Metabolism calculators

• METABOLIC ALLOMETRY... 'm' Use this
somewhat specialized utility to make estimates of an animal's resting metabolism,
based on its size and taxonomic affiliation. The metabolism calculator has many potential uses; for example, you might want to use it as a 'reality check' if you think your own metabolic data are unexpectedly high or low. The initial popup menu contains some very generalized equations, and also allows you to switch to submenus for specific taxa (arthropods, fish, birds, mammals, etc.). For most taxa, several different equations are available (from different literature sources (listed here). You can also pick the desired output units. The energy equivalence of metabolism (joules per ml of oxygen consumed) can be set with the 'O_{2} heat equivalence' selection in the "Respirometry" submenu (EDIT menu); the default value is 20.1 joules/ml. The mass coefficient in the allometric equation ('a' value) is adjusted to reflect whatever output unit is in use. Results can be stored for later use. Metabolism for all taxa are calculated from power functions: metabolism = a M^{b} (where a is the mass coefficient, M is mass, and b is the mass exponent)
This example shows an estimate of the resting metabolic rate (RMR) of
a 37.3 g bird, in units of ml O_{2}/min.
The equation was derived from a paper published by Andrew Mckechnie and
Blair Wolf (Click here for a list of the references from which allometric equations were obtained.). The 'Store' button 'remembers' the computed metabolism for later use (for example in other calculators). The 'Save' button, if present, lets you save the current mass coefficient and mass exponent values for future use, accessed as 'Custom coefficent and exponent' option in the Taxon popup. The 'Save' button is accessible only if the units are set to ml O2/min. NOTE: you will have to click the 'Save Current Preferences' button in the Preferences window if you want to have your custom values available the next time you run the program.
You can also adjust the activity intensity for the animal, ranging from inactive (minimal metabolism; MMR) to average daily metabolism (3 X MMR) to very vigorous activity  up to 100X MMR, which is reasonable for some large flying insects. This window calculates the washout rates of theoretical perfectlymixed chambers as a function of volume and flow rate. The computed value is the time for X% of intial gas volume to be replaced  akin to the 'halflife' concept for radioactive decay and related phenomena. back to top
If you measure only one of these two gas species, the program will use RQ to estimate the other. If you measure both O_{2} and CO_{2} concentration changes, the program will optionally use O_{2} in the calculation of VCO_{2}. NOTE: it is assumed that sample gas is dried before measurement, and the default settings are:
Equations notes:
To support these calculations  which are largely based on the small pressure fluctuations induced by the warming and wetting of tidal air  you need to provide a number of variables. Several of these are selfexplanatory (at least if you know something about respiratory physiology). Abbreviations for some of the more obscure ones are:
You can use the 'waveform analysis' routines in the ANALYSIS menu to obtain breathing frequeny, calibration volts, and sample volts from recorded breathing records.
In this fairly typical example, the animal (a mouse) breathed about 6.3 times per second (not unusual for a small mammal in cold conditions) and had a tidal volume of 0.256 ml and a minute volume of about 97 ml/min. The oxygen extraction was about 25.7%.
Although there are a lot of data to enter, the program makes it as easy as possible. Most values are remembered between successive uses of the calculator, so you only have to change a few edit fields (like VO_{2}, frequency, and sample volts). You can tab (or hit return) to move between successive edit fields.
Thermoregulatory costs are calculated using the following thermal parameters: body temperature (T_{b}), lower critical temperature (LCT), thermal conductance (C_{th}; watts/°C), and basal metabolic rate (BMR; ml O_{2}/min or watts; selected in the 'options' window) in a set of edit fields. The program also asks for a channel containing time of day in hours (024) and two channels containing environmental temperatures (T_{e}), one for shade and one for sun. Note: If shade temperature is missing, the program can substitute sun temperature (if available), but only at night. If sun temperature is missing, the program can substitute shade temperature (if available). Select these settings in the Data Rejection Rules component of the Thermoregulatory Cost Options menu.
For each point in the data file, the necessary metabolic rate is computed according to the following rules:

Program output includes:
mean metabolic rate (watts)
factorial increase of mean metabolic rate above BMR
highest single metabolic rate (watts)
factorial increase of highest metabolic rate above BMR
percent of total samples for which metabolic rate = BMR (i.e., T_{e} > LCT)
mean metabolic rate for all samples where T_{e} < LCT
factorial increase above BMR for mean metabolic rate for all samples where T_{e} < LCT
maximum daily average (watts), and expressed as factorial increase above BMR
maxima over 6 and 12 hours (watts), and expressed as factorial increase above BMR
mean metabolic rate while in torpor (watts), and expressed as factorial change from BMR
percent of time spent in torpor
NOTE: For nightime data, if a value for shade temperature is missing, the program will attempt to use the sun temperature value instead. This substitution does not occur for daytime data.
These thermal calculations are performed in one of two ways:
One individual at a time (click the 'compute costs' button): The user enters the animal's thermal parameters in edit fields in the main program window, selects the time, sun, and shade temperature channels, and then starts calculations. Results are shown after all T_{e} data are processed:
Multiple individuals (species) in a spreadsheet (click the 'read .csv file and save results' button): The user selects the time and two T_{e} channels (sun and shade) and then opens a spreadsheet file (comma separated variables; .csv) containing a series of thermal parameters for different species, sexes, etc. The maximum number of variables in the .csv spreadsheet is 50. Each row of the spreadsheet (up to 800) contains data for one individual or species. You need to select the columns that contain:

For each spreadsheet entry, the program runs through the T_{e} channels from the main data file. The combined results can be saved, along with the raw data from the 'source' .csv file, in a userselected spreadsheet file. The program always saves a column containing the mean thermoregulatory cost in watts.
Other thermoregulatory data columns to be placed in the spreadsheet are selected from the window at right:
For both methods, the 'options' button opens a window where you can select a number of alternate ways of handling data and calculations, including:
This flowchart shows how T_{e}, time, and physiological parameters are used to compute thermoregulatory energy costs: back to top
