Cgs Talk Jan 2009

Cooperative Defense by Non-Kin Related Caribbean Cooperative Defense by Non-Kin Related Caribbean Spiny Lobsters Under Attack by Cooperating Spiny Lobsters Under Attack by Cooperating

PredatorsPredators

Cooperative Defense by Non-Kin Related Caribbean Cooperative Defense by Non-Kin Related Caribbean Spiny Lobsters Under Attack by Cooperating Spiny Lobsters Under Attack by Cooperating

PredatorsPredators

Kari LavalliKari LavalliCGS, Division of Natural Science, Boston UniversityCGS, Division of Natural Science, Boston University

William F. HerrnkindWilliam F. HerrnkindDept. of Biological Science, Florida State UniversityDept. of Biological Science, Florida State University

Kari LavalliKari LavalliCGS, Division of Natural Science, Boston UniversityCGS, Division of Natural Science, Boston University

William F. HerrnkindWilliam F. HerrnkindDept. of Biological Science, Florida State UniversityDept. of Biological Science, Florida State University

Natural SelectionNatural SelectionNatural SelectionNatural Selection

Main process responsible for evolutionary change

Produces adaptation by elimination of less fit genotypes

Maladaptive traits should be eliminated

Certain genes gain representation in the following generations at a greater frequency to that of other genes located at the same chromosome positions

Is compatible with most patterns/phenomena seen in nature, including behavioral traits

Main process responsible for evolutionary change

Produces adaptation by elimination of less fit genotypes

Maladaptive traits should be eliminated

Certain genes gain representation in the following generations at a greater frequency to that of other genes located at the same chromosome positions

Is compatible with most patterns/phenomena seen in nature, including behavioral traits

Natural Selection & EvolutionNatural Selection & EvolutionNatural Selection & EvolutionNatural Selection & Evolution

It acts on individuals to maximize their own reproductive output

Paradox?

We see LOTS of animals living in cohesive social groups, cooperating, and appearing to behave

“altruistically”

Natural Selection is a “Selfish” Natural Selection is a “Selfish” Process in Many RespectsProcess in Many Respects

Natural Selection is a “Selfish” Natural Selection is a “Selfish” Process in Many RespectsProcess in Many Respects

Behaviors that Seem to Violate Behaviors that Seem to Violate Natural Selection PrinciplesNatural Selection Principles

Behaviors that Seem to Violate Behaviors that Seem to Violate Natural Selection PrinciplesNatural Selection Principles

Darwin recognized one behavioral trait that was not compatible with Natural Selection

It posed, “one special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory.”

Evolution of sterile castes in social insectstermites, ants, bees, waspssterile individuals forego reproduction to raise queen’s offspringDarwin suggested that natural selection might operate on the level of the family here, rather than on the individual

Darwin recognized one behavioral trait that was not compatible with Natural Selection

It posed, “one special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory.”

Evolution of sterile castes in social insectstermites, ants, bees, waspssterile individuals forego reproduction to raise queen’s offspringDarwin suggested that natural selection might operate on the level of the family here, rather than on the individual

Seemingly Cooperative ActivitiesSeemingly Cooperative ActivitiesSeemingly Cooperative ActivitiesSeemingly Cooperative Activities

Food Giving –Food Giving – Altruistic? Kinship?Altruistic? Kinship?Food Sharing –Food Sharing – Altruistic? Kinship?Altruistic? Kinship?Prey Capture –Prey Capture – Cooperative? Selfish?Cooperative? Selfish?Parasite Removal –Parasite Removal – Altruistic? Selfish?Selfish?Predator Vigilance & Warning –Predator Vigilance & Warning – Cooperative? Selfish?Cooperative? Selfish? Defense Against Predators –Defense Against Predators – Cooperative? Selfish?Cooperative? Selfish?Heat Retention –Heat Retention – Cooperative? Selfish?Cooperative? Selfish?Helping to Rear Offspring (skip reproduction) –Helping to Rear Offspring (skip reproduction) – Kinship? Kinship? Selfish?Selfish?Care-giving Behavior (for sick/injured individuals) –Care-giving Behavior (for sick/injured individuals) – Kinship?Kinship?

Food Giving –Food Giving – Altruistic? Kinship?Altruistic? Kinship?Food Sharing –Food Sharing – Altruistic? Kinship?Altruistic? Kinship?Prey Capture –Prey Capture – Cooperative? Selfish?Cooperative? Selfish?Parasite Removal –Parasite Removal – Altruistic? Selfish?Selfish?Predator Vigilance & Warning –Predator Vigilance & Warning – Cooperative? Selfish?Cooperative? Selfish? Defense Against Predators –Defense Against Predators – Cooperative? Selfish?Cooperative? Selfish?Heat Retention –Heat Retention – Cooperative? Selfish?Cooperative? Selfish?Helping to Rear Offspring (skip reproduction) –Helping to Rear Offspring (skip reproduction) – Kinship? Kinship? Selfish?Selfish?Care-giving Behavior (for sick/injured individuals) –Care-giving Behavior (for sick/injured individuals) – Kinship?Kinship?

