Lecture 4 Flashcards
What was previously used to measure flight costs in albatross? What was the estimated flight metabolic rate?
. Used DLW and activity monitor
. Measured the energy cost of being at sea- time on the water, time in flight
. Flight metabolic rate was estimated to be 3-4 times BMR (in other birds it would be about 20 times)
What is the most energetically expensive activity you can undertake?
Flight
What are the problems with using heart rate to estimate energy expenditure?
. Has to be calibrated with respirometry
. May need multiple calibrations
. Calibrations are species specific
. fH (the H is like the 2 on the VO so below) and VO2 have to be calibrated over a wide range of values
. Different muscle groups may have different relationships e.g. birds
. All the parameters have to vary systematically
. Measures only aerobic metabolism
. Technically very difficult to record in the field
. Got to do it in the lab to begin with
. Wide range means you have to get them working hard to get them over the full range
. The different muscle groups being used is really only birds because most mammals, regardless of the species will use their whole body when they move
. Anaerobic metabolism has to paid off at some point so in the end it will be recorded as an aerobic component (don’t know if they is a problem or a positive)
What are the benefits of using heart rate to estimate energy expenditure?
. Long periods of monitoring- potential for circa-annual estimates of MR
. Short time resolution
. Easy to integrate with behavioural data
. Can be used to estimate the MR of specific activities/ behaviours
. Good estimates obtained
. A physiological measure
. The short time resolution- can record down to the minute. We can record heart rate down to seconds but when it comes to energy expenditure the you are down to minutes (don’t know if this is a positive or negative)
What is side-side movement called?
Sway
What is front to back movement called?
Surge
What is up and down movement called?
Heave
What is overall dynamic body acceleration?
If you have sway, surge and heave of an animal data in an accelerometry then you can put all that data together and build up a picture of what the animal is doing and come up with the overall dynamic body acceleration. So you are taking all that accelerometry data and coming up with a single figure
What can do when you have the overall dynamic body acceleration of an animal?
Take an animal and put it onto a treadmill
What can ODBA (overall dynamic body acceleration) be used to estimate in some studies? What does this allow you to do?
In some studies that have been done you can use ODBA to measure oxygen consumption.
Then you can look at animals in the field (there is an exponential increase in the number of studies using this
What does accelerometry measure? But what is an issue with this?
. It measures animal movement
. Whether it actually measures your overall movement depends on where the actual device is put
Where do you want to be an accelerometry to measure animal movement? However few studies will do that, where is it usually put?
Want it to be in the centre of gravity of the animal (inside the animal).
Most studies will be in a collar or on the back
What is the problem with most accelerometry (ODBA) studies using collars or on the back of the animal?
Collars will move side to side anyway
So when putting it on as a collar or on the back of the animal you don’t necessarily get the right acceleration of the animal
What is a drawback of ODBA?
Potential errors due to changes in animal energy expenditure that are independent of activity. So might underestimate when an animal is post absorptive as its metabolic rate technique will increase because it has just eaten a meal, no movement but its metabolic rate may go up 3 fold
When might ODBA studies underestimate energy expenditure?
Where an animal is: . Post-absorptive . Outside of its thermal neutral zone- might pick up shivering . Growing rapidly . Gestating or carrying an infant
