Lecture 11 – LIFE HISTORY STRATEGY

Life History Strategy A suite of traits that improve an individual's chances of surviving and reproducing in a particular environment

1.Energy committed to one function is not available for others. COST/BENEFIT ANALYSIS

1.Energy committed to one function is not available for others. 2.Every evolutionary ‘choice’ has costs and benefits COST/BENEFIT ANALYSIS Settles on wave exposed shore Costs -energy in holding on -restricted movement for food gathering Benefits -less exposure to predators -more food delivery -size restriction -less energy directed to growth

1.Energy commited to one function is not available for others. 2.Every evolutionary ‘choice’ has costs and benefits 3.Every organism represents a compromise of a number of evolutionary ‘choices’ COST/BENEFIT ANALYSIS Periclimenes yucatanicus Colour - bright & obvious to predators - disruptive Hides in anemone – restricted foraging but has protection Exoskeleton – restricts movement but offers protection

Macarthur and Wilson (‘70’s) - Theory of Island Biogeography r strategists K strategists Equilibrium -slower colonizing, slow growth Opportunistic -rapidly colonizing, fast growth R.H. Macarthur E.O. Wilson

Attributes of r and K - selected organisms r - selectedK - selected Climate Mortality Population Size Community Characteristics Lifespan Allocation of Energy Individual Attributes Variable, unpredictible Density independent, uncertain adult survival Variable, below K Few species, recolonization Short Rapid development, early reproduction, high rate of increase, small body size Greater % to reproduction Consistent, predictible Density dependent, uncertain juvenile survival Consistent More species, no recolonization Long Slow development, late reproduction, low rate of increase, larger body size Greater % to growth and maintenance Consistent, predictible Density dependent, uncertain juvenile survival Consistent More species, no recolonization Long Slow development, late reproduction, low rate of increase, larger body size Greater % to growth and maintenance

r - selectedK - selected ClimateVariable, unpredictibleConsistent, predictible Mortality Density independent, uncertain adult survival Density dependent, uncertain juvenile survival Population SizeVariable, below KConsistent Community Characteristics Few species, recolonization More species, no recolonization LifespanShortLong Individual Attributes Rapid development, early reproduction, high rate of increase, small body size Slow development, late reproduction, low rate of increase, larger body size Allocation of Energy Greater % to reproduction Greater % to growth and maintenance Attributes of r and K - selected organisms Productivity

r - selectedK - selected ClimateVariable, unpredictibleConsistent, predictible Mortality Density independent, uncertain adult survival Density dependent, uncertain juvenile survival Population SizeVariable, below KConsistent Community Characteristics Few species, recolonization More species, no recolonization LifespanShortLong Individual Attributes Rapid development, early reproduction, high rate of increase, small body size Slow development, late reproduction, low rate of increase, larger body size Allocation of Energy Greater % to reproduction Greater % to growth and maintenance Attributes of r and K - selected organisms ProductivityEfficiency

More r - likeMore K - like Look at our original energy allocation graphs

r-strategistK-strategist Frequent disturbance r - K continuum Less frequent disturbance

Death recruitment Aclonal Life History Sexual reproduction

Death recruitment Clonal Life History Fission Sexual reproduction

EGG AND SPERM PRODUCTION FERTILIZATION PATTERNS TYPES OF DEVELOPMENT LARVAL DISPERSAL STRATEGIES SETTLEMENT PATTERNS Life history pattern -- a genetically inherited pattern of resource allocation to that optimizes the passing of genes to the next generation

Fertilization Patterns 1. External (no copulation)

Fertilization Patterns 1. External (no copulation) Problems Gamete output Synchrony Gamete dispersal Gamete dilution

Fertilization Patterns 1. External (no copulation) Problems Gamete output Synchrony Gamete dispersal Gamete dilution % success Distance between individuals 0.5 m 100

Fertilization Patterns 1. External (no copulation) Allee Effect Reproductive rate Number or Density

Fertilization Patterns 2. Internal (no copulation)

Fertilization Patterns 2. Internal (copulation)

Fertilization pattern CostsBenefits External Fertilization-large gamete output -need for synchrony -unpredictable dispersion -gamete dilution -takes advantage of medium Internal Fertilization (no copulation) -large gamete output -unpredictable dispersion -gamete dilution -takes advantage of medium Internal Fertilization (copulation) -energy in mate searching -energy in courtship -less gamete wastage -greater efficiency in reproduction

