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Unworking ants are meaningful

Cat: ICT
Pub: 2010
#: 1905b

Eisuke Hasegawa (長谷川英祐)


Unworking ants are meaningful


  1. World of humans, world of insects:
  2. 70% of ants are off:
  3. The reason of unworking ants:
  4. Why work for others?:
  5. Care for myself only:
  6. Question of wheather Colony or Individual:
  7. What for the evolution?:
  1. ヒトの社会、ムシの社会:
  2. 7割のアリは休んでいる:
  3. 働かないアリはなぜ存在するのか?:
  4. 何で他人のために働くのか?:
  5. 自分が良ければ:
  6. 群れか個か、それが問題だ:
  7. その進化は何のため?:
; Age polyethism; Annus Mirabilis; Altruistic-Egoistic; Cheater; Constant population; Cooperation or kindred; Eusociality; Evolutionary confrontation; Free rider; Genetic drift: Group selecton; Hamilton's rule; Haplodiploidy; Inclusive fitness; Infection rate; ; Kindred; Kin selection theory; Law of Pareto;Natural selection; Raison d'êtle of unworking; Reaction threshold; Superorganism; Toxicity;

>Top 0. Introduction:

  • Significance of society; which gives enormous benefits as well as unavoidable stress to the constituent.
    • An individual cannot survive without society.
      • Individual and society exist simultaneously, as well as contradict and collide with individual or social profits or interests.
  • Eusociality exist in certain insects (ants, bees, and wasps) and in termites.
    • Is a human being a metaorganism?
      • A human being retains $10^{13} - 10^{14}$ bacteria in its intestine. The total number of genome of microbiome counts more than 100 times of the genome of a human.
  • Bees or ants in the colony are all female insects: worker ants, soldier ants, and Queen ant are all female.
    • Male ants appear in a short copulation period, after it they die immediately.
    • The Queen ant can keep their sperms in the body for more than a decade, and will use them as reproduction.
    • Male ants cannot move at all, which function only for copulation, which are black sheep in the colony.
      • On the contrary, mate termites can survive with their queen termite in the colony.

0. 序文:

  • eusociality: 真社会性
  • superorganism: 超個体
  • microbiome: microorganisms in a particular environment. 微生物 <-ome, all

>Top 1. 70% of ants are off:

  • The Aesop's Fable of 'the ant and the grasshopper' gives us the image that the ant is diligent.
    • We are looking at the ants walking around looking for foods on the surface, but there are more ants living in the underground nest.
    • The careful observation proves that about 70% of ants are not working. Are these unworking ants really lazy?
      • Researchers of social insects have interests on these unworking insects, as a subject of social psychology.
    • The research started from activities of bees. It is observed that the Queen bee mates with 20-30 male bees.
      • The famous figure-eight dance of bees, which inform other bees to guide to the target nectar.
    • As to the activities of ants or termites, there are many works inside the nest other than looking for food outside.
      • Antibacterial measures are particularly important to prevent from molding on eggs.
  • The organization of ants:
    • There are no supervisors in the colony:
      • If a dead cicada dropped on the ground, what ants should respond it?
      • The firs founder of ant leaves pheromone on the site as a notice of the food; then several hundred of ants can be gathered there to carry the huge food.
      • The information of the food is shared and processed locally.
        • The brain of insects are too small to have intelligent works; they respond according to preprogrammed actions (automatically responding to foods or fighting with enemy insects, etc.)
    • >Top age polyethism:
      • Young ants are involved internal works to care pupae or pupae in the colony, while older ants outside works to look for foods. The former is safer than the latter; which is a reasonable policy to maintain the whole colony.
      • There are neither experts nor abilities of particular jobs; jobs of ants are determined by the first experience.
      • Features of a small colony:
        • Slow and independent action, with larger difference of body parts; hardly replaceable workers.
      • Features of a big colony:
        • Quick and cooperative action (based of pheromone), with small different of body parts; easily replaceable workers.
        • It is not clarified that larger colony requires quick actions, or quick actions require larger colony.
          • This suggests that larger corporation of human organization use replaceable workers.
    • Accuracy of traceability:
      • The relationship of accuracy of traceability of fellow pheromone and effectiveness of food procurement:
        • Computer simulation shows interesting result; inaccuracy of certain level contribute more effectiveness of food procurement.
        • Inaccurate tracing of fellow pheromone may find more effective route to the target food; this means some foolish individuals in an organization may contribute as a result to the whole organization.
        • Organization which traces effectiveness may be effectively ineffective.
    • Behavior of soldier ants:
      • When a big sized food is found, large sized soldier ants come out and try to tear off the big food into small ones and put there, who will not carry the food to the nest.
      • It may be rational that large body of soldier ants consuming more energy avoid to spend further energy in carrying the food until the nest.
        • Furthermore, if other kind of ants try to intercept the food, the soldier ants run away first instead of fighting againt them; in this case smaller ants fight against the intercepters.
        • This can be understood that it took more energy and resources to grow large soldier ants. Thus it doesn't worth fighting for smaller food.

