Evidence for a short-range sex pheromone in female Maladera matrida beetle

Laboratory studies with live and frozen Maladera matrida female and male beetles showed that males were attracted to chemical substances emanating from the females at dusk. Beetles exhibited sexual activity (including mating) at dusk towards frozen females but not towards frozen males. Frozen females that had been extracted with methanol together with either hexane or dichloromethane or with a mixture of all three solvents did not elicit male sexual activity. Activity was fully restored when a concentrate of the extract was applied to the previously extracted frozen females. Males also responded with vigorous sexual activity to frozen males to which female extract had been applied. Deterrent chemicals appear to be absent from the male body. Males exposed to females that had been frozen during the morning displayed weak sexual activity, indicating that females lack active semiochemicals. Differences between dusk and morning extracts were found with respect to more than 20 compounds, some of which were present in much higher concentrations at dusk than in the morning, while others were not detected in the morning extract. The active component(s) of the short-range sex pheromone of female M. matrida is (are) presumably to be found among these compounds.     

Mating stimulant pheromone and cuticular lipid constituents ofFannia femoralis (Stein) (Diptera: Muscidae)

The cuticular lipids of male and femaleFannia femoralis were similar for recently emerged insects but soon began to develop chromatographic patterns characteristic of each sex. Mature females contained more C₃₁ and C₃₃ monoolefin in the cuticular lipid than males. Also, the double bonds in the monoolefins of the female lipid were situated predominantly at the eleventh and thirteenth carbons, while most of those from the males were centrally located in the molecule or at the ninth carbon.The female C₃₁ monoolefin stimulated copulation by the males, but more mating activity occurred when the saturated hydrocarbons present in the female cuticular lipids were added. The synthetic monoolefin most active as a mating stimulant pheromone was (Z)-11-hentriacontene, but the addition of female alkanes or of syntheticn-alkanes to (Z)-11-hentriacontene increased the activity of the synthetic pheromone.A portion of a dissertation intended for submission by the first author to the Graduate School of the University of Maryland in partial fulfillment of the requirements for the Ph.D. degree.Mention of a proprietary or commercial product in this paper does not constitute an endorsement of this product by the U.S. Department of Agriculture or the University of Maryland.     

Mating stimulant pheromone and cuticular lipid constituents ofFannia pusio (Wiedemann) (Diptera: Muscidae)

Chromatograms of the cuticular lipids washed from newly emerged male and femaleFannia pusio were nearly identical. By the time the flies were 1 day old, the chromatographic profiles for the sexes were different. Mature females contained more C₃₁- and C₃₃-hydrocarbons than the males. The double bonds of the female monoolefins were mostly at the eleventh and thirteenth carbons, but those of the males were predominantly at the ninth carbon. Most active in stimulating copulation by males were the unbranched monoolefins with 31 and 33 carbons from the females. When they were synthesized and tested, the most active compound was (Z)-11-hentriacontene.A portion of a dissertation intended for submission by the first author to the Graduate School of the University of Maryland in partial fulfillment of the requirements for the Ph.D. degree.Mention of a proprietary or commercial product in this paper does not constitute an endorsement of this product by the U.S. Department of Agriculture or the University of Maryland.     

Influence of lectins on female sex pheromone reception byHeterodera schachtii (Nematoda: Heteroderidae) males

A bioassay was developed in which the chemotactic behavior of males of the sugarbeet cyst nematodeHeterodera schachtii towards the female sex pheromone can be observed and documented at any time. The standardized test, performed under sterile conditions, gives reproducible results within 1–2 hr. Incubation of males with the lectins fromCanavalia ensiformis, Triticum vulgare, Arachis hypogaea, Helix pomatia, andLimax flavus did not affect chemotactic attraction to the sex pheromone. Supplementing the bioassay medium with the lectin fromC. ensiformis also had no effect.C. ensiformis lectin binding to the surface of the exudate produced by the secretory gland cell of the amphids, the main chemoreceptors, did not inhibit the passage of fluorochrome fluorescein isothiocyanate into the amphidial canals, where the receptor dendrites are localized. Amphidial exudate synthesis was enhanced during pheromone reception.     

