Acoustic Communication of Three Closely Related Psyllid Species: A Case Study in Clarifying Allied Species Using Substrate-borne Signals (Hemiptera: Psyllidae:<i>Cacopsylla</i>)

Abstract

Acoustic communications are prevalent in insects, and evidences show that acoustic characteristics could be used in taxonomy. With regard to Psylloidea, acoustic signals of 37 species have been recorded and described, indicating that acoustic knowledge of psylloids is limited compared with 3,800 described psylloid species, although the comparison emphasized on males only. Because many new psylloids were named based only on variations in the structure of male genitalia and host-plant records, we asked whether acoustic signal could be supplementary characteristics in recognizing the species. We studied the acoustic behavior of three closely related species of Cacopsylla Ossiannilsson, each explore and use distinct species of Pittosporum Banks, to examine the necessity of intergender duets and to determine their potential relevance in taxonomy. We conclude that duets are necessary for mating. The initial call and active search are usually made by the male. Females usually stay stationary and respond passively. Signals from males include two sections: a series of chirps followed by a long trill, whereas those from females include a long series of repeated chirps. The results of a discriminant analysis of acoustics showed that the three species of Cacopsylla were distinguishable from acoustic characteristics. We conclude that acoustic signals of psylloids provide useful information for the taxonomy of psylloids, especially at the species level.