Parasitism, Mutualism, and Community Ecology

Percentage of parasites on planet

50%

Examples of a microparasite

bacteria, viruses, protozoan

Examples of a macroparasite

flatworms, roundworms, lice, fleas, ticks, insects

Process where 1 egg that can give rise to multiple eggs or larval stages

Polyembryony

Why do parasites have high reproductive rates

To ensure completion of life cycle

A parasitic flowering plant that relies upon the host as a source of water and nutrients by penetrating the xylem, has some ability to photosynthesize

Hemiparasite

What is the Oklahoma State Floral Emblem, a hemiparasite

Mistletoe

A parasitic flowering plant that has no chlorophyll or photosynthetic ability, relies entirely on other plants for nutrients

Holoparasite

Holoparasite that penetrates the root system, primarily in oaks and other trees

Squawroot

Holoparasite that produces the largest flower on the planet and parasitizes root system of Malaysian vine, smells like decay to attract flies and beetles for pollination

Rafflesia

Exceptions for the rule that parasites usually don’t kill their host

Newly evolved virulent forms

weakening host to increase the likelihood of predation

parasitoid

Parasite that causes rats to seek out cats

Toxoplasma gondii

What is a parasitoid

A parasite that always kills host

Explain the Ichneumonid wasp

Parasitoids that use long ovipositor to drill into trees and look for wood boring beetles to attach eggs to, eggs hatch and burrow into beetle to consume it

Parasitoid that lays eggs on caterpillar, which larvae consume from inside out

Braconid wasp

Ecological effects of parasites

Can drive species to extinction

Influence host population cycles

Can change ecological communities

Example of parasite driving host to extinction

Chestnut tree and __Cryphonectria parasitica__

Example of parasites causing changes in host population cycle

Red grouse population crash every 4 years due to nematode infection

Example of parasite changing species interaction

Tribolium castaneum tends to be a better competitor than Tribolium confusum 67% of the time, when parasitic protozoan is introduce T. confusum is better 70% of time

Example of parasites changing community structure

Tidal mudflats: trematode impact Corophium microcrustaceans and cause mudflats to disappear

Transmission where parasite is in contact w/ host and infection is higher when overcrowding occurs

Direct transmission

Process where flies lay eggs on the hair of host (bots)

Myiasis

Horse botfly cycle

Eggs on hair → Horse licks itself and ingests eggs → 3rd instar is largest and most irritating, passed through feces → pupates and becomes adult

Obligatory myiasis

Needs a living host to complete life cycle

Facultative myiasis

Can use other means to complete life cycle such as carcass

Explain the warble fly

burrow into skin and have air hole to extract oxygen, feed on liking tissue until pupate

Explain the relationship between the warble fly and chipmunks

Chipmunks at high elevations tend to be more susceptible, warble fly can’t live in high elevations

Transmission where several hosts are required in a parasites life cycle, Host consumes eggs or is infected via a vector

Indirect transmission

What is an intermediate host

a host that houses asexually reproductive stages, usually a max of 3 in a life cycle

what is a Primary (Definitive) host

Final host that houses the sexually reproducing adults, usually a vertebrate

Explain the life stages of the meningeal worm

First stage infects snail → snails accidentally consumed by deer → infective stage travels to stomach and penetrates gut wall → spinal cord → brain where adults reproduce → larvae migrate to lungs → coughed up and swallowed by deer → passed through feces

Life cycle of Borrelia burodorferi (Lyme disease)

Vector is the larval and nymph stages of the Ixodes ticks, feed upon mice and other small rodents, humans can be effected, originated in Old Lyme Connecticut

What are some parasite specializations

Loss of symptoms

Abilities to deal with host defenses

Alter host biology to maximize use of host resources

Insure transmission to host

How does Trypanosoma evade the immune system

it switches its protein code

How can parasite impact host reproduction?

Reduce reproductive output by as much as 20%

Impact secondary sexual characteristics

Explain the Leucochloridium pardoxum life cycle, which one is prominent to snails?

Miracidium → sporocyst → Redia → Cercaria → Metacercaria

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Sporocyst migrates to tentacles of snail and them to be colorful and pulsate to attract birds

Explain the life cycle of Dicrocelium dentriticum

Consumed by snail → irritates mantle which produces slimeball infected with cercaria → Consumed by ants where the metacercaria migrate to ganglion causing it to clasp to the edge of vegetation → ant consumed by livestock

Explain the life cycle of Sacculina

Produce a free living larval stage (cypris)

In parasitic form, larvae attach via tentacles and sheds cirri → develops into a kentrogen larvae → injects into crab body and sheds carapace and shell → Develops into tumor like projection that burst out of where crab would carry eggs → causes crab to protect and aerate parasite mass

Requirements for direct transmission

Long lived infective stage

High host density

Requirements of indirect transmission

Low population level of parasites

Less dependent on high host density

Depends on vector or intermediate host

How can parasites act as biological control

Releasing parasites where host species are a problem

Explain Bacillus thuringiensis

Spores of bacteria are spread in water → ingested by mosquito larvae → interferes with feeding → grows into living adult in gut and produce more spores

What is Intraspecific brood parasitism

Parasitizes within its own species

What is Interspecific obligate brood parasite

lays eggs in nests of other species (less than 1% of birds)

