Persistence and fluctuation of lateral dimorphism of fishes
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Persistence and fluctuation of lateral dimorphism of fishes. Prof.Shirakihara. M.Nakajima lived in Switzerland. Mifuyu Nakajima  , Hiroyuki Matsuda  and Michio Hori  , in submission. K.Morita. M.Mori U.CateTown. M.Kai. back. back.

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Persistence and fluctuation of lateral dimorphism of fishes

Persistence and fluctuation of lateral dimorphism of fishes

Prof.Shirakihara

M.Nakajima

lived in Switzerland

Mifuyu Nakajima, Hiroyuki Matsuda and Michio Hori, in submission

K.Morita

M.Mori

U.CateTown

M.Kai


Lateral dimorphism of scale eating cichlids in lake tanganyika

back

back

Lateral dimorphism of scale eating cichlids in Lake Tanganyika

Hori 1991 Science 267

Righty

Lefty


Overview
Overview

  • What is predator specific defense?

  • What is antisymmetric predation?

  • Is laterality frequency really fluctuate?

    • If so, what is mechanism of fuluctation?


Prey is not solely victim but has antipredator traits

predator

3

prey

2

1

plant

Prey is not solely victim, but has antipredator traits.

  • Vigilance, Schooling, Refuge,

  • There may be a trade-off between antipredator effort and other fitness component (e.g., foraging time)


Antipredator effort against predator 1 is
Antipredator effort against predator 1 is …

  • [Nonspecific defense] effective against both predator species (types) 1 & 2;

  • [Partly-specific] partly effective against 2;

  • [Perfect-specific] not effective against 2 at all;

  • [overly-specific] riskier against 2 than when it pais no attention to any predator.


Antipredator trait mediated exploitative competition

Increase predator 2

2

Increase vigilance

Decrease predator 3

3

Antipredator trait-mediated Exploitative Competition

2

3

1


Exploitative mutualism matsuda abrams hori oikos 1993 68 549 559

Increase predator 2

2

3

Watch more against 2

Increase predator 3

Exploitative Mutualism(Matsuda, Abrams, Hori. Oikos 1993, 68:549-559)

2

3

1


How many points can you watch for simultaneously
How many points can you watch for simultaneously?

Quiz by Japan Automobile Fedaration

JAF News, the recent issue


Apparent competition holt 1979

Increase prey 2

1

Increase predator

Decrease prey 3

2

3

Apparent Competition(Holt, 1979)

1

2

3


Apparent mutualism abrams matsuda 1996 ecology 77 610 616

Increase prey 2

1

Predator focuses on prey 2

Increase prey 3

2

3

Apparent mutualism(Abrams & Matsuda 1996 Ecology 77:610-616)

1

2

3


Predator specific defense enhances
Predator-specific defense enhances

  • Coexistence of predators.

  • A more complex community strucutre

Food web in Lake Tanganyika

Matsuda with Abrams & Hori (1994, 1996, Evol. Ecol)


Coexistence of laterality dimorphism antisymmetry
Coexistence of laterality dimorphism (antisymmetry)

Scale eaters in Lake Tanganyika (Hori unpublished)

Frequencies of lefties

Year of birth


Overview1
Overview

  • What is predator specific defense?

  • What is antisymmetric predation?

  • Is laterality frequency really fluctuate?

    • If so, what is mechanism of fuluctation?


Three types of asymmetries van valen 1962

“Antisymmetry”

Fluctuating asymmetry (FA)

Directive asymmetry (DA)

Three types of Asymmetries(van Valen 1962)


Antisymmetry in fishes
Antisymmetry in fishes

  • Scale-eating cichlid in Lake Tanganyika

  • Lefties feed on scales of the left side, righties feed on scales of the right side

  • Frequency dependent natural selection

    • Hori 1991 Science 267:

  • Maintained by predator-specific defense


Antisymmetry
Antisymmetry

Mud Fiddler Crabs (Uca pugnax) have antisymmetry in pincers

http://www.assateague.com/mud-cr.html

  • Bimodal distribution of laterality in crabs, snails, …

  • Maintained by sexual selection

  • Few reports of antisymmetry maintained by predation


More story in fish laterality
More Story in Fish Laterality….

  • Another Tanganyikan fish has lateral asymmetry (Mboko et al. 1998: Zool. Sci. 15)

  • A fresh water goby has lateral asymmetry in a Japanese river(Seki et al. 2000: Zool. Sci. 17)

  • Many fishes and other aquatic invertebrates have lateral antisymmetry! (Hori unpublished)

  • In these fishes, lefty is dominant heritage.

  • Far too counterintuitive!

  • We need more evidence and theoretical reason...


Righty predators eat lefty prey and vice versa
Righty predators eat lefty prey, and vice versa.

  • Lefties of scale-eating fish feed only on left side scales of lefties, righties feed only on right side scales of righties (Hori 1993 stomach contents, unpublished lab experiment).

  • Circa 75% of the stomach contents of righty and lefty piscivorous predators (Lamprologus spp.) were the lefty and righty, respectively (Hori unpublished field data).


Is evidence still short
Is evidence still short?

