Raoul Mulder
Animal Behaviour Raoul Mulder
Resource competition
Lecture outline What to do when you are competing for food with others? Possible solutions: - ‘exploitative’ competition - resource defence - resource sharing
Rewards per individual!
Exploitative competition
Rich habitat!
Poor habitat!
a! Number of competitors!
Ideal Free Distribution
Animals distribute themselves according to their rate of food intake Ideal - complete information about resources Free - individuals free to move wherever they do best
0
Testing the IFD- mallard ducks
No. of ducks at site A
18
33 ducks
0 1
2
3
Time (min)
4
5
2:1 profitability ratio No. of ducks at less profitable site
1:1 profitability ratio 18
0 1
2
3
Time (min)
4
5
Answer: All geese will have access to the same amount of resources, regardless of the habitat they occupy. Ideal free distribution predicts that the number of animals in a habitat patch is proportional to its amount of resources. Therefore, all patches regardless of quality will eventually allocate the same amount of resources to each individual. The theory makes several assumptions, including: 1) animals are free to choose which patch they occupy; 2) animals have complete knowledge of the quality of each patch; and 3) all animals are competitively equal.
Number gaining access!
‘Despotic’ resource access
Rich habitat!
Poor habitat!
a!
b!
Number of competitors!
Benefits of resource defence Benefit: exclusive access to resource
Male chimps patrol territory boundaries, attack and kill neighbours One band killed 21 neighbours over 10 years
1km
Benefit: 20% expansion of territory (=more food, reproductive success)
Costs of resource defence Costs: e.g. energy expenditure, risk of injury
T-implanted ♂♂:
Percent of lizards active
80
Implants Control
60
40
20
• patrolled more 0600 • did more push-ups • used 30% more energy • died earlier 0
0800
1000
1200
Time of day
1400
1600
1. Lab studies: costs of activity Activity
Cost
Foraging for nectar
1,000 cal/h
Sitting on a perch
400 cal/h
Territory defence
3,000 cal/h
2. Field studies: time to extract nectar
Golden-winged sunbird Drepanorhynchus reichenowei
Nectar/flower
Time to get energy
1 µl
8 hours
2 µl
4 hours
3 µl
2.7 hours
(after Gill & Wolf 1975)
Average nectar per flower
Calculating activity costs defended undefended
6 4 2 0 7
9
11 13 15 Time of day
17
Defence favoured if Benefit > Cost
Economics of territory defence Energetic benefits of defence: - more nectar per flower (2µl to 3µl) means 1.3h foraging saved/day (1,000 x 1.3) (the energy it would otherwise have spent foraging) - (400 x 1.3) (the energy it now spends resting) 780 cal Energetic costs of defence: - birds spend about 0.28h/day on defence (3,000 x 0.28) (the energy now spent defending the resource) - (400 x 0.28) (the energy it would have spent just sitting on a perch) 728 cal
YES! 52Cal
Cooperative territory defence
40 minutes Pied wagtail Motacilla alba
20 minutes 20 minutes
Cooperative territory defence When to share? Solid triangles – satellite accepted Open triangles – satellite chased
Summary Ideal Free Distribution theory helps explain why animals sometimes select suboptimal habitat – less competition, equal fitness Resource defence evolves only when benefits from monopolisation exceed costs Resource sharing makes sense if cooperation reduces costs of territoriality
