Source Paper
The role of flower consumption in Howler Monkey Females’ diet: adjustment across reproductive states
Gisbrecht A, Aristizabal JF, Rodríguez-Landa JF, Hernández-Salazar LT
PeerJ • 2026
Food Intake Quantification
Objective: Quantify food intake and tannin consumption in mantled howler monkeys across different lactation states
Protocol Steps
Behavioral observation setup
Record female behavior monthly for 10-20 days from sunrise for 5 hours when most feeding occurs
View evidence from paper
“Female behavior was collected every month for 10–20 days throughout the month”
Food intake recording
Record time invested (seconds) and food intake (grams) for six food categories: mature leaves, young leaves, mature fruits, immature fruits, flowers, and petioles
View evidence from paper
“We recorded the time invested (seconds) and food intake (grams) of the items consumed”
Calculate food intake rate
Record number of discrete food units consumed during feeding session in 1-minute bite-rate intervals
View evidence from paper
“we recorded information on the number of discrete food units ( i.e., individual items or batches of items in 1-minute bite-rate)”
Sample collection
Collect consumed and dropped fruits or fruits in same condition, plus leaf and flower samples from feeding trees in condition similar to consumed items
View evidence from paper
“we first collected all consumed and dropped fruits or fruits in the same condition as consumed from that tree”
Sample drying
Dry leaves in cardboard box with 60W bulb, dry fruits and flowers in food dehydrator at 35°C
View evidence from paper
“leaves were dried in a cardboard box using the heat of a 60 W light bulb”
Extract preparation
Process dried and pulverized samples with methanol HPLC grade at 1:3 ratio, vortex for one minute, sit for five minutes
View evidence from paper
“dried and pulverized samples were processed into solvents with methanol HPLC grade at a ratio of 1:3”
Sample filtration
Pass methanol/powder mixture through 0.045 µm nylon filter to separate extract from residual mixture
View evidence from paper
“passed through a 0.045 µm pore size nylon filter to separate the extract”
HPLC analysis
Use HPLC-VWD method with UV-VIS detector at 270 nm, C18 column, mobile phase 15% acetonitrile, 15% methanol, 70% water at 0.5 mL/min flow rate
View evidence from paper
“HPLC equipment Agilent Technologies, model 1,200 infinity with a UV–VIS detector set at 270 nm”