Term 2 Lecture 3: Function Of Communication Flashcards
Interspecific communication between animal species
Usually signals from prey to predators (predator deterrents):
- ‘flash’ behaviour - revealing a startling feature e.g. frilled lizard
- warning colours e.g. to show venomous or poisonous or to mimic creatures that are e.g. hoverfly markings mimic those of wasps
- distracting patterns e.g. eye pattern on butterfly wing
Attention grabbing actions - killdeer bird distracts fox from nest by flying up high and pretending to crash land with a broken wing and limping away
The fox follows in hope of an easy meal - once far enough from the nest she flies back
‘Playing dead’
E.g. possums - as many predators do not eat carrion
Alarm signals
Let’s predator know it’s been detected and has lost the element of surprise - it may then not waste effort on an attack e.g. meerkats have lookouts
Interspecific signalling between animal and plant species
Flowers often have UV honey guide visible to pollinators which communicate readiness/pollen availability
Intraspecific - signalling within own specie
-group spacing and coordination - distance/proximity as in a fish shoal or a wolf pack
- recognition of identity
- alarm signals
-finding food
-giving /soliciting care
-social status and conflict
-courtship and reproduction
Group spacing and coordination
E.g. signalling in primates
1) distance increasing signals (usually between groups) such as violent branch shaking to announce the troops presence
2) distance maintaining signals - home range spacing - as in dawn chorus of Howler monkeys
3) distance reducing signals - keep group members in touch such as the ‘lost’ call of a Cebus monkey
4) proximity maintaining signals as during social grooming
Note: visual signals are no use in dense jungle - hence monkey mostly use audio signals
Recognition
-avoids infertile mating- between members of closely related species e.g. courtship songs of 3 species of drosophila are each remarkably different
-deme recognition - e.g. White crowned sparrows have different ‘dialects’ so diff mating calls depending on where they originated from - individuals are able to recognise mates adapted to local conditions by local dialects, local mates will be better adapted to local conditions with better chance of survival
Neighbour recognition - many animals tend to stay in one area so tend to contact the same individuals repeatedly. It is a waste of time to respond intensely to same known neighbours each time e.g. European robin - neighbouring males/females recognise the songs of neighbouring territory holders and do not interact unless their territory is encroached. Whereas the song of a newcomer will elicit an intense response, same for Banner Kangaroo rats who recognise foot drumming seismic vibration patterns of their neighbours.
Kin recognition - differential responses to close relatives e.g. house mice (and humans.) Will choose genetically dissimilar individuals as mates as heterozygous offspring are more resistant to diseases and this minimises inbreeding. Also parent-offspring recognition. Identification is linked to scent.
Individual specific recognition- maintains specific social associations e.g. bottle nosed dolphins have complex signature whistles that they perform to identify themselves
Alarm
Intraspecific - alert group members to danger e.g. Vervet monkeys have alarm calls specific to different dangers
Leopard alarm call → climb trees
Eagle alarm call → look up
Snake alarm call → look down
Semantic referential communication.
Finding food
Signalling is an advantage of group living and increases foraging efficiency
Signals aid in acquisition of food/ exploitation of food resources
Typically there is a ‘selfish’ motivation for signalling e.g African wild dogs - prepare the group for a hunt with pre hunt dances to get the pack aroused and focused - self motivated as the better the group cooperate the more likely an individual is to get food.
Another e.g. domestic chickens - roosters signal elaborately to hens on finding food to show off their ability to provide and therefore their qualities as a potential mate
Colonies act as info centres for food sourcing - via eavesdropping (as in sea bird colonies) or intentional communication as between bees
Giving and soliciting care
Begging and offering food - between parent and offspring or amongst relatives e.g. Herring gull chicks peck the red spot on their parents bill to elicit regurgitation of food
Distress calls- by young e.g. seal pup cry alerts mother of hunger or danger
Soliciting play- e.g. play bows in canids
Agonism and social status: conflict
Conflict definitions:
Aggression- any activity directed towards the discomfiture of another individual (excludes play fighting)
Agonistic behaviour - behaviour patterns used during conflict with a conspecific (ie intraspecific aggression - excludes play fighting and predator-prey interactions)
Causes of conflict:
-limited resources
-patchy resources aka a heterogenous environment where resources tend to occur in concentrated areas
-Aggression of individuals
Resolving conflict:
E.g. blue tit contest over food - only 1% of agonistic conflict leads to a physical fight. Females will abandon food when a male arrives (Dom/sub) 2 birds of the same sex use ritualistic visual display
Submissive - head level or facing up
Aggressive - head down and wings spread.
