What do you do when you find an unknown invertebrate?

a) squish itb) call Homeland Security Departmentc) use a dichotomous key to identify it

Annelida: Oligochaeta

Hermaphroditic; sexual and asexual reproduction. Usually paratomy (budding), also create cocoons filled with embryos.

Wide spread, many habitats and trophic levels

Some spp used as pollution indicators- very tolerant

Bioturbators

http://www.inhs.uiuc.edu/~sjtaylor/cave/oligochaeta.html

Bilaterally symmetrical

Segmented coelomates, each segment w/ chaetae (little hairs/bristles)

Annelida: Hirudinea (leaches)

Dorsoventrally flattened & segmented

Mouth surrounded by oral sucker, feeding modes range from parasites, scavengers and predators

Only 2 common U.S. genera that attack humans; sufficient blood taken so that leach may be 5 times original mass http://www.nanfa.org/akiweb/658.JPG

Used to support large industry in Europe during 18th and 19th centuries for medicinal purposes

Hirudo medicinalis raised in ponds in large numbers (has been introduced to NA several times but unsuccessful)

http://www.nytimes.com/2006/02/07/science/07leec.html

Famous invertebrates from Hollywood!

http://images.google.com/imgres?imgurl=http://test.dnr.nsw.gov.au/care/wetlands/facts/paa/invertebrates/images/water_mite_eylais.jpg&imgrefurl=http://test.dnr.nsw.gov.au/care/wetlands/facts/paa/invertebrates/watermites_aquaticspiders.html&h=338&w=400&sz=20&hl=en&start=14&sig2=eKOanf2HjZpwetS9dOHqEA&tbnid=Mqsx3hWcSPtdEM:&tbnh=105&tbnw=124&ei=OQEiR5adKaeceMq70KIC&prev=/images%3Fq%3Dwater%2Bmite%26gbv%3D2%26svnum%3D10%26hl%3Den

Arachnida: Hydrachnidia, water mites

Look like tiny spiders, 6 legs

Most carnivorous or parasitic

Separate males and females

Can be very abundant in weedy areas, usually found in shallow waters

Beautiful colors (fade w/ preservative)

Hard to identify

Phylum Mollusca(Life in a shell)

>100,000 spp.

Gastropods-snails & slugs

Bivalves- clams/mussels

Cephalopoda (squids, octapus, cuttlefish, nautilus- marine)

Higher taxonomy messy

You name it, some gastropod does it

70% of all mollusks

marine, freshwater and terrestrial habitats.

About 500 species in the freshwaters of North America, north of Mexico:

350 prosobranchs (derived from marine)gill (ctenidium)operculum

150 pulmonates (derived from terrestrial)lung=modified mantel cavity

Campeloma decisum

Valvata bicarinata

http://members.aol.com/mkohl1/FWshells.html =picture source

Physella/Physa spp.

Consider a snail & leech of about same tissue mass.

What is the primary physical diff between them?

How does this diff affect their predators & where they live.

What affects their habitat choice more- trophic level or potential predators?

Bivalves

NA bivalve fauna most diverse in word

Unionoidea ~278 spp

Corbiculacea 36 native and 4 introduced

Dreissenoidea 2 spp (zebra and quagga mussels)(more later)

sup

erfa

mil

ies

Mucket

Crustaceans

Specious, abundant and ecologically important

>35,000 species mostly marine, some fw & terrestrial -anatomically diverse--fused segments or specialized appendages -important trophic component of many systems

Crustaceans have:-2 pairs of antennae-most body segments bear paired, jointed appendages -all crustaceans go through a free nauplius stage or show evidence of an egg-nauplius stage

Crustaceans you should know

Order Anostraca; fairy shrimp

temporary pools or very saline habitats (e.g. brine shrimp: Artemia salina)

swim on backs by beating appendages; also serves to obtain food

either sexual or parthanogenic eggs; make resting eggs that can hatch out when put in water, “sea monkeys”

http://www.cdpr.ca.gov/docs/es/esgifs/fairy.gif

bilateral copulation (e.g. first one side then the other); after mating female sheds anterior half of exoskeleton so that brood chamber plates are functional; fertilized eggs and young stay in brood chamber, young find their way out the posterior end by trial and error. http://www.iii.to.cnr.it/limnol/bentos/foto/Asellus_aquaticus.jpg

