Photoperiodic and temperature control of diapause induction and colour change in the southern green stink bug Nezara viridula

Abstract. The effect of photoperiod and temperature on the duration of the nymphal period, diapause induction and colour change in adults of Nezara viridula (L.) (Heteroptera: Pentatomidae) from Japan was studied in the laboratory. At 20 °C, the developmental period for nymphs was significantly shorter under LD 10 : 14 h (short day) and LD 16 : 8 h (long day) than under intermediate photoperiods, whereas at 25 °C it was slightly shorter under intermediate than short- and long-day conditions. It is assumed that photoperiod-mediated acceleration of nymphal growth takes place in autumn when day-length is short and it is unlikely that nymphal development is affected by day-length under summer long-day and hot conditions. Nezara viridula has an adult diapause controlled by a long-day photoperiodic response. At 20 °C and 25 °C in both sexes, photoperiodic responses were similar and had thresholds close to 12.5 h, thus suggesting that the response is thermostable within this range of temperatures and day-length plays a leading role in diapause induction. Precopulation and preoviposition periods were significantly longer under near-critical regimes than under long-day ones. Short-day and near-critical photoperiods induced a gradual change of adult colour from green to brown/russet. The rate of colour change was significantly higher under LD 10 : 14 h than under LD 13 : 11 h, suggesting that the colour change is strongly associated with diapause induction. The incidences of diapause or dark colour did not vary among genetically determined colour morphs, indicating that these morphs have a similar tendency to enter diapause and change colour in response to short-day conditions.     

Surviving winter: diapause syndrome in the southern green stink bug Nezara viridula in the laboratory,in the field,and under climate change conditions

The southern green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) has long attracted attention not only as a serious pest of numerous agricultural crops, but also as a species expanding its range in many parts of the world. Nezara viridula has also been widely used as a model in different experimental studies. The present review focuses on reproductive (i.e. adult) winter diapause, which is the pivotal element of the species' seasonal cycle. Results from numerous field experiments and observations, as well as laboratory ecophysiological investigations conducted during the few last decades, are analyzed and interpreted. Experimental findings are used to describe in detail the dynamics of physiological changes during overwintering. Reproductive diapause in N. viridula is controlled in both sexes by photoperiodic conditions. The induction of diapause is associated with a reversible change of body colour from green or yellow to russet (or brown). The proper timing of adult emergence and the induction of diapause, as well as the size of adults, is vitally important for successful overwintering. Nezara viridula has been shown to respond strongly to the current trend in climate change by shifting the limit of its northern range, particularly in central Japan. Analysis of historic climate data suggests that the environmental conditions during the last few decades have become more favourable for the overwintering survival of N. viridula in many locations in central Japan. This has likely promoted the northward spread of the species. The relationships between reproductive diapause, reversible body colour change, overwintering success and the recent range expansion are analyzed. Perspectives of the range dynamics of the species are discussed in light of further predicted climate change.     

Photoperiodic response in the subtropical and warm‐temperate zone populations of the southern green stink bug Nezara viridula: why does it not fit the common latitudinal trend?

The photoperiodic response of diapause induction is studied in females of five subtropical and warm‐temperate zone populations of Nezara viridula (L.) (Heteroptera: Pentatomidae) in Japan (26.4–34.7°N; 127.4–135.7°E). Laboratory tests at 25 °C demonstrate that both warm‐temperate and subtropical populations have pronounced photoperiodic responses of adult diapause induction. Under short‐day conditions (LD 10 : 14 h), 73–100% of females enter diapause, whereas, under long‐day conditions (LD 15 : 9 h), 87–100% of females are nondiapause and reproduce. When the critical photoperiod for diapause induction is plotted against the latitude of origin of each population, the data points do not show the expected tendency of increasing critical photoperiod northwards but, instead, vary between 12 h 15 min and 13 h 30 min. It is suggested that adults from different populations of such a highly migratory species move often among subtropical islands (by themselves or being assisted by typhoons), thus constantly destabilizing the photoperiodic responses. Although important for general synchronization of seasonal development in the tropics and subtropics, winter diapause might not be so critical for survival in mild winters in these zones. Such circumstances might make the selective pressure over the photoperiodic response less severe in the tropics and subtropics than in the temperate zone. It is suggested that the current climate warming might contribute to this situation as well by promoting polewards migrations and lessening the selective pressure of overwintering conditions.     