1. 70%のアリは休んでいる:

  • postulate: 公理・公準
  • age polyethism: 齢間分業, regular changing of roles of colony members as they get oldrer.

>Top 2. The reason of unworking ants:

  • Effective organization needs hierarchical functions; various level of mangers and staff.
    • Decisions of top management seriously affect the fate of the organization.
    • In ant colony, the Queen ant is only machine of reproduction; she does not govern or manage the colony; there is not hierarchical management system in ants society.
  • >Top Reaction threshold: individual difference (or personality) of easiness of starting works.
    • E.g.: action of cleaning (tidiness); sensitivity to sugar; sensitivity to room temperature
    • Different reaction threshold among individuals differs mobilization of individuals to a certain action; bees with more sensitive to sugar quickly respond to the finding of nectar.
      • It is needed for the colony that there is a variety of sensitivity to certain actions according to individual members.
  • >Top Law of Pareto (20-80 rules):
    • Individual difference comes from difference of genes; the Queen ant mated with 20-30 male ants, which have different genes.
      • But workers ants' viewpoint, which expect less diversity of genes, because they share more common genes with the Queen ant and their larvae.
  • Control by actions:
    • The reaction threshold may not be decided by only difference of genes; the difference of actions may affect variety of the reaction threshold.
      • Difference of experience or encounter may cause different reaction threshold.
  • Death from overwork:
    • Lifespan of ants differ significantly; the Queen ant 20 years, while working ants 3 years.
      • Greenhouse cultivation; there are more flowers in narrow area, which enforces bees to work more hardly, and the lifespan of bees tend to be short.
      • It takes time to decompose lactic acid accumulated in the muscle due to working.
  • >Top Raison d'être of unworking ants:
    • The colony which retains unworking ants to a certain percentage can survive longer.
      • Unworking ants are neither lazy nor disable in essence; who have only less opportunity to work; or the opportunity is taken by quicker ants.
    • What about the human society:
      • The corporations or organizations are urged to pursue effectiveness, and to become winners in the market; globalism spurs this trend.
      • Even universities or research organizations are required to pay more attention to applied and practical researches rather than basic ones.

2. 働かなしアリはなぜ存在するか:

  • spring tide: 大潮
  • reaction threshold: 反応閾値
  • monoploid (N): 単数倍数性
  • biploid (2N): 倍数性

>Top 3. Why work for others?

