bio 205 chapter 14: the arthropods part 2

subphylum chelicerata (chelicerformes)

chelicerae develop first embryonically
typically 8 legs
most are terrestrial
class arachnida and class merostomata

subphylum crustacea

mandibles develop first embryonically
typically 10 legs
most are aquatic
biramian appendages
class malacostraca and class cirrepedia

biramian appendages

appendage with 2 points at the end

subphylum uniramia

mandibles develop first embryonically
typically 6 or many legs
most are terrestrial
uniramian appendages
class chilopoda, class diplopoda and class insecta (hexapoda)

class arachnida

spiders, scorpions, ticks and mites
cephalothroax and abdomen
no antennae
chelicerae exhibited as fangs
pedipalps used for sensory functions or feeding

pedipalps

used as sensory structures in spiders and defensive pincers in scorpions

spiders

possess venom glands with venom that can be poisonous
digestive enzymes liquify prey and “drinks” meal
possess spinnerets

spinnerets

produce silk to build webs

scorpions

possess a postabdomen with a stinging apparatus and barb
internal anatomy is similar to spiders but lack spinnerets
pedipalps used for defense

postabdomen

arches over scorpion body to deliver toxins to prey

class merostomata

horsehoe crabs
cephalothroax and abdomen
no antennae
chelicerae exhibited as feeding pincer
possess anterior pedipalps and a telson (tail spine)
internal anatomy similar to arachnids
eggs are valuable food source to migratory birds

anterior pedipalps in horseshoe crabs

serve as locomotory structures

telson

AKA tail spine, used to help turn the horseshoe crab right side up

class malacostraca

crabs, lobsters, crayfish, shrimp, copepods, amphipods and isopods
cephalothorax and abdomen
possess antennae and antennules
chelipeds for defense
numerous mouth parts

chelipeds

front pair of walking legs adapted for defense in class malacostraca

class malacostraca mouth parts

3 pairs of maxillipeds, 2 pairs of maxillae, 1 pair of mandibular palps and 1 pair of mandibles

class cirripedia

barnacles
sessile
cement glands and cirri
bodies enclosed in CaCO3 plates
hermaphrodites
larvae resembles typically crustacean larave

cement glands

glands that produce an adhesive substance allowing a barnacle to adhere to hard substrates

cirri

appendages used to wave food towards a barnacles mouth

class chilopoda

centipedes
1 pair of walking legs per body segment → fast movers
numerous legs
1 pair of antennae
carnivorous
chelicerae exhibited as forcipules that can deliver painful and poisonous bite

forcipules

poison claws in centipedes

class diplopoda

millipedes
2 pairs of walking legs per body segment → slow movers
numerous legs
1 pair of short antennae
herbivorous
chelicerae exhibited as gnathochilaria that scrape plant tissue

class insecta (hexapoda)

6 legs
most possess 1 pair of antennae
wings (1 or 2 pairs)
flight allows for search of new food sources, escape predation and search for new mates
mouth parts vary based on lifestyle and feeding
most diverse of all animal species

order odonata

dragonflies
predacious insects with 2 pairs of long, narrow, net-veined membranous wings
large compound eyes
chewing mouth parts
gradual metamorphosis with aquatic larvae

order orthoptera

crickets, grasshoppers and locusts
large headed insects with strong chewing and biting mouth parts
large compound eyes
2 pairs of wings → one leathery, one membranous
femur of hind leg enlarged for jumping
gradual metamorphosis with terrestrial larvae
herbivorous and can damage crops

order blattaria

roaches
fast, usually nocturnal, omnivorous runners
harbor endosymbiotic zooflagellates like termites
chewing mouth parts
gradual metamorphosis with terrestrial larvae

order isoptera

termites
social insects
winged males (2 pairs) and wingless females
chewing mouth parts
gradual metamorphosis with terrestrial larvae

order dermaptera

earwigs
elongated nocturnal insects with chewing mouth parts
large compound eyes
cerci
2 pairs of wings → one leathery, one membranous
some are wingless and do not fly
gradual metamorphosis with terrestrial larvae

cerci

posterior pincers on an earwig

order anoplura

lice
ectoparasites of birds and mammals
sucking mouth parts
wingless
small, flattened bodies with reduced eyes
claw-like tarsi for clinging
gradual metamorphosis

order hemiptera

true bugs
piercing and sucking mouth parts
2 pairs of wings → one leathery, one membranous
gradual metamorphosis with terrestrial larvae

order homoptera

cicadas
herbivorous insects (only feed during larval/grub stage)
forewings are membranous
wings sometimes held in tent-like position above body or alone dorsal surface
complete metamorphosis with long terrestrial larval stage

order coleoptera

beetles
largest of insect orders
armored exoskeleton
2 pairs of wings → one leathery, one membranous
biting and chewing mouth parts
elytra
complete metamorphosis

elytra

protective wing covers in beetles

order lepidoptera

butterflies and moths
proboscis for sucking
2 pairs of wings covered with pigmented scales
large compound eyes
complete metamorphosis
larvae (caterpillars) are herbivorous while adults feed little or not at all

order diptera

flies and mosquitoes
1 pair of membranous wings
reduced hindwings (halter) for balancing
sucking, piercing or lapping mouth parts
complete metamorphosis
adults can be vectors of disease

order hymenoptera

ants and bees
2 pairs of membranous wings
some are wingless
highly mobile head
chewing or sucking mouth parts
posterior stinging organ on posterior of some females
many species are social
complete metamorphosis

order siphonaptera

fleas
wingless
adults are ectoparasitic bloodsuckers of birds and mammals
piercing and sucking mouth parts
hind legs designed for jumping
complete metamorphosis