Water Quality Macroinvertebrates and Fauna Science Olympiad 2018-2019

Mayfly - Adult

Class 1 pollution sensitive. Also known as shadflies or fishflies in Canada and the upper Midwestern U.S. Over 3,000 species are known worldwide, grouped into over 400 genera in 42 families. They may live for several years in the water. They have an elongated, cylindrical or somewhat flattened body and vary in length, depending on species, from 0.12 to 1.18 in.Adult mayflies, or imagos, are relatively primitive in structure, exhibiting traits that were probably present in the first flying insects. These include long tails and wings that do not fold flat over the abdomen. Mayflies are delicate-looking insects with one or two pairs of membranous, triangular wings, which are extensively covered with veins. At rest, the wings are held upright, like those of a butterfly

Incomplete metamorphosis - larval development can last 3 months to 3 years

• Nymphs have 3 tail filaments - occasionally 2 tail filaments - never paddle or fan-like

• Color of nymph can be green brown, gray but usually black

• Nymphs are flattened to reduce the force of fast currents

• Nymphs are collector-gathers or scrapers - small plant and animal debris as algae, diatoms & plankton- they are found on underside of rocks

• Nymphs are a high proportion of the diet of many fish

• Adults do not eat

Caddisfly - adult

Class 1 pollution sensitive. Adult caddisfly is medium-sized insect with membranous, hairy wings, which are held in a tent-wise fashion when insect is at rest. The antennae are fairly long. They are models for artificial fishing flies for fly fishing in trout streams. Useful as bioindicators (of good water quality), since they are sensitive to water pollution, and are large enough to be assessed conveniently in the field. Together with stoneflies and mayflies, they feature importantly in bioassessment surveys of streams and other water bodies. Most adults have short lives during which they do not feed.

Caddisfly - Larva or immature

Class 1 pollution sensitive. Most early stage larvae and some late stage ones are collector-gatherers, picking up fragments of organic matter from the benthos. The predatory species either actively hunt their prey, typically other insects, tiny crustaceans and worms, or lie in wait for them to come too close. They are an indicator of good water quality; they die out of streams with polluted waters. They are an important part of the food web, both larvae and adults being eaten by many fish. Caddisflies are best known for the portable cases created by their larvae. The case is a tubular structure made of silk.

Dobsonfly - Adult

Class 1 Pollution sensitive. The nine genera of dobsonflies are distributed in the Americas, Asia, and S. Africa. Those in the US and Canada have a wingspan of up to 7.1 in. The Asian Acanthacorydalis fruhstorferi can have a wingspan of up to 8.5 in, making it the largest aquatic insect in the world by this measurement. The wings vary from grayish to translucent, and the anal region of the hindwing is wide and folded at rest. Despite the large wings, adults are weak, fluttery fliers and only live up to 7 days. The body is soft and color varies from yellow to dark brown. They are intolerant of polluted waters and are potential indicators of water quality. They are attracted by an additive in natural gas and propane, and may behave as an animal sentinel in the presence of these gasses.

Dobsonfly - Larva or immature

The larvae (commonly called hellgrammites) are aquatic, living in streams. They bear eight pairs of lateral legs as well as anal prolegs with a pair of terminal hooks. At the end of the abdomen is a pair of claw-like structures. They are some of the largest larvae and are most often found in clean rivers with rocky bottoms, near soft rotting logs or stumps.

The larvae are carnivorous predators and may bite; the mouth has large chewing pinchers. Body color is black or dark brown. The larvae live for up to five years.

stonefly

• Incomplete metamorphosis

• Eggs are laid in the water or are placed in cracks near the water's edge.

• Nymphs hatch in early spring. Have two tails & no gills visible on the abdomen - also 2 tarsal claws

• Nymphs usually live beneath stones in fast-moving, clean water.

• They feed on algae, lichens, and rotting vegetation.

• As they grow the nymphs molt

Some take a year to become adults, some take two years.

• Adults emerge near the edge of the stream, sometimes when the ice has just melted.

• They are not active fliers, usually remain near the ground.

