www.dlia.org for the most recent
numbers), some of which are entirely new species to science. Of the 3901 new species
discovered in the Park since the start of the ATBI, approximately 80%, are invertebrates.
Species new to science found in Great Smoky Mountains National Park include 26
species of beetles, 32 species of flies, 39 species of spiders, and 72 new species of moths
and butterflies! Because there are few studies involving this kind of blitz to learn all
species, scientists are able to hypothesize that most invertebrate species are still left to be
discovered and described.
How do we find terrestrial invertebrates?
Terrestrial invertebrates are all around us, we just have to think small. Aside from the
gnats and no-see-ums that fly around our faces on a hot, humid day or the worms we use
to lure fish, there are thousands of creatures working their way through the soil, up the
bark of trees, hiding under rocks, or chewing their way into leaves. The tools used by
ATBI scientists to find invertebrates are primarily their eyes and a hand lens. To collect
invertebrates you can look at or under anything found on the ground or on plants. A fun
and easy way to collect is with a leaf litter sifter. This handy tool allows us to shake
critters out of the fallen leaf layer on the forest floor into a container that can then be
searched. Anything moving can be sucked out of the container using an aspirator or
picked out carefully with tweezers and identified or placed into a specimen jar for later
identification. A beat sheet is a tool used to catch insects shaken out of bushes or tree
branches. A Berlese Funnel is a more technical tool which uses heat from a light source
to force insects out of leaf litter and down into a container filled with alcohol or soapy
water.
Why do we need to look at bugs?
The importance of terrestrial invertebrates is immeasurable. Aside from products we can
use like bees’ honey and wax, and silk from the silkworm, invertebrates play an
imperative role in natural ecosystems. For example, many plants would not be able to
grow and reproduce without bees, flies, and other airborne insects. These are the primary
carriers of pollen from flower to flower. Relationships between plants and their
pollinators can be as specific as the one between the Monarch butterfly and the milkweed
plant. Both species are unable to survive without each other, in what is called a symbiotic
relationship. Monarch butterfly larva feed on the milkweed plant and then spread it’s
pollen to other milkweed plants as an adult. Soil invertebrates help decay materials and
create the nutrient-rich humus layer in soil necessary for plant growth. They also serve as
a food source for many birds and small mammals, reptiles, and amphibians. Either way
you look at it, invertebrates play a major role in the cycle of life on this planet.
Some species of invertebrates are detrimental to ecosystems. In the Great Smoky
Mountains we have lost large numbers of some tree species due to infestation from exotic
species. Many of our older Frasier fir trees at high elevations have been destroyed by the
Balsam Wooly Adelgid and the young ones continue to be threatened. This non-native
insect was brought into the United States on garden stock from Asia. It has no natural
predator here and in less than 60 years has drastically altered the appearance and
vegetation type of our high elevation environments. The hemlock trees in the park are
currently being attacked by the Hemlock Wooly Adelgid. Cooperating research with the
University of Tennessee, has found a species of beetle, Pseudoscymnus tsugae (Pt beetle)
that feeds solely on the Hemlock Wooly Adelgid. Along with others treatments, we hope
to control the adelgid by establishing a self-sustainable beetle population.
Monitoring invertebrate populations can tell us the health of an ecosystem. We can
determine water quality by looking at the diversity of invertebrates and their larva in
aquatic environments (see the Hands on the Land water quality study for more
information) . We can also monitor the terrestrial invertebrate population to establish the
health of a forest or grassland. This is especially important in areas threatened by air
pollution or acid rain, such as Great Smoky Mountains National Park. We are often afraid
of those things which we do not understand. By studying the diversity of invertebrate life,
we can determine which critters are indicators of healthy or indicators of changing
environments. Creepy crawlies aren’t so creepy and crawly anymore, are they?
Useful Websites
http://www2.lsuagcenter.com/Inst/Research/Departments/arthropodmuseum/index.htm Louisiana State Arthropod Museum, Louisiana State University
http://buzz.ifas.ufl.edu/ - Singing Insects of North America
http://insected.arizona.edu/info.htm - Arizona State Center for Insect Outreach Education,
tons of general insect info
http://www.dlia.org/ - Great Smoky Mountains National Park ATBI homepage, contains
list of new species, new park records, etc.
