THE RESPONSE OF INTERNEURONS IN THE SPIDER CNS (CUPIENNIUS-SALEI KEYSERLING) TO VIBRATORY COURTSHIP SIGNALS

1. We studied the response of plurisegmental interneurons in the suboe sophageal ganglionic mass of female spiders (Cupiennius salei) to male vibratory courtship signals. 2. The opisthosomal vibrations (low freq uency component) and the pedipalpal percussions (high frequency compon ent) are processed in parallel by interneuron type I and type II, resp ectively (Figs. 3, 7). 3. Type III, IV and V interneurons represent th e macrostructure of the male courtship signals (Figs. 8, 9, 10), i.e. the beginning and the end of a series (type III, V) or the end of the series only (type IV). The macrostructure is known to influence the re sponse probability of the female. The spontaneous bursting activity of a type VI neuron undergoes slow and long lasting changes upon stimula tion with natural courtship signals (Fig. 11). 4. Many interneurons re sponded to natural signals but not to behaviourally effective computer models. This is presumably due to the lack of spectral complexity of the model compared to natural signals. Differences in the natural cons pecific and heterospecific signals, however, are represented by the ne uronal response (Fig. 3).