• Many adults do not have functional mouth, so they cannot eat and they live only a short time

• Adults are found near the streams and rivers from which they emerged.

gilled snail

• Rely on oxygen in the water for respiration

• Have gills for breathing

• Shell is made of calcium carbonate

• Soft body inside a hard, spiral shaped shell

• Plate-like door (called the operculum) protects the opening of the shell

• Shells usually open on the right side

• They are grazers found on a variety of substrates

water penny

• Complete metamorphosis

• The water penny is the aquatic larva of a beetle

• The body is often stuck flat to surfaces as rocks and other flat substrates and looks like a tiny round leaf

• Larva is green, brown, black, or tan

• Segmented plate-like covering on larva

• Six tiny segmented legs beneath the round body

• Larva eat plant debris as algae and diatoms

• The adult of the species is not aquatic but found above water on rocks in riffles - resembles extremely large riffle beetle

riffle beetle

• Complete metamorphosis

• Larvae body is long, stiff, and segmented (up to ¾ ")

• Larvae resemble small "torpedoes"

• Six segmented legs on upper middle section of larvae

• Back end of larva has two tiny hooks and short hairs

• Adults have small oval body only about ¼" long

• Adult are aquatic and walks very slowly under water on the bottom

• Adults found more often than larva - live longer in water

• Eat primarily plant material such as algae and diatoms

• Larvae body is long, stiff, and segmented

• Six segmented legs on upper middle section of larvae

• Back end of larva has two tiny hooks and short hairs

• Adults have small oval body only about ¼" long

• Adults have only one pair of antennae

• Adults found more often than larva - live longer in water

• Eat primarily plant material such as algae and diatoms

water scorpion

• Incomplete metamorphosis

• Resemble elongated sticks with slender elongated bodies and long breathing tubes to take in oxygen from air as they move on surface of water

• Not good swimmers - move very slowly

• They hang head down from twigs and weeds

• Aquatic predators - grab the prey, hold it with their front legs and seem to suck the juices out of the victim, until its body is limp and shriveled.

• Adult is also aquatic predator

aquatic sowbug

• Crustacean and isopod

• Can be found on substrates or overhanging vegetation tend to crawl along surface

• Omnivorous

• Have 7 pr. of legs, 2 pr. antennae - one much longer than the other

• Similar in appearance to terrestrial sowbugs or "roly-polys"

damselfly

• Incomplete metamorphosis

• Nymphs have slender bodies with 3 long tail-like gills

• Nymphs have no abdominal gills and tail

• Long legs are close to the head

• Large compound eyes and extendable jaws fold under the head - very good vision

• Nymphs found among stones and in leaf litter at bottom

• Nymphs are predators and feed on other macroinvertebrates in the water - may also be cannibals

• Nymphs have 10 to 12 stages of development to become adults

• Adults have long abdomens, 2 pr. wings held upright, and are very colorful - reds, greens and blues

• Wings are held vertical when at rest

• Adults use their hind legs covered with hairs to capture prey

dragonfly

• Incomplete metamorphosis

• Most nymphs have oval and flattened robust, elongated bodies or spider-like bodies -

• Nymphs are usually grey, brown or green

• Often have algae growing on their backs

• Nymphs have large eyes, are predators

• Feed on aquatic macroinvertebrates, small fish and tadpoles

• 6 legs and a pair of small wings may be seen developing on the back

• Adults similar to adult damselflies but the 2 pr. of wings are flat or horizontal when at rest rather than vertical as the damselflies

• Adults are agile predators eating mainly other insects-eating food equal to its own weight in 30 minutes

scuds

• Are tiny Crustacean Amphipods

• Sometimes called freshwater shrimp

• Are laterally compressed - side swimmers

• Have 2 pr. antennae and 7 pr. of legs

• Found in shallow water near overhanging vegetation

• Stay close to bottom - use it to hide from predators

• Predators include tadpoles, aquatic insects, small fish

• Do not like light and are active at night

• Filtering collector scavengers - eat dead plant and animal matter

• Help keep water clean by eating dead decaying material

• Primary food source for many varieties of fish including trout

• After mating, eggs are held by the female in a sac until they hatch

cranefly

• Complete metamorphosis

• Larvae are worm-like with thick skinned segmented body - somewhat transparent with digestive tract visible- may be greenish or grayish

• Larvae are rounded at one end and disc like spiracles at the other end

• Larvae are shredders - eat plants and plant debris some are predators

• Adults nicknamed giant mosquitoes with long legs

but are do not bite humans

• Adults normally do not eat and live only long enough to mate - are food for birds, spiders and some carnivorous plants

• Females deposit eggs on submerged vegetation and other debris

water mite

• Small Arachnids

• Have a complex life cycle - egg, larva, nymph and adult

• Female attaches fertilized eggs to submerged plants

• Larvae hatch with only 6 legs

• Larva are usually parasitic on aquatic insects

• Nymphs called deutonymph resemble adults with 8 legs but are sexually immature

• Deutonymphs feed on aquatic insects, crustaceans, and other mites, and grows in size as it feeds

• Adults- round or globular with 8 legs.

