1. Towards Accurate Calculation of Field Metabolic Rates for Bats
R.D. (Bob) Bullen
Bat Call WA Pty Ltd
13 July 2017

2. Bat FMR Modelling - Objective
A BALANCED ENERGY BUDGET IS THE KEY TO AN ANIMALS ABILITY TO SURVIVE AND REPRODUCE
UNDERSTANDING THIS BUDGET for a flying animal IS A VERY DIFFICULT CHALLENGE
ESTIMATES FOR BATS BASED ON SCALING MASS IS TYPICALLY ACCURATE TO +/- 50%
FOR INTRA AND INTER-SPECIES ENERGY BUDGET ASSESSMENTS FOR BATS IN GUILDS, COMMUNITIES AND ALSO AT CONTINENTAL LEVEL, ACCURACY OF BETTER THAN 10% IS NEEDED.

3. Bat FMR Modelling – Mass Scaling

4. Bat FMR Modelling - Strategy
TO ACHIEVE ESTIMATES WITHIN 10% OF FIELD DATA IT IS NECESSARY TO MODEL ACCURATELY THE VARIOUS PROCESS THAT MAKE UP THE ENERGY BUDGET.
IT IS RECOGNISED (SEE SPEAKMAN AND RACEY 2003) THAT FMR CAN BE ESTIMATED USING TIME-ENERGY BUDGETS (TEBs) AND THAT THESE ESTIMATES PROVIDE PARTITIONING BETWEEN DIFFERENT THERMOREGULATORY AND PHYSICAL ACTIVITIES BUT EARLY ATTEMPTS PROVIDED ACCURACIES NO BETTER THAN SIMPLE SCALING RELATIONSHIPS.
MY METHOD COMBINES THE ACCURATE CALCULATION OF A BATS METABOLIC POWER LEVEL DURING SEVERAL FLIGHT PHASES, E.G. COMMUTING AND FORAGING, AND COMBINES THIS WITH ESTIMATES OF ENERGY CONSUMED DURING OTHER PHASES OF A DAILY CYCLE.
IT REQUIRES ON AN ACCURATE TEB AS A BASIS OF THE CALCULATION.

5. Bat FMR Modelling - TEB
TEBs FOR FIVE DIFFERENT FORAGING STRATEGIES HAVE BEEN DISTILLED USING BOTH PUBLISHED DATA AND OUR OWN OBSERVATIONS.
THESE STRATEGIES ARE:
INSECTIVOROUS BATS
SMALL NECTARIVORES, OMNIVORES AND FRUGIVORES UNDER 40 G
LARGE NECTARIVORES, OMNIVORES AND FRUGIVORES OVER 40 G
LARGE CARNIVORES OVER 50 G
SANGUINIVORES

6. Bat FMR Modelling – TEB EXAMPLE TEB FOR COMMON INSECTIVOROUS SPECIES
Adult
male and
non-repro
adult
female
(hours)
Pregnant
Female
Lactating
Day Roost Inactive
(default is BMR) 8
Day Roost Active at RMR = 130% BMR
10.5 18
Night Roosting at 130% BMR 3
( 0 – 3 )
0.5
Time Commuting at Vsan
0.5 typical
(0 - 1)
Time Foraging at Vae with 115% to allow for manoeuvre, catch and carry costs. 2
( 1.5 – 3)
2.5
5.0
( 4 to 6 )

7. Bat FMR Modelling
BASIC ECOLOGICAL INFORMATION FOR THE SPECIES IS NEEDED
BASIC MORPHOLOGICAL DATA
MASS – WING AREA – WING SPAN – GOOD QUALITY IMAGE
FORAGING STRATEGY
FORAGING MICROHABITAT
TROPICAL OR TEMPERATE GEOGRAPHIC SPREAD
THE ABILITY TO HOVER
PREFERENCE FOR A CAVE OR TREE/BUILDING ROOST
PRIMARY FOOD PREFERENCE – INSECTS, NECTAR, ETC.

