projects 1.the mating system of red squirrels at kluane and the correlates of male mating success...
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Projects
1. The mating system of red squirrels at Kluane and the correlates of male mating success
2. Energetics of reproduction in male red squirrels
3. Reciprocal effects of physiological condition and reproductive success
4. Sperm competition and the correlates of male siring success
5. Inbreeding avoidance
Project 1: The mating system of red squirrels at Kluane and the correlates of male mating success
Objectives
• Define the mating system of red squirrels at Kluane
• Determine the correlates of male mating success
Mating
• Male– KLOO: 3.2 ± 2.3 copulations/male– SUL: 4.5 ± 2.6 copulations/male
• Female– KLOO: 5.9 ± 3.2 copulations/female– SUL: 8.5 ± 2.3 copulations/female
• Proportion of males in chase receiving a copulation = 0.77 ± 0.19 (N = 41)
Chase attendants Successful mates
024681012141618
0 1 2 3 4 5 6 7 8 9 10 11 12
Number of Mates/Chases
Num
ber
of M
ales
CopulationChase
0
2
4
6
8
10
12
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Chases Attended
Cop
ulat
ions
Atta
ined
R2 = 0.7; P <.001
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000 3500 4000
Total Distance (m)
Co
pu
lati
on
s 2
00
3
Males that traveled further during the mating season had a higher mating success
Conclusions
• Scramble competition polygynandry• Mating success largely driven by mating
effort• To Do:
– Pre-estrous mate searching• General• Specific females
• Behaviour publication incorporating– Mating system– Search effort– Copulatory Success
Project 2: Energetics of reproduction in male red squirrels
Collaborators: Murray Humphries, John Speakman, Dave
Coltman
Objectives
• Measure the costs of reproduction to male red squirrels
• Determine the differential costs of reproduction to males with variable mating effort
• Do males with greater energetic resources invest more in the mating system?
Progress to date
• 20 FMRs (2004)
• 10 males in mating chases/10 males not
• Blood being analyzed in Aberdeen
• Cone count indices of middens (2003 and 2004)
-1
0
1
2
3
4
5
6
7
8
Adult Male Adult Female Juv Male Juv Female
Sex/Age Class
Mid
de
n Q
ua
lity
Sc
ore
Adult males have more cones over winter than all other age/sex classes
Conclusions
• Adult males cache more than adult females• High variability in cache index for individual males• High variability in mating effort of males• To Do:
– Analyze FMR data– Compare cache indices to mating effort and ultimate
reproductive success
• Physiology or Ecology publication incorporating– Mating season energetics– Cache indices– Copulatory Success
Project 3: Reciprocal interactions of physiological condition and reproductive success
Collaborators: Rudy Boonstra, Dave Coltman
Objectives
• Determine how the physiological condition of male red squirrels influences their reproductive success
• Determine how variable reproductive success influences a male’s physiological condition
Hypothalamus
Pituitary
Adrenals
Blood
CRF +
ACTH
Cortisol
Negative Feedback Under Acute Stress
Adapted from Boonstra et al. 1998
Energy Mobilization
Growth Suppression
Immune Suppression
Digestive Suppression
Reproductive Suppression
Stress
BASE sample and ACTH Injection
Sample (P120)
• BASE Sample:
• Basic hematological properties
• Baseline cortisol level
Sample (P60)
Sample (P30)
• ACTH Injection:
• Stimulate Stress Response
• Map changes in plasma cortisol over 120 min
30 min 60 min30 min
Injection Sample
4 d
• Sample (~ 100µL) at day 4
• Differential agglutination indicates humoral immune response
Conclusions
• 24-26 males before and after mating season
• Tissue samples from adults/offspring
• To Do:– Hormone and immune assays (December)– Paternity analyses
• Publication incorporating– Condition data – Cache indices/Body condition– Reproductive success
Project 4: Sperm competition and the correlates of male siring success
Collaborators: Melissa Gunn, Dave Coltman
Objectives
• Determine the direction (if any) of sperm precedence in red squirrels
• How does the testes size of a male influence his siring success?
Paternity Data
• Nine mating chases
• Multiple paternity (1-3 fathers/litter)
• First male/Last male precedence not apparent
Conclusions
• 75 Mating chases
• Offspring from 2003, 2004
• Testes sizes from 2004
• Publication incorporating:– Copulation order, genetic sires, multiple paternity,
testes sizes, age – Good genes/Compatible genes?
Project 5: Inbreeding avoidance in red squirrels
Collaborators: Melissa Gunn, Dave Coltman
Objectives
• Map spatial degree of relatedness
• Assess potential mechanisms of inbreeding avoidance in red squirrels: pre- and post-copulatory
Conclusions
• Pedigree with matrilines
• Copulation and sire identities
• To Do:– Paternal relatedness
• Publication incorporating:– Pre-copulation mechanisms:
• Mating chase distances by males• Avoidance of kin
– Post-copulation mechanisms?