• Bright red is common, but can be green, blue, orange, yellow, brown or black.

• Found in shallow water (1-2 meters beneath the water surface)

• Adults - mostly piercer-predators preying on insect and fish eggs, insect larva, dead organisms and bivalves

• Water Mites are food for a wide variety of aquatic invertebrates

midge

• Complete Metamorphosis

• Eggs laid in a mass on surface of water in a gelatinous substance

• Larvae are cylindrical, thin, soft, and often curled with anterior and posterior prologs and hardened head capsule

• Larvae burrow in the mud and use salivary secretions to bind substrate particles into tubes or tunnels in which they live

• Larvae feed on suspended matter in water and organic matter in the mud - gathering collector

• After the first molt, most take on a pink color then turn into a deep red in low oxygen conditions

• Larva turn into pupa and remain for about 3 days

• Adults usually swarm at night to mate and do not feed. They live only 3-5 days.

• Adults sometimes nicknamed "Blind Mosquitoes"

blackfly

• Complete metamorphosis (true fly)

• Eggs are deposited in shallow, fast-running water on suspended objects as rocks, leaves, or vegetation

• Larvae have brush-like mouthpart that collect tiny organisms or organic matter like a sieve out of water - collectors/filterers

• Larvae tend to stay attached to substrate by producing a silk thread to adhere- tiny hooks on the abdomen help to attach

• Pupa usually found on downstream side of rocks or aquatic vegetation where current is slower

• Adults emerge at the same time in large numbers

• Adults - many females require a special diet for egg maturation

• Adult females are blood-feeders and can be very aggressive - not all adults feed on human targets - most prefer other hosts

• Adult females can also transmit blood and skin parasites between mammals

flatworm

• Complete metamorphosis (true fly)

• Eggs are deposited in shallow, fast-running water on suspended objects as rocks, leaves, or vegetation

• Larvae have brush-like mouthpart that collect tiny organisms or organic matter like a sieve out of water - collectors/filterers

• Larvae tend to stay attached to substrate by producing a silk thread to adhere- tiny hooks on the abdomen help to attach

• Pupa usually found on downstream side of rocks or aquatic vegetation where current is slower

• Adults emerge at the same time in large numbers

• Adults - many females require a special diet for egg maturation

• Adult females are blood-feeders and can be very aggressive - not all adults feed on human targets - most prefer other hosts

• Adult females can also transmit blood and skin parasites between mammals

leeches

• Annelids

• Segmented, flattened and a sucker on both ends of the body

• Tan to brown in color

• Found in areas high in organic debris or mud in shallow, still water (ponds)

• Active at night

• Can be carnivores, detritivores, but mostly external parasites

• Free-living detritovores hid under stones or other objects and eat decomposing organic matter

• Predatory leeches eat frequently

• Parasitic species feed on host sucking blood from the host - releasing an anesthetic

lunged snail

• Left opening with no plate-like covering (operculum) over opening

• Respire via lungs so they are not dependent on dissolved oxygen in the water

• Found grazing on a variety of substrates

• Grazers

deer/ horse fly

• Complete metamorphosis (true fly)

• Larva are caterpillar-like and segmented

• Larva body is tapered on both ends with no appendages

• Usually milky, light brown or greenish with digestive tract often visible

• Larvae are predators, collectors and can be cannibalistic - usually eat small organisms as aquatic insects and other small invertebrates

• Larva found under rocks, overhanging vegetation, or in leaf-pack

• Adults emerge from pupa state, are good fliers, and immediately start mating with males and females feeding on nectar

• Females feed on blood and develop eggs

• Most species have only one generation per year

tubifex

• aquatic annelids

• slender segmented worms - resemble slender earthworms

• color can be reddish, brown or gray

• often found in clumps in large numbers indicate poor water quality

• found in mud bottoms

• eat large quantities of mud and filter organic matter from it

• serve as food for fish and other bottom feeders

• reproduce similar to earthworms - hermaphroditic and a cocoon serves during fertilization and development of embryos

blood midge

• Complete metamorphosis

• Larva of the Midge

• Midge Larva turn blood red under low oxygen conditions

• Contain a substance similar to haemoglobin which holds oxygen absorbed through gills at the base of the body

• Eat dead plant and animal matter (detritus)

• Serve as food for fish, water mites and insect larvae

whirligig beetle

• Complete metamorphosis -see similar life cycle under predacious diving beetle

• Larvae stay at the bottom and feed on microbes and plant matter

• Adults normally live on the surface of a "gentle" ponds or lakes

• Adults have short antennae and forelegs that are very long and mid and hind legs that are short and paddle-like

• Adults are oval-shaped and dark with a metallic sheen

• Adults are capable of trapping air bubbles so that they can submerge.