8. Bat FMR Modelling PHYSIOLOGICAL DATA
PARAMETERS TO APPLY DIRECTLY TO FMR ESTIMATES ARE ALL EITHER KNOWN (MEASURED FOR THE SPECIES) OR CALCULATED FROM THE ECOLOGICAL DATA
BASAL METABOLIC RATE - BMR
MUSCULOSKELETAL MECHANICAL EFFICIENCY
HEART MASS
BLOOD HAEMOGLOBIN
EFICIENCY OF CIRCULATORY AND BREATHING SYSTEMS
FLIGHT MUSCLE MASS
USE OF TORPOR

9. Bat FMR Modelling CHARACTERISTIC FLIGHT SPEEDS AND POWER POLARS
FIVE CHARACTERIASTIC FLIGHT SPEEDS ARE CALCULATED USING THE METHOD OF BULLEN et al. (2016).
MINIMUM SPEED – VMIN
EFFICIENT SPEED RANGE – VEFF
MAXIMUM AEROBIC SPEED – VAE
SUSTAINABLE ANEROBIC SPEED – VSAN
MAXIMUM ANEROBIC SPEED – VMAN
FMR CALC. TYPICALLY USES THE MIDDLE THREE

10. Bat FMR Modelling CHARACTERISTIC FLIGHT SPEEDS AND POWER POLARS
FOR MOST SPECIES METABOLIC POWER IS CALCULATED FOR THE THREE FLIGHT SPEEDS VEFF(UPPER), VAE and VSAN
FOR A FEW SPECIES WITH UNUSUAL FORAGING STRATEGIES VMIN AND VEFF(LOWER) ARE NEEDED e.g. Vampire bat (D. rotundus).
VEFF(UPPER) IS USED BY LARGE OMNIVORES, FRUGIVORES AND CARNIVORES
VAE IS USED BY INSECTIVORES AND SMALL OMNIVORES DURING FORAGING
VSAN IS USED BY INSECTIVORES WHILE COMMUTING.

11. Bat FMR Modelling CHARACTERISTIC FLIGHT SPEEDS AND POWER POLARS

12. Bat FMR Modelling COMBINING TEB AND POWER POLAR
DAILY CYCLE OF EACH GROUP IS BROKEN INTO FIVE ELEMENTS
INACTIVE DIURNAL ROOSTING WHILE TORPID
ACTIVE DIURNAL ROOSTING WHILE NORMOTHERMIC
NOCTURNAL ROOSTING WHILE NORMOTHERMIC
COMMUTING FLIGHT
FORAGING FLIGHT
CONTRIBUTIONS DUE TO PREGNANCY AND LACTATION ARE REQUIRED

13. Bat FMR Modelling PUBLISHED EMPERICAL FMR DATA
FROM THE LITERATURE WE HAVE DISTILLED RELIABLE FMR DATA FOR 16 SPECIES
THESE ARE ALL DOUBLY LABELLED WATER (DLW) DATA FROM FREE LIVING OR RECENTLY CAUGHT BATS IN CONTROLLED LABORATORY CONDITIONS.

14. Bat FMR Modelling FMR components – Air superiority insectivore

15. Bat FMR Modelling COMPARISON OF EMPERICAL DATA WITH MODELLED RESULTS
INSECTIVORES – SIX SPECIES
NON-REPRODUCTIVE AVERAGE ERROR OF ESTIMATE IS 2.8%
LARGEST EoE IS 8.2%
NECTARIVORES ANDS SMALL FRUGIVORES – SIX SPECIES
NON-REPRODUCTIVE AVERAGE ERROR OF ESTIMATE IS 3.0%
LARGEST EoE IS 7.6%
LARGE OMNIVORES AND FRUGIVORES – THREE SPECIES
NON-REPRODUCTIVE AVERAGE ERROR OF ESTIMATE IS 2.9%
LARGEST EoE IS 6.2%
SANGUINIVORES – ONE SPECIES
NON-REPRODUCTIVE MALE ERROR OF ESTIMATE IS 4.0%
NON-REPRODUCTIVE FEMALE ERROR OF ESTIMATE IS 12.0%

16. Bat FMR Modelling COMPARISON OF EMPERICAL DATA WITH MODELLED RESULTS
PREGNANT FEMALES – TWO SPECIES
EoE RANGE IS 2.5% TO 5.4%
LACTATING FEMALES – FOUR SPECIES
AVERAGE EoE IS 6.5%
MAXIMUM EoE IS 25%

17. Bat FMR Modelling COMPARISON OF EMPERICAL DATA WITH MODELLED RESULTS

18. Bat FMR Modelling OBJECTIVE ACHIEVED

19. Bat FMR Modelling OBJECTIVE ACHIEVED
Thanks:
My collaborators on the various elements of the project
Norman McKenzie
Ariovaldo Cruz-Neto
IMC 12 Organisers for the op’ to present