Elevation of pheromone response threshold in almond moth males pre-exposed to pheromone spray

Abstract. High percentages of naive Cadra cautella (Walker) (Lepidoptera: Pyralidae) males not pre-exposed to pheromone flew upwind to sources containing 50 ng (83%) and 500 ng (97%) of pheromone, but not to sources containing 5 μg (23%) and 50 μg (4%).Of the naive males that flew upwind in response to 50 ng sources, 67% located and landed on the source, whereas fewer than 19% of the naive males that flew upwind in response to higher doses located and landed on the sources.A 2-minute pre-exposure of C.cautella males to a spray cloud containing 50 ng, 500 ng, 5 μg or 50 μg of pheromone, induced shifts in response levels such that in wind-tunnel bioassays performed 1 h later, there was an increase in the doses that optimally elicited upwind flight and landing on the source that was proportional to the pre-exposure dose.Few of the pre-exposed males flew upwind to (10–43%) and landed on (0–33%) 50 ng sources, whereas they now perferentially flew upwind to(58–81% and 52–73%) and landed on (33–68% and 55–60%) pheromone sources of doses of 500 ng and 5 μg, respectively.Therefore pre-exposure to pheromone promoted a shift of threshold for response, and not an overall reduction in responsiveness to pheromone.     

Sex pheromone of the tsetse species, Glossina austeni: isolation and identification of natural hydrocarbons, and bioassay of synthesized compounds

Copulatory responses of male Glossina austeni (Newstead) (Diptera: Glossinidae), that were elicited after contact with frozen female tsetse, were not observed after solvent washing of cuticular lipids. Chromatographic analysis of extracts from laboratory-reared and field-collected G. austeni females yielded natural hydrocarbons that were highly stimulatory to males. Most of this activity was produced by compounds in the alkene fraction. Gas chromatograms (GC) contained five natural alkenes; these were separated by preparative GC for bioassays conducted in Tanzania. The two major alkenes were identified using gas chromatography-mass spectrometry (GC-MS) to be 13,17-dimethyltritriacont-1-ene and 13,17-dimethylpentatriacont-1-ene, after the samples had undergone derivatization using dimethyl disulphide and saturation with deuterium. These alkenes and natural alkanes were quantified from G. austeni of both sexes from laboratory and field samples to confirm that their presence was consistent in this species. Trials of synthetic samples resulted in the order of biological activity for the stereoisomers of 13,17-dimethyltritriacont-1-ene as follows: S,R-33:1 > R,S- 33:1 > S,S-33:1 > R,R-33:1. Dose-response data showed an ED(50) at 5 microg per treated, solvent-washed male decoy. Of the four stereoisomers of 13,17-dimethylpentatriacont-1-ene, R,R-35:1 showed the most activity. This is the first report of alkene-induced sexual activity in males of the genus Glossina.     

Attraction of Planococcus ficus males to racemic and chiral pheromone baits: flight activity and bait longevity

The vine mealybug (VM), Planococcus ficus (Signoret), is a worldwide pest and affects mainly grapevine and figs. In Israel, (S)-lavandulyl senecioate [(S)-LS] and (S)-lavandulyl isovalerate [(S)-LI] were identified from VM reared for several generations on potato sprouts, when compared with the identification of only (S)-LS from feral females. Racemic lavandulyl senecioate (LS) can be used for fieldwork because the unnatural enantiomer is benign and does not affect the activity of the pheromone. Lures loaded with 200  μ g of LS remained active for 24 weeks but it is recommended to replace lures after 12 weeks to preserve constant and high attractiveness. Delta sticky traps, baited with 50 or 200  μ g of LS were used to determine the daily flight pattern and the seasonal flight activity including vine plant infestation. A positive correlation between peak mealybug density and male capture was observed strengthening the usefulness of the pheromone traps for monitoring the pest. Addition of racemic or the two enantiomers of lavandulyl isovalerate (LI) to LS decreased the capture of VM males. The level of inhibition varied during 2003–2004. Both enantiomers of LI displayed the same antagonistic activity. Addition of (S)-lavandulol to the pheromone resulted in shut-down of the traps. Inhibition by the antipode, (R)-lavandulol, was moderate indicating a certain degree of chiral discrimination.     

