Exam 1 Flashcards
JBS Haldane
“… In inordinate fondness for beetles…”
beetle diversity
400K species of described species, 40% of all insects, and ~26% of all described living things.
insect diversity decline
- what is the baseline
- sampling error
- snapshot comparison
- causes
why are insects so successful?
- an exoskeleton for protection and to prevent desiccation
- variable size
- flight
- internal fertilization of an egg
- early colonization of land
- complete metamorphosis
why should we care about insects?
*decomposers
*pollination
food webs
ecosystem services
nutrient cycle
predation
medicine
commercial products
environmental quality
insect detriment
- disease (malaria, plague, typhus, sleeping sickness, yellow fever, dengue
- economic damage
- direct and indirect ( crop, forests, products)
Order Protura ‘coneheads’
- no eyes, wings, antennae
- prefer moist organic soil
- feeding habitat not well known
- mouthparts are styliform
order collembola ‘springtails’
- small
- furcula
- eyes absent or reduced
- moist habitat
- very common
order diplura
-small
-eyeless
- long, beaded antennae
- pair of caudal
- many feed on plant matter
800 spp.
order archeaognatha ‘bristletails’
- chewing mouthparts
- ametabolous development
- 250 spp
- under leaf litter
order zygentoma: silverfish and firebrats
- common in leaflitter
- common in basements
- 450 spp
- firebrats prefer warm places near fireplaces and heaters
evolution of mandibles
An early shift from monodondylic to dicondylic mandibles.
monocondylic: crustaceans, millipedes, centipedes, early hexapods, archeaognatha
more simple set of mandibles. crustaceans, millipedes, centipedes, early hexapods, archeaognatha
dicondylic mandibles
stabilize movements of mandibles and open new niches for insects
ametabolous
no change in body morphology during growth and development
hemimetabolous
having no pupal stage in the transition from larva to adult.
holometabolous
Complete, or holometabolous, metamorphosis is characteristic of beetles, butterflies and moths, flies, and wasps. Their life cycle includes four stages: egg, larva (q.v.), pupa (q.v.), and adult. The larva differs greatly from the adult.
apterygotes
ametabolous
exopterygotes
hemimetabolous
order ephemeroptera
- mayflies
- immature nymph stage
- unpolluted habitats with fresh moving water
- most species herbivorous
- subimago = subadult
- cannot fold their wings
- ~2000 species worldwide
order odonata
dragonflies and damselflies
- another ancient order with a nymph stage
- very large eyes
- greatly lengthened abdomen
- damselflies have wings held parallel at rest
- dragonflies have wings held perpendicular
- ~5000 species worldwide
Order Plecoptera
- adults do not disperse far from water.
- poor fliers
- nymph in well-oxygenated water
- adults feed off of soft plant tissue
- nymph feed on other invertebrates or detritus
hind wings are pleated and foldable
>2000 spp - stoneflies
Order Blattodea
- Roaches and termites
- mandibulate: fore or hind wings, membraneous, similar
order mantodea
- mantids
- elongated prothorax
- raptorial forelegs for catching prey
- triangular head
- most diverse in the tropics
- of the 20 N. American species only 5 are common and 3 are non-native
- the pet trade causes the release of new mantid species
- 1800 spp worldwide
Order orthoptera
- crickets, grasshoppers, katydids
- saltatorial legs
- front legs smaller than the hind wind wings
- most are herbivorous
- 2nd thoracic segment smaller than the 1st and the 3rd
- ~1000 spp in N. America
- > 20,000 spp worldwide
Order Plasmodea
stick insects
- medium to large sized insects
- usually slender and elongated
- typically flattened and wide
- many wingless.
order dermoptera
- earwigs
- elongated
- simple, slender antennae
- legs, thin, adapted to running
- some wingless but if wings present forewings harden covering hindwing
- abdomen with cerci, purpose unclear
Order Paraneoptera
- many derived in morphology than polyneoptera
- simplification of some structures such as reduced wing venation
- Major modification to mouthparts
- relationship between some of the paraneopteran order have not been resolved and several different higher classifications have been proposed
Insect mouthparts
- mouthparts have undergone a significant evolutionary change.
- mouthparts evolved from ancient walking limbs
- the ancestral condition is thought to be mandibulate.