Living in Groups for Predation Living in Groups for Predation AvoidanceAvoidance

Living in Groups for Predation Living in Groups for Predation AvoidanceAvoidance

More efficient predator detectionMore efficient predator detection

May be more difficult to detect than scattered May be more difficult to detect than scattered individuals (encounter effect)individuals (encounter effect)

May be more difficult to target (confusion effect)May be more difficult to target (confusion effect)

Less likely to be victim of predator’s attack Less likely to be victim of predator’s attack (dilution effect)(dilution effect)

Possibility for coordinated group defense (if you Possibility for coordinated group defense (if you possess weaponry)possess weaponry)

Examples of Arthropod Groups

Phalanx of musk Phalanx of musk ox formed when ox formed when threatened by threatened by wolves (calves wolves (calves and cows on the and cows on the inside, bulls on inside, bulls on the outside rim)the outside rim)

The phalanx can The phalanx can also initiate also initiate coordinated coordinated counterattacks upon counterattacks upon attacking wolvesattacking wolves

Aspects of StudyAspects of StudyAspects of StudyAspects of Study

Grouping of prey

Cause & Function

Survival success

Cooperation?

Group attack by predator

Affect of Dominance Hierarchies

Degree of cooperation

Grouping of prey

Cause & Function

Survival success

Cooperation?

Group attack by predator

Affect of Dominance Hierarchies

Degree of cooperation

Subject of today’stalk

Why Lobsters?Why Lobsters?

Two families of lobsters have gregarious Two families of lobsters have gregarious speciesspecies

ScyllaridaeScyllaridae (slipper or shovel-nosed (slipper or shovel-nosed lobsters)lobsters)PalinuridaePalinuridae (spiny lobsters) (spiny lobsters)

StridentesStridentesSilentesSilentes

Both families have:Both families have:species that communally denspecies that communally denspecies that migrate communallyspecies that migrate communallysolitary speciessolitary specieslong, dispersive larval liveslong, dispersive larval lives

unlikely adults share kinshipunlikely adults share kinshipFirst we examined slipper lobsters First we examined slipper lobsters (weaponless); then spiny lobsters (have (weaponless); then spiny lobsters (have weaponry)weaponry)

Prey Life CyclePrey Life CyclePrey Life CyclePrey Life Cycle

Methods 1: Weaponless Slipper Lobsters

Tethered 8 single lobsters and scattered Tethered 8 single lobsters and scattered them, at least 2 m apart, on a limestone reef them, at least 2 m apart, on a limestone reef at a depth of 20 m off Haifa, Israelat a depth of 20 m off Haifa, Israel

Tethered 8 lobsters togetherTethered 8 lobsters together Repeated 6 timesRepeated 6 times Examined differences in relative predation Examined differences in relative predation

rates of solitary and grouped lobstersrates of solitary and grouped lobsters Examined differences in attack behavior of Examined differences in attack behavior of

predator (triggerfish)predator (triggerfish)

Lavalli & Spanier, 2001. Mar. Freshwat. Res. 52: 1133-1143.

Tethering Technique


Aspects Examined: Slipper LobstersAspects Examined: Slipper Lobsters

Individual attack rate on lobstersIndividual attack rate on lobsters

Capture risk per individual lobsterCapture risk per individual lobster

Fish capture successFish capture success

Group attack rateGroup attack rate

total # of attacks by all fish on individual lobsterstotal #of lobsters in group

total # of captures per encountertotal # of lobsters in group

total # of successful capturestotal # of attacks

total # of attacks by all fish on individual lobsters in a group

total # of groups


Results: Slipper Lobsters Grouped lobsters:Grouped lobsters:

At 3 hours: 1 dead/ 1 injuredAt 3 hours: 1 dead/ 1 injured At 24 hours: 16 dead/ 8 injuredAt 24 hours: 16 dead/ 8 injured

Solitary lobsters:Solitary lobsters: At 3 hours: 3 dead / 1 injuredAt 3 hours: 3 dead / 1 injured At 24 hours: 12 dead / 6 injuredAt 24 hours: 12 dead / 6 injured

No significant differenceNo significant difference (Wilcoxin sum rank test) in: (Wilcoxin sum rank test) in: individual attack probabilities individual attack probabilities at 3 hrs or 24 hrsat 3 hrs or 24 hrs individual lobster capture risk individual lobster capture risk at 3 hrs or 24 hrsat 3 hrs or 24 hrs or or fish capture successfish capture success at 3 hrs or 24 hrs at 3 hrs or 24 hrs group attack probability at 3 hoursgroup attack probability at 3 hours

Significant differenceSignificant difference at at 24 hours24 hours, with groups having a , with groups having a higher attack probability; P < 0.016 (Wilcoxin sum rank higher attack probability; P < 0.016 (Wilcoxin sum rank test)test)


Differences Seen in Predator Behavioral Circuits at 3 Hours

Solitary Lobsters Grouped Lobsters

Conclusion: Confusion Effect Operates only in Short-Term

Time to identify the individual to be attacked increases in a group because individuals

are hard to delineate.