http://sain.nbii.org/phpqueries/arthropods.php?page=2&scope=myNode – Southern
Appalachian Information Node, taxonomic info for arthropods and other links
http://www.cdli.ca/CITE/creepy_crawlies.htm - Gander Academy’s Elementary Insect
site, info and extra web resources on invertebrates
http://www.cdli.ca/CITE/invertebrates.htm - Gander Academy’s Elementary Invertebrate
site
http://tolweb.org/tree?group=arthropoda – Tree of Life Web Project’s site on
invertebrates
Spiders:
www.arachnology.org – International Society of Arachnology
www.stemnet.nf.ca/CITE/spiders.htm - Gander Academy’s Elementary spider info page
Berlese Funnel instructions:
http://www.cals.ncsu.edu/course/ent591k/berlese.html
http://www.albany.edu/natweb/berlese.html
GLOSSARY
Invertebrates- animals without backbones
Aquatic Animals – animals living in the water
Terrestrial Animals – animals living on land
Arthropod- an invertebrate animal (such as an insect, arachnid, or crustacean) that has a
segmented body and jointed appendages, usually with an exoskeleton that molts
Insects- a small invertebrate animal, an arthropod, with 3 well-defined body parts (head,
thorax, and abdomen), three pairs of legs, and usually one or two pairs of wings
Arachnids- terrestrial invertebrates (arthropods like spiders, scorpions, mites, and ticks)
with 2 segments to their body and four pairs of legs but no antennae
Crustaceans- aquatic arthropods with an exoskeleton or shell, a pair of appendages on
each segment, and two pairs of antennae (like lobsters, shrimps, crabs, and barnacles)
All Taxa Biodiversity Inventory (ATBI)- a project of Discover Life in America (DLIA),
seeks to list and describe the estimated 100,000 species of living organisms in Great
Smoky Mountains National Park. For more information click on www.dlia.org
Leaf litter sifter- a tool used to collect, or strain, insects shaken out of the forest leaf litter.
The students in the photo are using an aspirator to collect very small invertebrates they
found using a leaf litter sifter.
Aspirator- a tool used to collect insects by sucking them into a vial through a tube. The
student in the photo is using an aspirator to collect spiders during a visual search.
Beat sheet- a piece of light colored material used to collect insects that have been shaken
from brush or low tree branches, a white umbrella or sheet placed under a plant makes a
good beat sheet.
Berlese funnel- a tool used to collect insects out of leaf litter using the heat from a lamp.
Bugs try to move downward away from the heat and end up falling into a collecting jar or
bucket. For directions on how to make and use a Berlese funnel, click on
http://www.cals.ncsu.edu/course/ent591k/berlese.html
http://www.albany.edu/natweb/berlese.html
Symbiotic relationship- two dissimilar organisms living together in a mutually beneficial
relationship, they each help each other survive
Balsam Woolly Adelgid- an insect pest that infests and kills stands of Fraser fir in the
spruce-fir zone. Before the arrival of the Balsam Woolly Adelgid, the Fraser fir was the
dominant tree at elevations over 6,000 feet in the Southern Appalachians. The adelgid
was introduced on trees imported from Europe, and the fir has little natural defense
against it. By injecting the tree with toxins through its bark, the adelgid blocks the path of
nutrients through the tree. The trees literally starve to death, and thousands of dead snags
are all that are left on the highest mountain peaks.
Hemlock Woolly Adelgid- a tiny exotic invasive species that gets its name from it’s
woolly white protective covering and because its host is the hemlock tree. Adults, as well
as the nymphs, suck sap from young twigs on hemlock trees and cause the hemlock
needles to dry out and drop, eventually killing the trees. Great Smoky Mountains
National Park is currently involved in an aggressive attempt to manage this invasive
exotic pest using several methods. For more information, click on
www.saveourhemlocks.org
Pseudoscymnus tsugae (Pt beetle)- a beetle species known to feed only on the hemlock
woolly adelgid and is used as a biological control measure for the hemlock woolly
adelgid. For more information, click on
www.saveourhemlocks.org/features/feature1.shtml
This drawing is of a species of moth that was determined to be new to science. It was
discovered in a high elevation forest in Great Smoky Mountains National Park.
The graphic below links to ATBI in the main text
National Park Service
Great Smoky Mountains National Park
Invertebrates
Non-Vascular Plants / Fungi
Vascular Plants
Vertebrates
Known
Estimated Unknown
Red shows how many of each group researchers estimate are unknown in Great Smokies
Mountains National Park. The size of the circle relates to how common the group is in
the park as compared to the other groups.
The photo below is a millipede that had not been previously seen in the Park so it is
considered a new park record.