Three new species of lsospora (Apicomplexa, Eimeriidae), from the White-cheeked Bulbul (Pycnonotus leucogenys) in Saudi Arabia

This paper describes three new species of Isospora from Pycnonotus 1eucogenys in Saudi Arabia ( I. gatifenensis sp.n.; I. khobarensis sp.n. and I. hafoufenensis sp.n.). Sporulated oocyats of I. gatifenensis are ovoidal, 23-26.5 ± 16.5-19(25.03 ± 0.12 ± 18.13 ± 0.09))μm and sporocysts are elongated ovoidal 17-20.5 ± 8-11 (18.9 ± 0.09 ± 9.3 ± 0.07) μm. Sporulated oocysts of I. khobarensis are ovoidal 22-26 ± 15.5-19 (24.3 ± 0.18 ± 17.1 ± 0.19)μm and sporocysts are pyriform 13-16 ± 9-11.5 (14.8 ± 0.15 ± 9.9 ± 0.13)μm. Sporulated oocysts of I. hafoufenensis are ovoidal 22-27 ± 19-24(25.4 ± 0.25 ± 22.1 ± 0.26) μm and sporocysts are ovoidal 14.5-18 ± 8-13 (16.5 ± 0.14 ± 11.4 ± 0.18) μm.     

Sex pheromone traps for monitoring the codling moth: effect of dispenser type, field aging of dispenser, pheromone dose and type of trap on male captures

The effects of dispenser type, dispenser aging in the field, pheromone dose in the dispenser and trap type on trapping efficiency of codling moth,Cydia pomonella (L.), males were investigated in Israel. An Israeli-manufactured rubber septum was significantly better than the CM Pherocon cap in attracting males to a Pherocon 1C cap trap or an IPS trap. The effect of aging of the dispenser in the field on trapping efficiency was significant in CM Pherocon caps and the Israeli septa. Captures in traps were negatively correlated with aging of septa. The effect of aging of dispensers was more marked during summer than during spring. The fairly rapid loss of attractancy indicates that the lures should be replaced after 2 weeks at the most. The release rate of the pheromone from the dispensers was measured in a flow system. The emission from the Israeli septa and Pherocon caps decreased sharply after 2 weeks and then was almost constant, which explains the lower attractancy of aged septa. However, there was a marked difference in the release profiles of the pheromone from the two types of dispensers, which may explain the different performance of the two dispensers. Within the range of 0.1 to 100 μg pheromone per dispenser, male response increased positively with the pheromone dose. Pheromone loadings of 100 or 1000 μg per dispenser did not differ significantly in their attractiveness for males. A load of 5000 μg per dispenser was significantly less attractive to males than was 100 or 1000 μg per dispenser. The non-sticky IPS trap was significantly better in capturing codling moth males than was the sticky, commonly used Pherocon 1C trap, provided it was baited with the Israeli dispenser. The two traps were equally effective when baited with the CM Pherocon caps. The possibility of using the non-sticky, nonsaturating and easy-to-handle IPS traps for monitoring codling moth is of great importance. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan 50-250, Israel. No 3702-E, 1992 series.     

Responsiveness of Pseudaletia unipuncta males to the female sex pheromone

ABSTRACT. In wind tunnel experiments male response to different concentrations of synthetic pheromone varied with age. At 25°C responsiveness increased up to day 5 and then declined slightly on day 7. For any given age the level of response generally increased with an increase in pheromone concentration. Males held at 15°C (since emergence) showed a continual increase in responsiveness with age; however, overall response levels were less than at 25°C. At 25°C male response to low concentrations of pheromone (10 and 30 μg) varied markedly over a 24 h period but no differences were observed at higher concentrations (100 and 300 μg).     

Behaviour of male pine sawflies, Neodiprion sertifer, released downwind from pheromone sources

This study investigated the behaviour of male European pine sawflies, Neodiprion sertifer Geoffroy (Hym., Diprionidae), that were released and observed downwind from pheromone traps baited with 100 g of the sex pheromone, (2S,3S,7S)-3,7-dimethyl-2-pentadecyl acetate. Releases were done at three distances; either at 5 m from one trap, or at 50 or 200 m from five traps, placed in a line perpendicular to the current wind direction. As control, males were released identically but without any pheromone source present. The behaviour of the males prior to take-off was studied. A total of 1729 males were released, and 80% of them took flight. Males took off significantly faster in the presence of pheromone. Grooming was significantly more frequent in presence of pheromone compared with control. In all pheromone experiments significantly more males displayed grooming, wing fanning and take-off towards the wind compared with the control. Weather data was simultaneously collected at the study site. Wing fanning was negatively correlated with wind speed. Grooming was not influenced by wind speed. Reduced levels of incoming short-wave radiation lowered the take-off frequency significantly. Pheromone-induced behaviour in diprionids seems to be less distinct than in other insects, e.g., Lepidoptera.     

