01487nas a2200109   4500008004100000245011600041210006900157520092800226100002201154700001901176856018201195       1971                        eng d00aFirst recording of the sound produced by the black citrus aphid, <i>Toxoptera aurantii</i>               (Boy.)0 aFirst recording of the sound produced by the black citrus aphid 3 a<p>The black citrus aphid, Toxaptera aurantii (Boy.), produces a distinct scraping sound by rhythmic movements of whole colonies. It is the only species of aphid known to produce audible sounds and the acoustical content of a preliminary recording of these sounds is reported in detail. During one recording the aphids stridulated 15 times in 21 seconds, giving an average period of 1&ndash;4 seconds between emissions and this rate remained virtually constant for at least an hour. Analysis of the recording established a clear peak frequency band at about 4&ndash;6 kHz with another around 800 Hz-1 kHz and possibly another in the ultra-sonic range above 18 kHz. Morphological adaptations of the abdominal cuticle and of the hind tibiae to form a stridulatory apparatus are illustrated and possible functions of stridulation as a defence mechanism or as a means of intraspecific communication are briefly discussed.</p>
1 aBroughton, W., B.1 aHarris, K., M.  uhttps://www.cambridge.org/core/product/identifier/S0007485300042322/type/journal_articlehttps://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007485300042322