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OHIO / Biological Sciences / BIOS 1000 / What are the types of mollusks?

What are the types of mollusks?

What are the types of mollusks?


School: Ohio University
Department: Biological Sciences
Course: Animal Diversity
Professor: Patrick hassett
Term: Fall 2016
Tags: BIOS and 1000
Cost: 50
Name: BIO 1000 EXAM 2
Description: Animal Diversity Exam 2
Uploaded: 10/20/2016
18 Pages 286 Views 2 Unlocks

TEST 2  

What are the types of mollusks?

• Mollusks  

◦ Include:  

‣ Gastropods  

‣ Bivalves  

‣ Cephalopods  

◦ Nearly 100,000 species in marine, freshwater, and terrestrial habitats  ◦ Mollusk Evolution  

‣ Smallest mollusk  

• Small wormlike forms with no shell  

• Few millimeters  

‣ More advanced  

• Complex forms with advanced brains and eyes  

• Ex: Squid and Octopus  

◦ Building a Mollusk

‣ Shell for defense  

‣ Heart and circulatory system  

‣ Food for locomotion  

‣ Radula, an abrasive tongue, for feeding  

‣ More complex nervous system, culminating in the eye and brain of  cephalopod  

What are the types of gastropods?

◦ Shell  

‣ Formed by mantle  

‣ The mantle is a layer of tissue lining the shell  

‣ It deposits new material at the shell edge, and maintains older shell  material  

◦ Radula  

‣ Feeding structure for scraping surfaces  

‣ Like a toothed tongue that consistently grows  

‣ Form is adapted to function: scraping algae, tearing flesh, drilling  through shells or rocks  

◦ Body Forms  

‣ Primitive form  

• Was just a hard covering for the body  

• Still found in deep sea  

‣ Shell elongates, and gas-filled chambers are added to allow  swimming  

• Chambers for buoyancy  

‣ Coiling produced Cephalopods, while loss of chambers produces  gastropods

What is the meaning of cephalopods?

• No chambers, live on bottom  We also discuss several other topics like What interacts physically and chemically with one another and extracellular material to form defined tissues?

‣ Sides compress to allow shell to slide into sediment  

‣ Bivalve (two-shelled) shape provides greater protection and  efficiency  

• Gastropods  

◦ 1. Snails and relatives, limpets, abalone  

◦ 2. Air-breathers: Land Snails and Slugs  If you want to learn more check out What is the content of the stamp act of 1765?

◦ 3. Nudibranchs: Have lost the shell  

‣ Many can 'steal' the cnidocytes of their cnidarian prey  

◦ How to build a shell  

‣ Basic material is calcium carbonate laid down in layers  

‣ Layers of protein can strength  

‣ Outer layer is often covered with thicker protein layer  

◦ Shell shapes- cost and benefits  

‣ Calcium carbonate more soluble in cold water  

• Makes shell more costly to build and maintain  

‣ Thick shells are good protection, but are costly to build and hard to  carry around  

‣ Protein layers will reduce weight for same strength  

◦ Shell extensions in Murex spp.  

‣ elaborate shells seen more often in tropics due to costs  

◦ Exposure to sun is a problem for intertidal mollusks, especially in tropics  ‣ Shells often lighter colored and more pointed, oriented towards the  sun  

‣ Can keep shell 5-6 C cooler than adjacent rock  

◦ Predation  

‣ Oyster Drill  

• Oyster Drill uses radula to drill holes in shells to prey on other  mollusks  

‣ Fish  Don't forget about the age old question of What are the two body systems that control internal communication and coordination?

• Porcupine fish  

• Some have teeth for cracking shell  We also discuss several other topics like What are the cellular and molecular events that allow muscle contraction?

