Simple Syllabic Calls Accompany Discrete Behavior Patterns in Captive Pteronotus parnellii: An Illustration of the Motivation-Structure Hypothesis

Figure 9

A bubble-plot (filled dark grey circles) showing the association of different sounds with different behavioral actions. The size of the bubble is proportional to the normalized (percentage of total events) frequency of occurrence of a call type. Per the Motivation-Structure hypothesis, which states that animals motivated by aggression produce relatively low-frequency, noisy, broadband calls (here illustrated by rBNB and fSFM calls) and those motivated by fear and/or appeasement produce tonal high frequency calls (here illustrated by QCFl calls). No calls were emitted during yawning, marking, and crouching. Fighting, which can be a complex and long-lasting behavior, produced the largest variety of call types. Unfilled circles are proportional to the percentage of the total number of events when a call did not accompany a particular behavior. Adapted from [26].