1 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)

2 3 types of 3 species system prey predator plant herbivore carnivore

3 The paradox of pesticides Pesticide attacks herbivore Pesticide also attacks carnivore Herbivore will increase and the plant will decrease.

4 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

5 Exploitative Competition Increase predator 2 1 Decrease prey 3 Decrease predator 3

6 Exploitative Competition dN 1 /dt = (-d 1 - b 1 N 1 + a 1 R)N 1 dN 2 /dt = (-d 2 - b 2 N 2 + a 2 R)N 2 dR/dt = (d 0 - a 1 N 1 + a 2 N 2 )R N 1 = (a 1 b 2 d 0 +a 1 a 2 d 2 -a 2 2 d 1 )/(a 2 2 b 1 +a 1 2 b 2 ), N 2 = (a 2 b 1 d 0 +a 1 a 2 d 1 -a 1 2 d 2 )/(a 2 2 b 1 +a 1 2 b 2 ) R = (b 1 b 2 d 0 +a 1 b 2 d 1 -a 2 b 1 d 2 )/(a 2 2 b 1 +a 1 2 b 2 ) dN 1 */dd 2 > 0

7 Apparent Competition Increase predator Decrease prey Increase prey 2

8 Apparent mutualism Abrams & Matsuda 1996 Ecology 77: Increase prey Increase prey 2 1 Predator focuses on prey 2

9 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,

10 Exploitative Mutualism (Matsuda et al. Oikos 1993, 68: ) Increase predator 2 3 Increase predator 3 Watch more against 2

11 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.

12 Quiz by Japan Automobile Fedaration JAF News, the recent issue How many points can you watch for simultaneously?

13 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

Example: indirect effects in a 10 species system

15 群集行列 Community Matrix

16 Sensitivity frequency Matrix “–C -1 ” 種

17 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”.

18 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

19 Paradox of Kyoto Declaration Optimal solution is either to catch sardine after tuna goes extinct; or to catch tuna only.

Examples of biological community at MSY (Matsuda & Abrams in review) (b) (a) 12 5 (c) Solution maximizing total yield from community MSY solution often reduces species and links; (d) (e)

Examples of biological community at MSY (Matsuda & Abrams in review) (b) (a) 12 5 (c) 100%92%61%12%6% exploit more species, more trophic levels (d) (e) Constrained MSY that guarantee coexistence

22 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

23 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 surplus production

24 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. Stock size N f(N) N*N*N*N*N*N*

25 Feedback control with community interactions also result in undesired outcomes. (M & A in preparation) r = (0.454,1.059,1.186,0.247,-0.006,-0.028,-0.059,-0.704,-0.308,-0.238) A = (a ji ) = e 9 = 0.1, e i =

26 Feedback control may result in extinction of other species (sp. 6). de 9 /dt = u(N 9 -N 9 *) ratio

27 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.

28 Wasp-waist is a classic dream... Anyway, we need to investigate how to fluctuate the total biomass of small pelagics. birdssealstunas 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

29 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

30 共進化的に安定な群集 Coevolutionarily stable community dN j /dt = [-d j + Σ i f ji a ji R i ]N j dR i /dt = [r i - b i R i -Σ j f ji a ji N j ]R i tradeoff Σ i f ji =1 optimal prey preference Σ i f ji a ji R i maximize at CSC, a ji R i = a jk R k ｒ if f ji >0, f jk >0 # equations = #links - #predator species

31 Link-species scaling law (1) # equations = # links - # predator species # unknowns = # prey species R1R1 R2R2 R3R3

32 Link-species scaling law (2) # equations < # unknowns # links (L) < # prey + # predator species L < 2S (Cohen et al. 1993).

33 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

34 Polis’ opinion Food web is –L is proportional to S 2 –link-species scaling law is an artifact from short-term, narrow range observation.

35 Foodweb changes temporally Matsuda, H. & Namba, T. (1991) Ecology 72(1): predator prey

36 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

37 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

38 Lateral dimorphism of scale eating cichlids in Lake Tanganyika Righty Lefty Hori 1991 Science 267

39 Three types of Asymmetries (van Valen 1962) Directive asymmetry (DA) Fluctuating asymmetry (FA) “Antisymmetry” 

40 Antisymmetry in fishes Scale-eating cichlid in Lake TanganyikaScale-eating cichlid in Lake Tanganyika Lefties feed on scales of the right side, righties feed on scales of the left sideLefties feed on scales of the right side, righties 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

41 More Story in Fish Laterality…. Another Tanganyikan fish has lateral asymmetry (Mboko et al. 1998: Zool. Sci. 15 )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 )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)Many fishes and other aquatic invertebrates have lateral antisymmetry! (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...

42 Coexistence of laterality dimorphism (antisymmetry) Frequencies of lefties Scale eaters in Lake Tanganyika (Hori unpublished) Year of birth

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

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

45 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.

46 Two-platoon lineups in MLB No fluctuation is reported in the frequency of lefty pitchers and batters in MLB or College baseball

47 Question… Does it really fluctuate? –Statistically significant (Hori unpubl) Does it really synchronize? If so, what mechanism promote fluctuation? %lefties

48 Hori 1997 Scale eaters Piscivores Omnivory is common in Lake Tanganyika Fish Community Algal eaters

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

50 Extension to Holt and Polis (1997) x z y Where k = K/2

51 Three trophic levels xLxL xRxR yLyL yRyR zLzL zRzR 6 “populations” (3 sp.×{Lefty, Righty} X: scale eaters Y: piscivores Z: algal feeders X preys on both y and z.

52 Does omnivory destabilize or stabilize the antisymmetric predation system? Lefties increase Righties increase if X is omnivory, lefties increase

53 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)

54 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

55 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

56 Competitive exclusion of laterality in amino acids L-amino acids D-amino acids Omnivory is probably important for coexistence