‣ Box Crab  

• Powerful leverage from pincers  

• Claws chip away at opening to shell, exposing the soft tissue  ‣ Shell defense  

• Shell healing  

• Smooth surfaced shells are difficult to grip  

• Thickening of shell opening strengthens shell against attack  • Corrugations in opening help anchor body and make opening  smaller

• Spines and projections make handling difficult  

◦ Projections may also make it hard for fish to swallow whole  shell  

◦ Projections can also anchor shell in sand  

• Bivalves  

◦ Clam Shell Features  

‣ Reduced head  

‣ Large gill in mantle cavity  

‣ Hinged shell  

◦ Bivalve Gill  

‣ Gill used for both breathing and feeding in advanced bivalves  ‣ Bivalve pumps water over gill, and oxygen and microscopic algae  are both removed  

‣ Primitive bivalves live in sediment  

‣ Later, bivalves adapt life on surface, attached to hard surfaces, or  even by boring into wood  

‣ Threads anchor mussels  

• Mussels can release threads to move into open patches  ◦ Scallops  Don't forget about the age old question of Is epithelial tissue found in skin?

‣ Scallops are capable of short bursts of swimming  

‣ Eyes are located along edge of scallop mantle  If you want to learn more check out What did lerner and loewe write?

• (Need senses to swim)  

◦ Tridacna  

‣ Giant clam that host symbiotic algae in its mantle  

‣ As adult, most of their food comes form symbiont  

◦ Shipworms (Piddocks)  

‣ Bore holes into wood for protection  

‣ (Not actually worms)  

• Cephalopods  

◦ Predatory Mollusks  

◦ Cephalopod Groups  

‣ Ammonoids: Gas-filled shells  

‣ Nautilus: Gas-filled shell  

‣ Squid: Reduced internal shell  

‣ Octopus: No shell  

◦ Ammonoid  

‣ Extinct  

‣ Heavy, often large shells  

‣ Corrugation of septa strengthens structure, allowing larger shell  ◦ Nautiloids  

‣ Ancient group

‣ Shell divided by walls. chamber connected by tube called a  siphuncle  

‣ Siphuncle  

• Is an organ that pumps water from the sealed chambers  • Gas then replaced water  

• As animal grows, chambers are added  

◦ Squid  

‣ Sacrifices shell for speed  

‣ Are most successful of the cephalopods in terms of numbers  ‣ Can be found throughout the world's oceans  

‣ Squid Anatomy  

• Cephalopods body wall from mantle  

• Tentacles derived from food  

• Have beak and radula for feeding  

• Most have ink sac for defense  

• Funnel provides jet propulsion  

• Water fills mantle cavity and is forced out throughout funnel  • Very powerful, but uses lots of energy  

◦ Only short bursts  

• Slow swimming provided by tail fins and tentacles  

‣ Squid Intelligence  

• Can communicate by chromatophores- cells in skin that can  change coloration, often during mating  

• Humboldt squid are known to hunt cooperatively  

‣ Giant squid  

• Deep living giant squid occasionally wash up on beaches  ‣ Colossal squid  

• Even larger than giant squid  

• Found in deep water off Antarctica  

• Tentacles clawed  

• Can grow to 50 feet, including tentacles  

• Eye was measured at 11 inches in diameter  

◦ Octopus  

‣ Have eliminated shell entirely  

‣ Body Design  

• 8 arms, usually with suckers  

• Soft flexible body  

• Beak for killing prey (often crabs)  

• Can use jet propulsion, forcing water through 'funnel"  ‣ Life Span  

• Are surprisingly short-lived

◦ As little as 6 months  

• Giant octopus - 3-5 years  

• Die soon after eggs hatch  

‣ Size  

• Giant Pacific Octopus, most roughly 35 pounds, 15' arm span  • Smallest octopus wolf, less than 1"  

‣ Cephalopod Eye  

• Sophisticated eye similar in structure to human eye  

• Advanced brain, capable of learning  

‣ Octopus Intelligence  

• Can solve mazes  

• Retain both shot and longterm memory  

• Some use tools  

• Legs have many nerves, can function somewhat independently  • Annelids - Segmented Worms  