Disruption of male spruce budworm orientation to calling females in a wind tunnel by synthetic pheromone

Male spruce budworm [Chorisloneura fumiferana (Clem.)] moths were held for 3 hr in a wind tunnel and subjected to various concentrations of background synthetic pheromone. They were then exposed to calling females and their response was recorded. The background pheromone was presented either as discrete turbulent plumes or as a uniform permeation throughout the tunnel. The numbers of males wing-fanning and flying in response to the calling females decreased as the concentration of background pheromone increased. Of the males which flew, a higher proportion progressed upwind in the discrete plumes than in the uniform permeation, an indication that structure in the pheromone cloud is necessary for upwind progression. In both discrete plumes and uniform permeation fewer males were able to locate the females (i.e., disruption was greater) as the concentration of synthetic pheromone increased, but for the same total release rates, disruption was greater when the synthetic pheromone was released in discrete plumes rather than in a uniform permeation. This implies that disruption which involves luring males to sources of synthetic pheromone is more effective than masking female plumes by uniform permeation and suggests that it is more efficient to release pheromone from a few potent sources than from numerous low-potency sources.     

Alkadienes mediating courtship in the parasitoidCardiochiles nigriceps (Hymenoptera: Braconidae)

Courtship inCardiochiles nigriceps (Viereck) (Hymenoptera: Braconidae) involves male attraction to females and male antennation of females followed by mounting and copulation. Once the female is located, antennation and mounting of the female are mediated by the hydrocarbon fraction of female's Dufour's gland and cuticle. The identification of the cuticular hydrocarbons of males and females revealed a mixture of alkanes and alkenes, in addition to a series of alkadienes specific to females. These female-specific alkadienes reported from Braconidae are unusual among insect alkadienes in that the second double bond occurs in the middle of the molecule. Bioassays with three available alkadienes revealed that contact behaviors (antennation and mounting) are in part mediated by the (Z,Z)-7, 13-heptacosadiene and at least one other alkadiene in combination with other hydrocarbons found in males and females.     

Arrestment of male twospotted spider mite caused by female sex pheromone

A glass slide bioassay was used to evaluate male twospotted spider mite,Tetranychus urticae Koch, arrestment caused by quiescent deutonymph extract. Males that were guarding quiescent deutonymphs prior to being tested were arrested by a 3-mm-diameter circle of quiescent deutonymph extract; nonguarding males and adult females were not arrested. Extracts of allT. urticae instars tested caused male arrestment, but mean arrestment duration was longest with quiescent deutonymph extract. Arrestment by volatile perception of pheromone and upwind orientation to point sources of extract were not observed. The mono- and sesquiterpene alcohols previously identified as components of the pheromone did not arrest males. HPLC separation of extract resulted in four active fractions; a subtractive bioassay showed that three were essential to elicit maximum male response.     

Sex pheromone of the stable fly: Evaluation of methyl- and 1,5-dimethylalkanes as mating stimulants

Each of 20 methyl-branched and 1,5-dimethyl-branched alkanes that comprise the active principle of saturated hydrocarbons of the female stable fly,Stomoxys calcitrans (L.), was synthesized and evaluated for mating stimulant activity. The compounds that showed the highest degree of activity in bioassays were 15-methyl- and 15,19-dimethyltritriacontanes.Diptera: Muscidae.Mention of a proprietary or commercial product in this paper does not constitute an endorsement by the U.S. Department of Agriculture.     

Pheromone Analysis of Wild Female Moths with a PBAN C-Terminal Peptide Injection for an Estimation of Assortative Mating in Adzuki Bean Borer, Ostrinia scapulalis

