What do you do when you find an unknown invertebrate?

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

~1500 species, size between 0.04 and 2.5 mm~1500 species, size between 0.04 and 2.5 mm Generation time is a few days (temperature dependent)Generation time is a few days (temperature dependent)

Can tolerate lower Water Residence Time than larger Can tolerate lower Water Residence Time than larger zooplanktonzooplankton

Populations respond quickly to an increase in food resources Populations respond quickly to an increase in food resources Most are filter-feedersMost are filter-feeders

Use corona to create feeding currentUse corona to create feeding current A few are predaceous (A few are predaceous (AsplanchnaAsplanchna)) Prey species may exhibit cyclomorphorosisPrey species may exhibit cyclomorphorosis

RotifersRotifers

www.microscopy-uk.org.uk/mag/artfeb02/fresh/freshimg/rotifers.jpg

www.tolweb.org/tree/ToLimages/cava042p.jpg

Corona

cyclot.hp.infoseek.co.jp/wamusi/mituude1.jpg

Asplanchna

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, 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

Branchiopods• Most are filter feeders

– feeding appendages act as electrostatic filters

– Feed on phytoplankton, bacteria, protozoa

• Often the dominant herbivores in lake systems (before zebra mussels)

• Generation time is a few weeks• Some are predators on other

cladocerans and rotifers (Leptodora, Bythotrephes)

www2.biologie.uni-halle.de/zool/dev_biol/lect/pk_lim/limno/Daphnia.jpg

webs.lander.edu/rsfox/rsfoximages3/clad99L_x550_x_643x.gif

www.cof.orst.edu/project/plankton/bos.jpg

/www.internal.eawag.ch/~steiner/Zoo/Bilder

Leptodora

Bosmina

Bythotrephes

• Branchiopods are usually parthenogenetic– Produce eggs (clones) after each molt (~3-30 eggs)

• Sexual reproduction can be triggered by– Low food condition– Decreasing photoperiod– Overcrowding

• Resting eggs are contained in an Ephippium– Can be dried, transported on legs of waterfowl– Eggs from Ephippia buried in sediments can

survive decades

Male Daphnia

First antennae

Ephippium with 2 resting eggs

Copepods

http://www.emporia.edu/biosci/invert/lab6/copnaup1.jpg

centexnaturalist.com

Adult male Adult female Female with egg sacs

Three major groups: Three major groups: CyclopoidaCyclopoida, , Calanoida,Calanoida, (pelagic) and (pelagic) and Harpactocoida Harpactocoida ((benthic)benthic) Always sexual reproduction, near equal numbers of Always sexual reproduction, near equal numbers of

males and femalesmales and females CyclopoidsCyclopoids

Life CycleLife Cycle• Shorter generation time (1-2 months)Shorter generation time (1-2 months)• Eggs hatch asEggs hatch as nauplius nauplius larvae larvae• Several juvenile molts (copepodids) before becoming adultsSeveral juvenile molts (copepodids) before becoming adults• Juvenile stage may enter Juvenile stage may enter diapause diapause in fall and re-activate in the springin fall and re-activate in the spring

Copepods

Adult maleAdult female

www.glerl.noaa.gov

www.sahfos.ac.u www5.pbrc.hawaii.edu

CalanoidsCalanoids Life CycleLife Cycle

• Longer generation time (6 months or more)Longer generation time (6 months or more)• Eggs hatch asEggs hatch as nauplius nauplius larvae larvae• Several juvenile molts (copepodids) before becoming adultsSeveral juvenile molts (copepodids) before becoming adults• No diapauseNo diapause

Avoidance of Predation CyclomorphosisCyclomorphosis

Daphnia and others may grow long helmets and tail spines Daphnia and others may grow long helmets and tail spines (inducible defenses) to help avoid invertebrate predators(inducible defenses) to help avoid invertebrate predators

www.unb.ca

www.nature.com www.esf.edu/efb/schulz/Art.html

CyclomorphosisCyclomorphosis

Why not have long spines and helmets Why not have long spines and helmets allall the time? the time? Energetically expensive, lowers reproductive rateEnergetically expensive, lowers reproductive rate Interferes with feeding in some cases (Bosmina)Interferes with feeding in some cases (Bosmina)

www.ecostudies.org/images www.fbl.ku.dk

Avoidance of PredationAvoidance of Predation Escape TacticsEscape Tactics

Calanoid copepod “jump” reactionCalanoid copepod “jump” reaction• Flex 1Flex 1stst antennae to achieve burst of speed, acceleration up to 30G antennae to achieve burst of speed, acceleration up to 30G

and 100 body lengths/secondand 100 body lengths/second ““Dead Man” responseDead Man” response

• Some small cladocerans (Some small cladocerans (Bosmina, DiaphanosomaBosmina, Diaphanosoma) may avoid ) may avoid detection by invertebrate predators by stopping all activity and detection by invertebrate predators by stopping all activity and allowing themselves to sink slowlyallowing themselves to sink slowly

www.glerl.noaa.gov

www.microscopy-uk.org.uk

www.lbm.go.jp/emuseum

Bosmina

Diaphanosoma

Epischura

Avoidance of Fish Predation Diel (Daily) Vertical Migration Diel (Daily) Vertical Migration

(DVM)(DVM) Most zooplanktivorous fish are visual Most zooplanktivorous fish are visual

predators that feed during the day.predators that feed during the day. Larger zooplankton species typically Larger zooplankton species typically

migrate downward during the day to migrate downward during the day to avoid being seen by fishavoid being seen by fish

Migrate upward at night to feed on Migrate upward at night to feed on algae near the surface, more algae near the surface, more dispersed at nightdispersed at night

www.wellesley.edu

Avoidance of Fish PredationAvoidance of Fish Predation Try to be as Try to be as transparenttransparent as possible as possible

Especially true for large invertebrate predators (Especially true for large invertebrate predators (Chaoborus, Chaoborus, LeptodoraLeptodora) and slow-moving species () and slow-moving species (Daphnia, BosminaDaphnia, Bosmina, etc), etc)

www.lbm.go.jp/emuseumwww.internal.eawag.ch

www.microscopy-uk.org.uk

Leptodora

Chaoborus“Phantom midge”

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

How do the defense strategies of pelagic and benthic animals differ?

Why?

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

OdonataAnisoptera: 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