‣ Polychaete  

• Diverse group of marine worms  

‣ Earthworms  

‣ Leeches  

◦ Polychaete Trochophore Larvae  

‣ Body  

• Layers of circular and lengthwise muscles  

• Body separated by membranes into segments  

• Organ systems  

◦ Circulatory, nervous, digestive, extend through this  


‣ Significance of segmentation  

• 1. Protects worm from damage to one part of body  

• 2. Aids in tunneling through sediment and soil  

• 3. Allowed evolutionary pathway to specialization of appendages  ‣ Hydrostatic Skeleton  

• Bristles grip sediment as wave of muscle contractions push head  forward  

‣ Polychaete (Bristle Worms)  

• All are marine species  

• Can be divided into two groups based on body plan and mode of  living  

◦ Errant  

‣ Usually predators  

‣ Body segments tend to very little  

‣ Have paddle like legs and distant head, often with jaws

◦ Sedentary  

‣ Have more diverse body shapes  

‣ Feeding Methods  

• A wide variety of invertebrate animals (animals without  backbones) use a few basic feeding methods  

• Sedentary Polychaete  

◦ Filter feeding with ciliated tentacles, often use mucous to  cause particles to stick  

‣ Sand Sorting  

• As particles move down tentacles they are sorted by  size  

• Small particles are eaten  

• Larger grains may become part of tube (or discarded)  ◦ Surface feeding  

‣ Feed on particles on surface using ciliated tentacles  ‣ Spaghetti Worm  

• Tentacles have grooves that can sort particles by size  ◦ Filter feeding with mucous net to trap particles  

‣ Parchment Worm  

• Segments are highly specialized  

• Legs fiction as paddles, gills, and feeding  

appendages in different regions of body  

• Tough, paper-like tube  

◦ Subsurface feeding (feed on particles under the surface,  earthworms do)  

‣ The lugworm can be found in very high densities in some  intertidal mud flats  

• Reworked sediment  

• Mixes sediment, constantly turning over and aerating  the mud  

• Predatory Feeding  

◦ Chemosynthetic feeding  

‣ Some animals have symbiotic bacteria that use chemical  energy, not sunlight, as the source of energy to make  food  

◦ Ecological roles  

‣ Polychaete play important role on ocean bottom  

‣ Some, such as the lugworm, mix sediment, allowing  oxygen to reach greater depths  

‣ Others, particularly tube-builders, stabilizer sediments  and keep it from being wasted away

◦ Earthworms  

• Use seta, which grips soil during digging  

• Hermaphrodites  

• Lighter region secretes egg cocoon  

‣ Ecological Role  

• Earthworms tunnel through soil, ingesting and breaking down  dead plants, making soil more permeable  

• May be nearing 2,000,000 earthworms in an acre of rich  farmland  

• Most are small, but an Australian earthworm can reach 10 feet  long  

◦ Leeches  

• Most are freshwater  

• Mainly feed as predators on small invertebrates  

• Some also suck blood, but most often feed as scavengers  • Bloodsuckers secrete hirudin, an anticoagulant  

‣ Medicinal Leeches  

• Sometimes used in modern microsurgery to remove blood from  neighboring tissue  

• The Deep Sea  

◦ 50% of earths surface lies below 2 km ocean depths  

◦ Deep sea bed covers 270 million km2  

◦ We have quantitatively sampled about 500 m2 of this  

◦ Challenges for life in the deep sea  

‣ Stresses  

• Cold temperatures (though constant)  

• High pressure  

• Very low or no light  

• Low food ability (with few exceptions)  

• Mesopelagic Zone  

‣ The lower limits of the sunlit zone  

‣ 200m-1000m  

‣ High species diversity  

‣ Low, but detachable light  

‣ Many animals migrate to surface at night  

‣ Countershading by bioluminescence is common  

‣ Countershading: appear dark from above, light from below  ◦ Lanternfish  

‣ Most common fish in the ocean, lives in mesopelagic zone  ‣ May account for over half deep sea fish biomass (estimated at  roughly 1 billion tons)

◦ Mesopelagic Fish Biomass  

‣ Recent study estimated that the biomass of mesopelagic fish may  be 10x higher than thought  

