Figure 7
From: Two matched filters and the evolution of mating signals in four species of cricket
The opening status of the acoustic spiracle and directional tuning. A: Close-up of the right spiracle opening of a female G.b. while performing phonotaxis towards a model song. The cuticular flap (asterisk) leaves the acoustic spiracle only partially open. The opening status is passively modulated during the swing and stance phase of the foreleg, as indicated by the two sketches in A (the right one recorded during the swing phase; opening indicated by arrow). In all experiments, the directional tuning of the ear was monitored in an opening status of the spiracle as indicated in A. Only when the cuticular flap was completely removed this resulted in a shift of the best frequency in directional tuning towards unusual high frequencies in all 4 cricket species (here shown for G.c., T.o. and T.c.). Blocking of the spiracle with wax abolished the tuned directionality completely (only shown for G.c. in B).