Midterm 3 Flashcards
Benefits and negatives of communication
- provide clues of how to behave
- receivers don’t waste energy by responding incorrectly
- can get away form predation
- reduction in level of uncertainty of environment
-some organisms can give away location by communicating
Deliberate or intentional signalling
Non intentional signalling
Where natural selection has resulted in behavioural or physiological events that produce Intro for which the function is communication
When the presence of or activity of an animal leaves detectable traces in the environment
Costs of signalling for transmitted and receivers
Resources devoted to production and processors, possibility of exploitation by “unfriendly” receivers.
Resources devoted to receptors and processors, possibility of exploitation by “unfriendly” transmitters
For the cuckoo and reed warbler and the orchid and wasp examples, who are the unfriendly receivers or transmitters?
Cuckoo is unfriendly transmitter to foster warbler who must fee it.
Orchid is unfriendly transmitter to thynnine wasp
Parasitoid fly
Female flies lay parasite eggs in host tissues of an insect. They listen to cricket songs to find host. Female flies can hear the frequency of crickets because they have sensitive sound. Males ears are tuned differently and can’t hear. Male crickets voice is exploited. Female fly is an “unfriendly receiver”
Hyena signalling
Female hyenas have a pseudopenis (enlarged clitoris) that acts as a signal of subordination to show she doesn’t want to fight.
Male hyenas approach group of hyenas with an erect penis to show submission and avoid aggression.
Male Red deer example
Bugleing (vocalizing) sends a message to
- Show stays to other males (bigger body= lower frequency, high intensity and longer sound. If mother bull hears a sound equal to there’s they will fight.
- Tells females how good a mate they are
Semiochemical
A chemical (molecule, atom) that in the natural context conveys info in an interaction between two individuals, evoking in the receiver a behavioural response.
Pheromone
A semiochemical that mediated an Intraspecific interaction (signaller/ received may benefit or be harmed.
(+,-)
(-,+)
(+,+)
Allelochemical
Semiochemical that mediates an interspecific interaction
Ex: beetle and ant
Types of allelochemicals
Allomone- adaptive to signaller
(+,-)
kairomone-adaptive to receiver
(-,+)
Synomone-adaptive to both
signaller and receiver
(+,+)
(Transmitter, receiver)
Bolas spider
Drops mimic sex pheromone with silk, swinging it to disperse into air. Attracts a moth which is eaten.
Allomone (+,-)
Interspecific
Rabbit and coyote
Rabbit leaves smell in Forrest, coyote follows and eats it.
Kairomone (-,+)
Interspecific
Aphids
Tiny bugs that ruin crops produce sugary water fluid=honeydew. Carbs in honeydew are good energy sources. Ants game aphids and eat honeydew and ants drive away predators. Aphids release chemical alarm signal to drive off predator.
(+,+)
Interspecific
(+,+) pheromones
Sex pheromones of same species
(+,-) pheromone example
Honey bees lice in colonies with queen who just lays eggs. All worker females are reproductively sterile because queen produces pheromone to make their ovaries stop developing but the queen is immune to.
(-,+) pheromone example
If female are close to ovulation. the males can tell by a smell. An unqualified male may approach to mate. Males can be aggressive and mate regardless
(-,+)
Why are chemicals good info carriers
- they work in dark environments, visually interrupted environments
- messaging situations where sender and receiver are not present simultaneously (smells linger)
- currents (air or water downstream)
- distance signalling
Turbulent flow
In nature air moves in this form which is not a straight line, but irregular.
Not laminar flow (only in lab)
How do bees communicate location of good sources of nectar?
Scout bees go out and find good flowers, then they go back to colony leaving a trail of pheromones specific to their colony for others to lead.
Works up to hours after
Message dispersal by fluid movement
In air or water
Saves energy and increases the range over which chemicals may be effective because it is quicker than diffusion, but decrease the number of directions in which info can be transmitter.
Only disperse downstream
Describe how chemicals released disperse in air and result in casting behaviour
As chemical moves away molecules move downstream and outward which drops the concentration. Is it moved further it breaks up chemicals leaving patches of pheromone and pockets of nothing. Followers turn into wind and then left or right to pick up more. If smell is faint they turn other way, if strong follow. This creates a zig zag flight or casting. Once stimulation stops they turn back or opposite way. Amplitude if turns shorten the closer to the plume they get.
Volatility
Varies with molecule weight
- small molecules evaporate quicker
- bigger molecules are subject to gravity more
Describe volatility of CO2 and how water vapour attracts mosquitos
Sleeping humans breathes and produces moisture,CO2 and body odour. Closer to human has more moisture (water is heavy), CO2 has intermediate volatility, more CO2 near human than surrounding environment.
Body odours are very small and travel far distances