Hori et al. (unpublished field data)


Why does a lefty catch a righty michio hori s idea
Why does a lefty catch a righty?(Michio Hori’s idea)


Definition of antisymmetric predation
Definition of Antisymmetric Predation

  • Both prey and predator have anti-symmetric traits (laterality);

  • “Lefty” predators feed on “righty” prey; “Righty” predators feed on “lefty” prey.


Overview2
Overview

  • What is predator specific defense?

  • What is antisymmetric predation?

  • Is laterality frequency really fluctuate?

    • If so, what is mechanism of fuluctation?


Question
Question…

%lefties

  • Does it really fluctuate?

    • Statistically significant (Hori unpubl)

  • Does it really synchronize?

  • If so, what mechanism promote fluctuation?


Is evidence still short1
Is evidence still short?

  • If frequency fluctuates, this is non-random sampling over several years.

  • This is an evidence for either

    • Existence of antisymmetric predation or

    • Existence of laterality frequency fluctuation

Hori et al.

(unpublished field data)


Two platoon lineups in mlb
Two-platoon lineups in MLB

No fluctuation is reported in the frequency of lefty pitchers and batters in MLB or College baseball


Our hypothesis for laterality fluctuation
Our hypothesis for laterality fluctuation

Persistence and fluctuation in lateral antisymmetry is

  • Maintained by Antisymmetric Predation, in analogy to Predator-specific defense



Lyapunov type function of the symmetric 4 population system
Lyapunov-type function of the symmetric 4 “population” system

  • Trajectories converge the “line” zL+ zR=2c/Bm (constant).

< 0


Laterality frequency fluctuation mediated by antisymmetric predation

Increase Lefty Predators system

Decreasing righty prey = Increasing lefty prey

yL

yR

Laterality frequency fluctuation mediated by antisymmetric predation

zL

zR

predator

Frequencies of lefties

prey

time


The system always has a neutrally stable equilibrium cyclic orbits with any amplitude
The system always has a systemneutrally stable equilibrium & cyclic orbits with any amplitude.

Predator xR

% Rigties

Righty

Prey zR

time

A = B = C = 1, r = 1, K=10, m=0.8, d=0.05, c=0.15

Lefty

Any modification makes it stable or unstable.


Omnivory is common in lake tanganyika fish community
Omnivory is common in Lake Tanganyika Fish Community system

Piscivores

Scale eaters

Hori 1997

Algal eaters


Extension to holt and polis 1997

x system

y

z

Extension to Holt and Polis (1997)

  • Where k = K/2


Three trophic levels

6 “populations” system(3 sp.×{Lefty, Righty}

X: scale eaters

Y: piscivores

Z: algal feeders

X preys on both y and z.

Three trophic levels

xL

xR

yL

yR

zL

zR


Does omnivory destabilize or stabilize the antisymmetric predation system

if X is systemomnivory, lefties increase

Does omnivory destabilize or stabilize the antisymmetric predation system?

Righties increase

Lefties increase

Righties increase



Invasibility analysis
Invasibility analysis system

xR

yL

dxR/dt/xR >0 if xR is invasible


Asymmetric equilibrium is always invasible
Asymmetric equilibrium is always invasible. system

A

B

Axy=1 m=0.8 K=5 r=1 c=0.5 d=0.5


6 population dynamic model

For systemlefties (asexual reproduction model)

6 “population” dynamic model

Prey on zR

Prey on yR

Preyed by xR

Prey on zR


Population genetic model 1 locus 2 alleles
Population genetic model system(1-locus-2-alleles)

Righties: allele a: gene frequency pi

Lefties: allele A: gene frequency 1-pi

fx = m Axy Ny (1-py2) + m AxzNz(1-pz2) – c


Equilibrium gene frequency
Equilibrium gene frequency system

Phenotypic frequency:

From local stability analysis, this is always an unstable focus.

b0

b0b1-b2 < 0


Simulation exhibits a stable limit cycle

% Righties system

time

Simulation exhibits a stable limit cycle.

y

x

z

A=1.3 B=0.25 C=1

m=0.8 K=5 r=1

c=0.5 d=0.5

It qualitatively explains the field observation.



Our model results
Our model results system

  • Under the perfect anti-symmetric predation, no force (“friction”) to stabilize a 1:1 laterality ratio exists.

  • Omnivory destabilizes 1:1 laterality ratio and enhances a stable limit cycle (coexistence with fluctuation).

    • Nakajima, Matsuda, Hori (in review)


Why did laterality evolve
Why did laterality evolve? system

  • Scale-eaters first evolved laterality, because they attack either side scales.

  • “Prey” needed to evolve laterality to improve predator-specific defense

  • …What story is possible in the absence of scale-eaters???

  • Measure quantitative trait in laterality

I don’t know


Lateral dimorphism is
Lateral dimorphism is system

Single-locus Mendellian inheritance

Seen in most of fishes (Hori unpubl)

Maintained by antisymmetric predation

Fluctuation & coexistence in omnivory

[Overly?] predator-specific defense

This is a new story of Antisymmetry


Competitive exclusion of laterality in amino acids
Competitive exclusion of laterality in amino acids system

L-amino acids

D-amino acids

Omnivory is probably important for coexistence


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