A sex pheromone component novel to the Geometridae identified fromEpirrita autumnata

(Z,Z,Z)-1,3,6,9-Heneicosatetraene was identified as a sex pheromone component ofEpirrita autumnata (Borkhausen), (Lepidoptera: Geometridae). Gas chromatography coupled with electroantennographic detection revealed one active peak from female pheromone gland extracts. The chemical identification of the compound was based on gas chromatography-mass spectrometry, chemical micro-reactions and unambiguous synthesis. In a field test, a rubber septum loaded with 3000 μg of this compound showed highest attraction of maleE. autumnata moths compared to lower doses and the control. The attraction of males to a 300 μg bait was equivalent to that obtained using live virgin females.     

The effects of temperature, body mass and feeding on metabolic rate in the tsetse fly Glossina morsitans centralis

Abstract.  Metabolic rate variation with temperature, body mass, gender and feeding status is documented for Glossina morsitans centralis . Metabolic rate [mean ± SE; VCO₂= 19.78 ± 3.11 μL CO₂ h⁻¹ in males (mean mass = 22.72 ± 1.41 mg) and 27.34 ± 3.86 μL CO₂ h⁻¹ in females (mean mass = 29.28 ± 1.96 mg) at 24 °C in fasted individuals] is strongly influenced by temperature, body mass and feeding status, but not by gender once the effects of body mass have been accounted for. A significant interaction between gender and feeding status is seen, similar to patterns of metabolic rate variation documented in Glossina morsitans morsitans . Synthesis of metabolic rate-temperature relationships in G. m. centralis , G. m. morsitans and Glossina pallidipes indicate that biting frequency as well as mortality risks associated with foraging will probably increase with temperature as a consequence of increasing metabolic demands, although there is little evidence for variation among species at present. Furthermore, metabolic rate–body mass relationships appear to be similarly invariant among these species. These data provide important physiological information for bottom-up modelling of tsetse fly population dynamics.     

The activation of resting tsetse flies (Glossina) in response to visual and olfactory stimuli in the field

ABSTRACT Studies were conducted in Zimbabwe of the responses of Glossina morsitans morsitans Westwood and Glossina pallidipes Austen resting in a refuge to various host stimuli. Tsetse took off in response to 100% ox odour, 0.08% carbon dioxide or a visual stimulus consisting of a 0.75 × 0.75 m black target placed c . 5 m from the refuge moving at 4^o s^-1, but the level of response was low with only 35%, 19% and 29% responding, respectively. Tsetse did not take off in response to any one of 25% ox odour, 0.8% carbon dioxide, acetone (3 μg 1^-1) or octenol (0.03 μg 1^-1). In the absence of any host stimuli, flies emerged from the refuge later on hotter days (35–37^oC) than on cooler days (32–34.5^oC). Male G.pallidipes emerging later in the afternoon contained significantly more haematin than those emerging relatively earlier. There were no significant differences between the responses of G.m. morsitans and G.pallidipes. It is suggested that the initial activation of resting flies is primarily mediated through endogenous, rather than host, stimuli.     

Kairomonal effect of sex pheromone components of two lepidopteran olive pests on Trichogramma wasps

Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae (Lepidoptera: Yponomeutidae) and Palpita unionalis (Lepidoptera: Pyralidae) was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae (Hymenoptera: Trichogrammatidae). The response of T. oleae wasps to ( Z )-7-tetradecenal and ( E )-11-hexadecenal, major sex pheromone components of P. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. ( E )-11-hexadecenal elicited maximum attraction (70%) at a dose of 1 μg, while a dose of 100 μg ( Z )-7-tetradecenal attracted 80% of the tested wasps. ( E )-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis , and the binary blend of ( E )-11-hexadecenyl acetate: ( E )-11-hexadecenal (7:3) were not attractive at these doses. The results of this research are discussed in view that they may be considered as alternatives in the biological control of these pests.     

