use of space: territory and habitat selection. some basics of natural selection evolution –...

USE OF SPACE:TERRITORY AND HABITAT SELECTION

Some basics of Natural Selection

Evolution – pattern of change

Natural Selection – process by which evolution occurs-change in gene frequency in a population

Sexual Selection – subset of natural selection dealing with different reproductive interests of the sexes

Some basics of Natural Selection

Individuals do not evolve

Evolutionary change happens through the differential reproduction of organisms with different suites of characteristics

Behavioural Ecology

- Look at costs and benefits

Cost –any factor that reduces reproductive success (directly or indirectly)

Benefit –any factor that increases reproductive success (directly or indirectly)

Strategy – a set of behavioural courses of action with a given survival value under a particular set of conditions

In a successful strategy

C < B or CB

<1

Territory vs. Home Range

Territory

- an area occupied by an animal or group of animals from which others are excluded by aggression or threat

Functional Classification of Territories

Mating Territory


Breeding Territory


Feeding Territory

Greater Shearwater (Puffinis gravis)


Multipurpose Territory

Territory - Participation Level

Individual


Pair


Group

Territory - Structure

Size affected by:1) Species2) Function

Mating Breeding Feeding Multipurpose


Size affected by:1) Species2) Function3) Body Size

Log body size

Log territory size


Size affected by:1) Species2) Function3) Body Size4) Food habits

Non predator

Predator


Size affected by:1) Species2) Function3) Body Size4) Food habits5) Age


Size affected by:1) Species2) Function3) Body Size4) Food habits5) Age6) Population density7) Predator pressure8) Food abundance

Size

Population density or Predator pressure or Food abundance


Defining the Boundaries

Tendency to fightTendency to flee

Tendency High Low

Distance from centre of territory

Tendency

Fight Flee

Boundary

Territory - Advertising

Modalities

Visual


Modalities

Acoustic


Modalities

Chemical

Territory - Economics and Costs vs Benefits

Resource quality and distribution

Quality

Distribution

High

Low

Sparse Clumped

Defendability


Resource quality and distribution (Holldobler & Lumsden, 1980)

Honey AntMyrmecocystus mimicus

Harvester AntPogonomymex barbatus

Weaver AntOecophylla longinoda

Insects in vegetation

Uniform distribution in space and stable over time

Patches of seeds on the ground

Patchy distribution in space and stable over time

Termites under dung

Patchy distribution in space and unstable over

time

What kind of territory is most effective for each??


Resource quality and distribution (Holldobler & Lumsden, 1980)

Honey Ant - Myrmecocystus mimicusHarvester Ant - Pogonomymex barbatusWeaver Ant - Oecophylla longinoda

Insects in vegetation Patches of seeds on the ground Termites under dung

3 dimensional territorymultiple nests Central nest

temporary foraging trails

Temporary territory around resource

Territory - Economics and Costs vs BenefitsResource quality and distribution

Territory Size

costs

benefits

Costs orbenefits

x y

x = smallest economically defendable territory

y = largest economically defendable territory

Z

Z = territory with the greatest net benefit


Territory Size

costs

benefits

Costs orbenefits

x yZ

= increased costs

Z’

decrease territory size

y’


Territory Size

costs

benefits

Costs orbenefits

x yZ

= increased benefits

Z’

decrease territory size

x’


Currency - what is being optimized

- maximum net calorie intake ?

- maximum net nutrient intake ?

- minimize daily variation in food intake ?

- decrease exposure to predators?

- maximize the number of mates attracted?

An currency is optimized within the context of the overall energy budget


Case study #1 - Rufous hummingbird (Selasphorus rufusi)



Day 1 Day 7

FlowersTerritories

4000

3000

2000

1000

0

20

15

10

5

0



LogTerritory

Size

Log Flower Density

Predicted

Observed


LogTerritory

Size

Log Floral Unit Density

Predicted

Observed


Motacilla alba Pied wagtail


Motacilla albaRenewal time = 40 mins


Motacilla albaRenewal time = 20 mins


Motacilla alba

Food supply Behaviour

Very low - feed elsewhere- return to evict intruders

Moderate - stay & feed on territory- evict intruders

High - share territory with satellite

Very high - feed on territory- no attempts to defend

Territory - Economics and Costs vs BenefitsCosts of holding a territory

Territoryholder

Satellite

Mnais pruinosa

Lif

esp

an (

day

s)


Yarrow’s spiny lizard

Experimentals

Controls

Capture in non-territorial season

Implant with testosterone capsule

Release

Implant with empty capsuleRelease

Capture in non-territorial season



Time of Day

0600 1200 1800

Implants

Controls

% a

ctiv

e



Days

0 10 20 30 40 50 60 70

Implants

Controls

% a

live

Controls + supplement


Side blotched lizard


Side blotched lizard

Yellow Blue Orange

Tes

tost

eron

e le

vel

Surv

ivor

ship

Orange Blue Yellow

Large territories,multiple females

Small territories,one female

No territory,‘sneaker’

Territory - Economics and Costs vs BenefitsBenefits of holding a territory

American redstartSetophaga ruticilla

Winter territories

Territory - Economics and Costs vs BenefitsBenefits of holding a territory

American redstartSetophaga ruticilla

Winter territories

April May

12 30 1 15

% Departing

Mangrove residents

Forest residents

use of space: territory and habitat selection. some basics of natural selection evolution –...

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