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スイッチング捕食と天敵特異的防御がもたらす食物網構造と群集動態

More stories of community ecology with adaptive fish behaviors and ada

ptive fisheries management

松田裕之（横浜国大・環境情報）Hiroyuki Matsuda (Yokohama Nat’l Univ)

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3 types of 3 species system

1 2

3

1

2 3

prey

predator

1

2

3

plant

herbivore

carnivore

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The paradox of pesticides

1

2

3

Pesticide attacks herbivore

Pesticide also attacks carnivore

Herbivore will increase and the plant will decrease.

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間接効果 Indirect Effects

• 個体数変化を通じた間接効果 Density-Mediated Indirect Effects

• 行動や形質変化を通じた間接効果Trait-Mediated Indirect Effects

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Exploitative Competition

1

322Increase predator 2

1

Decrease prey3

Decrease predator 3

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Exploitative Competition

• dN1/dt = (-d1 - b1N1 + a1R)N1

• dN2/dt = (-d2 - b2N2 + a2R)N2

• dR/dt = (d0 - a1N1 + a2N2)R

• N1 = (a1b2d0+a1a2d2 -a22d1)/(a2

2b1+a12b2),

• N2 = (a2b1d0+a1a2d1 -a12d2)/(a2

2b1+a12b2)

• R = (b1b2d0+a1b2d1 -a2b1d2)/(a22b1+a1

2b2)

• dN1*/dd2 > 0

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Apparent Competition

1

32

1

Increase predator

Decrease prey 332

Increase prey 2

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

1

32Increase prey 3

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Increase prey 211

Predator focuses on prey 2

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Apparent Mutualism

• Suppose Prey A & B and 1 Predator.

• Prey A increases.

• Predator focuses on A, consequently ignores B (Predator switching).

• Fitness of Prey B may increase with A.

• Few empirical data,

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Exploitative Mutualism (Matsuda et al. Oikos 1993, 68:549-559)

1

322Increase predator 2

3

Increase predator 3

Watch more against 2

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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.

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Quiz by Japan Automobile FedarationJAF News, the recent issue

How many points can you watch for simultaneously?

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• dN/dt = f(N, p) 　　　群集動態• dN/dt = (f/N) (N-N*) 　線形近似• = C (N-N*) 群集行列f/p+(f/N)(N*/p)=0 陰関数微分N*/p = –(f/N)-1(f/p)

• = – C-1(f/p)

Yodzis(1988) の間接効果理論

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2 3

6

1

75

4

9

10

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Example: indirect effects in a 10 species system

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群集行列Community Matrix

2 3

6

1

75

4

9

10

8

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Sensitivity frequencyMatrix “–C-1 ”

種 1 2 3 4 5 6 7 8 9 10

1 1000 101 953 511 0 934 511 653 658 157

2 101 1000 267 959 101 81 959 722 738 53

3 953 267 1000 112 953 81 112 747 728 51

4 511 959 112 1000 511 941 0 669 643 140

5 1000 899 47 489 1000 66 489 347 342 843

6 66 919 919 59 66 1000 59 402 420 733

7 489 41 888 1000 489 59 1000 331 357 860

8 653 722 747 669 653 598 669 1000 12 202

9 658 738 728 643 658 580 643 12 1000 188

10 843 947 949 860 843 733 860 798 812 1000

2 3

6

1

75

4

9

10

8

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Kyoto Declaration and Plan of Action on the Sustainable Contribution of Fisheries to Food

Security in 1992 (FAO)

• Article 14 “When and where appropriate, consider harvesting multiple trophic levels in a manner consistent with sustainable development of these resources”.

http://www.fao.org/fi/agreem/kyoto/kyoe.asp

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イワシ x とマグロ y の数理模型

• dx/dt = (r - a x - b y - f) x

• dy/dt = (-d + e b x - g) y

• Maximize total yield fx+pgy at the equilibrium

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Paradox of Kyoto Declaration

• Optimal solution is either

• to catch sardine after tuna goes extinct; or

• to catch tuna only.