Behaviour of male oriental fruit moth, Grapholita molesta, in overlapping sex pheromone plumes in a wind tunnel

The behaviour of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) males was studied in overlapping sex pheromone plumes in a wind tunnel. The ultimate aim of the study was to assess the effect of different treatments on male behaviour and consider the observed changes within the context of the suggested mechanisms underlying mating disruption. Two baits were placed either in series or parallel using both synthetic pheromone blends and female extracts. One bait, the reference containing (Z)-8-dodecenyl acetate/(E)-8-dodecenyl acetate/(Z)-8-dodecenol in a ratio of 100/6/10 was kept constant at a dose of 100 g of the main component, giving a composition and a release rate close to that of a female. The dose of the other bait varied between 0.1 and 100 times the concentration of the reference and was a mixture of one, two or three pheromone components. Males clearly discriminated between different blends and doses in the overlapping plumes, for regardless if the lures were presented in series or in parallel they followed the complete plume. Complete suppression of the response to the reference was only achieved with 300 g of the optimal three-component blend on the other lure. When tested singly, a bait consisting of Z8-12:OAc/E8-12:OAc/Z8-12:O Hin a 100/0.2/0.4 ratio, attracted a high proportion of the males when placed 75 cm upwind of the male release site, but no males from 150 cm. Our data suggest that complete pheromone blends should be more effective than any incomplete blends in mating disruption formulations for G. molesta.     

Evidence for the involvement of calcium in the hatching of Globodera rostochiensis

Low concentrations of ruthenium red and lanthanum chloride inhibited hatching of juveniles from eggs in cysts of Globodera rostochiensis in potato root diffusate. Pro-bit analysis for 31 cysts at seven concentrations of ruthenium red showed that 50% inhibition with 95% fiducial limits occured at 47 ± 23 μm; a similar value of 59 ± 14 μm was obtained using eggs removed from cysts. Results for 10 to 20 cysts at six concentrations of lanthanum chloride suggested a somewhat higher value for 50% inhibition of 110 ± 83 μM. In contrast hatching of eggs in cysts of Heterodera schachtii in water was unaffected by 5 ITIM lanthanum chloride and 625 μM ruthenium red, concentrations which cause over 90% inhibition of hatch in G. rostochiensis.
Two calcium ionophores synergised hatching of a 1971 population of G. rostochiensis in dilute diffusate. Optimal concentrations of 2 μM for A23187 and 10 μM for BrX537A increased the hatch from 17 ± 3–6 juveniles/cyst to 114 ± 44 juveniles/cyst and 138 ± 40 juveniles/cyst respectively. Ionophores in the absence of diffusate hatched very few eggs of this population but caused a greater hatch in a second (1975) population which gave a high hatch in water of 43 ± 10 juveniles/cyst. This was increased by A23187 to 181 ± 41 juveniles/cyst. The results with both the inhibitors and the ionophores suggest that hatching in G. rostochiensis might be a calcium-mediated process.     

Communication disruption of maleAgrotis segetum moths with one or several sex pheromone components

Attraction of maleAgrotis segetum Dennis & Schiffermüller (Lepidoptera: Noctuidae) to sex pheromone traps in fields, which were treated with one or three pheromone components was investigated. Small plots of 1/4ha size were treated with synthetic pheromone, released by 25 evenly dispersed latex rubber tube dispensers. The dispensers were loaded with either 500 μg Z5-10:OAc (50 mg/ha), or 1000 μg Z7-12:OAc (100 mg/ha), or a 3-component mixture consisting of 500 μg Z5-10:OAc+1000 μg Z7-12:OAc+1000 μg Z9-14:OAc. Pheromone traps were placed both within and outside of the treated area in a cross design, with an intertrap spacing of 15 m. Release rates from disruption dispensers were measured in the laboratory after being exposed in the field. The release rates of the components were estimated to be 0.44, 0.11, and 0.06 μg/h/dispenser for Z5-10:OAc, Z7-12:OAc and Z9-14:OAc, respectively. The highest effect of disruption was achieved by the three-component blend, resulting in a significant suppression of trap catches extending 5 m outside of the treated area. The Z5-10:OAc treatment resulted in reduced trap catches inside the treated area, but the effect did not extend outside. Z7-12:OAc alone did not result in any significant reduction in trap catch. The results indicate that different mechanisms may explain the disruptive effect of the treatments and that the single pheromone components are not as effective as the three-component blend.     

