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See
a photo album of all insects in this article.
Biodiversity and the ecological roles
of insects
 Insects are the most diverse and abundant of all terrestrial animals.
A full listing of the Lakeshore Nature Preserve's inhabitants has never
been tabulated, but it is safe to say that the number of insect species
is larger than all other groups combined.
Insects play crucial roles in ecosystem functioning. As pollinators,
they contribute to the reproduction of most flowering plants. Insects
are often the first decomposers of dead plants and animals, and introduce
microorganisms that continue this process and release nutrients for new
plant growth. Insects serve as food for other animals, such as fish, birds,
and amphibians.
None of the ecosystems represented at the Lakeshore Nature Preserve could
exist in their current form without insects. Insects often have very specialized
requirements, so each species is typically found within a particular microsite,
such as in the soil, under bark, or along the underside leaf veins of
a particular tree species. Each also has a specific rhythm as to time
of year and day when they are most active.
Article sections:
Types of insects you can find at the Lakeshore Nature
Preserve
Aquatic insects
 The
lakeshore environment attracts a number of unique insect orders that require
water to complete their life cycles. Both dragonflies (2.1)
and damselflies (2.3) and (2.4) have aquatic immature stages. Adult
(2.2 at right) and immature dragonflies feed on small insects including
mosquitoes.
Many other insect orders require water to develop. You can expect to
find mayflies (Ephemeroptera), dobsonflies and fishflies
(Megaloptera), and caddisflies (Trichoptera) near the lake. Some members
of the true flies, beetles, and true bugs also have aquatic or semi-aquatic
species. If you paddle along the lakeshore, damselflies will often land
on your boat, and dragonflies will swoop by while mating in flight.
 Orthoptera
Many species of the Orthoptera create sounds that are synonymous with
summer evenings. These insects produce sound by rubbing a "file and
scraper" together on the front edges of their forewings. Most species
have well developed rear legs that are used for jumping. The katydids (3.2) are large, green long-horned grasshoppers with long antennae. Males
have a raspy call that can be heard in trees during late summer evenings.
A recent study has identified 70 species of short-horned grasshoppers (3.1) in the state. Snowy tree crickets and field crickets can also be
found on the lakeshore property.
Hemiptera
The
order Hemiptera includes many common insects with sucking mouthparts.
The rise and diversification of this order in Earth's history coincides
with that of the vascular plants. Thus, most species, like aphids (4.1),
scale insects, leafhoppers (4.2), and spittlebugs (4.3)
feed on plant sap. Some aphids are commonly seen with ants that protect
them in return for honeydew, a sticky, watery, sugar-rich excretory product
most aphids produce abundantly. Immature cicadas (8.4) dwell underground,
feeding on plant sap obtained through the plant root system;  adults (4.4)
are arboreal and make the sometimes nearly deafening "buzzing" sounds
often heard in mid- and late summer.
One of the suborders of Hemiptera is the Heteroptera,
or "true
bugs".
Most members of this large and common suborder, like the stink bugs (4.5
at right, 4.6) produce smelly defensive chemicals through "scent glands".
The black and orange milkweed bugs (4.7) commonly seen on milkweeds and
on milkweed pods in late summer and fall feeding on the endosperm of milkweed
seeds with their sucking mouthparts. Another late summer member of this
group, the yellow and black ambush bug, is common on
goldenrod and similarly colored flowers, where it is well camouflaged
in stalking prey. Some common aquatic bugs include the water boatmen,
back swimmers, giant water bugs, and the very familiar water striders that
skate across the water surface.
Beetles (Coleoptera)
 The four largest and most diverse groups are the beetles, wasps, moths
and butterflies, and flies. Beetles (Order Coleoptera) represent the largest
order of insects, or anything else for that matter. Some 350,000 species
have been named, and it is estimated as many as a million or more are
still to be discovered and formally named.
To better comprehend such vast
numbers, beetle diversity (species richness) is approximately equal
to the total number of plant species in the world, or one-quarter
of all animal species. Beetles comprise 40% of all insect species,
about 60 times the total number of vertebrate species, and nearly 90 times
the number of all mammal species on Earth.
