12: eusociality Flashcards

1
Q

what are the 3 main orders with eusocial systems ?

A

hymenoptera
isoptera
homoptera

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2
Q

within hymenoptera how many species are eusocial? (3)

A

bees: 1,000
wasps: 800
ant: 9,500/all

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3
Q

in isoptera how many species are eusocial?

A

termites: 2,000

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4
Q

in homoptera what species is eusocial?

A

aphids

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5
Q

what are the 3 main features of eusocial species?

A
  • cooperative brood care (non parents help raise brood)
  • sterile castes
  • overlapping generations (workers raise subsequent broods)
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6
Q

how many total species of social insects? - how many birds and mammals?

A

14,000

birds: 10,000
mammals: 4,000

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7
Q

how many ants in the driver ant colony?

A

22 million

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8
Q

in the brazilian rainforest what % of insect and animal biomass is eusociall?

A

insect: 70-80%
animal: 33%

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9
Q

what is an example of sophisticated communication in eusocial species?

A

waggle dance

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10
Q

what is the ant myrmica rubra life cycle? (6)

A
  1. queen founds nest
  2. sterile workers produced
  3. 9 years for colony to be large enough
  4. after 9 years winged females and males produced
  5. nuptial flight and mating
  6. males die and females find a nest
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11
Q

list the 2 hypotheses for why eusociality evolved

A
  • staying at home/subsocial

- sharing a nest/ parasocial

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12
Q

what is the ecology for how eusociality evolved by the staying at home hypothesis? (4)

A
  • ancestors are solitary parasitoids
  • advantage to nest guarding by females against parasites
  • if enough predation pressure young stay and help mother defend and build nest
  • will stay at home and never breed
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13
Q

what is the genetic predisposition for how eusociality evolved by the staying at home hypothesis? (3)

A
  • for daughters at home raising full siblings (r=0.5) is the same as raising offspring (r= 0.5)
  • for queen producing offspring (0.5) is better that grand offspring (0.25)
  • queen should prefer daughters to stay as workers
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14
Q

what is the ecology for how eusociality evolved by the sharing a nest hypothesis? (4)

A
  • cooperating sisters build nests close together
  • cooperative defence but separate reproduction
  • one female dominates reproduction
  • young females become workers
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15
Q

what is the genetic predisposition for how eusociality evolved by the staying at home hypothesis? (3)

A
  • for cooperative sisters there is benefit to raising dominants offspring
  • this may outweigh benefit of breeding alone if it is risky
  • relatedness ensures non reproductive female benefits from queens reproduction
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16
Q

what is an example of a species that fits with the stay at home hypothesis?

A

subsocial halictine bees

17
Q

what is an example of 2 species that fit with the sharing a nest hypothesis?

A

polistes

stenogastrine waps

18
Q

what did W.D Hamilton say about haplodiploidy?

A

it predisposes hymenoptera to evolve sterile castes

19
Q

what are features of M and F in haplodiploidy?

A

M: from unfertilised eggs, haploid and form gametes without meiosis so all sperm identical
F: from fertilised eggs, diploid and form gametes with meiosis

20
Q

where do sons and daughters receive their genes in terms of mother and father?

A
  • sons: only from mother

- daughters: identical genes from father and other half from diploid mother

21
Q

in the sister-sister pedigree what is the relatedness

a) via mother
b) via father
c) total

A

a) 0.5 X 0.5 =0.25
b) 0.5 X 1 = 0.5
c) 0.25 + 0.5= 0.75

22
Q

in the sister-brother pedigree what is the relatedness

a) via mother
b) via father
c) total

A

a) 0.5 X 0.5 =0.25
b) 0.5 X 0 = 0
c) 0.25

23
Q

in the brother-sister pedigree what is the relatedness

a) via mother
b) via father
c) total

A

a) 1 X 0.5 =0.5
b) 0.5 X 0 = 0
c) 0.5

24
Q

what is the genetic relatedness between female and

a) mother
b) father
c) sister
d) brother
e) son
f) daughter

A

a) 0.5
b) 0.5
c) 0.75
d) 0.25
e) 0.5
f) 0.5

25
Q

what is the genetic relatedness between male and

a) mother
b) father
c) sister
d) brother
e) son
f) daughter

A

a) 1
b) 0
c) 0.5
d) 0.5
e) 0
f) 1

26
Q

what is it better the female worker produces and what does it explain?

A

sisters rather than daughters

- explains why females rear sisters

27
Q

in hymenoptera what are workers always?

A

female

28
Q

what are diploid termites like?

A

M and F equally related to siblings and both sexes become sterile workers

29
Q

what are clonal aphids like?

A
  • all are genetically identical r=1

- sterility is not an evolutionary puzzle as is no conflict over reproduction

30
Q

what is the preferred sex ratio for the queen and why?

A

son r=0.5
daughter r=0.5
1F:1M

31
Q

what is the preferred sex ratio for the worker and why?

A

brother r=0.25
sister r=0.75
3F:1M

32
Q

what did Trivers and Hare 1976 study and find? (3)

A
  • sex ratio in 21 ant species
  • suggested workers win
  • but the preferred ratio is influence by local mate competition and queen mating frequency affecting relatedness
33
Q

what is local mate competition? (2)

A
  • if sons/brothers compete to mate such as in fig waps then it should pay to produce fewer of them
  • benefit to female biased sex ratio
34
Q

what is queen mating frequency affecting relatedness? (3)

A
  • if females mate with multiple males then workers are less closely related
  • if 2 possible fathers: r= 1 X 0.5 X 0.5 = 0.25 (+ 0.25 from mother = 0.5 relatedness)
  • if infinite males then r= 0
35
Q

what are ecological constraints important in?

A

evolutionary origins

36
Q

what can eusocial species also be characterised by?

A

conflict within and between castes