  • Darwin'S Natural selection:
    • Kin Selection:
      • the Queen ant and other ants shared almost same genes.
      • Other ants assist the Queen ant to breed their sisters and brothers, instead of breeding by themselves.
      • This assistance to the Queen can contribute to pass on more genes to the next generation.
        • >Top $br-c>0$ (called Hamilton's Rule), where $b$ is the number of children bred by the Queen ant; $r$ is degree of relatedness of genes; $c$ the number of children bred by themselves.
        • Actually, it is very difficult to prove the Hamilton's Rule, because there is no worker who is a single mother.
          • Inclusive fitness of egotistic worker is difficult to estimate, though that of alturistic is easier.
          • It is needed to observe both type of individuals; either observing the merit of altruistic behavior ($b$) or that of egoistic behavior ($c$).
  • Sex-determination system of Hymenoptera (bees, ants, wasps):
    • Males develop from unfertilized eggs and are haploid (N):
      • A male has no father and cannot have sons.
    • >Top Females develop fro fertilized eggs and are diploid (2N)
      • if a eusocial insect colony has one Queen, and she has only mated once, then relatedness between workers (diploid females) is 3/4.
      • This means that workers in such monogamous single-queen colonies are more closely related. (Kin selection theory)
  • Degree of relatedness of gene:
    • From the Queen ant; the relatedness of gene is the same between daughter and son (both are 1/2).
    • But from the daughter, the relatedness with its sister (3/4) and with its brother (1/4).
    • The sex ratio will tend to converge to 1:1 (subject to the same vale of male and female)
      • >Top But the case of Haplodiploidy ant is different.
      • There is a conflict of sex ratio of the next generation.
      • Daughters want more their sisters than their brothers.
      • It is observed that the workers will selectively kill their brothers.
        • Thus the workers may choose the next Queen.
  • >Top Group Selection:
    • If the cooperation of two individuals are more efficient than the sum of each efficiency (synergy effect), then there will be a group who cooperate each other though there is blood relationship (kindred).
      • Altruistic individuals may rather choose to cooperate to egoistic ones than having their own children (or by decreasing the number of their children).
      • Detection of such synergy effect to estimate Group Selection is noticed in the cases of cooperative breeding of certain birds or mammals (Cooperation or kindred).
        • Helping behavior (or collective security) may functions in the battle of neighbors. (Enemy of one's enemy is one's friend.)

3. 何で他人のために働くのか:

  • natural selection: 自然選択, organisms better adapted to their envrionment tend to survive and produce more offspring.
  • kin selection: = Hamilton's rule 血縁選択・血縁淘汰説
  • kindred: 血縁
  • inclusive fitness: 包括適応度
  • hymenoptera: 膜翅目, order of insects that includes bees, wasps スズメバチ, ants, and sawflies ハバチ
  • isoptera: 等翅目, order of insect that comprie termites.
  • Haplodiploidy: 半倍数性
  • altruistic: 利他的 ⇔egotistic, selfish
  • group selection: 群選択
  • Family Tree of Ant (Genome type):
    3/4 common genome between sisters:


>Top 4. Care for myself only:

  • Genetic profit or cooperation to society:
    • Eusocial insects contribute to colony by the labor of nursing larvae, or humans contribute to society via taxation.
    • But act of treachery (Free rider or Cheater) happen in such normal society.
      • Cheaters may appear in a society where altruistic members exist.
      • Cheaters could not increase forever as long as the society is maintained.
        • The society with more cheaters is less productive.
        • But a certain coexistence can be observed in some colonies.
    • >Top The balance of infection rate (by cheaters) and toxicity:
      • If the both are high, then the society collapses.
      • If the infection rate is low, the society infected by cheaters collapses.
      • If the infection rate and the toxicity is well balance, the coexistence occurs. (local collapse and local recovery occurs simultaneously.)
        • The relationship of pathogen and its host is same.
  • Various patterns of cheaters:
    • Social parsitism:
      • If a Queen of parasite species intrudes into a host colony, then kill the original Queen of colony and make workers of the colony nurture would-be workers of the parasite.
        • In this case, the colony will be extinct; thereafter workers of the parasite maintain the colony with Queen of the parasite (Temporal social parsitism)
    • Slavery:
      • If a Queen of parasite species invade into a host colony and kill the original Queen, then make workers of the parasite to a certain numbers; then order them to attack and abduct pupae, larvae or newborn workers of other species; who then become slaves of the parasite.
    • Mixture of colonies:
      • union will be made; when there are only workers of the conquered.
      • genocide will occur; when there is a nymph (who will be Queen)
    • Clone Reproduction (case of formicidae):
      • The next Queen is a clone of the Queen.
      • Male insect is also a clone of the father.
      • Workers are made by sexual reproduction

4. 自分が良ければ:

  • act of treachery: 裏切り行為
  • infection rate: 感染率
  • toxicity: 毒性
  • pathogen: 病原体
  • host: 宿主
  • social parsitism: 社会寄生
  • parasite species: 寄生種
  • formicidae: アリ科, コカミアリ
  • clone reproductrion: クローン生殖
  • sexual reproduction: 有性生殖⇔asexual
  • Formicidae:
    make succesive clone Queen:


>Top 5. Question of whether Colony or Individual:

  • Group, flock or herd:
    • There is an interaction among the individuals, whose group has some function, or joint action if needed.
      • Mammals like lions, monkeys, elephants, wolves, etc, or migratory birds or mixed-species of birds.
      • Small fish sometimes take predator avoidance.
  • A loner:
    • Being a loner in case of pandemic of influenza could be a wise decision.
  • Complete individual:
    • Our body started from one cell - a fertilized egg:
      • The degree of relatedness of all our body cells is 1 or almost 1.
      • Higher degree of relatedness becomes more inclusive fitness.
      • Only germ cell can reproduce children by its kin selection.
    • But only cancer cell is a traitor, which concentrates to proliferate without cooperating individual maintenance (like a genetic cheater)
    • Eusocial ants developed mutual surveillance system; checking eggs to be male is really Queen bred ones; workers eat and remove doubtful eggs.
      • From the viewpoint of worker ants, degree of relatedness with own son is 1/2; brothers bred by the Queen is 1/4; half-nephew is 1/8.
      • If the Queen mates only once, degree of relatedness with own son is 1/2; own sister's son (nephew) is 3/8, while brothers bred by the Queen is 1/4.
      • But it is mostly the Queen who breed male ants; almost prohibiting to breed male ants by other workers.
  • >Top Evolutionary confrontation:
    • Genetic difference among individuals in the colony causes evolutionary confrontation.
      • Who will be beneficial when who flourishes.
    • If a pupa of Queen is put in a no-Queen colony, the grown-up Queen breed workers and the next Queen by virgin birth.
      • As the workers have no ovary, and the Queen (and the next Queen) has an ovary.
      • This resembles that the workers correspond to various organs, while the Queen is the only reproductive organ.
      • Thus eusocial colony can be said a kind of superorganism.
    • Why not adopt such superorganism by all living creatures?
      • Probably a colony composed of identical genes is that the resistance power against epidemic is weak.
      • Division of wok cannot be smoothly operated without difference of threshold of response due to the difference of genes.
    • Suggestion of human society:
      • Raising labor productivity by increasing non-regular employment may causes deterioration of the foundation of life.
      • Economic globalization also may cause endanger long-term national production base.
      • Cheaters' invasion occurs in a limited local colonies; but expansion of economic sphere to worldwide may lose the equilibrium by balancing local proliferation of cheaters and local revival of altruistic persons.

5. 群れか個か、それが問題だ:

  • mixed-species: 混群
  • predator avoidance: 捕食回避
  • loner: 一匹狼
  • degree of relatedness: 血縁度
  • inclusive fitness: 包括適応度
  • ovary: 卵巣
  • testicle: 精巣
  • germ cell: 生殖細胞
  • genetic cheater: 遺伝的チーター
  • monitering system: 監視システム
  • mutual surveillance: 相互監視システム
  • evolutionary confrontation: 進化的対立
  • virgin birth: 処女懐胎

>Top 6. What for the evolution?:

  • Two principles of evolution:
  • Natural selection: survival of the fittest; to what? is the question.
    • Herein, environment include not only natural environment, but biological environment (predator, competitor, cheater, etc.).
    • This theory is tried to prove in a constant population; 1) no coexistence of parent and children generations, 2) unchanged number of individuals in each generation, and 3) completely random mating inside the group.
      • Relation of mutual interference; one who eat and one who is eaten.
      • Creation of colony, and society
      • Short-term or long-term labor efficiency
    • But recent ultra-aging society like in Japan need different approach other than constant population theory.
      • the number of population per generation differs.
      • individuals can mate only with visible counterpart in a certain area.
      • fitness of the next generation and that of far future generation may differ.
        • The unworking ants issue could be a battle between near and far future fitness.
      • There will be no complete fitness in living creatures; if it is, it will be almighty in any environment.
      • Human society is consisted with genomic diversity; which has common phenomena with the insect society.
        • A new theory appears as a weird, then others will recognize it and paradigm shift occurs.
        • It may be more sincere to say that there is something unexplained.
  • Genetic drift:
    • Relation of male and female
    • Kin selection

6. その進化は何のため?:

  • mutual interference: 相互干渉
  • selection pressure: 選択圧力
  • population: 個体数・個体群
  • fitness: 適応度
  • Biology is the only science base on the knowlede on the earth.
  • The development of astrobiology or xenobiology will open further breakthrough of biology.
  • 生物学は唯一地球上の知識に基づいた科学である。
  • 宇宙生物学の発展によって生物学のさらなる突破が図れることであろう。

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