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

1. What do you do when you find an unknown invertebrate? a) squish it b) call Homeland Security Department c) use a dichotomous key to identify it

2. Rotifers • ~1500 species, size between 0.04 and 2.5 mm • Generation time is a few days (temperature dependent) • Can tolerate lower Water Residence Time than larger zooplankton • Populations respond quickly to an increase in food resources • Most are filter-feeders • Use corona to create feeding current • A few are predaceous (Asplanchna) • Prey species may exhibit cyclomorphorosis Corona www.tolweb.org/tree/ToLimages/cava042p.jpg Asplanchna www.microscopy-uk.org.uk/mag/artfeb02/fresh/freshimg/rotifers.jpg cyclot.hp.infoseek.co.jp/wamusi/mituude1.jpg

3. Annelida: Oligochaeta Bilaterally symmetrical Segmented coelomates, each segment w/ chaetae (little hairs/bristles) http://www.inhs.uiuc.edu/~sjtaylor/cave/oligochaeta.html 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

4. 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

5. Famous invertebrates from Hollywood!

6. 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 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

7. Phylum Mollusca (Life in a shell) >100,000 spp. Gastropods-snails & slugs Bivalves- clams/mussels Cephalopoda (squids, octapus, cuttlefish, nautilus- marine) Higher taxonomy messy

8. 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

9. Valvata bicarinata Campeloma decisum Physella/Physa spp. http://members.aol.com/mkohl1/FWshells.html =picture source

10. 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?

11. 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) superfamilies Mucket

12. 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

13. 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) webs.lander.edu/rsfox/rsfoximages3/clad99L_x550_x_643x.gif Bosmina Leptodora www.cof.orst.edu/project/plankton/bos.jpg /www.internal.eawag.ch/~steiner/Zoo/Bilder Bythotrephes www2.biologie.uni-halle.de/zool/dev_biol/lect/pk_lim/limno/Daphnia.jpg

14. Male Daphnia • 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 First antennae Ephippium with 2 resting eggs

15. Three major groups: Cyclopoida, Calanoida, (pelagic) and Harpactocoida (benthic) • Always sexual reproduction, near equal numbers of males and females • Cyclopoids • Life Cycle • Shorter generation time (1-2 months) • Eggs hatch asnauplius larvae • Several juvenile molts (copepodids) before becoming adults • Juvenile stage may enter diapause in fall and re-activate in the spring Copepods Adult male Adult female Female with egg sacs http://www.emporia.edu/biosci/invert/lab6/copnaup1.jpg centexnaturalist.com

16. Copepods • Calanoids • Life Cycle • Longer generation time (6 months or more) • Eggs hatch as nauplius larvae • Several juvenile molts (copepodids) before becoming adults • No diapause Adult female Adult male www.glerl.noaa.gov www.sahfos.ac.u www5.pbrc.hawaii.edu

17. Avoidance of Predation • Cyclomorphosis • Daphnia and others may grow long helmets and tail spines (inducible defenses) to help avoid invertebrate predators www.unb.ca www.esf.edu/efb/schulz/Art.html www.nature.com

18. Cyclomorphosis • Why not have long spines and helmets all the time? • Energetically expensive, lowers reproductive rate • Interferes with feeding in some cases (Bosmina) www.ecostudies.org/images www.fbl.ku.dk

19. Avoidance of Predation • Escape Tactics • Calanoid copepod “jump” reaction • Flex 1st antennae to achieve burst of speed, acceleration up to 30G and 100 body lengths/second • “Dead Man” response • Some small cladocerans (Bosmina, Diaphanosoma) may avoid detection by invertebrate predators by stopping all activity and allowing themselves to sink slowly Bosmina www.microscopy-uk.org.uk Diaphanosoma www.glerl.noaa.gov Epischura www.lbm.go.jp/emuseum

20. Avoidance of Fish Predation • Diel (Daily) Vertical Migration (DVM) • Most zooplanktivorous fish are visual predators that feed during the day. • Larger zooplankton species typically migrate downward during the day to avoid being seen by fish • Migrate upward at night to feed on algae near the surface, more dispersed at night www.wellesley.edu

