Analysis of Male Courtship Patterns and Mating Behavior of Brachymeria intermedia11,3

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Abstract
Twenty-four discrete, stereotyped behaviors were identified in the parasitic chalcid wasp, Brachymeria intermedia (Nees), in addition to copulation. Four were used in mate-finding, 9 in courtship, and 11 were nonsexual. Six of the 9 courtship displays occurred frequently and comprised a linear sequence leading to copulation. Successful males, i.e., those that copulated, (1) spent more time in the final stages of courtship, (2) gave relatively more bouts of courtship displays, (3) gave relatively fewer bouts of mate-finding and nonsexual behaviors, and (4) had higher conditional frequencies in the main courtship sequence than did unsuccessful males. Males showed mate-finding behaviors in petri dishes containing female odor, indicating that a pheromone has a role in mate-finding. Since males readily courted etherized females, female-produced tactile or auditory stimuli are not required to induce normal courtship. Females countersignaled acceptance by exposing the genitalia and lifting the abdomen. There were no postcopulatory displays. Males frequently repeated a courtship song consisting of 3 distinct auditory displays in a specific order: rock, wing quiver, and buzz; these songs were analyzed on an oscilloscope. The rock display, lasting 0.5 sec and consisting of 6-8 pulses, was repeated in tandem 3-20 times. Wing quiver, a transitional display between rock and buzz, consisted of more or less continuous sine waves and lasted ca. 8 sec. The buzz display, lasting 0.5-1.5 sec and consisting of a series of 5-15 successively louder, complex pulses, was repeated 2-16 times in tandem. Individual males showed courtship song stereotypy; i.e., buzzes/song varied significantly among males, and coefficients of variation within individuals were relatively small (range = 9-48).