Incredibly, the weevils and bark beetles, the single
largest beetle family, boast nearly 65,000 species. Beetle success has
been due largely to their ability to occupy a wide array of ecological
niches: aquatic, terrestrial, predatory (like most ladybird beetles: 5.1),
parasitic, plant- and fungus-feeding. Some of the microhabitats they occupy
are extremely specialized. This ability has probably been enhanced by
their generally compact, heavily armored bodies.
Some additional groups of familiar beetle
families with immense numbers of species include the ground beetles,
rove beetles, scarab beetles - like the common hermit
flower beetle (5.2),
metallic wood-boring beetles, click beetles, fireflies, soldier beetles,
darkling beetles, long-horned wood-boring beetles (5.3 at right, 5.4,
6.2), and leaf beetles.
Hymenoptera (wasps, ants, and bees)
Wasps, ants, and bees comprise a very diverse order (Hymenoptera), and
include some of the insects with which we come into most frequent contact.
 One of the most frequently encountered groups includes the yellow jackets
and hornets (8.1). Although they may seem frightening, they only sting
when threatened. These are highly social insects, with sophisticated division
of labor. They begin founding their nests in the spring, and populations
become highest in late summer. These insects play a valuable role as predators
of plant-eating insects.
Bees are among the most important pollinators. For example, bumble bees
(8.2) are the major pollinators of many prairie plants, and so serve as
an important component of prairie restoration.
Perhaps
the least familiar but most diverse group are the parasitic
wasps. The
females insert their eggs into another insect. The larvae then emerge
inside their food supply and eat their way out, killing the host. There
are parasites of almost all insect groups, regardless of how protected
their habitat may seem (8.3 Ichneumon wasp at right).
Parasitic wasps
play a crucial role in biological control and organic farming. Without
them, the Eagle Heights Gardens would be under constant pressure from
plant-eating insects!
See a photo album of all insects in this
article.
Lepidoptera
Moths and butterflies (Lepidoptera) have a fine
powder-like scaling on their wings (7.1) that gives them colorful markings
and makes them "living
jewels." There are over 150 species of butterflies (7.2, 10.3)
and 10 times that number of species of moths (7.3) in Wisconsin. The
larvae, called caterpillars (7.4), are eating machines that process
2-3 times their weight a day in plant tissue. Most species of plants
have at least one species of Lepidoptera that feed on it. Conversely,
each caterpillar species (7.5) has a limited number of host
plants on
which they can successfully feed. The adults often feed on flower nectar,
but some species are associated with carrion and others do not have
functional mouthparts and need to live on food reserves stored up by
the larvae.
Diptera
The Diptera, or "true flies," are unique.
As their ordinal name, Di (= two) + -ptera (= wings) implies, adult flies
have a single pair of wings, whereas most other flying insects  are
equipped with two pairs. Nonetheless, members of this group are among
the fastest and most acrobatic fliers in the insect world. This has been
achieved in part by the evolution of "halteres." Originally
serving as hind wings, these structures have become highly modified through
time into exceedingly complex and delicate balancing organs.
Flies
have sucking mouthparts and these generally take the form piercing stylets,
such as in blood-feeding individuals like female mosquitoes, deer flies,
and black flies or as in predatory flies, such as the robber
flies (6.1
at right). Other flies take in fluids by means of a "sponging" or "lapping" mouthpart
modification, such as the house flies and many of their relatives (6.2
in the photo album showing a fly as well as a long-horned beetle that
mimics an ant).
Some of the first insects you see flying in the early spring are midges.
These form mating swarms, in which they use almost any object, including
you, as a focal point for getting together. They are often mistaken for
mosquitoes, but do not bite.
Spiders and more
In addition to insects, there are many types of spiders,
millipedes, centipedes, and mites that you can observe.
Spiders are predators; some use webs to snare prey (11.1), while others
lie in ambush in places insects visit (11.3). Spiders often tend to their
egg masses (11.2) instead of leaving the eggs. Millipedes and centipedes
might look the same but do differ. Millipedes have more than one leg pair
per segment while centipedes have only one pair per segment. As for lifestyle,
millipedes are typically scavengers while centipedes are predators.