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2

54

3

5

3

6

4

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Examples of biological community at MSY (Matsuda & Abrams in review)

1 2

3

5

6

(b)

1 2

3

5

6

4

(a)

1 2

5

(c)

3

6

4

Solution maximizing total yield from community

MSY solution often reduces species and links;

1 2

6

4

(d)

1

3

6

(e)

2

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3

54

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2

4 5

3

5

Examples of biological community at MSY (Matsuda & Abrams in review)

1 2

3

5

6

(b)

1 2

3

5

6

4

(a)

1 2

5

(c)

100% 92% 61% 12% 6%

4

3

6

4

exploit more species, more trophic levels.

1 2

6

4

(d)

1

3

6

(e)

Constrained MSY that guarantee coexistence

2

4 5

4

3

6

4

3

5

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Conclusion of story 2

• MSY theory does not guarantee species coexistence

• Fisheries must take care of biodiversity conservation explicitly

= Foodweb constraint to reconciling fisheries with conservation

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Requiem to Maximum Sustainable Yield Theory

• Ecosystems are uncertain, non-equilibrium and complex.

• MSY theory ignores all the three.

• Does MSY theory guarantee species persistence?- No!!

Stock abundance

surp

lus p

rodu

ctio

n

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Feedback control in fishing effort is powerful...

A straw man says;• Even though the MSY

level is unknown, the feedback control stabilizes a broad range of target stock level.

( )dN f N qENdt

*dE U N Ndt

Stock size N

f(N

)

N*N* N*

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Feedback control with community interactions also result in undesired outcomes.

(M & A in preparation)

1. 0.74 0.19 0.31 0. 0. 0. 0. 0.7 0.460.74 1. 0.87 0.08 0.46 0.66 0.48 0.73 0.84 0.0.19 0.87 1. 0.96 0.08 0.14 0.83 0. 0. 0.680.31 0.08 0.96 1. 0. 0. 0. 0.28 0. 0.880. 0.46 0.08 0. 0.1 0. 0. 0.92 0.15 0.840. 0.66 0.14 0. 0. 0.1 0.01 0. 0.5 0.690. 0.48 0.83 0. 0. 0.01 0.1 0.56 0. 0.0. 0.73 0. 0.28 0.92 0. 0.56 0.1 0.28 0.0.7 0.84 0. 0. 0.15 0.5 0. 0.28 0.1 0.0.46 0. 0.68 0.88 0.84 0.69 0. 0. 0. 0.1

r = (0.454,1.059,1.186,0.247,-0.006,-0.028,-0.059,-0.704,-0.308,-0.238)

ii ji j i i

j

dNr a N qe N

dt

A = (aji) =

e9 = 0.1, ei = 0

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5 6

7

8

9 10

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Feedback control may result in extinction of other species (sp. 6).

de9/dt = u(N9-N9*)ratio

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Conclusion of story 3

• Single stock monitoring is dangerous

• Target stock level is much more sensitive than we have considered in single stock models.

• We must monitor not only stock level of target species, but also the “entire” ecosystem.

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Wasp-waist is a classic dream...

• Anyway, we need to investigate how to fluctuate the total biomass of small pelagics.

birds seals tunas

copepods krill ....

, is this illusion?

pelagic

sardine/anchovy lantern fish

deep sea

Only 5 to 10 percent of us succeed of the weight-loss industry

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非定常群集nonequilibrial community

• 環境が変化する Changing Environment

• 個体数が変化する Unstable Population

• 行動や形質が変化する– Change in Behavior & Traits

• 餌選好や住み場所が変われば、群集構造も変化する– Change in Community Structure

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共進化的に安定な群集Coevolutionarily stable community

• dNj/dt = [-dj + ΣifjiajiRi]Nj

• dRi/dt = [ri - biRi -ΣjfjiajiNj]Ri

• tradeoff Σifji=1

• optimal prey preference ΣifjiajiRi maximize

• at CSC, ajiRi = ajkRk ｒ　 if fji>0, fjk>0

• # equations = #links - #predator species

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Link-species scaling law (1)

• # equations = # links - # predator species• # unknowns = # prey species

R1 R2 R3

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Link-species scaling law (2)

• # equations < # unknowns

• # links (L) < # prey + # predator species

• L < 2S (Cohen et al. 1993).