Influence of wind conditions and intertrap spacing on pheromone trap catches of male european pine sawfly,Neodiprion sertifer

The spatial distribution of catches of male European pine sawfly,Neodiprion sertifer (Geoffr.) (Hymenoptera, Diprionidae), was studied using different pheromone trap arrays. In hexagonal trap groups, trap interference was evident by reduced catch in the central of seven traps spaced 10 to 40 m apart. When the trap spacings were either 5 or 80 m no significant reduction could be shown. The interaction was more pronounced for strong (100 μg) pheromone ([2S, 3S, 7S]-3,7-dimethyl-2-pentadecanyl acetate) lures than for weak ones (10 μg). Similarly, the inner traps caught less than the outer traps in grids of 6×6 traps spaced 20 or 50 m apart. Mark-release-recapture experiments in the grid array confirmed that a majority of the males originated from outside the trap group and were caught in the first trap they encountered. There were no differences between catches in downwind, crosswind and upwind traps. Thus, no ‘overshooting’ was evident during average conditions, i.e. the sawflies did not divert from the trap initially attracting them by flying to the upwind trap. However, the proportion caught in the upwind traps increased with increasing wind velocity, suggesting more overlapping pheromone plumes at higher wind speeds. Also, the recapture rate of released males increased with increasing wind velocity up to a daily average of 3.1 m/s at 2m, indicating that sawflies more easily find the pheromone source, probably due to a more stable pheromone puff trajectory during higher wind velocities. The application of pheromone traps in e.g. monitoring studies is discussed and a distance of at least 50 m between the traps with strong lures used in the present study is recommended to avoid trap interaction.     

旋花蛾性信息素成分的鉴定

提取和鉴定了杂草田旋花Convolvulus arvensis的天敌旋花蛾Tyta luctuosa的性信息素主要成分,并应用风洞实验对雄蛾进行了测试。结果表明,腺体提取物和雌蛾求偶时所释放的主要性信息素成分均为2种化合物：顺-9-十四碳烯醛（Z9-14∶Ald）和顺-11-十六碳烯醛（Z11-16∶Ald）。腺体提取物中2种化合物的总量在个体间差异很大（22～167 ng）,但二者的比率相对稳定（Z9-14∶Ald/Z11-16∶Ald=0.3±0.15）。雌蛾所释放的性信息素量及比率在个体间也存在差异。每只雌蛾求偶时平均每小时释放94 ng Z9-14∶Ald和45 ng Z11-16∶Ald,平均比率为2.2。风洞实验结果显示,48%的雄蛾可被合成的性信息素混合物（0.4 μg Z9-14∶Ald, 2 μg Z11-16∶Ald）引诱完成逆风飞行并最终触及刺激源,而2种对照组（以求偶期雌蛾或性信息素腺体提取物为刺激源）的引诱率则分别为62%和44%。     

Effects of cadmium chloride on the development of rainbow trout Oncorhynchus mykiss early life stages

The sub-chronic (28–56 days) effects of exposure to low concentrations of cadmium (Cd; 0·05, 0·25, 0·50 and 2·50 μg l⁻¹) shortly following fertilization on embryos, larvae and juvenile rainbow trout Oncorhynchus mykiss were examined. Premature hatching occurred at lower concentrations (0·05 and 0·25 μg l⁻¹ Cd), however, delayed hatching was seen in the 2·50 μg l⁻¹ Cd group, with >90% of hatching occurring on the last day of the hatching period. Larval growth was negatively affected by Cd exposure in a concentration-dependent manner. Larvae exposed to 2·50 μg l⁻¹ Cd were 13·9 ± 0·8% shorter in total length ( L _T) and weighed 22·4 ± 3·5% (mean ± s . e .) less than controls at the end of the exposure period. Plasma sex steroid concentrations (oestradiol in juvenile females and 11-ketotestosterone in juvenile males) were elevated (four- to 10-fold over controls) in exposed fish in both males and females, following 28 days of exposure to 0·05, 0·25 and 0·50 μg l⁻¹ Cd, respectively. These results suggest that environmentally realistic concentrations (in the μg l⁻¹ range) of Cd can affect the development of O. mykiss impacting embryos, larvae and juvenile fish.     

