In sexual communication, partners often form a duet, an exchange of species- and sex-specific signals, and in such systems mate recognition is likely to be reciprocal. We studied the role of ...vibrational signals in reproductive isolation in the genus Aphrodes (Hemiptera: Cicadellidae) in which mate recognition is based on highly divergent male advertisement calls and similar female replies. We first determined in playback experiments the preferences of females of four Aphrodes species to conspecific and heterospecific male advertisement calls as well as to species-specific elements in these calls. Females of all four species responded preferentially to calls of conspecific males; however, male calls composed of similar elements played only a limited role in mate recognition. In particular, females of Aphrodes aestuarina and Aphrodes bicincta showed higher responsiveness to each other's male calls than to calls of other species. In this species pair we further examined the role of female signals and duet structure in assortative mating using ‘no-choice’ mating experiments. The generally higher responsiveness of A. aestuarina females to male calls of A. bicincta did not translate into higher mating success in this heterospecific cross; lengthy replies of A. aestuarina females resulted in a breakdown of a complex species-specific duet structure and associated difficulties in locating the female reduced the probability of heterospecific mating. Our study shows that in mating systems based on a duet, males may contribute more than females to sexual isolation between species. Males' contribution to assortative mating may stem not only from mate recognition but also from inability to locate the source of the heterospecific female reply.
•Sexual communication in Aphrodes is based on species-specific vibrational duet.•In duetting systems both partners contribute to sexual isolation.•Male calls composed of similar elements have a limited role in mate recognition.•Complex species-specific duet structure is crucial for reproductive isolation.•Males' contribution results also from inability to locate the heterospecific female.
Sexual communication in animals often involves duetting characterized by a coordinated reciprocal exchange of acoustic signals. We used playback experiments to study the role of timing of a female ...reply in the species-specific duet structure in the leafhopper Aphrodes makarovi (Hemiptera: Cicadellidae). In leafhoppers, mate recognition and location is mediated exclusively by species- and sex-specific substrate-borne vibrational signals and a female signal emitted in reply to male advertisement calls is essential for recognition and successful location of the female. In A. makarovi, males have to initiate each exchange of vibrational signals between partners, and in a duet the beginning of a female reply overlaps the end of the male advertisement call. Results of playback treatments in which female replies were delayed and did not overlap with the male call revealed that in order to trigger an appropriate behavioural response of the male, female reply has to appear in a period less than 400 ms after the end of the initiating male call. Results also suggest that males are not able to detect a female reply while calling, since female reply that did not continue after the end of male call triggered male behaviour similar to behaviour observed in the absence of female reply. Together, our results show that vibrational duets are tightly coordinated and that the species-specific duet structure plays an important role in mate recognition in location processes.
Vibrational signalling is a widespread form of animal communication and, in the form of sexual communication, has been generally regarded as inherently short-range and a private communication ...channel, free from eavesdropping by generalist predators. A combination of fieldwork and laboratory experiments was used to test the hypothesis that predators can intercept and exploit such signals. First, we developed and characterized PCR primers specific for leafhoppers of the genus Aphrodes and specifically for the species Aphrodes makarovi. Spiders were collected from sites where leafhoppers were present and screened with these primers to establish which spider species were significant predators of this species during the mating period of these leafhoppers. Analysis using PCR of the gut contents of tangle-web spiders, Enoplognatha ovata (Theridiidae), showed that they consume leafhoppers in the field at a greater rate when signalling adults were present than when nymphs were dominant, suggesting that the spiders were using these vibrations signals to find their prey. Playback and microcosm experiments then showed that E. ovata can use the vibrational signals of male leafhoppers as a cue during foraging and, as a result, killed significantly more male than female A. makarovi. Our results show, for the first time, that arthropod predators can exploit prey vibrational communication to obtain information about prey availability and use this information to locate and capture prey. This may be a widespread mechanism for prey location, one that is likely to be a major unrecognized driver of evolution in both predators and prey.
Reliable delimitation and identification of species is central not only to systematics, but also to studies of biodiversity, ecology and pest management. In the era of Internet‐based biodiversity ...databases misidentifications are rapidly disseminated and may have far‐reaching consequences. Leafhoppers from the genus Aphrodes (Hemiptera, Cicadellidae) are common and abundant, but, nevertheless, they are still a taxonomically challenging group whose members are often assessed in ecological studies and are also potential vectors of plant diseases. Previous study has shown that the syntype series for A. aestuarina (Edwards) includes also specimens of A. makarovi Zachvatkin and has suggested that misidentifications may be widespread in museum collections. We studied Aphrodes individuals collected from the U.K. and Slovenia in order to provide a more comprehensive analysis of this genus using multiple criteria. Combined work using male and female vibrational signals emitted during courtship, and a 600‐bp fragment within the barcoding region of the COI mtDNA gene, provided validated specimens that we also used for morphometric study. Analyses confirmed A. aestuarina, A. bicincta, A. diminuta and A. makarovi as behaviourally, genetically and morphologically distinct species. Although any of these approaches could be used alone to distinguish between species, combining morphological and molecular approaches will help to improve reliability, especially when identifying females. Morphological investigation of validated individuals from the U.K. and Slovenia also revealed geographic differences within species. By combining several body and aedeagus morphological characters males can be reliably identified, however, morphological differences between species are, nevertheless, relatively small. By contrast, observed genetic distances between Aphrodes species are relatively large (4.2–7.0%). At about half of our collecting sites more than one Aphrodes species was found and A. makarovi was collected together with every other species, including A. aestuarina on tidal saltmarshes. Due to low morphological variation between syntopic congeners it is likely that many museum specimens of Aphrodes have been assigned to the wrong species and species identification in ecological and vector studies may also be questionable.
Mate recognition and location in Cicadellidae is mediated exclusively via substrate-borne vibrational signals. In the present study we investigated vibrational signals and mate searching behaviour of ...the leafhopper Aphrodes makarovi. We studied mating behaviour and exchange of vibrational signals between live insects and in playback experiments. Males emitted long and complex calling signals composed of several sections. Female reply was long and always overlapped the end of the male call. The exchange of male and female vibrational signals was a complex and dynamic interaction during which both partners modified their signals according to partner’s reply. The duration of female reply was influenced by the duration of the male call to which she was responding, while the duration of male call was influenced by the duration of the previous female reply. Such relationship suggests the role of sexual selection in the evolution of male vibrational signals.
Eleven microsatellite markers were developed for the leafhoppers of the genus Aphrodes using shotgun pyrosequencing and will be used to study the genetic diversity, population structure and gene flow ...within and between species in this genus in order to assess their conservation status. The number of alleles per locus ranged from 3 to 10, while observed and expected heterozygosity values varied from 0.421–1.000 to 0.542–0.876, respectively. Cross-species amplification was successful among the four congeners.
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