‣ That would mean there are far more of these small fish than all other  fish in the world combined (estimated at 1-2 billion tons)  

◦ Bioluminescent  

‣ Product of light by living organism  

‣ Common in ocean, occurs in wide ranges of animals  

‣ May be used for defense(camouflage, distraction), offense(prey  attraction), as well as communication(mating)  

‣ For illumination: A dragonfish can produce a beam of red light  • Many deep sea animals are red  

‣ Red color common  

• Red pigmentation is common in midwater animals  

• Red light absorbed rapidly  

• Most bioluminescent is blue-green  

‣ Color mismatch  

• Bioluminescent color slightly different than natural light  

• Predators can respond by having eyes sensitive to  

bioluminescent spectrum  

◦ Bioluminescent Countershading  

‣ Breaks up pattern of animal when seen against weak surface light  ‣ Intensity can match background  

• The Deep Zones  

‣ No light  

‣ Abyssal plain, 4,000-6,000 m depth  

‣ Covers 40% of ocean floor  

‣ Ocean trenches can extend to 11,000 m deep  

‣ Extreme pressure, little food, relatively few species  

◦ Food and energy  

‣ In most of the deep sea these is little food  

‣ Animals must conserve energy, many move little and have weak  muscles  

‣ Weak bones and muscles reduce density, make floating easier  ‣ Many deep sea squid are also weakly muscled  

◦ Red color common  

‣ Red pigmentation is common in midwater animals, where there is  some light  

‣ Appear black due to rapid absorption of red light  

◦ Deepest living animals  

‣ Red pigmentation is uncommon in deepest dwelling animals,many

lack any kind of pigmentation  

‣ Little bioluminescence in these animals  

‣ Deep ocean bottom mostly covered in fine mud  

‣ Few suspension feeders  

‣ Mostly sediment feeders and scavengers  

◦ Gigantism  

‣ Common in deep, cold waters  

‣ Causes of gigantism  

• Seen in deep-sea and polar oceans  

• Cause is unknown  

• Temperature effect?  

• Slow growth, longer life span, delayer maturity may play a role  ◦ Deep-sea  

‣ Cold water(2-4 C), little food, leads to slow metabolism  

‣ Animals often long-lived (100 years for deep sea clam; some take  25-30 years to reach sexual maturity)  

‣ Deep-sea colonies measured at 500-1000 years  

◦ Bottom Fish  

‣ Excellent sense of smell  

‣ Can detect scent of food from long distances  

‣ Many bottom fish roam widely, have stronger bones and muscles  ‣ Living on bottom, higher dusty not a problem  

◦ Biodiversity in the deep sea  

‣ Originally thought to be barren, deep sea diversity (# of species) is  actually high  

‣ In some cases biodiversity rivals rainforest  

‣ Exceptions are deep-sea trenches, which ave few species  ‣ Calculating Biodiversity  

• In low diversity areas you can take many samples and you will  find the same species  

• In deep oceans, al,most every sample yields new species  • Unusual Deep-Sea Communities  

◦ Vent Communities  

‣ Hydrothermal or 'hot' vents  

‣ Methane seeps or 'cold' vents  

‣ Whale falls  

‣ (Mostly along mid-ocean ridges and trenches)  

• Hydrothermal or Hot Vents

‣ Make use of hydrogen sulfide emitted by vents, such as this 'black  smoker'  

‣ 350C

◦ Vent Worm  

‣ Note red color of plume: hemoglobin which gives our own blood its  red color  

‣ Plume acts like a gill, absorbing hydrogen sulfide and carbon dioxide  (for bacteria) and oxygen (for worm)  

‣ Heart pumps blood to symbiotic bacteria in feeding body  

‣ There is a large range of vent worms  

◦ Pompeii Worm  

‣ Can withstand temperatures of 80 C (almost 180 F)  