Natural control of populations of the southern green stink bug,Nezara viridula

Based on the results of five-year study on the Nezara population, it was concluded that the level of abundance of the insect was determined partly by the combination and relative adundance of the host plants and partly by the climatic factors. The endless increase of the population was checked by the deleterious effects associated with the overpopulation which occurred locally. The degree of such overpopulation was determined by the relative abundance of host plants to the current level of the population. Therefore, even when the general level of Nezara population seemed to be low, there still exists the possibility of overpopulation in some areas. Winter was the critical period which threatened the persistence of Nezara population. The survival of the hibernating adults was partly dependent on the physiological state of adults which was determined in the period of pre-hibernation. But when the severity of a winter exceeded the tolerance limit of the insect, the only safety-valve which prevented the elimination of Nezara was the heterogeneity of hibernacula. Therefore,Milne's theory (1957) was closest to the known facts.     

Dissecting insect responses to climate warming: overwintering and post‐diapause performance in the southern green stink bug,Nezara viridula,under simulated climate‐change conditions

The effect of simulated climate change on overwintering and post‐diapause reproductive performance is studied in Nezara viridula (L.) (Heteroptera: Pentatomidae) close to the species' northern range limit in Japan. Insects are reared from October to June under quasi‐natural (i.e. ambient outdoor) conditions and in a transparent incubator, in which climate warming is simulated by adding 2.5°C to the ambient temperatures. Despite the earlier assumption that females of N. viridula overwinter in diapause, whereas males do so in quiescence, regular dissections show that the two sexes overwinter in a state of true diapause. During winter, both sexes are dark‐coloured and have undeveloped reproductive organs. Resumption of development does not start until late March. During winter, the effect of simulated warming on the dynamics and timing of physiological processes appears to be limited. However, the warming significantly enhances winter survival (from 27–31% to 47–70%), which is a key factor in range expansion of N. viridula. In spring, the effect of simulated warming is complex. It advances the post‐diapause colour change and transition from dormancy to reproduction. The earlier resumption of development is more pronounced in females: in April, significantly more females are already in a reproductive state under the simulated warming than under quasi‐natural conditions. In males, the tendency is similar, although the difference is not significant. Warming significantly enhances spring survival and percentage of copulating adults, although not the percentage of ovipositing females and fecundity. The results suggest that, under the expected climate‐warming conditions, N. viridula will likely benefit mostly as a result of increased winter and spring survival and advanced post‐diapause reproduction. Further warming is likely to allow more adults to survive the critical cold season and contribute (both numerically and by increasing heterogeneity) to the post‐overwintering population growth, thus promoting the establishment of this species in newly‐colonized areas.     

Prevalence of a trypanosomatid in the southern green stink bug, Nezara viridula

The southern green stink bug, Nezara viridula (L.), and certain of its host plants were examined to determine the prevalence and biological characteristics of an intestinal trypanosomatid. Promastigotes with short (< or = 17.5 microm excluding flagellum) and long forms (> or = 25.0 microm) usually infected < 50% of the bugs before August and > 50% (maximum 95%) during August-October, but prevalence was not host-density dependent. The flagellate was detected in adults and in all nymphal instars, at all sampling sites where at least 10 bugs were captured, and in bugs from all host plants sampled (soybean, red clover, vetch). Of bugs with flagellates, 27% were heavily infected (> 20 flagellates per 160X microscope field). Weights of infected and uninfected adults did not differ. Live flagellates were detected in bug feces and in one stem of red clover. When bugs were fed soybean pods, tomatoes, or snap beans in the laboratory, only once were flagellates detected in plant tissue (snap beans). The flagellate was cultured in modified Medium 199. This flagellate is prevalent in N. viridula populations in Louisiana and apparently does not cause significant pathological effects in N. viridula or its host plants, including soybean.     

