evolution of group living: insights from a social foraging bat
TRANSCRIPT
Evolution of group living:insights from a social foraging bat
Dina Dechmann
Teague O’Mara
Rachel Page’s lab
Olivier Gimenez
Stephen Rossiter’s lab
Yann GAGER
“True sociality:
Persistence in associations
between individuals
in space and time
[Lee 1994]
[Van Schaik & VanHoof 1983]
[Schult et al. 2001]
Multiple
Convergent
evolution
of sociality
e.g. Primates
Ecological drivers
of sociality
Predators
Temperature Roost
Food
Spatial and temporal food constraints
Spatial Temporal
Sunrise Sunset
Time
Social foraging & information transfer
[Safi & Kerth 2007]
Social foraging
in bats
=
+
Feeding buzzes (cues)
Solitary=
Echoes up to 5m
Group=
Eavesdropping up to 50 m
Numerous benefits and costs of group living
Fitness ~ Group size
[Van Schaik & VanHoof 1983]
How does group size affect fitness components?
Group size
Fitn
ess
Foraging efficiency ~ Group size?
Group size
Fora
gin
g
effi
cien
cy
[Beauchamp 1998]
Group size
Su
rviv
al
[Beauchamp 1998]
Survival ~ group size ?
How does group size affect fitness components?
Survival?
Foraging efficiency?
Group size
The social bat M. molossus
Total size of social groups
Adult size of social groups
Sunset
Sunrise
Morning foraging
period
Evening foraging
period
A narrow ecological niche
[Dechmann et al. 2010]
Two energetic strategies
Group foraging
Lowered metabolism
[Dechmann et al. 2011]
Weight at return
Weight at emergence
The mass data
Foraging efficiency ~ group size
5 social groups with automated recorders
Artificial group size manipulation
Linear Mixed-Effect Model+ Bayesian simulations
Molecular ecology
78 marked individuals
20 to 50% of individuals
kept in captivity
Fixed + Random effects
5000 simulations
Up to 18 microsatellites
for most individuals
Mass variation over foraging period
- Linear model with Mixed-effects
- Ecological + genetic data
- Polynomial function for group size
- Interactions with time
Model: Quadratic function of group size (+ 95% CrI )
Survival ~ group size
201 recaptures of 126 adult females of 14 social groups
Survival ~ group size
No influence of group size on survival
Continuous monitoring of 63 marked adult females from 4 social groups
Survival ~ group size
Transitions between group size
Continuous monitoring of 63 marked adult females from 4 social groups
Main results
Foraging efficiency ~ GS
Survival ~ GS
Fitness components ~ group size:
Various patterns!
PhD Milestones
Next months: - Write foraging efficiency chapter- Analyses on reproductive success - Analyses on emergence order
December 2015: PhD defense (Konstanz)
Next weeks: - Submit survival chapter- Finish microsatellite note
@Bat_Yann
chiroblog.com