1. 1. Ecological determinants of foraging efficiency: insights from the group foraging bat Molossus molossus Yann GAGER
2. 2. Adapted from [Cvikel et al. 2015] Information transfer about food
3. 3. Information transfer about food Adapted from [Cvikel et al. 2015]
4. 4. Information transfer about food [Dechmann et al. 2010] Social foraging confirmed by telemetry, 37 mins foraging time
5. 5. Optimal group size for foraging efficiency? Group size Foraging efficiency Improved prey detection Inspired from [Cvikel et al. 2015]
6. 6. Group size Foraging efficiency Improved prey detection conspecific interference Optimal group size for foraging efficiency? Inspired from [Cvikel et al. 2015]
7. 7. Small harems of stable size [81 captures 14 social groups] Adultgroupsize Roost identity Recruitment of juveniles dispersing Death of group members + -
8. 8. Automated data collection: transponder reader + scale
9. 9. Reader data from one adult of each sex SunriseSunset Typical female: foraging (x = 38 mins)
10. 10. Reader data from one adult of each sex Typical female: foraging (x = 38 mins) Typical male: foraging (x = 32 mins) + roost guarding SunriseSunset
11. 11. Mass data for one femaleMass(g) Month of the year
12. 12. Mass data for one femaleMass(g) Month of the year Emergence Return
13. 13. Mass data for one female Birth Pregnancy Mass(g) Month of the year
14. 14. Modelling mass data for after-sunset period - 5 social groups with group size manipulation - Evening foraging period [sunset: 3 h after sunset] - 37 days, 73 individuals, 8681 mass points The automated dataset of mass
15. 15. Modelling mass data for after-sunset period - 5 social groups with group size manipulation - Evening foraging period [sunset: 3 h after sunset] - 37 days, 73 individuals, 8681 mass points The automated dataset of mass Day 1 Day 6 Day 11 Day 15 Natural size (100%) Artificial size (50-75%) Natural size (100%)
16. 16. Modelling mass data for after-sunset period Linear mixed-effect models - Response variable: Mass - Fixed predictor variables (sex, group size, day, time, weather [rain, wind speed, temp., moon]) - Random effect variables (transponder, roost) - 5 social groups with group size manipulation - Evening foraging period [sunset: 3 h after sunset] - 37 days, 73 individuals, 8681 mass points The automated dataset of mass
17. 17. Important predictor variables for mass > Sex [Female-defense polygyny]
18. 18. Important predictor variables for mass > Sex [Female-defense polygyny] Time [Sunset: 3 h after sunset]
19. 19. Important predictor variables for mass > Sex [Female-defense polygyny] Rain & wind speed [Effect on foraging] Time [Sunset: 3 h after sunset]
20. 20. Important predictor variables for mass > Sex [Female-defense polygyny] Rain & wind speed [Effect on foraging] Time [Sunset: 3 h after sunset] Group size [Optimal for mass gain]
21. 21. Mass gain over 3 h ~ group size Massgain(g)over3h Group size
22. 22. Mass gain over 3 h ~ group size 95% Credibility Interval Group size Massgain(g)over3h
23. 23. A cooperative piece of work
24. 24. yanngager.weebly.com
25. 25. Fitness ~ group size Higashi~1993 Compromise Stable Optimal
26. 26. Mass variation: the Linear Mixed-Effect model
27. 27. What are the multiple benefits of bat sociality? Predator avoidance Food sharing Social thermoregulation Information transfer about food