BUT, over time, fish figures out individuals within a group and then concentrates on

group members.

Conclusion: Dilution Effect Not Seen in Short- or Long-Term

Dilution Effect predicts that:

chance of death = 1/N where N = number of individuals in group

Solitary lobsters had <50% chance of death or injury; grouped lobsters had a 50%

chance of death or injury

1/8 1/8

1/8 1/8

1/8

1/8

1/8

1/8

1/1

Lobsters with WeaponsLobsters with WeaponsLobsters with WeaponsLobsters with Weapons

Possession of weapons allows for cooperative Possession of weapons allows for cooperative defense above and beyond a simple dilution or defense above and beyond a simple dilution or confusion effectconfusion effect

Possession of weapons allows for cooperative Possession of weapons allows for cooperative defense above and beyond a simple dilution or defense above and beyond a simple dilution or confusion effectconfusion effect

Grouping in Panulirus spp.

Codenning and Codenning and emerging emerging en masseen masse is common in some is common in some spiny lobster speciesspiny lobster species

Herrnkind, Childress, & Lavalli, 2001. Mar. Freshwat. Res. 52: 1113-1124.

Panulirus argusPanulirus argus Lobsters Queue to Lobsters Queue to Move Across Featureless TerrainMove Across Featureless Terrain

Panulirus argusPanulirus argus Lobsters Queue to Lobsters Queue to Move Across Featureless TerrainMove Across Featureless Terrain

Most (95%) queues Most (95%) queues have 5-20 membershave 5-20 membersMost (95%) queues Most (95%) queues have 5-20 membershave 5-20 members

Few solitary lobsters Few solitary lobsters or small groups (5%)or small groups (5%)Few solitary lobsters Few solitary lobsters or small groups (5%)or small groups (5%)


Queues Coil into “Rosettes” Queues Coil into “Rosettes” If DisturbedIf Disturbed

Queues Coil into “Rosettes” Queues Coil into “Rosettes” If DisturbedIf Disturbed

Antennae directed Antennae directed outwardoutward

Antennae directed Antennae directed outwardoutward


QuestionsQuestionsQuestionsQuestions

In the open, how are outcomes of encounters of In the open, how are outcomes of encounters of lobsters and their piscine predators influenced lobsters and their piscine predators influenced by:by:

# of lobsters within the queue/rosette?# of lobsters within the queue/rosette?

# of attacking predators?# of attacking predators?

In the open, how are outcomes of encounters of In the open, how are outcomes of encounters of lobsters and their piscine predators influenced lobsters and their piscine predators influenced by:by:

# of lobsters within the queue/rosette?# of lobsters within the queue/rosette?

# of attacking predators?# of attacking predators?

Lavalli & Herrnkind, 2008. N.Z. Mar. Freshwat. Res. 42: (in press).

PredictionsPredictionsPredictionsPredictions

Group Size of LobstersGroup Size of LobstersAs group size increases:As group size increases:

Per capitaPer capita risk of death should risk of death should Fewer lobsters should be killedFewer lobsters should be killed

Group Size of Predator*Group Size of Predator*As group size increases:As group size increases:

Per capitaPer capita risk of death of prey should risk of death of prey should More lobsters should be killedMore lobsters should be killedTime needed to subdue lobster should Time needed to subdue lobster should

**presupposes that predators cooperate and don’t interfere with others’ attackspresupposes that predators cooperate and don’t interfere with others’ attacks

Group Size of LobstersGroup Size of LobstersAs group size increases:As group size increases:

Per capitaPer capita risk of death should risk of death should Fewer lobsters should be killedFewer lobsters should be killed

Group Size of Predator*Group Size of Predator*As group size increases:As group size increases:

Per capitaPer capita risk of death of prey should risk of death of prey should More lobsters should be killedMore lobsters should be killedTime needed to subdue lobster should Time needed to subdue lobster should

**presupposes that predators cooperate and don’t interfere with others’ attackspresupposes that predators cooperate and don’t interfere with others’ attacks


Methods 2: Group Sizes Methods 2: Group Sizes of Spiny Lobstersof Spiny Lobsters

Methods 2: Group Sizes Methods 2: Group Sizes of Spiny Lobstersof Spiny Lobsters

Group Size of LobstersGroup Size of LobstersField Studies off FSUML, Gulf of MexicoField Studies off FSUML, Gulf of Mexico

Tethered solitary or a group of 5 lobsters on reefsTethered solitary or a group of 5 lobsters on reefsNo difference in size among lobstersNo difference in size among lobsters90 min trials90 min trialsNo control over fish group size or fish speciesNo control over fish group size or fish speciesNo control over fish hunger levelNo control over fish hunger level