Quantitative method for pheromone delivery in studies of sensory adaptation of moth antennae

Abstract.  A pheromone sprayer and an electroantennogram (EAG) are used to study sensory adaptation in the antennae of male obliquebanded leafrollers, Choristoneura rosaceana and oriental fruit moths, Grapholita molesta , to the main pheromone compounds ( Z )-11-tetradecen-1-yl acetate ( Z 11-14:Ac) and ( Z )-8-dodecen-1-yl acetate ( Z 8-12:Ac), respectively. The atomization of 0.125, 0.25, 0.5 or 1 μL ethanol min⁻¹ into the EAG air delivery tube at an airflow rate of 2 L min⁻¹, with resultant concentrations of 6.25, 12.5, 25 or 50 × 10⁻⁵μL ethanol mL air⁻¹, respectively, does not affect the EAG response of C. rosaceana or C. molesta after a 30-min exposure period. The atomization of 0.125 μL min⁻¹ of a solution of 8 mg Z 11-14:Ac mL⁻¹ ethanol into the EAG air delivery tube at an airflow rate of 2 L min⁻¹, with a resultant concentration of 0.5 ng pheromone mL⁻¹ air, reduces the EAG response of C. rosaceana by approximately 70% after a 15-min exposure period. An additional 15 min of exposure to pheromone does not result in increased sensory adaptation. Antennae recover 32% of the lost responsiveness when exposed to pheromone-free air for 15 min. The atomization of 0.125 μL min⁻¹ of a solution of 8 mg Z 8-12:Ac mL⁻¹ ethanol into the EAG air delivery tube at an airflow rate of 2 L min⁻¹, with a resultant concentration of 0.5 ng pheromone mL⁻¹ air, reduces the EAG response of C. molesta antenna by approximately 80% after a 15- or 30-min exposure period. The antennae of this species do not recover responsiveness when exposed to pheromone-free air for 15 min.     

G protein mutations that alter the pheromone response in Saccharomyces cerevisiae.

The GPA1 gene of Saccharomyces cerevisiae encodes a G alpha protein that couples the membrane-bound pheromone receptors to downstream elements in the mating response pathway. We have isolated seven mutant alleles of GPA1 that confer pheromone resistance: G50D (a glycine-to-aspartate change at position 50), G322E, G322R, E355K, E364K, G470D, and an E364K-G470D double mutant. All of the mutations lie within large regions that are highly conserved between Gpa1 and four other G alpha proteins; four of the changes are located in domains with proposed functions. On the basis of a gentic analysis, the pheromone-unresponsive GPA1 alleles can be divided into two classes: those that encode constitutively activated proteins and those that encode proteins unable to respond to the upstream signal. Our results support the hypothesis that the activated form of Gpa1 stimulates adaptation to pheromone.     

Autodetection and chemistry of female and male pheromone in both sexes of the tiger moth Panaxia quadripunctaria

Female moths of Panaxia quadripunctaria PODA (Lepidoptera, Arctiidae), produce (Z,Z)-6,9-heneicosadiene (I) as the major and (Z,Z)-6,9-eicosadiene (II) as the minor component of a putative pheromone. Related compounds occur in trace amounts. The abdominal scent glands contain 5–10 μg of (I) and 50–100 ng of (II). Recordings of electroantennogram (EAG) responses to (I), (II), and to female glands are of equal amplitude in both sexes. Females are thus capable of pheromone autodetection in contrast to the majority of moths where females are considered to be anosmic for their own attractant. The EAG threshold to (I) was below 1 ng at the odour source. The odour of the male scent gland (corema) elicited significant EAGs in both sexes. The chemical contents of coremata varied with the provenience of the moths. A variety of ethyl esters was always found, yet hydroxydanaidal (up to 20 μg/corema) and traces of danaidal, only in some samples. All these scents might be components of a male pheromone. Peculiar scent scales on the coremata are exposed during the extrusion. Antennae of both sexes have similar inventories of trichoid sensilla. Accepted: 11 July 1997