Transport of orally delivered dsRNA in southern green stink bug,Nezara viridula

The southern green stink bug (SGSB, Nezara viridula) is an emerging polyphagous pest in many regions of the world. RNA interference (RNAi) is a valuable method for understanding gene function and holds great potential for pest management. However, RNAi efficiency is variable among insects and the differences in transport of double-stranded RNA (dsRNA) are one of the major factors that contribute to this variability. In this study, Cy3 labeled dsRNA was used to track the transport of dsRNA in SGSB tissues. Cy3_dsRNA was detected in the hemocytes, fat body (FB), epidermis, and midgut tissues at 24–72 hr after injection. Orally delivered Cy3_dsRNA or Cypher-5E labeled dsRNA was mostly detected in the midgut and a few signals were detected in parts of the FB and epidermis. Both injected and fed Cy3_dsRNA showed stronger signals in SGSB tissues when compared to Cy3_siRNA (small interfering RNA) or Cy3_shRNA (short hairpin RNA). dsRNA targeting the gene for a vacuolar-sorting protein, SNF7, induced higher knockdown of the target gene and greater SGSB mortality compared to siRNA or shRNA targeting this gene. ³²P-labeled dsRNA injected into SGSB was processed into siRNA, but fed ³²P-labeled dsRNA was not efficiently processed into siRNA. These data suggest that transport of orally delivered dsRNA across the midgut epithelium is not efficient in SGSB which may contribute to variable RNAi efficiency. Targeting genes expressed in the midgut rather than other tissues and using dsRNA instead of siRNA or shRNA would be more effective for RNAi-mediated control of this pest.     

Phylogeographic relationships of the southern green stink bug Nezara viridula (Hemiptera: Pentatomidae)

Abstract The sequences of 16S rDNA, cytochrome oxidase subunit I (COI) and cytochrome b (Cyt b) genes from nine field collections (seven provinces in China: Guangxi, Hubei, Guangdong, Guizhou, Zhejiang, Hunan, Jiangxi, and also southern and northern part of Iran), plus the sequences of Africa, Europe, Americas and Japan obtained form GenBank were used to re-analyse the genetic variation in the southern green stink bug Nezara viridula (Linnaeus). The phylogeographic re-analysis by using four algorithms (NJ, MP, ML and Bayesian) showed three main lineages. The Iranian haplotypes fell into lineage II formed from Europe and America, rather than in lineage III from Asia; the Chinese haplotypes fell into the Asian clade. Our results suggested that African and non-African gene pools have been isolated since the Miocene era with the molecular clock calibrations for Heteroptera mtDNA, and not since the Pliocene as mentioned previously. The corresponding age of the separation of the eastern and western Asia clades is estimated to be 4.0–1.6 million years ago, coinciding with the Pliocene–Pleistocene epoch and with acute rising events in the Tibet Plateau locates in the western China, which may have formed the barriers observed today.     

Tarsal attachment devices of the southern green stink bug Nezara viridula (Heteroptera: Pentatomidae)

Based on analyses with cryo‐scanning and transmission electron microscopy, the present study reports on the morphology and ultrastructure of the attachment structures of the green stinkbug Nezara viridula L. (Heteroptera: Pentatomidae), a cosmopolitan pest of different crops in most areas of the world. In addition, the presence and distribution of large proportions of the elastic protein resilin in these structures was revealed by confocal laser scanning microscopy. The attachment structures of each leg comprise two sclerotised claws, a pair of smooth flexible pulvilli and a hairy adhesive pad located at the ventral side of the basitarsus. No sexual dimorphism is evident. Contact areas of resting individuals on a smooth surface show that N. viridula creates contact to the substrate with the ventral surface of (a) the distal portions of the pulvilli, (b) the setae of the hairy adhesive pad, (c) the two paraempodia representing mechanosensory setae, and (d) the tips of the claws. Each pulvillus is a sac‐like structure formed by complex cuticular layers that vary in their structure and resilin content. The dorsal side consists of sclerotised chitinous material, while the ventral cuticle consists mainly of resilin and shows a very thin epicuticle and a thick exocuticle. The setae of the hairy adhesive pad are pointed and socketed. They exhibit a pronounced longitudinal gradient in the material composition, with large proportions of resilin being present in the setal tips. In most of these setae, especially in those of the distal‐most part of the pad, also a transverse gradient in the material composition is visible.     

