Lecture 29 Flashcards
mutualism
an ecological interaction b/w spp that benefits both interacting spp
Should be better off through their engagement than without it
what are 3 exs of insect mutualism?
Pollination: bees & plants
Improved nutrition of blood: sucking lice, bed bugs, tsetse flies, etc. & microbes
Have special microbes in their gut enabling the digestion of blood
Farming?
describe how humans farming cattle is a mutualistic relationship
Humans use livestock to process low quality food (grass etc.) into high quality food (meat, milk, etc.)
Livestock benefit b/c here are more cattle b/c of farming
Ants locate aphid groups & control them by: (3)
Herding behaviour
Maintain aphids in areas of younger parts of plants b/c it is more nutritious
Wing removal of alate aphids
Aphids can be polymorphic – ants don’t want the aphids to leave so they remove their wings
Secretion of chemicals that slow aphid walking
how do ants protect aphids against their aggressors (predators/parasitoids)?
Attacking with their mandibles (Ladybeetles have a protective body shape)
Spraying formic acid
who is a parasitoid of aphids?
hover fly larvae
how do ants harvest the aphids?
“milk” aphids by swallowing excreted droplets of honeydew
occasionally eat aphids when their demand for PRO is required
what is the carb-rich material secreted by aphids that ants harvest?
honeydew
Ants travel from aphid herds to nests aided by ____ ____
trail pheromones
how do ants transfer their food to other ants?
trophallaxis
Drink the honeydew & transfer it to other ants orally
trophallaxis
Ant to ant food transfer (oral transfer)
T or F - all ants can act as storage
T
what are repletes?
honey pod ants have a caste (social stratification) where these ants are specialized to store food for times of shortage by expanding their membranes
how are the repletes emptied?
trophallaxis
when are repletes used?
When production is higher than demand they store the honeydew
what are the 2 food sources that honey pod ants harvest?
honeydew
nectar
only the ____ tribe of ants farm for fungus
Attini
where are the Attini ants distributed?
Central & South America
who are the equivalents in Africa & Asia to Attini ants?
termites
Attini tribe has an _______ ________ on _____ _____ for food
obligate dependence
symbiotic fungi
Atta nests up to _____ tons of soil
40 tons of soil
what spp of ants have polymorphic spp (castes of workers specialized)? & what is the form of polymorphism?
Atta & Acromyrmex
polymorphic size
_____% leaf damage & ____% biomass consumption in rainforests (most productive ecosystem)
80%
17%
In grasslands Atta spp consumes the same biomass of vegetation per hectare as _____
cattle
what % of cellulose is converted in carbs by Atta spp?
45%
Describe how ants make their fungus nests
A. ants harvest leaf pieces
Done with powerful mandibles
Requires a lot of force
Acquired with quick shivering movement of mandibles
B. Pheromone trail of transporter workers
Go into nest
C. Transporter workers give pieces to processing workers
Bring material to fungus garden
D. Leaf pieces converted to mulch substrate for fungal growth (chew)
Fungus produces gongylidia which are food for ants
E. The queen sits on the fungus garden laying her eggs
Larvae eat the gongylidia & are cared for by nurse workers
F. Waste leaf material, dead ants & dead fungus are transported to dump chambers
Located separately from gongylidia
gongylidia
specialized structure produced by the fungus to provide ants with a food source
does the fungus benefit by creating gongylidia?
nope
gongylidia are rich in _____
carbs
the separation of waste materials provides what ecological service?
important for fertility of soil
Fungus growth in ideal conditions of _________, __________ & _________
temperature, humidity & darkness
how do ants encourage the growth of the fungus?
remove wax on plant material
what compound does the fungus feed on?
cellulose
what crop management do ants practice?
Fertility management
Waste management
Cultivar selection & monocultures
Collection of ______ leaf fragments/year
6000kg
do ants feed on a variety of fungi spp?
no
how does the queen ant est her colony?
Before a mating flight, a queen collects a small amount of fungus in her mouth
She carries the fungus until she establishes a nest, then uses it to start a new fungus garden
After mating the queen stores 206 – 320 million sperm (last ~10 years of queen life)
Female will make a tunnel, leave some fungi, lay eggs & has workers to begin the colony
In the most evolved fungal farmers, the fungus ________
cannot survive without the ant
Each ant grows a _____ range of fungal cultivars
narrow
describe pest management strategies
can be invaded by other fungi & bacteria
Gardeners weed the garden & secrete compound that promote fungal growth & suppress pests
describe the role of the fungicide producing bacteria
Patches of bacteria on thorax of ant
Produces fungicide compounds that attacks pest fungus
Queens on mating flights carry bacterial fungicide producers to use in the new colony
Myrmecochory
seed dispersal by ants
Elaiosomes
food bodies on seeds with chemical attractants for ants
nutritious & easy for ants to eat
Elaiosomes are present in plants of what distribution?
Australia & Africa
how do elaiosomes spread?
Soft structure, but seeds are hard to the ants so they move the seeds to the waste chambers
ants carry them to the nest but are hard so they’re discarded