Cita%ons Slide-1 !_MG_2581!peacock!spider!Maratus!volans!by!Jurgen!O=o!(h=p://www.flickr.com/photos/59431731@N05/5521738809/).!!Reproduced!with!permission!from!Jurgen!O=o. ! Slide-3 ExploitaRve!compeRRon!graph!by!Milly!Formby!based!on!concepts!expressed!in:!(Davies!et!al.)"An"Introduc,on"to"Behavioural"Ecology."Fourth"Edi,on.!(2012)!John!Wiley!&!Sons!Ltd. ! Slide-4 Supermarket!check!out!(h=ps://commons.wikimedia.org/wiki/File:Supermarket_check_out.JPG)!By!Velela!(CC]BY]SA]3.0),!from!Wikimedia!Commons ! Slide-5 a)!!!!!!Figs!1!&2!from!Animal"Behaviour,!Volume!30.!!D.!G.!C.!Harper,!CompeRRve!foraging!in!mallards:!‘Ideal!Free’!Ducks,!pages!575]584,!1982.!Reproduced!with!permission!from!Elsevier b)!!!!!!Mallard!duck!about!to!fly!(h=p://www.public]domain]image.com/fauna]animals]public]domain]images]pictures/birds]public]domain]images]pictures/duck]mallard]pictures/mallard]duck]aboout]to]fly.jpg.html)!by! Art!Straub![Public!Domain] Slide-7 DespoRc!resource!access!graph!by!Milly!Formby!based!on!concepts!expressed!in:!(Davies!et!al.)"An"Introduc,on"to"Behavioural"Ecology."Fourth"Edi,on.!(2012)!John!Wiley!&!Sons!Ltd. ! Slide-8 a)!!!!!!Family...(SINGAPORE!ZOO/CHIMPANZEE)!IV!(h=p://www.flickr.com/photos/8285539@N07/753514880/)!by!Chi!King!(CC!BY!2.0) b)!!!!!!Figure!1!from!Current"Biology,!Volume!20,!Issue!12.!!Mitani,!J.!C.,!Wa=s,!P.D!and!Amsler,!S.J,!Lethal!intergroup!aggression!leads!to!territorial!expansion!in!wild!chimpanzees,!pages!R507]R508,!2010.!!Reproduced!with! permission!from!Elsevier.!! Slide-9 a)!!!!!!Vincent,!CJ!(2009)!‘CJ’s!Desert!Dwellers:!Desert!Spiny!Lizard!(Sceloporus"magister)!h=p://vimeo.com/5172000!Reproduced!with!permission!from!CJ!Vincent!and!WowArizona.com!Marshal!Hedin!(CC!BY]SA!2.5),!via! Wikimedia!Commons b)!!!!!!Graph!by!Milly!Formby!based!on!data!sourced!from:!!(Marler,!C.!A.!&!Moore,!M.C)!Supplementary!feeding!compensates!for!testosterone]induced!costs!of!aggression!in!male!mountain!spiny!lizards,!Sceloporus"jarrovi."" Animal"Behaviour!(1991)!42,!pp!209!–!219.!!The!AssociaRon!for!the!Study!of!Animal!Behaviour.!Elsevier. Slide-10 a)!!!!!!Golden]winged!Sunbird!(!Drepanorhynchus!reichenowi)!(h=p://www.flickr.com/photos/50079771@N08/4949237180)!by!Steve!Garvie!(CC!BY]SA!2.0) b)!!!!!!Tables:!Data!sourced!from!(Gill,!F.G!and!Wolf,!L.!L.)!Economics!of!Feeding!Territory!in!the!Golden]Winged!Sunbird.!!Ecology!(1975)!56,!pp!333]!345. c)!!!!!!!Graph!by!Milly!Formby!based!on!data!from!(Gill,!F.G!and!Wolf,!L.!L.)!Economics!of!Feeding!Territory!in!the!Golden]Winged!Sunbird.!!Ecology!(1975)!56,!pp!333]!345.!! Slide-11 Nectarinia!Reichenowi!Keulemans!(h=p://commons.wikimedia.org/wiki/File%3ANectariniaReichenowiKeulemans.jpg)!by!John!Gerrard!Keulemans![Public!domain],!via!Wikimedia!Commons
Slide 12 a) Pied Wagtail (Motacilla alba) (12) (http://commons.wikimedia.org/wiki/File%3APied_Wagtail_%28Motacilla_alba%29_%2812%29.JPG) By Ken Billington (Own work) (CC-BY-SA-3.0), via Wikimedia Commons b) Territory defence diagram by Milly Formby (CC BY-SA-3.0) [featuring “Pied Wagtail (Motacilla alba) (10) by By Ken Billington (Own work) (CC-BY-SA-3.0), via Wikimedia Commons] based on concepts expressed in: (Davies et al.) An Introduction to Behavioural Ecology. Fourth Edition. (2012) John Wiley & Sons Ltd. Slide 13 Food sharing within territory graph by Milly Formby based on data from: Chapter 5: (Davies et al.) An Introduction to Behavioural Ecology. Fourth Edition. (2012) John Wiley & Sons Ltd.
