Ch 5 Part 2.docx

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26 Apr 2012
11/5/2010 10:37:00 AM
aposematic colouration wasps will sting you in response to a threat (it is
expensive to sting) if you get squashed and producing compounds
wasp stinger like a hypodermic needle, can sting repetitively even
when dead
honeybee: stinger remains in skin they will die after stinging you
both release an alarm pheromone to recruit more
generally organized in their defense
- figure
- alarm pheromone to recruit others bc they live in groups!
- Bioassay system for alarm pheromones in wasps
- how differently do they respond: movement or non movement?
White or black?
- swinging some things
see when they were agitated what they would attack
- diff types of extracts used as well
blood made no response
but if you use venom sac, 66 indiv responded, 64 responded attacked the
moving dark and none the pale (DON’T WEAR DARK COLOURS) – they
Japanese Hornet can actually cause serious problems when you get stung
- much larger than honeybees
- attack honeybees when they presence of the wasp, bees circularize
around, and flap wings until the predator passes out
Aphid make a droplet when attacked by enemies/threats
- when exposed to threats of diff intensities, how far away do they go and
what behaviours do they express?
- alarm pheromone made up of 1 compound called B farnesene
- most of them stay where they are when air is just blowing at them
- as the concn of alarm pheromone increases, they detect the danger, and
leave (behavioural displacement in response to the alarm pheromone) the
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more there is, the more danger = move farther alarm pheromones are
released by conspecifics
- play dead when it’s from the wind… thanene? only when its wind and
now when its real predators
B-farnesene can we used this to modify the behaviour of aphids (pests)
- the amount req to induce a response is diff bw sp!
- need a higher concn to get a response when its not the same thing bc not
the same “fit” by all diff sp
Effect of beta farnescene concn on the response of diff morp the green
peach aphid
- non feeding alates individuals with wings they respond very quickly
when they detect danger
- feeding alates sucking up good nutrients = TRADE OFF how important
are the dangers? Vs food? requires more alarm pheromone to initiate the
same response
- young adults leave at relatively low concn even with no wings (1-2 stage
little ones may not be detected, or preferred by predators so they
may not leave they are in less danger so less likely to respond
the ones closer to being sexually mature (wingless still) will respond
the really old individuals don’t move a lot, bc they have already
reproduced! They don’t really care if they are eaten!
- responses that you will see must be taken in an ECOLOGICAL CONTEXT
AND LIFE HISTORY OF ANIMAL and where they are in their lifetime
Chemical cues can be in an association with other cues
- only adult responds to a vibration (whack the plant) when predators walk
on a plant when there is a consistent vibration, they get an association
- same reasons as above!
Response of diff developmental stages of pea aphids to the alarm
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- 0 diff responses
- most instars don’t do anything (small, tiny, wont be found anyways)
- 4th instars more back up, more go
- now combine what happens when there is a vibration (predator) and bc
conspecific that reeleased an alarm pheromone!
more response when both are used
- take into consideration the geographic (WHERE u do the exper)
- diff when 2 cues compared to one
- response differ bw 2 poplns : Vancouver & Kamloops
bc diff ecological situations
near the coast cooler, more humidity (V.)
o higher dropping off plant (land on ground) ground not as
hot, losing humidity lower
o more likely to express this behaviour bc the environment
allows u to
inside; warmer, less humidity (Kamloops)
o less dropping of plant onto the ground you are like a lil ball
of water on DRY ground at hot temp = U WILL DESSICATE
- aphids produce alarm pheromones.. BUT NOT EVERYONE BEHAVES THE
SAME! You need to think about this. EXAM…
Ants are body guards for aphids
- how do diff sp affect it
- when exposed to lots of ants (mymercophilous), aphids drop less from the
plant bc they are protected
when exposed to same concn of alarm pheromone, non mymercophilous
respond and drop off plant bc not protected
mymercophilous = ANT LOVING (have them around you all the time)
- ants milk aphids for sugar water
- in return, they are body guards
Strongly mymercophilous aphids
- waggle bums around in the air releasing recruitment pheromone
when ants are there, most are stationary and waggle rear ends to recruit
and bring body guards in!
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