The adzuki bean borer, Ostrinia scapulalis, has distinct genetic variation in the blend of two sex pheromone components, (E)- and (Z)-11-tetradecenyl acetates. This variation is largely controlled by a single autosomal locus with two alleles, E and Z. E-type (EE) females produce a pheromone with a mean E:Z ratio at 99:1 whereas Z-type (ZZ) and I-type (ZE) produce pheromones with mean of 3:97 and 64:36, respectively. Interestingly, in many natural populations of O. scapulalis in Japan, this pheromone polymorphism appears to be stably maintained. We tried to predict the changes in relative abundance of each pheromone type by estimating the pheromone production genotype of wild females and their male mates. The pheromone titer in the wild, mated females was increased without changing the blend ratio by an injection of a peptide with pheromone biosynthesis activating activity (TKYFSPRL-NH2). The frequencies of E-, I-, and Z-types at Matsudo were 15, 52, and 33%, respectively, and did not deviate from the Hardy-Weinberg expectations. The estimated mating patterns were concordant with the assumption that no assortative mating was occurring in this population, and this is suggested as a cause of sustained polymorphism at Matsudo.     

Laboratory experiments to determine if crayfish can communicate chemically in a flow-through system

The importance of chemical cues for transmitting information concerning sexual identity, agonistic state, and stress-related condition in the crayfishProcambarus clarkii (Girard) was examined in a flow-through system. Experiments tested the effects of conditioned water from stimulus tanks on the behavior of solitary male or female crayfish. Twenty males and 20 females were subjected to a random sequence of five treatments: unconditioned water (control), conditioned water flowing through tanks containing a solitary male or female, and conditioned water from tanks holding either two males or two females. Durations of the following behaviors were recorded: chelae up, chela(e) in baffle hole, chela waving, climbing, digging, grooming, gross body movement, and meral spread. Results indicated that crayfish chemically detected another animal within 0.25 m without additional visual or tactile stimuli; however, crayfish apparently did not communicate information on sexual identity, agonistic state, or stress condition, nor does this detection necessarily imply discrimination between stimuli from crayfish and other taxa (e.g., fish). Our conclusions are contrasted with the two previous reports on chemical communication in crayfish in which experimental animals were tested in static systems. We suggest that a temporal separation of molting and copulation and a long reproductive receptivity period for females (which would allow abundant intersexual encounters) could account for a lack of selective pressure to evolve long-distance sex pheromones.     

Sex pheromone communication in the screwworm,Cochliomyia hominivorax: Ontogenetic and strain effects

A laboratory behavioral assay was used to examine ontogenetic and strain effects on sex pheromone production and reception in the screwworm, which employs a female-produced contact pheromone to stimulate male copulatory attempts. Pheromone levels peaked between three and six days after adult emergence in females of two strains that had been colonized fewer than 50 generations. Pheromone was detectable at low levels in newly emerged flies of both sexes but disappeared from males by two days of age, when males first became responsive to females. A similar decline in pheromone with ontogenetic age was previously described for females of a strain colonized over 100 generations. Interstrain tests between the two newer strains, which differed by 35 generations in duration of colonization, demonstrated lower female pheromone activity but higher male responsiveness to pheromone in the older strain, despite the similar shape within these strains of curves relating female age and pheromone activity. The data suggest that conditions of screwworm colonization result in gradual loss of the pheromone peak that develops three to six days after emergence in newly colonized females. Higher male responsiveness associated with longer colonization involved change in both thresholds and dose dependency and may be relevant to control of the screwworm via the sterile insect technique.     

Evidence for a multicomponent sex pheromone in the yellowheaded spruce sawfly

The existence of a female-produced sex pheromone in the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) was demonstrated by field and greenhouse bioassays. Virgin females, their empty cocoons (with which they were confined during handling procedures), and the hexane extract of these cocoons were attractive in the field. The only Florisil fraction of this extract consistently attractive by itself was that eluted with hexane, but three, more polar fractions (eluted with 5%, 25%, and 50% ether in hexane) each synergized the hexane fraction, increasing bioassay responses 10–30 times. Fractions derived directly from virgin females yielded comparable results. The greenhouse data corroborated the field data, except that the 5% ether-hexane fraction, while very synergistic in the field, was consistently inactive in the greenhouse.     

