Iowa Invertebrates
More
than 97% of the animal species on Earth are invertebrates. Invertebrates are
small animals that do not have backbones. There are many types of
invertebrates, from fluid-filled jellyfish, and squishy earthworms to hard
shelled insects like beetles, and eight-legged arachnids. This fascinating and
diverse group of animals spans the globe – invertebrates live on every
continent and in every body of water!
BrainPOP:
Invertebrates
Science
for Kids: Invertebrates Poem
Creature Feature – Water
Scorpion
Water
scorpions are not really scorpions - they're insects! Their name comes from the fact they look slightly like a real scorpion. Water scorpions have grasping forelimbs which look similar to real scorpion's pincers, and they have an elongated “tail” (actually a breathing tube) which looks similar to a real scorpion's tail.
Water
scorpions are aquatic and live in ponds and streams in Iowa. They are slender and may resemble a stick. They grow to about 1 ½ inches in length. They hang upside
down at the water surface and use their long tube at the tip of their abdomen
(their “tail”) to breathe air. They are
brown to tan in color. Another name for them is “water stick insects”.
Water
scorpions are predatory and eat other insects which they catch with their
grasping front legs. They ambush prey to catch them. Once caught they suck out
their insides using their piercing mouth parts. They
eat insect larvae, water fleas, water lice, and water worms. Water scorpions
can inflict a painful bite so handle with care.
Mating
occurs in spring and the female lays eggs on aquatic plants just below the
water surface. The eggs hatch in 3 to 4 weeks. Water scorpions undergo a type
of development known as incomplete metamorphosis. Incomplete metamorphosis
means the young go through several molts (shedding of the hard exoskeleton), their appearance is similar to
adults, and they do not have a pupal stage. The young develop into full-grown adults
after 6 to 8 weeks.
National
Geographic: Water Scorpions
Water
Scorpion Facts
Water Quality and Aquatic Insects
Aquatic
insects are good indicators of water quality in a water body. Some insect
species can tolerate a high level of pollutants in the water while other
species cannot. By examining the species of aquatic insect larva within a water
body you can estimate the water quality. For example, stonefly nymphs are very
sensitive to most pollutants and their presence in a stream indicates a very
healthy water system.
For more
information about insects as indicators of water quality visit:
Aquatic
Macroinvertebrates
Aquatic
Insects and Water Quality in the Watershed
For
factsheets, activity sheets and MORE visit:
IDNR: Education – Classroom
Resources (go to the Document Library at the bottom of the page for fact sheets
and activity sheets!)
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