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Projects

Projects. The mating system of red squirrels at Kluane and the correlates of male mating success Energetics of reproduction in male red squirrels Reciprocal effects of physiological condition and reproductive success Sperm competition and the correlates of male siring success

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Projects

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  1. Projects • The mating system of red squirrels at Kluane and the correlates of male mating success • Energetics of reproduction in male red squirrels • Reciprocal effects of physiological condition and reproductive success • Sperm competition and the correlates of male siring success • Inbreeding avoidance

  2. 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

  3. 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)

  4. Chase attendants Successful mates

  5. R2 = 0.7; P <.001

  6. Males that traveled further during the mating season had a higher mating success

  7. 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

  8. 1992 1:10 000

  9. 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?

  10. 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)

  11. Adult males have more cones over winter than all other age/sex classes

  12. 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

  13. 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

  14. Stress Hypothalamus CRF + Pituitary Negative Feedback Under Acute Stress ACTH Adrenals Cortisol Adapted from Boonstra et al. 1998 Blood Energy Mobilization Immune Suppression Reproductive Suppression Growth Suppression Digestive Suppression

  15. 30 min 30 min 60 min BASE sample and ACTH Injection Sample (P30) Sample (P60) Sample (P120) • ACTH Injection: • Stimulate Stress Response • Map changes in plasma cortisol over 120 min • BASE Sample: • Basic hematological properties • Baseline cortisol level

  16. 4 d Injection Sample • Sample (~ 100µL) at day 4 • Differential agglutination indicates humoral immune response

  17. 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

  18. 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?

  19. Paternity Data • Nine mating chases • Multiple paternity (1-3 fathers/litter) • First male/Last male precedence not apparent

  20. 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?

  21. 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

  22. 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?

  23. Next steps • Agnes 2. Heritabilities of “mating effort” (w/ Andrew, Dave) 3. Larger scale inbreeding avoidance analysis (w/ Mark) 4. Scat analyses: • Genetics • Endocrinology • FECs 5. Parasite treatment

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