Interspecific attractivity of female sex pheromone components ofPeriplaneta americana

Female sex pheromones ofPeriplaneta americana, P. australasiae, andBlatta orientalis elicit locomotion and upwind orientation in conspecific males. Interspecific attraction between these species was observed in a wind tunnel assay for most species combinations, with the exception ofP. australasiae males not being attracted toP americana females. The role of twoP. americana sex pheromone components, periplanone-A (PA) and periplanone-B (PB) in male attraction was analyzed. PA induced locomotion in males of all three species, with highest threshold concentration inP. americana. PB was effective inP. americana andB. orientalis, but not inP. australasiae. Experiments with mixtures of both components confirmed an inhibitory influence of PB onP. australasiae males when it was added to PA in a ratio of 31 or higher. SinceP. americana andP. australasiae have been found to be syntopous, and their daily mating periods overlap, the female sex pheromone ofP. americana is discussed as an isolating factor between both species.     

Rhythms of maleAntheraea polyphemus Attraction and female attractiveness,and an improved pheromone sythesis

WildAntheraea polyphemus (Cramer) (Lepidoptera:Saturniidae) males were attracted to synthetic pheromone and to laboratory-reared females from 2300 (EDT) until dawn. Males were attracted to the synthetic pheromone at a mean time of 01:33 and to the females at 0323 (EDT). Synthetic traps accumulated the most males (61 compared to 19 in the female-baited traps), but there was no large difference in catch during the main interval of female attractiveness. Pheromone used in the study was prepared by an improved synthesis that utilizescis-4-nonen-1-yl bromide as a key intermediate.Lepidoptera:Saturniidae.     

Sex pheromone of the face fly,Musca autumnalis De Geer (Diptera: Muscidae)

Components of a sex pheromone that cause male face flies to strike at females were found to be the straight-chain monoalkenes (Z)-14-nonacosene, (Z)-13-nonacosene, and (Z)-13-heptacosene. Although these compounds were found in the extracts of both sexes, extracts from sexually mature males contained a much higher proportion of nonacosane and heptacosane, which attenuated the activity of the active monoalkenes. The monoalkenes were readily synthesized by a Wittig reaction modified by the use of hexamethylphosphoric triamide as a cosolvent with tetrahydrofuran to produce a product containing 94–96% (Z) isomer.     

Male bugs modulate pheromone emission in response to vibratory signals from conspecifics

Male Nezara viridula emit a volatile sex pheromone that acts as a long-range attractant to females. Both sexes communicate through vibrations once they are on the same plant. Males respond to the female calling song by emitting a male courtship song, and they orient to the female calling song on a plant. Simultaneity between vibratory and chemical communication during the last steps of mate finding suggests that pheromone emission might be modulated by signals from conspecifics. Male volatile emissions were collected with fibers for solid-phase microextraction, while male bugs were stimulated with natural and artificial signals. Percentages of males releasing pheromone and collected amounts of pheromone increased when males were stimulated with female calling song. Pheromone emission was stable in males stimulated with male rivalry songs, and it decreased in males stimulated with a 100-Hz artificial signal. The ability of male bugs to modulate their pheromone emission may reduce metabolic costs, reduce parasitism, and offer a better synchronization of sexual activity.     

Sex pheromone ofEupoecilia ambiguella female: Analysis and male response to ternary blend

Sex gland extracts and washes ofEupoecilia ambiguella contain 10–20 ng/female of the primary sex pheromone componentZ-9-dodecenyl acetate (Z9–12Ac), accompanied by a number of related compounds. These areE-9-dodecenyl acetate (E9–12Ac),Z-9-dodecen-1-ol (Z9–12OH), saturated acetates of 12, 16, 18, and 20 carbons, and traces of a doubly unsaturated acetate, tentatively identified as a 9,11-dodecadienyl acetate. Octadecyl acetate predominates among the pheromone-related components, making up 1–2, occasionally 20–30 times the amount ofZ9–12Ac. The same compounds were also found in field-collected females and in effluvia.Z-9-Undecenyl acetate, which is a male attractant on its own, was also found in a sample of female effluvia. A hierarchy is observed in the ethological function of the pheromone components.Z9–12Ac is an attractant forE. ambiguella males. Dodecyl acetate (12Ac) is not attractive on its own but augments male catch when added to the main attractant. Addition of 18Ac augments attraction only when bothZ9–12Ac and 12Ac are present. Windtunnel tests demonstrate that 18Ac also raises the disorientation threshold, as previously shown for 12Ac. Other compounds, with the possible exception of additional saturated acetates, had either no effect on trap catch or, in the case ofE9–12Ac,Z9–12OH, andE-9,11-dodecadienyl acetate, were inhibitory above a certain level. A blend of roughly equal parts ofZ9–12Ac, 12Ac, and 18Ac provides the best attractant blend forE. ambiguella known to date.     