Studies on the adult polymorphism in the southern green stink bug,Nezara viridula (hemiptera: Pentatomidae)

Polymorphism in adult colour pattern of Nezara viridula is determined on the genetic basis. The basic colour patterns of adult are classified into four types, i. e. G, O, R and F. No appreciable differences between these types were observed in respect to various physiological traits of nymphs and adults, except that type G seems to be superior in reproductive ability but to be inferior in ability of surviving winters at least to types R and F. Inter-generation changes in percentage frequency of G type were examined from 1959 to 1967 covering more than 30 generations. Percentage frequencies of G types prior to the severe winter of 1962–3 fluctuated greatly around a mean of 87.9%, while they did to a lesser extent than before with a mean of 85.0% after the winter. Unexpected high percentages of G type were recorded frequently in summer generations, viz. 1st and 2nd. On the other hand, the relative frequencies of G and O types decreased after hibernation in contrast to the increases in those of F and R. This sort of changes in genetic composition related to the winter of 1962–3 was observed in several populations segregated from each other. This seasonal alternation of selective activity in the environments is considered to be responsible for retention of the polymorphism. Alternative possible causes, i. e. difference in habitat preference, non-random mating and selective predation by predators among polymorphs, may safely be rejected as irrelevant to the mechanism in maintaining polymorphism. The polymorphism of this insect seems to be in a transient state rather than balanced one contributing little to population regulation, but the persistence of N. viridula in the periphery range may be assisted by retention of the polymorphism.     

Vibrational directionality in the southern green stink bug, Nezara viridula (L.), is mediated by female song

We tested the hypothesis that male southern green stink bugs, Nezara viridula (L.), use substrate-borne songs to locate females. We recorded the responses of bugs on plants to the vibrations caused by a prerecorded female song and by an artificial sound. The female song caused males to walk, to respond with the calling and courtship songs and to approach the source of the song with characteristic search behaviour at junctions between branches on the plants. At a junction, a searching male stopped, stretched his legs and antennae and compared the vibratory signals on the two branches, with different combinations of legs and antennae. The males then left the junction and approached the source of the vibration. Males located the loudspeaker significantly more frequently in the presence than in the absence of vibratory stimuli on cyperus, Cyperus alternifolius L., and beans, Phaseolus vulgaris L. Vibrational directionality was also elicited by artificial pure tones whose spectral and temporal parameters were similar to those of natural female song. Females showed no reaction to vibratory stimulation and no vibrational directionality. We discuss possible mechanisms underlying vibrational directionality in the light of expected signal changes during transmission through plants. Copyright 1999 The Association for the Study of Animal Behaviour.     

Transmission of cotton seed and boll rotting bacteria by the southern green stink bug (Nezara viridula L.)

AIMS: To determine the ability of the southern green stink bug (SGSB) (Nezara viridula L.) to transmit Pantoea agglomerans into cotton (Gossypium hirsutum) bolls. METHODS AND RESULTS: An SGSB laboratory colony was kept on fresh green beans. A P. agglomerans variant resistant to rifampicin (Rif) (strain Sc 1-R) was used as the opportunistic cotton pathogen. Adult insects were individually provided green beans that were sterilized and then soaked in either sterile water or in a suspension of strain Sc 1-R. Insects were individually caged with an unopened greenhouse-grown cotton boll. After 2 days, live SGSB were collected, surfaced sterilized, ground, serially diluted, and then plated on nonselective media and media amended with Rif. Exterior and interior evidence of feeding on bolls was recorded 2 weeks after exposure to insects. Seed and lint tissue were harvested, ground, serially diluted, and then plated on media with and without Rif. Bacteria were recovered on nonselective media from all insects, and from seed and lint with signs of insect feeding at concentrations ranging from 10(2) to 10(9) CFU g(-1) tissue. The Sc 1-R strain was isolated only from insects exposed to the marked strain and from seed and lint of respective bolls showing signs of insect feeding. Evidence of insect feeding on the exterior wall of the carpel was not always apparent (47%), whereas feeding was always observed (100%) on the interior wall in association with bacterial infections of seed and lint. CONCLUSIONS: Nezara viridula readily ingested the opportunistic P. agglomerans strain Sc 1-R and transmitted it into unopened cotton bolls. Infections by the transmitted Sc 1-R strain caused rotting of the entire locule that masked internal carpel wounds incurred by insect feeding. Bacteria were recovered from penetration points by insects not exposed to the pathogen, but locule damage was limited to the area surrounding the feeding site (c. 3 mm). SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that demonstrates the ability of SGSB to acquire and transmit plant pathogenic bacteria into cotton bolls.     