‣ Has coast of bacteria growing on back  

◦ Vent Clams  

‣ Dense congregations of clams  

‣ Clams host symbionts too  

‣ Bacteria produce sulphur as byproduct, can give shells yellow color  ◦ Other Vent Species  

‣ Yeti Crabs  

‣ Sea anemone  

◦ Vent Productivity  

‣ In addition to symbiosis, primary production also comes from fields  of bacteria growing on rocks  

◦ Vent Shrimp  

‣ found at Atlantic vents  

‣ 'Farm' chemosynthetic bacteria under shell  

• Methane seeps or cold seeps  

‣ Arise where methane seeps through ocean floor  

‣ Sometimes brine pool can be observed on bottom  

• methane is usually trapped under layer of brine within undersea  rock formations  

‣ Bacteria utilize methane as energy source, forming base of  community similar to hot vent community  

‣ Methane and Hydrogen Sulfide provide energy source for cold-seep  community  

◦ Cold-Seep Animals  

‣ Vent worms also occur around other types of vents, such as cold  seeps or methane  

‣ Mussels  

‣ Tube worms that have roots that absorb sulfide  

• Whale Falls

◦ Whale carcasses on ocean bottom  

‣ Provide another habitat where chemosynthesis can occur  ‣ Provide unique environment on ocean bottom

◦ Whale Falls  

‣ Too large to be scavenged before sinking to bottom  

‣ Initially fed on by hagfish, shark and others  

‣ Bacterial decomposers create anoxic conditions, particularly inside  bones (in the marrow)  

‣ This produces hydrogen sulfide, similar to vents, so there are many  species in common  

‣ Whale fall communities have many of the same species as vent  communities  

‣ Can provide food source for decades in deep sea  

‣ May be carcasses every 5-10 miles in the deep sea  

• Arthropods  

‣ Spiders  

‣ Scorpions  

‣ Crustaceans  

‣ Insects  

◦ Arthropod body plan  

‣ Segmented body  

‣ Jointed legs, often highly modified  

‣ Exoskeleton with cuticle containing chitin  

◦ Early arthropods: Trilobites  

◦ Chelicerates (horseshoe, crabs, spiders, and scorpions)  ◦ Arthropod Phylogeny  

‣ Grouped by primary feeding appendage  

◦ Arthropod cuticle  

‣ Made up of three layers  

‣ Must be shed for the animal to grow  

‣ Molting Cycle  

• Old cuticle separates  

• New cuticle is secreted layer by layer  

• Old cuticle is dissolved and reabsorbed  

• Old cuticle is discarded  

• Animal swells with water, new cuticle stretches out  

• Cuticles harden, animals expels water, and slowly grows into  new cuticle  

◦ Trilobite  

‣ Every leg looks the same  

‣ Primitive anthropoids show little specialization  

◦ Chelicerates  

‣ Horseshoe Crabs  

• Arachnids (scorpions and spiders)

• Common Features  

• 6 pairs of appendages  

◦ First comes a pair of chelicera (often used for sucking fluid  from prey, in spiders connected to poison glands)  

◦ Next come a pair of pedipalps (sensory or feeding function,  may be claw-like)  

◦ 4 pairs of walking legs  

• 4 species  

◦ One along the US Atlantic coast, the other in the tropical  Pacific  

• Have mass spawning in spring, laying eggs under the sand at  the high tide mark, an important food source for migrating birds  • Horseshoe crab blood  

◦ Extremely sensitive to bacteria  

◦ Used in pharmaceutical industry to detect bacteria  

contamination in medicines  

◦ Several million horseshoe crabs are bled and returned to the  sea each year  

◦ Arachnids  

‣ Scorpions, siders, ticks, mites  

‣ Scorpions  

• Whip scorpion or Vinegaroon  

• No venom, but can spray a mist that is 70% acetic acid (or  vinegar)  

‣ Spiders  

• Most have 8 eyes  

◦ Forward binocular vision and side vision  

◦ Despite many eyes, most spiders have poor eyesight, relying  on tech, vibrations, and smells  