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Predator-specific defense enhances

• Coexistence of predators.

• A more complex community strucutre

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

Food web in Lake Tanganyika

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Polis’ opinion

• Food web is– L is proportional to S2

– link-species scaling law is an artifact from short-term, narrow range observation.

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Foodweb changes temporallyMatsuda, H. & Namba, T. (1991) Ecology 72(1):267-276.

predator

prey

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長期と短期を分けて考えようImportance of short-term structure

• Temporal niche overlap is reasonable for abundant resource

• Predator may avoid short-term competition. (behavioral response)

• It is different from long-term coexistence and population dynamics

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非定常群集nonequilibrial community

• 環境が変化する Changing Environment

• 個体数が変化する Unstable Population

• 行動や形質が変化する Change in Behavior & Traits

• 餌選好や住み場所が変われば、群集構造も変化する　 Change in Community Structure

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Lateral dimorphism of scale eating cichlids in Lake Tanganyika

Righty

Lefty

Hori 1991 Science 267Hori 1991 Science 267

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-10 -5 0 5 10

relative trait values

freq

uen

cyThree types of Asymmetries

(van Valen 1962)

Directive asymmetry (DA)

Fluctuating asymmetry (FA)“Antisymmetry”

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Antisymmetry in fishes

• Scale-eating cichlid in Lake TanganyikaScale-eating cichlid in Lake Tanganyika

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

• Frequency dependent natural selectionFrequency dependent natural selection– Hori 1991 Science 267:

• Maintained by predator-specific defenseMaintained by predator-specific defense

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More Story in Fish Laterality….• Another Tanganyikan fish has lateral asymmetAnother Tanganyikan fish has lateral asymmet

ry ry ((Mboko et al. 1998: Mboko et al. 1998: Zool. Sci. 15Zool. Sci. 15))

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

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

• In these fishes, lefty is dominant heritage. In these fishes, lefty is dominant heritage. • Far too counterintuitive!Far too counterintuitive!• We need more evidence and theoretical reason...We need more evidence and theoretical reason...

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Coexistence of laterality dimorphism (antisymmetry)

Fre

qu

enci

es o

f le

ftie

s

Scale eaters in Lake Tanganyika (Hori unpublished)

Year of birth

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Righty predators eat lefty prey, and vice versa.

• Lefties of scale-eating fish feed only on left side sLefties of scale-eating fish feed only on left side scales cales of leftiesof lefties, righties feed only on right side scal, righties feed only on right side scales es of rightiesof righties (Hori 1993 stomach contents, (Hori 1993 stomach contents, unpublunpublished lab experimentished lab experiment). ).

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

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

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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.

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Two-platoon lineups in MLB

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

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Question…

• Does it really fluctuate?– Statistically significant (Hori unpubl)

• Does it really synchronize?

• If so, what mechanism promote fluctuation?

%le

ftie

s

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Hori 1997

Scale eaters

Piscivores

Omnivory is common in Lake Tanganyika Fish Community

Algal eaters

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We must apply our model to the entire community (Hori unpublished)

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Extension to Holt and Polis (1997)

x

z

yyz xy

dyy

dtmA z A x d

1 xz yzdz z

r A x A y zdt k

xy xz

dx

dtA y A z xm c

• Where k = K/2

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Three trophic levelsThree trophic levels

xL xR

yL yR

zL

zR

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

• X: scale eaters• Y: piscivores• Z: algal feeders• X preys on both y and z.

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Does omnivory destabilize or stabilize Does omnivory destabilize or stabilize the antisymmetric predation system?the antisymmetric predation system?

Lefties increase

Righties increase

Righties increase

if X is omnivory, lefties increase

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Our model results• 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 (2004 Am.Nat)

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Why did laterality evolve?

• 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

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Lateral dimorphism is

Single-locus Mendellian inheritanceSeen in most of fishes (Hori unpubl)Maintained by antisymmetric predation Fluctuation & coexistence in omnivory[Overly?] predator-specific defenseThis is a new story of Antisymmetry

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Competitive exclusion of laterality in amino acids

L-amino acids D-amino acids

Omnivory is probably important for coexistence