21. Avoidance of Fish Predation • Try to be as transparent as possible • Especially true for large invertebrate predators (Chaoborus, Leptodora) and slow-moving species (Daphnia, Bosmina, etc) Leptodora Chaoborus “Phantom midge” www.lbm.go.jp/emuseum www.internal.eawag.ch www.microscopy-uk.org.uk

22. 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

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

25. Order Isopoda(aquatic sow bugs) most spp. marine or terrestrial; 130 f.w. spp. in N.A. flattened dorsoventrally scavengers males carry females before mating, waiting for preadult exoskeleton shed 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

26. Order Amphipoda(superorder Pericarida, scuds) laterally compressed crawl or swim respiration through gills usually 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

27. Fresh water Insects 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."

28. 5 aquatic orders, almost all spp have aquatic larvae Ephemeroptera Trichoptera Odonata Megaloptera Plecoptera 5 partially aquatic orders, most species are terrestrial, but some spp have aquatic life stages Heteroptera Lepidoptera Coleoptera Neuroptera Diptera

29. Ephemeroptera: mayflies ~675 spp Streams and littoral areas of lakes Important fish food Usually 3 caudal filaments Abdominal gills http://www.waterbugkey.vcsu.edu/php/orderdetails.php?idnum=8

30. Adults do not feed Females oviposit usually at water surface Burrowing mayflies (Hexagenia) important species in western Lake Erie Mating swarm near Sandusky River Collecting females at Windsor http://www.heidelberg.edu/depts/wtr/krieger.html

31. Odonata Anisoptera: dragonflies Zygoptera: 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

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

33. 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 weeks http://www.weeksbay.org/newsletter/Sum_2003/Pg8_1.htm

34. Trichoptera: Caddisflies http://www.wildscape.com/earrings.asp

35. ~1400 spp Lotic & lentic Adults terrestrial and easily identified, but many larvae unknown Some build silk nets to catch prey Some free living predators Some build cases http://www.nativefish.org/Gallery/other/Caddisfly.htm Can be dominant in streams Many fish feed on larvae Can have large hatches http://www.epa.gov/bioindicators/html/caddisflies.html

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

37. 5 aquatic orders, almost all spp have aquatic larvae Ephemeroptera Trichoptera Odonata Megaloptera Plecoptera 5 partially aquatic orders, most species are terrestrial, but some spp have aquatic life stages Diptera Lepidoptera Coleoptera Neuroptera Heteroptera

38. 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)

39. Chironomidae: midge larvae (+ 2000 spp) Very important fish food Wide range of ecology http://www.biol.wwu.edu/407/407/Crustaceans.html

40. Tipulidae: cranefly larvae http://alpaca.cs.umb.edu/gallery/Aquatic-Invertebrates/tipulidD_thm Chaoboridae: phantom midge larvae Pelagic predators http://www.iii.to.cnr.it/limnol/bentos/cauborus.JPG

41. 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

42. “water pennies” Larvae aquatic, adult riparian http://dnr.state.il.us/orep/ecowatch/RIVER/bugs/page1.htm Whiligigg beetles Adults and larvae aquatic http://academic.emporia.edu/aberjame/wetland/wildlife/wild24.jpg

43. Heteroptera: true bugs Gerridae: water striders Aquatic larvae and adult Predators http://www.inhs.uiuc.edu/~sjtaylor/gerromorph/striders.html Notonectidae: backswimmers Sucking predators Creepy!!

44. Belostomatidae: giant waterbugs Voracious predators Adults can fly In some spp males carry eggs on back http://creatures.ifas.ufl.edu/misc/bugs/belostomatid01.htm http://www.agls.uidaho.edu/ento/SixleggedWonders/insects_of_idaho/hemiptera.htm

45. Things zoobenthos can eat: location and quality -Floating plankton: phyto, zoo, seston stream drift: animal or detritus -On a surface (moving or still water) plant: low quality algae: on sediment, rock, plant animal: probably hiding detritus: 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.

46. Relatively few benthic inverts eat live macrophytes. Why? Duarte, C.M. 1992. Nutrient concentration of aquatic plants: pattern across species. Limnol & Oceonog 37:882-889

47. So why are the invertebrates in the littoral zone if they don’t eat the plants? pelagia high benthos density & diversity low benthos density & diversity See 24.5

48. 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