Insect signs
 There are many occasions when you may not see the insect itself, but
will rather see signs of it. Such signs can be quite useful in determining
exactly what insect was here and what it was doing.
For example, you may
see the insects nest, as with the yellow jacket (see 8.1 in the photo
album). Other insects such as bark beetles and wood borers leave
galleries behind as they tunnel through wood. Sometimes insects leave
behind evidence of their earlier life stages, such as the cocoons of moths
and butterflies, or a cast skin, as with cicadas (8.4).
One sign that you might not immediately recognize as being of insect
origin is a plant gall (9.1 at right, 9.2, 9.3). These are caused by insects
and mites that stimulate abnormal plant growth, and then use this new
structure for shelter—genetic engineering at its finest! Most are
quite recognizable by their shape and color.
How insects spend the winter in the Lakeshore Nature
Preserve
What happens to insects during the winter months? A handful of species
like the common monarch butterfly (10.1 below and 10.2)
and potato leafhopper do not overwinter here. However, the vast majority
remain here year around.
 Yes, most of our insect fauna spends these months in a metabolically
inactive manner, just like a number of the vertebrate species with which
most of us are more familiar. But, should you venture out for a nice,
crisp winter's hike in a snow-covered forest, especially on a relatively
sunny day, take an insect's eye view of the landscape around you.
You
might come upon a depression in the snow made by some woodland vertebrate—or
another hiker—that upon close examination literally "springs" up
at you with very tiny jumpers. These are called springtails (Class and
Order Collembola), or "snowfleas". These 6-legged, near-insect
relatives are incredibly abundant year around, mostly feeding as decomposers.
But during the winter, with a wee bit of "tracking snow" these
tiny specks are actually easier to spot than during other times of the
year. The best time to see them is after a fresh snowfall on a sunny day.
You could also happen upon some bizarre, wingless winter
crane flies (Order Diptera, family Tipulidae, genus Chionia), or perhaps an even less
commonly encountered winter scorpionfly (Order Mecoptera, family Boreidae,
genus Boreus). On an even more mellow evening during a mid- or late-winter
thaw, it is even quite possible to see butterflies, moths, and certain
other insects like leafhoppers, flies, beetles, and many spiders (arthropod
relatives to the insects) checking out their haunts.
Unwanted invaders
Many insects have been accidentally, or in some cases deliberately, introduced
from one region to another. These insects often cause problems in the
new area, because their major predators and parasites remain behind, or
because local plants have not evolved resistance to them.
 The
Lakeshore Nature Preserve is threatened by a variety of alien insects,
each of which causes its own set of problems and affects specific areas.
Some of the most damaging insects threatening the wooded areas are the
gypsy moth (12.2 at right), a leaf feeder on deciduous
trees, and the smaller European
elm bark beetle, a vector of the fungus that causes Dutch
Elm Disease.
We are particularly wary of a new pest, the emerald
ash borer (12.1). It has killed millions of ash trees in neighboring
states, and could strongly affect the more bottomland sites in the Preserve.
For those who grow vegetables in the Eagle Heights gardens, the Japanese
beetle is a constant nuisance (8.5).
Some invasive insects cause indirect problems. For example, the multi-colored
Asian lady beetle can be both a nuisance with its early autumn swarms,
and a threat to biodiversity by displacing native species.
 See a photo album of all insects in this
article.
 Read a web article by Jill Feldcamp on "An overlooked insect: the dragonfly"
A great resource for people wishing to learn more about insects is http://www.insects.org/ .
Text and Photo credits:
- Article version 1b, Oct 28, 2006 by Ken Raffa,
Dan Young, and Phil Pellitteri,
Univeristy of Wisconsin-Madison.
- Photographs 2.1 to 8.5, 10.1 to 11.3 by Glenda
Denniston
- Photographs 9.1,
9.2, and 9.3 by Phil Pellitteri
- Photograph 12.1 by William Cronon
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