‣ Exceptions are hunting spiders  

• Toxins  

◦ Neurotoxic- paralyzes nervous system  

◦ Hemolytic- attacks tissues  

◦ All spiders posses venom and can bite, few are dangerous,  and very few fatalities occur among humans  

‣ Ticks  

• Bod feeding external parasites  

• Ticks often attach to hosts by 'questing', hold only blade of grass  with hand legs and wait for host  

• Once embedded in skin they engorge with blood  

• Drop off and mold (if young) or lay eggs on ground, they start

cycle over  

• Transmit many diseases  

◦ Lyme disease  

‣ Spread by deer ticks, becoming more common in US  

◦ Rocky mountain spotted fever  

◦ And many others  

• Tick Control  

◦ Pesticides ineffective  

◦ Guinea fowl willed on 'questing' ticks  

‣ Mites  

• Are everywhere  

• Very diverse, both free-living and parasites  

• Follicle mites live in hair follicle, particular base of eyelashes,  about 1 in 3 chance that you have them  

• Dust mites, found in carpets and bedding, are common allergen  (the feces, not the mite)  

• Mange is skin disease caused by mites  

• Crustaceans  

◦ Dominate the oceans  

◦ Crustacean features  

‣ Head and front part often covered by carapace, a hard shell-like  covering  

‣ Pair of antennae for sensing environment  

‣ Each segment with appendages modified for walking, swimming,  and feeding  

‣ Very common in oceans, though there are a few land species too  ◦ Molting  

‣ Indirect Development, young stages appear different from adult  ‣ each stage has numerous molts  

‣ Direct Development, young hatch with similar appearance to adult  ◦ Primitive Crustaceans  

‣ Have few specialization appendages  

‣ Include brine shrimp (sea monkeys) and water fleas  

‣ Bring Shrimp, Artemia  

• Repetitive appendages- primitive  

• Typically live in water 2-3X as salty as seawater  

• Important aquaculture food  

‣ Cyst Harvest  

• Cysts are eggs that are dormant (non-growing) and float on  water  

• Boats harvest cysts, dry and can them for use as aquaculture


• Dry cysts can remain viable for decades  

‣ Water Fleas (Cladocerans)  

• Parthenogenic life cycle  

◦ All females for several generations  

‣ Daphnia Lumholtzi  

• Have long protective spines  

‣ Barnacles  

• Common on rocks in marine intertidal zone  

• Will attach to almost any surface  

• Filter feed on microscopic algae  

◦ Have feeding appendage  

• Are preyed on by sea stars and snails  

• Copepods  

◦ Most abundant group of marine arthropods  

◦ Some have thick cuticles and short, stubby antennae, live in  sediment  

◦ Others are streamlines, swim in plankton  

◦ Hairs on antennae have mechanoreceptors as well as  chemoreceptors  

◦ Also many parasitic species with bizarre shapes  

◦ Copepod Mouthparts  

‣ Filter feeding  

◦ Some have large fat reserves to survive periods of low food,  making them a valuable food resource for predators  

• Amphipod  

◦ Are flattened side to side  

◦ They are important scavengers  

◦ Can be found in high abundances in a broad range of  habitats  

• Isopods  

◦ Scavengers  

◦ Flattened top to bottom  

• Decapods  

◦ Lobster  

‣ Thorax and abdomen about the same length  

‣ Despite heavy fishing pressure, lobster harvests have  boomed over the last 20 years  

‣ One likely factor is the loss of cod, a large predatory  bottom fish, due to overfishing  

‣ Are aggressive predators and scavengers

‣ In captivity they may also be cannibals, so they have  

never been successful in aquaculture  

‣ Crabs have short abdomens, often tucked under body  

‣ Females often hold eggs between abdomen and body, so  have wide abdomen  

◦ Shrimp  

‣ Longer abdomen  

◦ Crabs (hermit, coconut, blue)  

‣ Swimming crab  

• (note their hindmost legs)  