Order Isopoda (aquatic sow bugs)

most spp. marine or terrestrial; 130 f.w. spp. in N.A. flattened dorsoventrallyscavengersmales carry females before mating, waiting for preadult exoskeleton shed

Order Amphipoda (superorder Pericarida, scuds)

laterally compressedcrawl or swimrespiration through gillsusually benthic some “dart” into pelagic zone

omnivorous scavangers; will eat dead animals, leaves, organic debris and graze surface films

male carries female until she molts (amplexus), they separate briefly and re-join to copulate, shortly thereafter the female ovulates and oviposits; eggs and developing young reside in the marsupium, young are released at the females next molt

http://www.nativefish.org/Gallery/other/Gammarus-sp..htm

When J. B. S. Haldane, a British geneticist, was asked what his studies of nature revealed about God,

he replied, "An inordinate fondness for beetles."

Fresh water Insects

5 aquatic orders, almost all spp have aquatic larvae

Ephemeroptera TrichopteraOdonata MegalopteraPlecoptera

5 partially aquatic orders, most species are terrestrial, but some spp have aquatic life stages

Heteroptera LepidopteraColeoptera NeuropteraDiptera

Ephemeroptera: mayflies

http://www.waterbugkey.vcsu.edu/php/orderdetails.php?idnum=8

~675 spp

Streams and littoral areas of lakes

Important fish food

Usually 3 caudal filaments

Abdominal gills

Adults do not feed

Females oviposit usually at water surface

Burrowing mayflies (Hexagenia) important species in western Lake Erie

http://www.heidelberg.edu/depts/wtr/krieger.html

Mating swarm near Sandusky River

Collecting females at Windsor

Hexagenia spp.Ecologically Important

– Biological Indicator (sensitive to low oxygen)– Nearly extirpated in 1950’s due to eutrophic

conditions– Populations currently resurging in western Lake

Erie

http://www.grahamowengallery.com/fishing/fly-tying/Hexagenia_limbata-800.jpg

Hexagenia spp.Important food resource for fish

– ~ 20% (annually) of Yellow Perch diets in western Lake Erie (Tyson and Knight, 2001)

– Very large compared to other benthic prey – Hexagenia recolonization may be responsible

for increased growth and recruitment in Yellow Perch

http://www.flyfishusa.com/newsletter/070404/hex-hatch-opener.jpg

Dreissena spp.Ecosystem Engineers

– Dreissena colonizing soft sediments in western Lake Erie

– Results in change the physical structure of the lake bottom

Photo by C. Mayer and P. Bichierhttp://pubs.usgs.gov/fs/FS-036-99/images/tn-OH_fig04.jpg

Small Scale Habitat Selection

• 3 Habitat Types– 1) bare sediment 2) artificial clusters 3) live Dreissena

• 5 mayfly densities; 100 to 1200/m2

• 48 hours• 3 replicates (N=15)

Bare sediment

Artificial Dreissena

Live Dreissena

No structure or food

Structure and food

Structure only

Hexagenia select for live Dreissena clusters

0%

20%

40%

60%

80%

100%

100 200 400 800 1200

Hexagenia density (number/m2)

% H

ex

age

nia

in h

ab

ita

t

live mussels

artificial clusters

bare sediment

•All 3 habitats significantly different

DeVanna et al. in prep

75% of Hexagenia inhabited high-density Dreissena habitats

0%

10%

20%

30%

40%

50%

0% 25% 50% 100%

% Dreissena coverage

% H

ex

age

nia

in h

ab

ita

t

A

A

BB

DeVanna et al. in prep

Odonata

Anisoptera: dragonfliesZygoptera: damselflies

~434 spp

Most larvae in lentic (lake or slow water) habitats

Larvae large and predatory

Elongate hinged labium

1-6 yrs

http://www.naturewatch.ca/eman/reports/publications/99_montane/odonata/odonatafig06.html

