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

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
adaptive fisheries management
松田裕之（横浜国大・環境情報）
Hiroyuki Matsuda (Yokohama Nat’l Univ)
1
3 types of 3 species system
predator
2
3
3
carnivore
3
herbivore
2
1
1
prey
2
1
plant
2
The paradox of pesticides
3
Pesticide also attacks carnivore
2
Pesticide attacks herbivore
1
Herbivore will increase and
the plant will decrease.
3
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
4
Exploitative Competition
Increase predator 2
2
3
Decrease prey
Decrease predator 3
1
5
Exploitative Competition
•
•
•
•
•
•
•
dN1/dt = (-d1 - b1N1 + a1R)N1
dN2/dt = (-d2 - b2N2 + a2R)N2
dR/dt = (d0 - a1N1 + a2N2)R
N1 = (a1b2d0+a1a2d2 -a22d1)/(a22b1+a12b2),
N2 = (a2b1d0+a1a2d1 -a12d2)/(a22b1+a12b2)
R = (b1b2d0+a1b2d1 -a2b1d2)/(a22b1+a12b2)
dN1*/dd2 > 0
6
Apparent Competition
Increase prey 2
1
Increase predator
Decrease prey 3
2
3
7
Apparent mutualism
Abrams & Matsuda 1996 Ecology 77:610-616
Increase prey 2
1
Predator focuses on prey 2
Increase prey 3
2
3
8
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,
9
Exploitative Mutualism
(Matsuda et al. Oikos 1993, 68:549-559)
Increase predator 2
2
3
Watch more against 2
Increase predator 3
1
10
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.
11
How many points can you
watch for simultaneously?
Quiz by Japan Automobile Fedaration
JAF News, the recent issue
12
Yodzis(1988)の間接効果理論
•
•
•
•
•
•
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)
13
Example: indirect effects in a 10 species system
10
8
5
1
9
6
2
7
3
4
14
10
8
5
1
9
6
2
7
3
  a11

 0
 0

 0
 b
C   15
 0
 0

 0

 0
 0

4
群集行列
Community Matrix
0
 a 22
0
0
0
0
 b15
 b25
0
 b26
0
0
0
0
0
0
0
0
 a 33
0
0
 a 44
0
0
 b36
0
 b37
 b47
0
0
0
0
b25
0
0
 a 55
0
0
 b58
 b59
b26
0
0
0
b36
b37
0
0
0
b47
0
0
0
0
b58
b59
 a 66
0
b68
b69
0
 a 77
b78
b79
 b68
 b78
 a 88
0
 b69
 b79
0
 a 99
0
0
0
0
0
0
b80
b90
0 

0 
0 

0 
0 

0 
0 
 b80 

 b90 
 a 00 
15
10
8
5
1
9
6
2
7
3
4
Sensitivity frequency
Matrix “–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
16
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
17
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
18
Paradox of Kyoto Declaration
• Optimal
solution is either
• to catch sardine
after tuna goes
extinct; or
• to catch tuna
only.
19
Examples of biological community at
MSY (Matsuda & Abrams in review)
Solution maximizing total yield from community
MSY solution often reduces species and links;
5
5
4
1
5
4 5 6
4
4
3
2
6
5
4
3
(e)
6
6
6
(d)
(c)
(b)
(a)
3
3
1
2
1
3
2
1
2
1
2
20
Examples of biological community at MSY
(Matsuda & Abrams in review)
Constrained MSY that guarantee coexistence
exploit more species, more trophic levels.
(d)
(c)
(b)
(a)
6
6
6
5
5
4
1
100%
5
4 5 6
4
4
3
2
6
5
4
3
(e)
3
3
1
92%
2
3
1
2
61%
1
2
12%
1
2
6% 21
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
22
Requiem to Maximum
Sustainable Yield Theory
surplus production
• Ecosystems are uncertain, nonequilibrium and complex.
• MSY theory ignores all the three.
• Does MSY theory
guarantee species
persistence?
- No!!
23
Stock abundance
Feedback control in fishing effort
is powerful...
dE U N  N *


dt
dN  f ( N )  qEN
dt
N* N*N*
f(N)
A straw man says;
• Even though the MSY
level is unknown, the
feedback control
stabilizes a broad
range of target stock
level.
Stock size N
24
Feedback control with community interactions also
result in undesired outcomes.
(M & A in preparation)