Resource competition
Lecture outline What to do when you are competing for food with others? Possible solutions: - ‘exploitative’ competition - resource defence - resource sharing
Rewards per individual!
Exploitative competition
Rich habitat!
Poor habitat!
a! Number of competitors!
Ideal Free Distribution
Animals distribute themselves according to their rate of food intake Ideal - complete information about resources Free - individuals free to move wherever they do best
0
Testing the IFD- mallard ducks
No. of ducks at site A
18
33 ducks
0 1
2
3
Time (min)
4
5
2:1 profitability ratio No. of ducks at less profitable site
1:1 profitability ratio 18
0 1
2
3
Time (min)
4
5
Answer: All geese will have access to the same amount of resources, regardless of the habitat they occupy. Ideal free distribution predicts that the number of animals in a habitat patch is proportional to its amount of resources. Therefore, all patches regardless of quality will eventually allocate the same amount of resources to each individual. The theory makes several assumptions, including: 1) animals are free to choose which patch they occupy; 2) animals have complete knowledge of the quality of each patch; and 3) all animals are competitively equal.
Number gaining access!
‘Despotic’ resource access
Rich habitat!
Poor habitat!
a!
b!
Number of competitors!
Benefits of resource defence Benefit: exclusive access to resource
Male chimps patrol territory boundaries, attack and kill neighbours One band killed 21 neighbours over 10 years
1km
Benefit: 20% expansion of territory (=more food, reproductive success)
Costs of resource defence Costs: e.g. energy expenditure, risk of injury
T-implanted ♂♂:
Percent of lizards active
80
Implants Control
60
40
20
• patrolled more 0600 • did more push-ups • used 30% more energy • died earlier 0
0800
1000
1200
Time of day
1400
1600
1. Lab studies: costs of activity Activity
Cost
Foraging for nectar
1,000 cal/h
Sitting on a perch
400 cal/h
Territory defence
3,000 cal/h
2. Field studies: time to extract nectar
Golden-winged sunbird Drepanorhynchus reichenowei
Nectar/flower
Time to get energy
1 µl
8 hours
2 µl
4 hours
3 µl
2.7 hours
(after Gill & Wolf 1975)
Average nectar per flower
Calculating activity costs defended undefended
6 4 2 0 7
9
11 13 15 Time of day
17
Defence favoured if Benefit > Cost
Economics of territory defence Energetic benefits of defence: - more nectar per flower (2µl to 3µl) means 1.3h foraging saved/day (1,000 x 1.3) (the energy it would otherwise have spent foraging) - (400 x 1.3) (the energy it now spends resting) 780 cal Energetic costs of defence: - birds spend about 0.28h/day on defence (3,000 x 0.28) (the energy now spent defending the resource) - (400 x 0.28) (the energy it would have spent just sitting on a perch) 728 cal
YES! 52Cal
Cooperative territory defence
40 minutes Pied wagtail Motacilla alba
20 minutes 20 minutes
Cooperative territory defence When to share? Solid triangles – satellite accepted Open triangles – satellite chased
Summary Ideal Free Distribution theory helps explain why animals sometimes select suboptimal habitat – less competition, equal fitness Resource defence evolves only when benefits from monopolisation exceed costs Resource sharing makes sense if cooperation reduces costs of territoriality
