Phonotaxis in Ormia ochracea

Phonotaxis is the ability to locate spatially the source of a sound. O. ochracea can locate a host even when the stimulus (calling) is interrupted or halted altogether[i]. Regardless of her position in space when the stimulus is stopped, female Ormia initiate their spiral descent (they walk to final host location) at the appropriate time and placei to accurately locate a calling male. Female O. ochracea can locate a calling G. texensis to within 2 compass degrees[ii] because of the strong directional sensitivity derived from the coupling of the two tympani[iii]. This coupling provides sensitivity to tiny interaural time-differences (the difference in time it takes for a sound to reach each ear) arising from the minute separation of the two earsiii.

 Figure 13: Ormia external ear anatomy, showing both tympanal

membranes and the presternum (structure that results in tympanal pairing)

Photo taken from[iii]

Video: fly orienting towards cricket call http://www.utsc.utoronto.ca/~amason/Movie/flyball2.mpg

Video courtesy of the Mason Lab (University of Toronto) :

 http://www.utsc.utoronto.ca/~amason/research.html

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