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
Reproductive State Behavioral Monitoring
Objective: Monitor reproductive state behavioral differences in food and tannin intake among mantled howler monkey females across lactation states
Protocol Steps
Identify reproductive states
Classify females into three lactation categories: early lactating (EL) with dependent offspring birth to three months carried ventrally, late lactating (LL) with increasingly independent offspring consuming solid food, and non-lactating (N/L)
View evidence from paper
“EL was determined through the presence of a dependent offspring (birth to three months) carried mostly ventrally”
Conduct behavioral observations
Collect female behavior data every month for 10-20 days from sunrise for 5 hours in random order ensuring all females recorded per day
View evidence from paper
“Female behavior was collected every month for 10–20 days throughout the month, when possible”
Record feeding behavior
Record time invested (seconds) and food intake (grams) for 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 in 1-minute bite-rate during feeding session, multiply by simultaneous group feeding time
View evidence from paper
“recorded information on the number of discrete food units consumed during a feeding session”
Collect food samples
Collect consumed and dropped fruits or similar condition fruits from feeding trees, plus leaf and flower samples in condition most similar to consumed items
View evidence from paper
“collected all consumed and dropped fruits or fruits in the same condition as consumed”
Dry samples
Dry leaves in cardboard box using 60W light bulb heat, 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”
Process samples for tannin analysis
Process dried pulverized samples into methanol HPLC grade solvents at 1:3 ratio, vortex for one minute, sit five minutes, filter through 0.045 µm nylon filter
View evidence from paper
“dried and pulverized samples were processed into solvents with methanol HPLC grade at a ratio of 1:3”
Analyze tannin content using HPLC
Use HPLC-VWD method with Agilent 1,200 infinity equipment, 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”