Eusociality Flashcards
(11 cards)
What are the three features of eusocial systems
Cooperative brood care
Sterile castes
Overlapping generations
Briefly give the life cycle of Myrmica rubra
Nuptial flight
Queen founds nest
Production of sterile female workers
9 years later produce winged females and males
What is the staying at home hypothesis?
Subsocial
Start with solitary parasitoid
Get nest guarding by female
Young stay and help defend/build
Young permanently at home and never breed
What is the genetic predisposition of the staying at home hypothesis?
For daughters, raising full siblings is as good as raising offspring (relatedness is both 0.5)
For a queen, producing offspring (r=0.5) is better than producing grand-offspring (0.25)
Queen should prefer daughters to stay as workers
What is the sharing a nest hypothesis?
Parasocial
Sisters build nests close together
Get cooperative defence but still have separate reproduction
One female then dominates reproduction
Young females become workers
What is the genetic predisposition for the sharing a nest hypothesis?
For sisters that cooperate there is a benefit from raising dominant offspring
This may outweigh the benefit of breeding alone if it is high risk
What is haplodiploidy?
Males develop from unfertilised eggs = haploid
Females develop from fertilised eggs = diploid
Males from gametes without meiosis whereas females from them with
Daughters receive identical genes from father and the other half from diploid mother
Sons receive genes only from mother
What are the different relatedess for haplodiploidy?
Sister - sister = 0.75
Sister - brother = 0.25
Female - Daughter = 0.5
Better to produce sisters than daughters
This is why females rear sisters
What are the preferred sex ratios of investment in reproductivness?
Queen = 1F:1M
Worker = 3F:1M
What did Trivers and Hare suggest?
Workers win over queen for sex ratio