E.g. grey seals - breeding colony compete for females, <4% male-male encounters lead to actual fighting.
So fight is display based : body slaps, vocals (hissing,) wide open mouth
Why are physical fights rare?
-potential high cost (energy expenditure and risk of injury)
-selection favours evolution of conflict resolution mechanisms that avoid it
- most conflict is resolved through display - displays must be unambiguous so are often highly stereotyped and ritualised
Avoiding conflict
Maintaining social space:
territories - as in wolf pack territories - clearly divided or within gannet colonies where nests are clearly spaced - each nest is just out of reach of being pecked by a neighbour.
Humans also show respect for personal space as seen in queueing.
Methods: scent marking at periphery of territory, dawn chorus of monkeys and birds
Appeasement and submission:
Dominance relationship nuzzling in male lions, subtle facial expressions in wolves, facial signalling as in Gelada Baboons (dominant lip curl to expose teeth, closing eyes to flash white eyelids subordinate responds with a different lip curl and open eyes)
Pre-fight displays:
Often related to physical size. Male deers parallel walk to display their bulk, similar to broadside displays of fighting fish, mountain lions expose teeth to show weapons in same way as deers show their antlers
Physical fights
Last resort (severe potential cost) - often ritualised. There’s a high chance of injury as physical fights usually occur between evenly matched individuals (because their initial displays were matched in strength)
Examples:
Big horn rams slam their heads together
Hummingbirds conduct aerial conflict which requires agility
Bull seals smack their torsos together and bite - bulk is important here
Escalation of conflict in red deer:
Conflict occurs during the annual rut to resolve a fight for mates.
In a survey of 50 Red deer conflicts on the Isle of Ruhm in Scotland
33 engaged in a roaring contest of which 17 parallel walked (16 one withdrew at this stage) leading to 8 fights (9 one withdrew at this stage)
17 did not have a roaring contest, of this group 7 parallel walked (10 one withdrew at this stage) then one group fought and the other 9 one withdrew
So out of 50 conflicts only 9 physical fights occured
Physical fights: Escalation of conflicts
Escalated aggression- most likely when contestants are evenly matched e.g. male cichlid fish fight escalation relates to similarity of opponents
Persistence and perception: even if contestants are evenly matched one may be more prepared to persist for longer or escalate it further as it has more to gain from winning
- motivation e.g. hunger/thirst - how desperate?
- perceived resource value such as resident Vs intruder - may lead to special signals of ownership e.g. land iguanas live in hot rocky deserts and need deep burrows to lay their eggs where they will be protected from predators and heat - due to the nature of the terrain there are few suitable places to dig burrows so they become a limited resource contested over by females. When a female without a burrow tries to evict a resident there’s a difference in relative perception of value. Resident females know the depth and quality of the burrow which decides how strongly they will defend it. Ownership provides understanding of a resource.
Resident Vs intruder
Prior ownership can influence contest outcome e.g. male speckled wood butterflies defend woodland territories specifically sunspots where female lay their eggs and males can fertilize them. Aerial contest so agility and speed is important - rule = owner wins. When researchers captured and removed the ‘owner’ another takes its place, when the former ‘owner’ is reintroduced it loses to the new ‘owner’ - the current owner always has the advantage and this may be due to the thermal advantage of owning a sunspot which gives energy to the owner
Conflict and eavesdropping
Observing encounters between other combatants may affect the observers behaviour in subsequent battles e.g. Siamese fighting fish - if a pair display across a glass divide until one backs down and a third fish observes this through a one way glass that third fish modifies it’s behaviour according to the outcome of the conflict - it will be slower to approach the winner than if it had not observed the fight. Female fish prefer a male they have observed winning and according to the audience effect opponents may fight harder in the presence of potential mates