http://www.entomology.umn.edu/museum/links/coursefiles/Odonate%20characters.html

Plecoptera: stoneflies

~614 spp

Most common in fast, cold streams

Larvae predators

2 long tail filaments

Long antennae

Larvae crawl rather than swim

Adults live days to weekshttp://www.weeksbay.org/newsletter/Sum_2003/Pg8_1.htm

http://www.wildscape.com/earrings.asp

Trichoptera: Caddisflies

http://www.nativefish.org/Gallery/other/Caddisfly.htm

~1400 spp

Lotic & lentic

Adults terrestrial and easily identified, but many larvae unknown

Some build silk nets to catch preySome free living predatorsSome build cases

Can be dominant in streams

Many fish feed on larvae

Can have large hatches

http://www.epa.gov/bioindicators/html/caddisflies.html

Corydalidae

http://www.epa.gov/bioindicators/html/photos_invertebrates.html

Megaloptera: fishflies and alderflies

7-8 lateral filaments (O2 uptake) & large mandibles

Can be confused with Coleptera

Adults, large, secretive & terrestrial

Lentic larvae have caudal respiratory tubes

Larvae are predators

5 aquatic orders, almost all spp have aquatic larvae

Ephemeroptera TrichopteraOdonata MegalopteraPlecoptera

5 partially aquatic orders, most species are terrestrial, but some spp have aquatic life stages

Diptera LepidopteraColeoptera NeuropteraHeteroptera

Diptera: flies & midges

Many families and spp

Differ greatly in ecology (habitat – feeding…….)

Only larvae are aquatic Lack segmented thoracic legs

Trophic importance in many systems

Some vectors of disease (e.g. mosquitoes)

http://www.biol.wwu.edu/407/407/Crustaceans.html

Chironomidae: midge larvae (+ 2000 spp)

Very important fish food

Wide range of ecology

http://alpaca.cs.umb.edu/gallery/Aquatic-Invertebrates/tipulidD_thm

Tipulidae: cranefly larvae

http://www.iii.to.cnr.it/limnol/bentos/cauborus.JPG

Chaoboridae: phantom midge larvae

Pelagic predators

Coleoptera: beetles

Only 3% of beetles have aquatic stage (still many spp!)

1450 in NA

Spp w/ aquatic larvae and adults

http://www.ru.ac.za/academic/departments/zooento/Martin/elmidae.html

http://dnr.state.il.us/orep/ecowatch/RIVER/bugs/page1.htm

“water pennies”

Larvae aquatic, adult riparian

http://academic.emporia.edu/aberjame/wetland/wildlife/wild24.jpg

Whiligigg beetles

Adults and larvae aquatic

Heteroptera: true bugs

Gerridae: water striders

http://www.inhs.uiuc.edu/~sjtaylor/gerromorph/striders.html

Aquatic larvae and adult

Predators

Notonectidae: backswimmers

Sucking predators

Creepy!!

http://www.agls.uidaho.edu/ento/SixleggedWonders/insects_of_idaho/hemiptera.htm

http://creatures.ifas.ufl.edu/misc/bugs/belostomatid01.htm

Belostomatidae: giant waterbugs

Voracious predators

Adults can fly

In some spp males carry eggs on back

-Floating plankton: phyto, zoo, sestonstream drift: animal or detritus

-On a surface (moving or still water)plant: low qualityalgae: on sediment, rock, plantanimal: probably hidingdetritus: very low quality, but doesn’t hide, associated microbes = good food

Balance of algae-animal-microbe-detritus affects C:N:P ratio. In general high N & P = good food.

Things zoobenthos can eat: location and quality

Duarte, C.M. 1992. Nutrient concentration of aquatic plants: pattern across species. Limnol & Oceonog 37:882-889

Relatively few benthic inverts eat live macrophytes.Why?

pelagia

So why are the invertebrates in the littoral zone if they don’t eat the plants?

low benthos density & diversity

high benthos density & diversity

See 24.5

Take home points

--Benthos are much more diverse (and interesting ) than zooplankton --Humans tend to study larger size classes--Many different feeding modes--Richness and abundance highest in litoral zones, associated with macrophytes or other structures--Often important energy source to fish