雄性稻绿蝽对雌性鸣唱反应的物种特异性

雌性稻绿蝽的鸣唱开始了在基质中产生的通讯并引起雄性不同的特定反应。在两种自然情况下 ,我们检验了雄性稻绿蝽对N viridula ,Thyantapallidovirens和Thyantacustatoraccerra个体鸣唱刺激反应的物种特异性水平 ,并对反应强度和同种及异种刺激性鸣唱的时间特性进行了相关分析 ,证明雄性求偶鸣唱的发送和震动源的定位是最具物种特异性的反应。然而 ,即便是在这个水平上 ,雄性稻绿蝽不能将同种雌性个体的鸣唱与T .custatoraccera的第二个雄性个体的鸣唱区分开来 ,后者与前者有相似的脉冲持续时间和重复时间值。本文也讨论了涉及交配行为鸣唱期的有关信号的物种特定性的概念     

Population behaviour of the southern green stink bug,Nezara viridula,with special reference to the developmental stages of early-planted paddy

Population behaviour of adults and 5th-instar nymphs of Nezara viridula L. was analysed by means of the marking-and-recapture method in an early-planted paddy field. The field contained five varieties of rice which differend in growth states. It was estimated that a total of more, than 7,000 adults of the first generation, in which at least 3,000 were females, invaded the field from early July to middle August. Egg-mass census data, however, indicated that only 10 per cent or less of the females participated in egg-laying. This was largely due to the, low rate of adult survival. The adults preferred younger plants, for both feeding and oviposition. The method described byIwao et al. (1966) permitted estimate that 3,300–3,400 of the 5 th-instar nymphs and 1,100–1,200 of the adults of the second generation were produced from 298 egg-masses (25, 700 eggs); while 95–6 per cent of the individuals were thought to have died before reaching adulthood. Most of the 5 th-instar nymphs moved less than 4 m in three days as long as the condition of food plants remained suitable, but they tended to move more towards younger plants when those on which they lived became too mature. The apparent survival rate of the second generation adults was very low, probably due both to a rapid emigration and a high mortality of newly-emerged adults.     

Genetic differentiation of geographically separated populations of the southern green stink bug Nezara viridula (Hemiptera: Pentatomidae)

Genetic variation in the southern green stink bug Nezara viridula (Linnaeus) from 11 geographically separated sampling locations (Slovenia, France, Greece, Italy, Madeira, Japan, Guadeloupe, Galapagos, California, Brazil and Botswana) was studied by sequencing 16S and 28S rDNA, cytochrome b and cytochrome c oxidase subunit I gene fragments and random amplified polymorphic DNA (RAPD) analysis. Sequencing revealed 11 distinct haplotypes clustering into lineages A, B and C. Lineage C was characteristic for a single analysed specimen from Botswana. Lineage B was detected in Japan, and it probably arose in Asia. Haplotypes of European and American specimens belonged to lineage A; specimens from France, Slovenia, Madeira and Brazil shared highly similar haplotypes (>99%) from subgroup A1, while all the specimens from Greece, California, Galapagos and Guadeloupe shared a haplotype from subgroup A2. RAPD data were more variable but consistent with mtDNA sequences, revealing the same clustering. They separated the Botswanian specimen from Japanese specimens and from a group of more closely related specimens from Europe and America. Sequence and RAPD results both support the African origin of N. viridula, followed by dispersal to Asia (lineage B) and, more recently, by expansion to Europe and America (lineage A). RAPD analysis revealed two highly supported subgroups in Japan, congruent with mtDNA lineages A2 and B, suggesting multiple colonization of Japan. Invariant sequences at the 28S rDNA combined with other results do not support the hypothesis that cryptic (sibling) species exist within the populations investigated in this study.     

The effect of vibratory disturbance on sexual behaviour of the southern green stink bug Nezara viridula (Heteroptera, Pentatomidae)

The effect of vibratory disturbance on sexual behaviour and substrate-borne sound communication of the southern green stink bug, Nezara viridula L. was studied. Disturbance signals do not change the time N. viridula males need to locate the source of vibratory signals, but decrease the number of males responding with the calling and courtship song to calling females. Female N. viridula proceed calling during stimulation with disturbance signals but some of them change the song rhythm by skipping one or more signal intervals or emitting the repelling signals. The number of females which change the dominant frequency of the calling song decreases proportionally with increasing differences between the dominant frequency of the disturbance signals and the emitted female calling song. Variation of the song dominant frequency probably serves females to avoid interference by increasing the signal to noise ratio. Signal duration and repetition rate do not change significantly when the female is stimulated with the disturbance signals. This indicates that frequency shift by calling females is the main strategy for reducing interference by competitive signalers in N. viridula vibrational communication.     