Overview – Life History Patterns 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns ✓

Developmental Patterns -Kinds of eggs Isolecithal Telolecithal yolk 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Developmental Patterns -Kinds of eggs Isolecithal Telolecithal Cleavage through entire egg Cleavage not through entire egg 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Developmental Patterns -Kinds of eggs Isolecithal Telolecithal Cleavage through entire egg Cleavage not through entire egg Holoblastic Meroblastic 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Developmental Patterns -Kinds of eggs Isolecithal - HoloblasticTelolecithal - Meroblastic 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Developmental Patterns -Kinds of eggs Isolecithal Telolecithal Holoblastic Meroblastic Planktotrophic larvae Lecithotrophic larvae 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Kinds of Development Patterns Free spawning Planktotrophic, free-swimming larvae Settlement and metamorphosis Juvenile Maturation Weakly isolecithal egg Indirect Free spawning Planktotrophic, free-swimming larvae Settlement and metamorphosis Juvenile Maturation Strongly/moderately telolecithal egg Indirect Mating Brooding of embryos Hatch as juvenilesMaturation Strongly telolecithal egg Direct Mating Brooding of embryos Hatch as free- swimming larvae Juvenile Maturation Moderately telolecithal egg Mixed Settlement and metamorphosis 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement – Large Scale 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns 0.2 % recovery 0.18 % recovery 0.2 % recovery Scheltema ‘71

Larval Settlement – Large Scale 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Scheltema ‘71 Larval Settlement – Large Scale 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns Population size Frequency of dispersal

Scheltema ‘71 Larval Settlement – Large Scale 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns North Atlantic Drift Volume of water (m 3 )Total number of larvae North Equatorial Current Equatorial Undercurrent South Equatorial Current 2.45 x x x x x x x x 10 11

Point Conception Larval Settlement Large Scale 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Point Conception Larval Settlement Large Scale Current Patterns 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Point Conception Larval Settlement Large Scale Current Patterns Biogeographical Zones 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Embayment Flushing (Gaines & Bertness, ‘92) 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Wind & Tidal Currents Associated with internal waves 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Settlement - Behaviour of Larvae Lobster hatches -photopositive- Drifts in plankton (days/weeks) Preference switches to photonegative Lobster settles and undergoes metamorphosis Metamorphosis to postlarva 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

3. Benthic/Surface Phenomena Pawlik et al, ‘91. Science 251:421 - settlement of reef-building worm Current Speed -low -medium -high (>15 cm/sec) Phragmatopoma 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

3. Benthic/Surface Phenomena Pawlik et al, ‘91. Science 251:421 # settling Current No ‘sampling’Erosion 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Early models Larvae in water column Settle randomlyDifferential mortality Adult distribution More recent view Larvae in water column Passive depositionTesting substrate Settle Adult distribution Not settle 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Passive Deposition -due to 1) sedimentation rate 2) swimming behaviour 3) bottom flow patterns 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Bottom flow patterns Laminar flow 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Bottom flow patterns x x x xx Change in angular velocity 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Experiment on settling and flow Botman et al 1998 coarse sand rich muds Capitella Mercenaria

Experiment on settling and flow Glass beadsMud Flow

Experiment on settling and flow Still water Flow MudBeadsMudbeads Capitellayesnoyesno Mercenarianoyes No preference Conclusion - choice is species specific - Mercenaria couldn’t ‘sample’

General Model Free swimming larva Alternating photonegative & photopositive behaviour Passive deposition and contact with surface Surface texture Chemical cuesContact with conspecifics Attachment 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 1. Conspecifics 2. Microbial films 3. Prey species 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 1. Conspecifics Free fatty acids Larval settlement Phragmatopoma 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 2. Bacterial films Polysaccharides, Glycoproteins Increased searching or metamorphosis 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 3. Prey species - herbivores Settlement induced by GABA 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 3. Prey species - herbivores Gigartina Porphyra Abalone larva In field -not found on either -not induced to settle on whole fronds 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 3. Prey species - carnivores Onchidoris bilamellata Induces settlement 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns

Larval Settlement 3. Prey species - carnivores Phestilla Induces settlement < 500 Da protein (< 10 mM) 1) Fertilization patterns 2) Development patterns 3) Dispersal patterns 4) Settlement patterns