Order Psocodea
- barklice and booklice
- phytophagous, feed on organic matter including algae, lichen, fungi
- active, fast running
- stocky body, shades of brown and grey
- large heads with bulging faces and large eyes
- antennae face towards abdomen
- prothorax small compared to head
Mallophaga
- chewing lice
- secondarily wingless
- flattened
- parasitic on birds and some mammals
- chewing mouthparts
- most are host-specific
Anoplura
sucking lice
- secondarily wingless
- sucking mouthparts
- obligate ectoparasites or mammals
- host-specific and incapable of living off the host
- effective vector of disease in humans and animals
Order Thysanoptera
- thrips
- 4 long and narrow wings, fringed in hair.
- sucking mouthparts
- pests of plants especially in greenhouses
- disease vector
Order Hemiptera
- combination of 2 previous orders ( heteroptera and homoptera) now suborders
- all have piercing-sucking mouthparts
suborder heteroptera
- diverse: plant feeders, predators, external parasites, scavengers, aquatic species
- the presence of hemelytra
- > 50,000 species
Suborder Hemiptera
- 4 wings, front legs often hardened
- sucking mouthparts
- variable antennae
- all plant feeders, some pests
- some disease vectors
- unlike the Heteroptera, great diversity in morphology
Endopterygotes
- holometabolous
- majority of insect diversity is in these orders
- just four orders account for 80% of insect species
- coleoptera, lepidoptera, diptera, hymenoptera
- relationship between some of the orders is not well understood.
Order Coleoptera
- beetles
- modified hard shell called an elytra
- ~400,000 species.
- all functional roles represented: predators, herbivores, parasites, decomposers, scavengers, aquatic
order strepsiptera
- twisted wing parasites
- active first stage larvae attached to host
- develop as legeless internal parasite on their host until adulthood.
- adult males have wings
- adult females are wingless legless and never leaves the host
- fertilized female produce larvae that first consume their mother
order mecoptera
- scorpionflies
- small or medium size
- two pairs of membraneous wings
- threadlike antennae
- males with scorpion-like terminal segments
Order diptera
extremely diverse, many functional roles: predators, parasites, parasitoids, scavengers, herbivores, pollinators, decomposers, aquatic
- single pair of wings
- halteres
- many families pupate in the last larval skin: puparium
order trichoptera
- caddisfly
- sister group of the Lepidoptera
- scales on wings
- long antennae
- herbivores, detritivores, predators, all are aquatic
- well known for their larval cases.
order lepidoptera
- butterflies and moths
- mostly herbivores larvae, adults sip nectar
- lepid = scale
Order hymenoptera
- bees, ants, social wasps, sawflies, and parasitic wasps.
- great diversity in parasitoid wasp
- membraneous wings with few veins
- hymen = membrane
- ants and wasps have thread waists
- polyDNA virus
- remarkable symbiosis between parasitoid braconid wasps and the ancient group of virus
Early Forest entomology
was focused on reducing the impact of pest insect populations to increase forest health, growth, yield
Julius Theodor Christian Ratzeburg
Founder of forest entomology. 1837-1844; published 3 volumes and a supplement
Andrew Hopkins
Founder of North American Forest Entomology
insect phytophagy
phytophagy insects coevolved with plants. there are no plants known that do not have insects that feed on them. Plants have evolved numerous mechanisms to deal with herbivory.
Folivores
leaf-eating insects
- open feeding
- windowpane
- skeletonizing
- leaf/needle typing/rolling
- leaf mining
defoliators
groups of folivores that have damaging impacts. sometimes on a very large scale. may have seasonal outbreaks.
- largest agent of disturbance in the US and Canada.
- natural outbreaks are part of the ecology.
irruptive defoliator dynamics
species outbreak at irregular intervals.
periodic or cyclical defoliator dynamics
populations increase/decrease at a regular interval
Outbreak
high population density characteristic
Tent Caterpillars
6 species in N America species. spring feeding defoliators.
- except for the forest tent caterpillar, all spin silken tents where they rest.
Forest tent caterpillars
- one of the most widely disturbed forest insects in North America
- native species with the same lifecycle across its range
- population exhibits strong regional preference for certain host trees.
Budworms
-A complex of mostly conifer-feeding torticid moths.
- some of the most economically important forest pests in N. america.
- spruce budworms, western spruce budworms, jackpine budworms, large aspen tortrix
- eggs laid in late summer and hatch but the larvae makes hibernacula under bark to overwinter and eat the fresh buds in the spring.
- wasteful eaters
dendrochronology
quantitative dating method based on the analysis of tree ring growth.
can be a very sensitive and useful tool for looking at environmental events of the past
- not effective for some species of trees.