Group Size of LobstersGroup Size of LobstersField Studies off FSUML, Gulf of MexicoField Studies off FSUML, Gulf of Mexico

Tethered solitary or a group of 5 lobsters on reefsTethered solitary or a group of 5 lobsters on reefsNo difference in size among lobstersNo difference in size among lobsters90 min trials90 min trialsNo control over fish group size or fish speciesNo control over fish group size or fish speciesNo control over fish hunger levelNo control over fish hunger level


Field StudiesField StudiesField StudiesField Studies

Field StudiesField StudiesField StudiesField Studies

Description of Fish BehaviorsDescription of Fish Behaviors

APPROACH (APR):APPROACH (APR): Triggerfish swims to between one and Triggerfish swims to between one and two lobster antenna lengthstwo lobster antenna lengths

ATTACK (AT):ATTACK (AT): Triggerfish moves to within one lobster Triggerfish moves to within one lobster antennae lengthantennae length

BITE (B):BITE (B): Triggerfish makes contact with the lobster by Triggerfish makes contact with the lobster by either smashing the shell with its mouth or by using the either smashing the shell with its mouth or by using the mouth to remove antennal tips or eyesmouth to remove antennal tips or eyes

SWIM OVER (SO):SWIM OVER (SO): Triggerfish turns on side while Triggerfish turns on side while swimming over lobsters at a distance of approximately 2 swimming over lobsters at a distance of approximately 2 antennal lengthsantennal lengths


Description of Lobster Behaviors

ANTENNA POINT (AP):ANTENNA POINT (AP): Antennae moved and directed at Antennae moved and directed at approaching triggerfishapproaching triggerfish

ANTENNA WHIP (AW):ANTENNA WHIP (AW): Lobster uses one or both antennae to Lobster uses one or both antennae to lash at fishlash at fish

LUNGE (L):LUNGE (L): Lobster rapidly thrusts antennae against fishLobster rapidly thrusts antennae against fish

TAIL FLIP (TF):TAIL FLIP (TF): Rapid abdominal flexion causing backward Rapid abdominal flexion causing backward movementmovement

PIROUETTE (P):PIROUETTE (P): Animal spins rapidly, pointing antennae Animal spins rapidly, pointing antennae towards fish that are approaching in all directionstowards fish that are approaching in all directions


Pointing by An Individual Lobster

Pointing by All Group Members

Whipping Behavior

Lunging Behavior

Field Studies: ResultsField Studies: ResultsField Studies: ResultsField Studies: Results

Predators present on Predators present on reefs included both reefs included both triggerfish and triggerfish and sheepsheadsheepshead

also octopus, but also octopus, but saw no attackssaw no attacks

Predators present on Predators present on reefs included both reefs included both triggerfish and triggerfish and sheepsheadsheepshead

also octopus, but also octopus, but saw no attackssaw no attacks


0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

Survivors Victims

Mea

n S

ize

(mm

CL

)


40% of solitary 40% of solitary lobsters killedlobsters killed

0% of grouped 0% of grouped lobsters killedlobsters killed

significant significant difference in difference in size of survivors size of survivors and victimsand victims

40% of solitary 40% of solitary lobsters killedlobsters killed

0% of grouped 0% of grouped lobsters killedlobsters killed

significant significant difference in difference in size of survivors size of survivors and victimsand victims

t-test, P < 0.001

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Point Pirouette Rear Back Whip Lunge Tail Flip

Att

ac

k -

De

fen

se

Ra

tio

s

Solitary Surv ivor

Solitary Victim

Group Surv ivors

Field Studies: ResultsField Studies: ResultsField Studies: ResultsField Studies: ResultsN=10 solitaryN=4 groups

* ANOVA, p <0.001Bonferoni post-hoc test, p <0.001


0

20

40

60

80

100

120

140

160

180

200

Swim Over Approach Attack BA/Bite

Me

an

# o

f F

ish

Ac

tio

ns

Solitary Surv ivors

Solitary Victims

Group Surv ivors

N=10 solitaryN=4 groups

*

ANOVA, p < 0.001Tukey test, p < 0.001

Methods 3: Group Sizes of Methods 3: Group Sizes of Lobsters and FishLobsters and Fish

Methods 3: Group Sizes of Methods 3: Group Sizes of Lobsters and FishLobsters and Fish

Group Size of LobstersGroup Size of LobstersDoes it change in response to predator presence?Does it change in response to predator presence?

20 lobsters tested in 199920 lobsters tested in 1999With no fish presentWith no fish presentWith fish presentWith fish present

Group Size of FishGroup Size of FishFree-ranging lobstersFree-ranging lobsters

1, 3, 5, 10, 20 in 20001, 3, 5, 10, 20 in 20001, 5, 10 in 20011, 5, 10 in 2001

Used groups of 5 (2000) Used groups of 5 (2000) or 2 (2001) triggerfishor 2 (2001) triggerfishControlled fish hunger levelControlled fish hunger level

Group Size of LobstersGroup Size of LobstersDoes it change in response to predator presence?Does it change in response to predator presence?