‣ Hermit Crab  

• Uses mollusk shell for defense  

‣ Decorator Crab  

• Camouflages shell with pieces of seaweed, sponge,  


• Krill  

◦ Euphausids  

◦ Antarctic krill may be found in vast swarms that are miles  wide  

◦ Estimated biomass at 500 million tons  

◦ Found throughout the worlds oceans  

• Insects, Centipedes, and Millipedes  

◦ Millipedes  

‣ Have an insects-like head  

‣ Mouth designed for eating plants  

◦ Centipedes  

‣ Mouth designed for protection  

‣ Amazonian Giant Centipede  

• Is a formidable predator  

• Known to feed on bats and rodents  

• Can grow over 12" long  

◦ Insects  

‣ primitive insects have elongated wormlike body, much like primitive  crustaceans  

‣ Silverfish  

• Primitive wingless insect  

• Sometime found in pages of old books  

• Will feed on paper, cotton, silk, so can be a household pest  ‣ Have an assortment of mouthparts  

‣ The terrestrial invasion  

• Evaporation though skin reduced by thick, waxy cuticle

(insecticide soaps dissolve this)  

• Respiratory water loss reduced through lung system  ◦ Insect lung  

‣ Insecticidal oils cover pores, suffocate insect  

• Excretory water loss reduced through specialized organ  ◦ Cockroach digestive tract  

‣ Malpighian tubes  

• Tubes reabsorb water from urine, contracting the  

waste and saving water  

• Locomotion enhanced by development  

‣ Flight  

• Gliding ants are able to glide back to tree trunk if they fall off  branch  

◦ Exoskeleton is flattened to act like wing  

• Flying insects  

◦ Wings are extensions of the exoskeleton  

◦ Two types: direct and indirect wings  

‣ Direct  

• Direct muscles attach directly to wing  

• (Dragonfly)  

‣ Indirect  

• Most other insects  

• Lets insects fold wings  

• Most insects have indirect  

• Muscles attach to exoskeleton, flex it up and down  

‣ Some insect types  

• Periodical insects  

◦ Cicadas  

‣ Live underground for most of life, then emerge,  

metamorphose, and quickly mate and lay eggs  

‣ Some have 13 yr or 17 yr cycles  

‣ 17 yr cicada  

• Brood 5 occurs in central/southeast Ohio  

• last emerged in 1999, next emerge due in 2016  

‣ Why do cicadas emerge at one time?  

• Huge numbers overwhelm predators  

• By the time predator population increase, cicadas are  back underground  

• Social Insects  

◦ Ants, bees, termites  

◦ Social system ofter based on castes, genetic relations

◦ How many?  

‣ In South America, leaf cutter ants consume more plant  leaves than mammals do  

‣ In SW US harvester ants consume more seeds than all  other animals combined  

‣ In Japan, one super colony of 45,000 nests had roughly  300 million ants  

‣ Ants and termites may account for more than half of the  total insect biomass in tropics  

◦ Communication is key, including scent recognition and bee  'dances'  

◦ Honey bee decline  

‣ Colony Collapse Disorder  

• Bees fail to return to hives  

‣ Causes  

• Much uncertainty  

• Pesticides, disease among possible factors  

‣ Invasive Species: African honey bees  

• Sing is not venomous, but much more aggressive in  defending hive  

‣ Released in Brazil  

• Spread north, interbreed with more docile honey  bees, many reduce aggressiveness  

◦ Invasive Species: Fire Ants  

‣ Range expectations  

• Can rapidly expand by range  

• Carried by other animals (bird, for example)  

• Human intervention (particularly transporting plants  and agricultural products)  

• Wind (even tornadoes have been shown to move  animals about)  

• Floods, floating debris over rivers and streams  ‣ Fire Ant control  

• Recently a parasitic fly has been used to control fire  ants  

• Larvae eat way to head, head falls off  

• Zombie Ants  

◦ Phorid fly emerging from head of ant  

◦ Crazy Ants  

‣ A new invasive species, dubbed "crazy ants" are  invading the southeast and displacing fire ants

‣ Tiny, but very active

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