Primary N.A. brood parasite

Brown-headed cowbird

Primary S.A. brood parasites

Giant cowbird and Shiny Cowbird

Advantage of spreading parasitic eggs throughout different species nests

Reduces nest predation

More likely for some offspring to survive

Adaptions of cowbirds

Extra layer of calcium carbonate so eggs can be dropped from height

Incubate eggs in the oviduct to get a head start

What caused the adaption of egg races in Giant cowbirds and old world cuckoos

High rejection rates, eggs that mimic host are less likely to be rejected

Explain the relationship between Giant cowbirds in Oropendola colonies

Oropendola colonies will allow parasitic eggs in areas of high fly infestation because the cowbird chicks will protect host chicks by picking off maggots

How do the Whydah evolve and select hosts

Select and evolve to hosts with similar mouth markings that illicit feeding response

What is the adaption of rolling behavior, what practices this behavior

Rolls other eggs out of nest to eliminate competition, European Cuckoo

Adaptions of African honeyguide nestlings

Hatch with hooked bill that can puncture eggs or kill host nestlings, ensures survival and reduces competition

How do brood parasites effect hosts? Example?

They reduce host fecundity. Kirtland’s warbler

Reduce parent survivorship

Host responses to brood parasites

Reject host eggs

Build nest over parasitized nest

Desert nest completely

Explain temporary facultative parasitism in relation to ants

Parasitic queen invades → lays eggs → brood takes over

Thread-like structures that make up the body of a fungus, responsible for absorbing nutrients from the environment (Lichen)

Hyphae

Spongy body produced by algae and fungi in lichens

Thallus

Type of lichen that appears to be painted on

Leprose

Type of lichen that looks like leaves

Foliose

Type of lichen that extends downwards

Fruiticose

Name for the mutualistic relationship between fungi and plant roots

Mycorrhize

Explain Mycorrize

fungi penetrate plant root cells to give rise to endomycorrhize, provides more surface area to go from endomycorrhize to exomycorrhize, increases absorptive surface area for roots to take up more nutrients

What is the above ground fruiting body produced by mycorrhize called

mushrooms

What is below ground fruiting bodies produces by mycorrhize called

truffles

What is the mutualistic relationship between legumes and bacteria

Legumes need nitrogen fixing bacteria like Rhizobium to change N2 → NH3

Mutual relationship between ants and acacias

Thorns of acacia provide food material for ant and place to house larvae, when herbivore comes ants overwhelm it.

Herbivore defense of fungi and johnson grass

Fungi- produces alkaloid compounds to protect plants

Johnson grass- produces cyanide gas after 1st freeze

Structure on seeds that is rich in protein and attracts ants to bring back to colony where plant can grow in nitrogen rich environment

Elaiosomes

How do plants attract pollinators

Aroma and color

What attracts bees and wasps to flowers

Bright colors that emit in UV spectrum

Utilize reproductive mimicry

What attracts beetles to plants/flowers

white to off-white color

odor

inferior ovary

What plant produces a flower shaped and colored like a bee

Orchid

How does pollination work

Pollen gathers on chitinous hairs and forms pollen basket that comes off on the stigma oof plant to fertilize the ovary

How do flowers attract moths and butterflies

Butterflies- sweet odors, bright colors

Moths-odor

Both- long corollas due to shape of proboscis

Explain the relationship between Hawk moths and the Tobacco plant

Hawk moth is main pollinator, attracted by release of benzyl acetone, lays eggs on tobacco plant, saliva triggers defense mechanism to switch flowering schedule to attract hummingbirds

How do flowers attract birds

little odor

Bright color

Produce large amounts of nectar

How many families of flowers rely on birds as pollinators

Around 60

North American bird pollinators

Orioles, hummingbirds

South American bird pollinators

Honeycreepers

African bird pollinators

Sunbirds

How do flowers attract bats

Nocturnal flower production

Fermenting type smell

Shape of flower for echolocation

Examples of bat pollinated plants

Saguaro cactus, banana, mango, agave

What is special about the Anoura fistulata

Has longest tongue of any vertebrate, housed in sheath between heart and sturnum

Explain commensalism in epiphytes

Use tree as habitat, provides microhabitat for vertebrates such as frogs

Examples of commensalism

Bacteria on skin

Lichen on trees

Epiphytes

What is Spanish moss

Unique epiphyte that provides habitat for nesting birds

Commensalism relationship of oxpecker

Picks ticks off grazing herbivores after already engorged, can sometimes pick at wounds causing - relationship

Commensalism relationship of cattle egret

Uses cow as foraging prop, cow startles insects as it moves

What is the commensalism relationship where eggs are transported by flying insects

Phoresy

Highest level ecology is studied

community

What is a community

Multiple species interacting with biotic and abiotic factors in a given area

What can differentiate communities

vegetation and biomes

Types of stratification in communities

Horizontal and Vertical

Number of species in a community is called what

Species Richness

Relative abundance of species in a community is what

Species Eveness

What allows the diversity to be compared across communities

diversity index/ Beta diversity

Shannon Index Equation

H=E pi (ln pi)

Higher diversity=more stable community

What is the relationship between species diversity and latitude

Species diversity tends to follow a latitudinal gradient

Time theory of higher species diversity at lower latitudes

tropical communities have been around longer and had more time to evolve