20 lobsters tested in 199920 lobsters tested in 1999With no fish presentWith no fish presentWith fish presentWith fish present

Group Size of FishGroup Size of FishFree-ranging lobstersFree-ranging lobsters

1, 3, 5, 10, 20 in 20001, 3, 5, 10, 20 in 20001, 5, 10 in 20011, 5, 10 in 2001

Used groups of 5 (2000) Used groups of 5 (2000) or 2 (2001) triggerfishor 2 (2001) triggerfishControlled fish hunger levelControlled fish hunger level


Mesocosm StudiesMesocosm StudiesMesocosm StudiesMesocosm Studies



Fish CollectionFish CollectionFish CollectionFish Collection

1 group collected off FSUML reefs1 group collected off FSUML reefs

1 group collected off Big Pine Key1 group collected off Big Pine Key

1 group collected off FSUML reefs1 group collected off FSUML reefs

1 group collected off Big Pine Key1 group collected off Big Pine Key

1 2 3 4 5 6 7 8 9 10 11 12 13 14 1516

1718

1920

HOUR 1

HOUR 3

HOUR 5

0

5

10

15

20

25

30

35

40

45

Hourly Changes in Lobster Group Sizes Observed with No Fish Present

% O

bser

ved


Hourly Changes in Lobster Group Size Observed with Fish Present

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

HOUR 1

HOUR 3

HOUR 5

0

5

10

15

20

25

30

35

40

45

% O

bser

ved


Hourly Changes in Lobster Group Size Observed (20 Lobsters Total)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

HOUR 1HOUR 2

HOUR 3

0

10

20

30

40

50

60

70

80

90

100

% O

bser

ved


Hourly Changes in Lobster Group Size Observed (10 Lobsters Total)

12

34

56

78

910

HOUR 1

HOUR 2

HOUR 3

0

10

20

30

40

50

60

70

80

90

100

% O

bser

ved


Mesocosm ResultsMesocosm ResultsMesocosm ResultsMesocosm Results2000 Group Sizes2000 Group Sizes

No difference No difference in size in size among among intact, intact, injured, injured, or or victimsvictims

2000 Group Sizes2000 Group SizesNo difference No difference in size in size among among intact, intact, injured, injured, or or victimsvictims

0

10

20

30

40

50

60

70

80

90

1 Lobster 3 Lobsters 5 Lobsters 10 Lobsters 20 Lobsters

Mea

n S

ize

(m

m C

L)

Intact Lobsters

Injured Lobsters

Killed Lobsters

Mesocosm ResultsMesocosm ResultsMesocosm ResultsMesocosm Results

2001 Group Sizes2001 Group Sizes

No difference No difference in size among in size among intact, injured, intact, injured, or victimsor victims

2001 Group Sizes2001 Group Sizes

No difference No difference in size among in size among intact, injured, intact, injured, or victimsor victims

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

1 Lobster 5 Lobsters 10 Lobsters

Mea

n S

ize

(mm

CL

)

Intact Lobsters

Injured Lobsters

Killed Lobsters

Solitary Lobsters have GreaterSolitary Lobsters have Greater per Capita per Capita Death Risk, but No Difference for Grouped Death Risk, but No Difference for Grouped

Lobsters Regardless of # of FishLobsters Regardless of # of Fish

Solitary Lobsters have GreaterSolitary Lobsters have Greater per Capita per Capita Death Risk, but No Difference for Grouped Death Risk, but No Difference for Grouped

Lobsters Regardless of # of FishLobsters Regardless of # of Fish

N=13

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 Lobster 3 Lobsters 5 Lobsters 10 Lobsters 20 Lobsters

Pe

r C

ap

ita

De

ath

Ra

te

5 Triggerfish

2 Triggerfish

Predicted by Dilution

N=13

* *ANOVA, p < 0.001

Actual death risk close to risk predicted by dilution

Time to Kill Not Affected by # Time to Kill Not Affected by # Lobsters or # of PredatorsLobsters or # of Predators

Time to Kill Not Affected by # Time to Kill Not Affected by # Lobsters or # of PredatorsLobsters or # of Predators

N=13

ANOVA, p = 0.55

Removal of Stridulating Organ Has an Removal of Stridulating Organ Has an Effect on Attacks/Kills by Naïve FishEffect on Attacks/Kills by Naïve Fish

Removal of Stridulating Organ Has an Removal of Stridulating Organ Has an Effect on Attacks/Kills by Naïve FishEffect on Attacks/Kills by Naïve Fish

N =15 fish per lobster treatment

Pearson’s 2, p < 0.01

Types of Injuries Seen in Types of Injuries Seen in MesocosmMesocosm

Types of Injuries Seen in Types of Injuries Seen in MesocosmMesocosm

Solitary lobstersSolitary lobsters87.5% killed when fish targeted 87.5% killed when fish targeted eyestalkseyestalks 12.5% killed by a directed attack on 12.5% killed by a directed attack on abdomenabdomen (generally biting huge hole through it or tearing it off)(generally biting huge hole through it or tearing it off)