dNi 
  ri   a ji N j  qei  Ni
dt 
j

9
10
8
r = (0.454,1.059,1.186,0.247,-0.006,-0.028,-0.059,-0.704,-0.308,-0.238)
A = (aji) =
1.
0.74
0.19
0.31
0.
0.
0.
0.
0.7
0.46
0.74
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.
0.68
7
0.31
0.08
0.96
1.
0.
0.
0.
0.28
0.
0.88
0.
0.46
0.08
0.
0.1
0.
0.
0.92
0.15
0.84
0.
0.66
0.14
0.
0.
0.1
0.01
0.
0.5
0.69
0.
0.48
0.83
0.
0.
0.01
0.1
0.56
0.
0.
e9 = 0.1, ei = 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
5
6
1
4
2
3
25
Feedback control may result in
extinction of other species (sp. 6).
ratio
de9/dt = u(N9-N9*)
26
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.
27
, aisclassic
this illusion?
Wasp-waist is
dream...
birds
seals
sardine/anchovy
tunas
lantern fish
pelagic
copepods
krill
deep sea
....
Only 5 to 10 percent of
us succeed of the weightloss industry
• Anyway, we need to investigate how to fluctuate the
total biomass of small pelagics.
28
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
29
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 = ajkRkｒ if fji>0, fjk>0
# equations = #links - #predator species
30
Link-species scaling law (1)
R1
R2
R3
• # equations = # links - # predator species
• # unknowns = # prey species
31
Link-species scaling law (2)
• # equations < # unknowns
• # links (L) < # prey + # predator species
• L < 2S (Cohen et al. 1993).
32
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)
33
Polis’ opinion
• Food web is
– L is proportional to S2
– link-species scaling law is an artifact from
short-term, narrow range observation.
34
Foodweb changes temporally
Matsuda, H. & Namba, T. (1991) Ecology 72(1):267-276.
predator
prey
35
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
36
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
37
Lateral dimorphism of scale eating
cichlids in Lake Tanganyika
Righty
Lefty
Hori 1991 Science 267
38
Three types of Asymmetries
(van Valen 1962)
“Antisymmetry” Fluctuating asymmetry (FA)
frequency
Directive asymmetry (DA)

-10

-5
0
5
relative trait values
10
39
Antisymmetry in
fishes
• Scale-eating cichlid in Lake Tanganyika
• Lefties feed on scales of the right side,
righties feed on scales of the left side
• Frequency dependent natural selection
– Hori 1991 Science 267:
• Maintained by predator-specific defense
40
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...
41
Frequencies of lefties
Coexistence of laterality
dimorphism (antisymmetry)
Scale eaters in Lake Tanganyika
(Hori unpublished)
Year of birth
42
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).
43
Why does a lefty catch a righty?
(Michio Hori’s idea)
44
Definition of
Antisymmetric Predation
• Both prey and predator have antisymmetric traits (laterality);
• “Lefty” predators feed on “righty”
prey; “Righty” predators feed on
“lefty” prey.
45
Two-platoon lineups in MLB
No fluctuation is
reported in the
frequency of lefty
pitchers and
batters in MLB or
College baseball
46
%lefties
Question…
• Does it really fluctuate?
– Statistically significant (Hori unpubl)
• Does it really synchronize?
• If so, what mechanism promote
fluctuation?
47
Omnivory is common in Lake
Tanganyika Fish Community
Piscivores
Scale eaters
Algal eaters
Hori 1997
48
We must apply our model to the
entire community (Hori unpublished)
49
Extension to Holt and Polis
(1997)
dx
dt
dy
dt
  m  Axy y  Axz z   c  x


x
  mAyz z  Axy x  d  y

y


dz   z 
  r 1    Axz x  Ayz y  z
dt   k 

z
• Where k = K/2
50
Three trophic levels
• 6 “populations”
(3 sp.×{Lefty, Righty}
• X: scale eaters
• Y: piscivores
• Z: algal feeders
• X preys on both y and z.
xL
xR
yL
yR
zL
zR
51
Does omnivory destabilize or stabilize
the antisymmetric predation system?
if X is
omnivory,
lefties
increase
Righties increase
Lefties increase
Righties increase
52
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)
53
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
54
Lateral dimorphism is
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
55
Competitive exclusion of
laterality in amino acids
L-amino acids
D-amino acids
56
Omnivory is probably important for coexistence

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