• Adults prey on insects and other creatures that fall on the water surface.

• Common name for adults comes from their habit of swimming rapidly in circles when alarmed.

• Divided eyes in adults allow them to can see both above and below water

• The adults are often found in groups to avoid predators

water strider

Water Strider

• Incomplete metamorphosis (True bug) - see bug life cycle under Giant Water Bug

• Known to skate on the water surface (special adaptations that enable them to remain suspended on the surface film)

• Breathe from the atmosphere (when they occasionally dive or submerged, they trap air in the fine, water resistant hairs that cover their bodies

• Short, raptorial front legs to grasp their prey on the water surface (piercer-predator)

• A predator on other insects

• The front pair of legs is adapted for grasping prey

mosquito

• Complete metamorphosis

• Most lay eggs on surface of water as an egg raft but some species eggs are single

• Most eggs hatch within 48 hours

• Larvae are nicknamed "wigglers" or "wrigglers"

• Larvae stay near the water surface for feeding and breathing (collector-filterers or collector-gatherers)

• Larvae have siphon tubes for breathing and hang from the surface of the water

• larvae can live in almost every type of still-water habitat

• On the 4th molt the larva turns into a pupa

• Pupal stage is a resting, non-feeding stage where the adult develops

• Pupa takes in oxygen through two breathing tubes "trumpets"

• Males feed only on plant juices

• Only females bite humans and other animals using blood to allow her to develop eggs

• Female inserts its proboscis and probes for blood vessels where it injects saliva into the wound

• The saliva has an anticoagulant but also may contain pathogens such as malaria parasites or encephalitis viruses depending upon the type and habitat.

giant water bug

• Incomplete metamorphosis (True Bug)

• Female deposit their eggs on the backs of males, which carry them until they hatch (common with other surface swimming water bugs as water boatman, backswimmer, and water strider)

• Mostly inhabit ponds, edges of lakes, and pools of streams

• Nymphs molt several times before reaching adult

• Nymphs receive oxygen through their skin in pockets at the tip of the abdomen

• Adults breath air from the surface of the water

Adults will inflict a painful bite with their beak in defense if they are handled carelessly.

• Nymphs and adults are fierce predators - inject chemicals that kill prey and dissolve internal parts of prey - feeding on tadpoles, small fish, salamanders and small frogs

• Front legs are greatly widened and elbowed for grabbing and holding prey. (piercer-predators)

• May be up to 3 inches long

backswimmer

• Incomplete metamorphosis (True Bug) - see bug life cycle under Giant Water Bug

• Swims on its back paddling with long fringed hind legs

• Back is convex with wings white or lightly colored with cross striations - can have green, brown or yellowish color (wings are lighter than the body area)

• Nymphs of water bugs molt several times before reaching adult

• Nymphs receive oxygen through their skin in pockets at the tip of the abdomen

• Adults breath air from the surface of the water

• Nymphs and adults are predators and attack prey as aquatic insects up to large as tadpoles and small fish

• Can inflict painful bite even to humans

• Adults are also good fliers with well developed wings - attracted to lights and may invade home swimming pools

water boatman

• Incomplete metamorphosis (True Bug)

• Adult swims upright - back is dark

• Grayish, elongated oval body with large eyes

• Paddle along surface of water with oar-like back legs

• Nymphs of water boatman molt five times before reaching adult

• Nymphs receive oxygen through their skin in pockets at the tip of the abdomen

• Adults breath air from the surface of the water

• Can carry air bubble on body surface or under wings while they are under water

• Most species are herbivorous - living on algae and plant matter

• They live in clusters or groups - adults can fly

• Unlike other aquatic buds, they do not bite humans

predacious diving beetle

• Complete metamorphosis

• Live in ponds, lakes and slow-moving streams

• Larvae are predators

• Adults are black or brown; some with markings

• Adults come to water surface to get oxygen from air

• Eat tadpoles and small fish

• Are food for fish, frogs, water spiders