Cita%ons Slide-1 !_MG_2581!peacock!spider!Maratus!volans!by!Jurgen!O=o!(h=p://www.flickr.com/photos/59431731@N05/5521738809/).!!Reproduced!with!permission!from!Jurgen!O=o. ! Slide-3 ExploitaRve!compeRRon!graph!by!Milly!Formby!based!on!concepts!expressed!in:!(Davies!et!al.)"An"Introduc,on"to"Behavioural"Ecology."Fourth"Edi,on.!(2012)!John!Wiley!&!Sons!Ltd. ! Slide-4 Supermarket!check!out!(h=ps://commons.wikimedia.org/wiki/File:Supermarket_check_out.JPG)!By!Velela!(CC]BY]SA]3.0),!from!Wikimedia!Commons ! Slide-5 a)!!!!!!Figs!1!&2!from!Animal"Behaviour,!Volume!30.!!D.!G.!C.!Harper,!CompeRRve!foraging!in!mallards:!‘Ideal!Free’!Ducks,!pages!575]584,!1982.!Reproduced!with!permission!from!Elsevier b)!!!!!!Mallard!duck!about!to!fly!(h=p://www.public]domain]image.com/fauna]animals]public]domain]images]pictures/birds]public]domain]images]pictures/duck]mallard]pictures/mallard]duck]aboout]to]fly.jpg.html)!by! Art!Straub![Public!Domain] Slide-7 DespoRc!resource!access!graph!by!Milly!Formby!based!on!concepts!expressed!in:!(Davies!et!al.)"An"Introduc,on"to"Behavioural"Ecology."Fourth"Edi,on.!(2012)!John!Wiley!&!Sons!Ltd. ! Slide-8 a)!!!!!!Family...(SINGAPORE!ZOO/CHIMPANZEE)!IV!(h=p://www.flickr.com/photos/8285539@N07/753514880/)!by!Chi!King!(CC!BY!2.0) b)!!!!!!Figure!1!from!Current"Biology,!Volume!20,!Issue!12.!!Mitani,!J.!C.,!Wa=s,!P.D!and!Amsler,!S.J,!Lethal!intergroup!aggression!leads!to!territorial!expansion!in!wild!chimpanzees,!pages!R507]R508,!2010.!!Reproduced!with! permission!from!Elsevier.!! Slide-9 a)!!!!!!Vincent,!CJ!(2009)!‘CJ’s!Desert!Dwellers:!Desert!Spiny!Lizard!(Sceloporus"magister)!h=p://vimeo.com/5172000!Reproduced!with!permission!from!CJ!Vincent!and!WowArizona.com!Marshal!Hedin!(CC!BY]SA!2.5),!via! Wikimedia!Commons b)!!!!!!Graph!by!Milly!Formby!based!on!data!sourced!from:!!(Marler,!C.!A.!&!Moore,!M.C)!Supplementary!feeding!compensates!for!testosterone]induced!costs!of!aggression!in!male!mountain!spiny!lizards,!Sceloporus"jarrovi."" Animal"Behaviour!(1991)!42,!pp!209!–!219.!!The!AssociaRon!for!the!Study!of!Animal!Behaviour.!Elsevier. Slide-10 a)!!!!!!Golden]winged!Sunbird!(!Drepanorhynchus!reichenowi)!(h=p://www.flickr.com/photos/50079771@N08/4949237180)!by!Steve!Garvie!(CC!BY]SA!2.0) b)!!!!!!Tables:!Data!sourced!from!(Gill,!F.G!and!Wolf,!L.!L.)!Economics!of!Feeding!Territory!in!the!Golden]Winged!Sunbird.!!Ecology!(1975)!56,!pp!333]!345. c)!!!!!!!Graph!by!Milly!Formby!based!on!data!from!(Gill,!F.G!and!Wolf,!L.!L.)!Economics!of!Feeding!Territory!in!the!Golden]Winged!Sunbird.!!Ecology!(1975)!56,!pp!333]!345.!! Slide-11 Nectarinia!Reichenowi!Keulemans!(h=p://commons.wikimedia.org/wiki/File%3ANectariniaReichenowiKeulemans.jpg)!by!John!Gerrard!Keulemans![Public!domain],!via!Wikimedia!Commons
Slide 12 a) Pied Wagtail (Motacilla alba) (12) (http://commons.wikimedia.org/wiki/File%3APied_Wagtail_%28Motacilla_alba%29_%2812%29.JPG) By Ken Billington (Own work) (CC-BY-SA-3.0), via Wikimedia Commons b) Territory defence diagram by Milly Formby (CC BY-SA-3.0) [featuring “Pied Wagtail (Motacilla alba) (10) by By Ken Billington (Own work) (CC-BY-SA-3.0), via Wikimedia Commons] based on concepts expressed in: (Davies et al.) An Introduction to Behavioural Ecology. Fourth Edition. (2012) John Wiley & Sons Ltd. Slide 13 Food sharing within territory graph by Milly Formby based on data from: Chapter 5: (Davies et al.) An Introduction to Behavioural Ecology. Fourth Edition. (2012) John Wiley & Sons Ltd.
