TEMPORAL DYNAMICS OF HOST-MARKING IN THE TROPICAL TEPHRITID FLY, ANASTREPHA-LUDENS

The temporal dynamics of host-marking behaviour in the tropical tephri tid fly, Anastrepha ludens (Loew), is described and used to formulate a model of control of marking behaviour. The following temporal patter ns in host-marking behaviour were observed. Time spent marking increas ed as A.ludens females deposited clutches in a given fruit previously marked zero, one, two or three times. This trend was paralleled by an increase in the number of pauses in marking behaviour within the host- marking bout (and hence an increase in the number of sub-bouts separat ed by such pauses). Finally, within any given marking bout, the length of a sub-bout diminished progressively. The length of a pause, by con trast, showed no significant trend. Based on these results, we propose that host-marking pheromone, or HMP, while deterrent to females prior to egg-laying, actually stimulates continued host-marking behaviour a fter egg-laying. We argue that host-marking is regulated by sensory ad aptation or habituation to HMP in conjunction with a dosage-dependent restoration of inhibition of the motor pattern. Functional aspects of this pattern of motor control are discussed.