What do you do when you find an unknown invertebrate? a) squish it
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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