Individual variability in state-dependent feeding behaviour in three-spined sticklebacks

Area of Science:

• Ethology
• Animal Behavior
• Ecology

Background:

• Feeding behavior is crucial for survival and population dynamics.
• Understanding individual variation in feeding strategies can illuminate ecological interactions.
• State-dependent behavior, where an animal's internal state influences its actions, is a key concept in behavioral ecology.

Purpose of the Study:

• To investigate state-dependent feeding behavior in three-spined sticklebacks (Gasterosteus aculeatus).
• To determine how factors like stomach fullness, prey size, and individual history affect feeding decisions.
• To explore the heterogeneity of feeding behavior among individual fish.

Main Methods:

• Sequential encounters with two sizes of Asellus aquaticus prey (6-mm and 8-mm).
• Using stomach fullness as an indicator of the fish's internal state (hunger level).
• Employing dummy variable regression and logit regression models to analyze feeding parameters and decision-making.

Main Results:

• Significant individual variability in feeding behavior was observed.
• Feeding behavior was strongly correlated with an individual's recent feeding history within a day.
• Prey acceptance was influenced by both the fish's size and its stomach fullness.

Conclusions:

• Individual three-spined sticklebacks exhibit heterogeneous feeding behaviors.
• Internal state (stomach fullness) and recent feeding history are critical determinants of prey selection.
• This behavioral variation may play a role in population regulatory mechanisms.