Substrate-borne vibrational signals and stridulatory organs for sexual communication in leafminer, Liriomyza sativae (Diptera: Agromyzidae)

The vegetable leafminer(Liriomyza sativae[Burgess])is a highly polyphagous pest that threatens vegetables and horticultural plants.Although sexual communication is a key component of the animal behavioral repertoire,the mechanism underlying sexual communication in L.sativae remains to be elucidated.Here,we used laser vibrometry to characterize the vibrational signals emitted by L.sativae during pair formation.By emitting trains of vibrational pulses(male calling)the male initiated communication on the host plant.The female then became immobile and responded to the male calling by emiting replies(female replies),which in turn triggered male replies consisting of a rapid series of chirps and trills.If the female replied,a continuous exchange of male and female replies ensued,representing a duet.In playback trials,a playback signal caused responses from the opposite sex.Moreover,scanning electron microscopy revealed vibration-producing stridulatory organs in both male and female individuals.The files in males were more developed than those in females,and older male specimens had more signs of abrasion.The results provide new insight into the mating biology of L.sativae.

Pea leafminer Liriomyza huidobrensis (Diptera: Agromyzidae) uses vibrational duets for efficient sexual communication

The pea leafminer (Liriomyza huidobrensis) is a notorious pest of vegetables and ornamental plants worldwide. Despite a large number of studies on its biology and ecology, the courtship behavior and sexual communication of this species remain unclear. Here, we studied vibrational communication in the sexual interaction of the pea leafminer. On host plant leaves, females and males behaviorally displayed the bobbing-quivering alternation, which finally led to copulation. Moreover, records of laser vibrometry revealed threesignal duets underlying the behavioral alternation. Sexually mature males spontaneously emitted calls (MCs) to initiate the duets. The females rapidly responded to MCs by emitting replies (FRs) that are longer in duration. The FRs further triggered male replies (MRs) in their search for potential partners. Leafminer-produced vibrational signals convey efficient information to partners and generate pair formation on stretched substrates, such as plant leaves and nylon mesh, but cannot elicit responses on dense substrates, such as glass and plastic. Vibrational playbacks of both MCs and FRs can elicit replies in females and males, respectively. This study completely characterizes substrate-borne vibrational duets in a dipteran insect. The discovery of vibrational sex signals in the pea leafminer provides new insights for the development of novel approaches to control the pest and its relative species.

Female competition for availability of males in insects:the Nezara viridula(Linnaeus,1758)model

Multimodal communication in solitary stinkbugs enables them to meet,mate and copulate.Many plant-dwelling species exchange information during the calling phase of mating behavior using substrate-borne vibratory signals.A female-biased gender ratio induces rivalry and competition for a sexual partner.Female competition for males,first described among Heteroptera in three stinkbug species,revealed species specific differences and opened the question of plasticity in individually emitted temporal and frequency signal characteristics during calling and rival alternation.To address this question and gain an insight into the mechanisms underlying stinkbug female rivalry,we compared the characteristics of alternated signals in the southern green stinkbug Nezara viridula(Linnaeus,1758)(Hemiptera:Pentatomidae).Compared to male rivalry,female rivalry is more complex,lasts longer and runs through successive phases by a combination of different song types.The male pheromone triggers alternation between females,producing song pulses that occasionally overlap each other.One female initiates the rivalry by changing individual pulses into pulse trains of three different types.The competing female alternates with pulses of changed temporal characteristics at lower levels of rivalry and by varying the frequency characteristics of pulse trains at higher levels.During female rivalry,the male either stops responding or occasionally emits calling and courtship signals in response to the female that has produced signals of steady temporal characteristics.Female rivalry shows complex and species specific patterns of information exchange at different levels with a broad-range variation of temporal and frequency characteristics of,until now,unidentified vibratory emissions.

Female answer specificity to male drumming calls in three closely related species of the stonefly genus Zwicknia (Plecoptera: Capniidae)

This study examines the rate of female answers to conspecific versus heterospecific male vibratory calls in three,closely related stonefly species:Zwicknia bifrons,Z.acuta,and Z.rupprechti.In a previous study those three species were recognized on the basis of their distinct male drumming calls along with differences in genital morphology and genetic divergence.During this study no-choice playback experiments using original male call samples from each species were performed,and the answer rate of females to con・specific and heterospecific signal variants was measured.Mixed effect logistic regression models were used to test if male call species identity had a statistically significant effect on female answer probability.Females answered conspecific male calls with significantly higher probability than heterospecific calls in all the three examined species,suggesting that the divergence of vibrational communication can be an important component of the prezygotic isolation between them.Low,but well detectable responsiveness to heterospecific calls was observable between Z.bifrons and Z.acuta,the two species closest to each other regarding mitochondrial genetic divergence and male call pattern similarity.Thus,our results are most congruent with a tight,gradual coevolution of male calls and female preferences.