Grouped lobstersGrouped lobsters3L: 80% 3L: 80% eyestalkseyestalks removed; 20% removed; 20% abdomenabdomen attacks attacks5L: 76% 5L: 76% eyestalkseyestalks removed; 8% destruction of removed; 8% destruction of carapacecarapace and removal of vital organs; 8% 1 and removal of vital organs; 8% 1 eyestalkeyestalk and and tailfantailfan removed; 8% 1 removed; 8% 1 eyestalkeyestalk removed and removed and abdomenabdomen attackedattacked10L: 92% 10L: 92% eyestalkseyestalks removed; 8% removed; 8% abdomenabdomen attacked attacked20L: 93% 20L: 93% eyestalkseyestalks removed; 7% entire removed; 7% entire antennaantenna removed with subsequent attacks on removed with subsequent attacks on abdomenabdomen

Solitary lobstersSolitary lobsters87.5% killed when fish targeted 87.5% killed when fish targeted eyestalkseyestalks 12.5% killed by a directed attack on 12.5% killed by a directed attack on abdomenabdomen (generally biting huge hole through it or tearing it off)(generally biting huge hole through it or tearing it off)

Grouped lobstersGrouped lobsters3L: 80% 3L: 80% eyestalkseyestalks removed; 20% removed; 20% abdomenabdomen attacks attacks5L: 76% 5L: 76% eyestalkseyestalks removed; 8% destruction of removed; 8% destruction of carapacecarapace and removal of vital organs; 8% 1 and removal of vital organs; 8% 1 eyestalkeyestalk and and tailfantailfan removed; 8% 1 removed; 8% 1 eyestalkeyestalk removed and removed and abdomenabdomen attackedattacked10L: 92% 10L: 92% eyestalkseyestalks removed; 8% removed; 8% abdomenabdomen attacked attacked20L: 93% 20L: 93% eyestalkseyestalks removed; 7% entire removed; 7% entire antennaantenna removed with subsequent attacks on removed with subsequent attacks on abdomenabdomen

DiscussionDiscussionDiscussionDiscussion

Grouping does not confer much of an advantage to Grouping does not confer much of an advantage to slipper (weaponless) lobstersslipper (weaponless) lobsters

Solitary spiny lobsters are at greater risk for predation Solitary spiny lobsters are at greater risk for predation than grouped lobstersthan grouped lobsters

predation may be major evolutionary force driving predation may be major evolutionary force driving gregarious behavior of gregarious behavior of P. argusP. argus

Size of lobster group confers an advantage to individuals Size of lobster group confers an advantage to individuals that is close to that predicted by dilution effectthat is close to that predicted by dilution effect

number of predators does not impact predation rate number of predators does not impact predation rate (either per capita rate or time needed to make a kill)(either per capita rate or time needed to make a kill)

Likely the result of interference among fish individualsLikely the result of interference among fish individuals

Stridente lobsters may use sound as a deterrent to Stridente lobsters may use sound as a deterrent to attacksattacks

Grouping does not confer much of an advantage to Grouping does not confer much of an advantage to slipper (weaponless) lobstersslipper (weaponless) lobsters

Solitary spiny lobsters are at greater risk for predation Solitary spiny lobsters are at greater risk for predation than grouped lobstersthan grouped lobsters

predation may be major evolutionary force driving predation may be major evolutionary force driving gregarious behavior of gregarious behavior of P. argusP. argus

Size of lobster group confers an advantage to individuals Size of lobster group confers an advantage to individuals that is close to that predicted by dilution effectthat is close to that predicted by dilution effect

number of predators does not impact predation rate number of predators does not impact predation rate (either per capita rate or time needed to make a kill)(either per capita rate or time needed to make a kill)

Likely the result of interference among fish individualsLikely the result of interference among fish individuals

Stridente lobsters may use sound as a deterrent to Stridente lobsters may use sound as a deterrent to attacksattacks

True Cooperation?True Cooperation?True Cooperation?True Cooperation?

Unlikely in lobstersUnlikely in lobsters

Most likely due to selfish herd behaviorMost likely due to selfish herd behavior

AcknowledgementsIsraeli group:Israeli group:

Divers: Stephen Breitstein, Rami Israelov, Amir Yurman, Oz Divers: Stephen Breitstein, Rami Israelov, Amir Yurman, Oz Goffman, Yossi Tur-Caspa, Yossi Zilbiger, Micha Dadon, Joe Goffman, Yossi Tur-Caspa, Yossi Zilbiger, Micha Dadon, Joe Breman, Avinoam Breitstein, Dani Kerem, Diana BarshawBreman, Avinoam Breitstein, Dani Kerem, Diana Barshaw

Statistical Advice: Efrat YaskilStatistical Advice: Efrat YaskilFlorida group:Florida group:

Mark W. Butler, Jason Schratwieser, Scott Andree, Melissa Mark W. Butler, Jason Schratwieser, Scott Andree, Melissa Classon, Scott Donahue, Damon Karras, Sarah Kelly, Kent Smith, Classon, Scott Donahue, Damon Karras, Sarah Kelly, Kent Smith, Jennifer ZimmermanJennifer Zimmerman

SWT group:SWT group:

Videoanalysis: Andrea Miller, Jennifer Duran, Greg Cryer, Jeff Videoanalysis: Andrea Miller, Jennifer Duran, Greg Cryer, Jeff Foerster, Cassie Malcom, Lisa Quintanilla, Casey OttFoerster, Cassie Malcom, Lisa Quintanilla, Casey Ott

Data collection and analysis: Andrew Evans, David ClevelandData collection and analysis: Andrew Evans, David Cleveland

Fish dominance hierarchy work: David ClevelandFish dominance hierarchy work: David Cleveland

Questions?Questions?

Methods 4: WeaponsMethods 4: WeaponsMethods 4: WeaponsMethods 4: WeaponsExamination of Importance of Weapons (Antennae)Examination of Importance of Weapons (Antennae)

Mesocosm Studies at KML, Long KeyMesocosm Studies at KML, Long KeyFree-ranging solitary lobsters vs. 1 fishFree-ranging solitary lobsters vs. 1 fish

Intact, missing 1 antenna, missing bothIntact, missing 1 antenna, missing bothTethered solitary lobster vs. 1 fishTethered solitary lobster vs. 1 fish

Intact, missing 1 antenna, missing bothIntact, missing 1 antenna, missing bothChoice tests for fish: intact lobster vs. 1 missing antenna Choice tests for fish: intact lobster vs. 1 missing antenna lobster, both tethered and separated in spacelobster, both tethered and separated in space

Examination of Importance of Weapons (Antennae)Examination of Importance of Weapons (Antennae)Mesocosm Studies at KML, Long KeyMesocosm Studies at KML, Long Key

Free-ranging solitary lobsters vs. 1 fishFree-ranging solitary lobsters vs. 1 fishIntact, missing 1 antenna, missing bothIntact, missing 1 antenna, missing both

Tethered solitary lobster vs. 1 fishTethered solitary lobster vs. 1 fishIntact, missing 1 antenna, missing bothIntact, missing 1 antenna, missing both

Choice tests for fish: intact lobster vs. 1 missing antenna Choice tests for fish: intact lobster vs. 1 missing antenna lobster, both tethered and separated in spacelobster, both tethered and separated in space


Results for free-ranging Results for free-ranging lobsters differ from lobsters differ from tethered lobsterstethered lobsters

Lack of antennae likely to Lack of antennae likely to result in less survivalresult in less survival

Results for free-ranging Results for free-ranging lobsters differ from lobsters differ from tethered lobsterstethered lobsters

Lack of antennae likely to Lack of antennae likely to result in less survivalresult in less survival

Mesocosm ResultsMesocosm ResultsMesocosm ResultsMesocosm ResultsFish make more bite attempts, land more bites, and have to circle Fish make more bite attempts, land more bites, and have to circle less with free-ranging antennae-less lobstersless with free-ranging antennae-less lobstersFree-ranging antennae-less lobsters lunge more, rear-back more Free-ranging antennae-less lobsters lunge more, rear-back more and tailflip more than lobsters with antennaeand tailflip more than lobsters with antennae

Fish make more bite attempts, land more bites, and have to circle Fish make more bite attempts, land more bites, and have to circle less with free-ranging antennae-less lobstersless with free-ranging antennae-less lobstersFree-ranging antennae-less lobsters lunge more, rear-back more Free-ranging antennae-less lobsters lunge more, rear-back more and tailflip more than lobsters with antennaeand tailflip more than lobsters with antennae

Mesocosm ResultsMesocosm ResultsMesocosm ResultsMesocosm ResultsFish make more attacks, bite attempts, and land more bites with Fish make more attacks, bite attempts, and land more bites with tethered antennae-less lobsterstethered antennae-less lobstersTethered antennae-less lobsters rear-back more than lobsters with Tethered antennae-less lobsters rear-back more than lobsters with antennaeantennae

Fish make more attacks, bite attempts, and land more bites with Fish make more attacks, bite attempts, and land more bites with tethered antennae-less lobsterstethered antennae-less lobstersTethered antennae-less lobsters rear-back more than lobsters with Tethered antennae-less lobsters rear-back more than lobsters with antennaeantennae


Fish circle more when lobsters have 2 antennaFish circle more when lobsters have 2 antennaFish circle more when lobsters have 2 antennaFish circle more when lobsters have 2 antenna

Mesocosm ResultsMesocosm ResultsMesocosm ResultsMesocosm ResultsLobsters with 1 antennae more likely to be injured Lobsters with 1 antennae more likely to be injured and less likely to survive than those with bothand less likely to survive than those with bothLobsters with 1 antennae more likely to be injured Lobsters with 1 antennae more likely to be injured and less likely to survive than those with bothand less likely to survive than those with both


