Actual and Potential water volume 

In the field: The actual water volume is determined by pipetting the contents of the leaf into a 50mL macrocentrifuge tube (if the volume is larger, split the contents into two tubes). Read and record the volume reached on the centrifuge tube.

In the lab:  The total potential water volume is determined by filling the leaf with tap water until the leaf is completely full (until the mouth of the leaf). Pipette the water into a 50 mL tube and read and record the volume. If the leaf is damaged (e.g., by herbivory or mechanic forces), the potential volume is taken as the maximal possible volume with this damage (e.g., fill the leaf with water until the damaged part). Note the damage in the datasheet.

Leaf morphology

Morphometrics of the pitchers should be taken similarly as in Ellison and Gotelli (2002) with the following adaptations: 

• pitcher width is the broadest width of the pitcher (front to back)

• keel width is the width of the keel on the same line as the pitcher width

• pitcher length is the distance from the start of the pitcher bottom to the end on the top of the leaf

• mouth width (aperture) was the lateral diameter of the top opening

• Shoulder is the widest part of the pitcher from side to side 

To standardize finding the base of the pitcher for the length measurements, the stem can be carefully cut until the pitcher bottom is visible (i.e., small hole becomes visible where the intersection between the stem and the start of the pitcher bottom begins).  

For pitchers with very long stems: a stem measurement can additionally be recorded.

Use calipers to measure the width-, keel-, shoulder-, and mouth width (aperture), and a flexible measuring tape to measure pitcher length.  Measurements with calipers should be recorded in millimeters and for length in centimeters.

NOTE: You may need to cut open the pitcher after leaf morphology measurements have been taken to remove remaining prey before measuring the wet (and later dry) mass. If any additional intact prey are found that were not previously recorded, add those to the notes section of the final datasheet. 

PDF of the protocol can be found here.