European corn borer sex pheromone

The biological activity of analogs of the pheromone components of the European corn borer,Ostrinia nubilalis, (Z)- and (E)-11-tetradecen1-ol acetate, in which modifications were made in the terminal alkyl portion were studied in the three pheromonal types of the insect. European corn borer males respond to pheromonal stimuli at three levels of behavioral activity, i.e., short-range sexual stimulation, activation in the flight tunnel, and response in the field. Structural requirements for elicitation of response at these levels were found to be increasingly restrictive, respectively. Flighttunnel activity was induced only by compounds that had a total chain length of 13 or 14 carbons and in which branching at carbon 13 was limited to one methyl group or a cyclopropyl group. Three new analogs were active in the flight tunnel, viz., (E and (Z)-13-methyl-11-tetradecen-1-ol acetate and (Z)-12-cyclopropyl-11-dodecen-1-ol acetate. The cyclopropyl analog was the most active analog against theZZ type of the European corn borer. TheE isomer, however, was pheromonally inactive in theEE type and was shown to be a pheromone antagonist. This dissimilarity is most likely due to differences in structure of the receptors in the European corn borer strains. Analogs that were biologically active against the European corn borer were tested against the redbanded leafroller,Argyrotaenia velutinana, which also uses (Z)- and (E)-11-tetradecen-1-ol acetate as part of its pheromone. Results showed that the redbanded leafroller pheromone acceptor system is different from that of the European com borer; marginal behavioral response was elicited by only one of the new analogs. Thus, although both species use 11-tetradecen-1-ol acetate isomers as their pheromone, the mechanisms by which they are perceived are different.Mention of a commercial product does not constitute endorsement of that product by USDA.     

Reproductive biology of the yellow-spotted longicorn beetle,Psacothea hilaris (pascoe) (Coleoptera: Cerambycidae). III. Identification of contact sex pheromone on female body surface

A major component of female contact sex pheromone of the yellow-spotted longicorn beetle,Psacothea hilaris (Pascoe), was isolated from the elytra and identified as (Z)-21-methyl-8-pentatriacontene. The synthetic compound released the typical mating behavior including holding, mounting, and abdominal bending in males, although its activity was considerably lower than the extract of female elytra when treated on a gelatin capsule as an artificial female model.To whom correspondence should be addressed. Midori Fukaya is a postdoctoral fellow of the Research Development Corporation of Japan.     

Developmental and environmental sources of pheromone variation inColias eurytheme butterflies

Body size, age, ambient temperature, wing wear, and flight activity were investigated as possible sources of variation in the quantities and relative proportions of the three chemical components [n-heptacosane (C27), 13-methylheptacosane (13MH), andn-nonacosane (C29)] of the male courtship pheromone ofColias eurytheme butterflies. Size of the male has very little influence on the amount of any of the pheromone components present on the wings. Most of the deposition of all three components onto the surface of the hindwing occurs between 3 and 9 hr after emergence from the pupa. 13MH is deposited more rapidly than C27 and C29, and C27 more rapidly than C29. After the first 12 hr posteclosion, the pheromone phenotype of an individual male remains relatively constant through at least 96 hr of age. Experiments showed that none of the three chemicals volatilize to any appreciable extent at temperatures likely to be experienced in the field. The pheromones of actively searching and courting males did not differ from those of less-active feeding and resting males, suggesting that volatilization induced by flight activity is not an important source of pheromone variation. Loss of scales with age does seem to affect pheromone phenotype, but not in a readily interpretable way. Although the quantity of 13MH was lower in worn males than in fresh, C27 was higher.Lepidoptera: Pieridae.