Effects of low temperature on diapause termination and body colour change in adults of a stink bug, Plautia stali

Abstract. Diapause adults of Plautia stali Scott maintained at 20°C under short day conditions (LD 12:12 h) were exposed to four temperatures of 5–20°C to examine the effect on diapause development which was assessed in terms of oviposition. Diapause adults kept at 20°C under short day conditions changed their body colour gradually from brown to green and started egg laying after a prolonged preoviposition period. Those transferred to either 10 or 15°C also showed colour change but did not lay eggs. Bugs exposed to 5°C underwent neither body colour change nor oviposition and died more rapidly than those kept at higher temperatures. When 30-day-old diapause adults were chilled at 5, 10 or 15°C for 30 or 60 days and returned to 20°C and long day conditions (LD 16:8 h), the preoviposition period varied primarily depending on the chilling, but not on the temperature. On the other hand, when 60day-old diapause adults chilled for 30 days were observed at 20°C and long day conditions, their preoviposition period tended to be longer as the chilling temperature was lower In this case, a temperature of 10°C appeared to intensify diapause. Therefore, the effect of chilling on diapause development varied depending on the age at which insects were chilled. When chilled bugs were transferred to short day conditions at 20°C, most females failed to lay any eggs and some turned green, then after a while, some green bugs changed to brown again. These results indicate that bugs remained sensitive to short day conditions even after a 60-day chilling at 10 or 15°C.     

Possible egg positioning and gluing behavior by ovipositing southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae)

From March 2002 to January 2004, a colony of southern green stink bug, Nezara viridula (L.), was kept in the laboratory, and its oviposition behavior was observed. During oviposition, soon after the egg is expelled, the female touches the egg mass with the dorsal surface of the last tarsomere; this movement of one leg of the hind pair occurred once. This small component of the oviposition behavior of this pentatomid is little known and not yet fully understood; it may help to position and glue the newly deposited egg to the others.     

Long-range mate location and close-range courtship behaviour of the green stink bug, Nezara viridula and its mediation by sex pheromones

Temporal and sequential aspects of the courtship of the green stink bug, Nezara viridula are reported. The sequence of courtship behaviour can be divided into two phases: long-range mate location and short-range courtship. Long-range behaviour includes those components of the behaviour that lead to the arrival of females in the vicinity of males. Short-range behaviour includes those components that coordinate the interaction of both sexes once they are in close proximity. The individual components of both the long and short range behaviour were found to occur in stereotyped sequences, each step having a high probability of transition to the next. When the odour stimuli of live males were replaced by chemical extracts from males, obtained by aeration collection, only the long range sequences of female behaviour were elicited. The lack of close-range behavioural sequences may indicate that visual and acoustic stimuli have some role in the later stages of sexual communication. The pheromonal extract from males, which was elucidated by GC-MS analysis, contained n-dodecane, n-tridecane, sesquiterpene (hydrocarbon), sesquiterpene (mono-oxygenated) and n-nonadecane.

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Résumé Ce travail concerne les aspects séquentiels et temporels du comportement précopulatoire de N. viridula. Ce dernier peut être divisé en deux périodes: le repérage à grande distance du conjoint et le comportement de pariade à faible distance. Le comportement à grande distance comprend les éléments du comportement qui conduisent les femelles à proximité des mâles. Le comportement à faible distance comprend les éléments qui coordonnent les interactions des deux sexes jusqu'à ce qu'ils soient à proximité immédiate. Les éléments particuliers à chacun des comportements à faible et grande distances se produisent dans des séquences stéréotypées, chaque étape ayant une forte probabilité de passage vers la suivante.Quand les stimuli odorants de mâles vivants ont été remplacés par des extraits chimiques de ces derniers, récoltés par barbotage d'air sur colonne absorbante, seules les séquences du comportement à grande distance des femelles ont été induites. L'absence des séquences à faible distance peut indiquer une influence des stimuli visuels et acoustiques dans les stades ultérieurs de la communication sexuelle. L'extrait phéromonal des mâles, qui a été mis en évidence par GC-MS, contenait du n-dodécane, du n-tridécane, des sesquiterpènes (hydrocarbures), des sesquiterpènes (monooxygénés) et du n-nonadécane.