Differences between time to land Differences between time to land first bite between free-ranging first bite between free-ranging lobsterslobsters

Difference between time to land first Difference between time to land first bite between single antenna and no bite between single antenna and no antenna lobstersantenna lobsters

Differences between time to land Differences between time to land first bite between free-ranging first bite between free-ranging lobsterslobsters

Difference between time to land first Difference between time to land first bite between single antenna and no bite between single antenna and no antenna lobstersantenna lobsters

Triggerfish Trials: QuestionsTriggerfish Trials: Questions

What are triggerfish attack strategies on solitary and grouped lobsters?

What level of cooperation exists within a social grouping of triggerfish?

Is there a social hierarchy within a group of triggerfish and what effect does it have on cooperation?

Why Triggerfish?Why Triggerfish? Balistes capriscus and B. carolinensis are found

in social groups on reefs May be same speciesMay be same species

Can feed solitarily or can feed in groupsCan feed solitarily or can feed in groups Some evidence from our observations in the Some evidence from our observations in the

field (Barshaw et al. 1996) that they can field (Barshaw et al. 1996) that they can cooperate in subduing preycooperate in subduing prey

Also have evidence that triggerfish can Also have evidence that triggerfish can interfere with each other’s attacksinterfere with each other’s attacks

Fish Approaches & PassesFish Approaches & Passes(Pre-Attack Phase)(Pre-Attack Phase)

0102030405060708090

100

1 2 3 4 5

Fish

Approach

Pass

Triggerfish Hover & Bite BehaviorTriggerfish Hover & Bite Behavior(Attack Phase)(Attack Phase)

0102030405060708090

100

1 2 3 4 5Fish

Hover

Bite

Chased and Bitten TriggerfishChased and Bitten Triggerfish

0102030405060708090

100

1 2 3 4 5

Fish

Chased

Bitten

Fish Involved in the ChasesFish Involved in the Chases

0

10

20

30

40

50

60

70

80

90

100

Fish1=>2

Fish2=>4

Fish3=>2

Fish3=>5

Fish4=>5

Fish5=>3

Fish5=>4

Chaser Fish => Chased Fish

ResultsResultsResultsResults

Who cooperated with whom?Who cooperated with whom? and and ranked individuals most cooperative during attacks ranked individuals most cooperative during attacks

was able to get some food from lobster while attackingwas able to get some food from lobster while attacking interfered after lobster’s deathinterfered after lobster’s deathfish dealing “death blow” took over killfish dealing “death blow” took over kill

usually usually fish fish ranked individual most often did not interact with other fishranked individual most often did not interact with other fish

on few occasions of interactions, on few occasions of interactions, ranked fish chased ranked fish chased other fish awayother fish away

fish never cooperatedfish never cooperatedAttacking fish always displayed light bandingAttacking fish always displayed light banding

non-attacker frequently displayed white non-attacker frequently displayed white coloration with trigger up or AID coloration with trigger up or AID

Who cooperated with whom?Who cooperated with whom? and and ranked individuals most cooperative during attacks ranked individuals most cooperative during attacks

was able to get some food from lobster while attackingwas able to get some food from lobster while attacking interfered after lobster’s deathinterfered after lobster’s deathfish dealing “death blow” took over killfish dealing “death blow” took over kill

usually usually fish fish ranked individual most often did not interact with other fishranked individual most often did not interact with other fish

on few occasions of interactions, on few occasions of interactions, ranked fish chased ranked fish chased other fish awayother fish away

fish never cooperatedfish never cooperatedAttacking fish always displayed light bandingAttacking fish always displayed light banding

non-attacker frequently displayed white non-attacker frequently displayed white coloration with trigger up or AID coloration with trigger up or AID

DiscussionDiscussionDiscussionDiscussion

Hierarchical ranking seems to predict who is Hierarchical ranking seems to predict who is likely to cooperate with whomlikely to cooperate with whom

Cooperation is likely selfishCooperation is likely selfish

Prior to death of lobster, both striking fish can Prior to death of lobster, both striking fish can obtain food (legs, gills, internal organs, obtain food (legs, gills, internal organs, muscle tissue)muscle tissue)

After death, fish who deals final death blow After death, fish who deals final death blow “owns” lobster“owns” lobster

Hierarchical ranking seems to predict who is Hierarchical ranking seems to predict who is likely to cooperate with whomlikely to cooperate with whom

Cooperation is likely selfishCooperation is likely selfish

Prior to death of lobster, both striking fish can Prior to death of lobster, both striking fish can obtain food (legs, gills, internal organs, obtain food (legs, gills, internal organs, muscle tissue)muscle tissue)

After death, fish who deals final death blow After death, fish who deals final death blow “owns” lobster“owns” lobster

Technology

Cgs Talk Jan 2009