The sex pheromone glands ofDermacentor variabilis (Say) andDermacentor andersoni stiles

Evidence is presented indicating the presence of the tick sex pheromone, 2,6-dichlorophenol in lipid droplets in the foveal glands ofDermacentor variabilis (Say) andDermacentor andersoni Stiles. The pheromone appears to be dissolved in the lipid droplets. The droplets consist of neutral lipids, mostly triacylglycerides and cholesterol esters. The esterified fatty acid profiles of foveal gland triacylgylcerides are different from those of other tissues examined or reported for other ticks. The percentage of shorter chain, mostly saturated fatty acids were decreased, while the longer chain polyunsaturated fatty acids were increased. The biological advantages of lipid solution for storage, translocation, and release of the sex pheromone from the female tick are discussed.Supported by grant AI 10986, from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health, Education and Welfare, Bethesda, Maryland.     

2,6-Dichlorophenol,the sex pheromone of the Rocky Mountain wood tick,Dermacentor andersoni Stiles and the American dog tick,Dermacentor variabilis (Say)

2,6-Dichlorophenol is the only active sex attractant component detected in the extracts of the Rocky Mountain wood tick,Dermacentor andersoni Stiles and the American dog tick,Dermacentor variabilis (Say). It elicits from the male of each species a hierarchy of responses culminating in copulation. This compound probably occurs generally throughout the metastriate Ixodidae. 2,6-Dibromophenol, an artifact, also elicits the same sexual responses from the wood tick, but phenol andp-cresol do not.Supported by grants nos. AI 10,986 and AI 10,987 from the National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20014.     

Use of sex pheromone, 2,6-dichlorophenol,to disrupt mating by american dog tickDermacentor variabilis (SAY)

Treatment ofD. variabilis-infested dogs with formulations of the sex pheromone, 2,6-dichlorophenol, significantly reduced mating by the attached ticks. Aqueous emulsions of a gelatin microcapsule-xylene slurry and a pheromone-loaded, molecular-sieve powder were used. Concentration was an important variable influencing product efficacy. Such formulations combined with an acaricide may prove effective in reducing tick populations on livestock and pets.Supported by grants, AI 10,986 and AI 10,987 from the Institute of Allergy and Infectious Diseases, National Institute of Health, U.S. Public Health Service, DHEW, Bethesda, Maryland 20205.     

Occurrence of sex attractant pheromone, 2,6-dichlorophenol,in relation to age and feeding in American dog tick,Dermacentor variabilis (say) (Acari:Ixodidae)

No detectable sex pheromone, 2,6-dichlorophenol (2,6-DCP), was found inDermacentor variabilis engorged nymphs, teneral females, replete females, or unfed males. The amount of 2,6-DCP present in unfed females of different ages was extremely variable; no relationship between age and 2,6-DCP content in these unfed females was observed. Partially fed virgin females had less 2,6-DCP than unfed females, but there was no change in pheromone content during the course of feeding. Sex pheromone was also found in partially fed males.Supported by grants AI 10,986 and AI 10,987, from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health and Human Services, Bethesda, Maryland, 20205.     

Genital sex pheromones of ixodid ticks: 1. Evidence of occurrence in anterior reproductive tract of American dog tick,Dermacentor variabilis (Say) (Acari: Ixodidae)

The occurrence of a genital sex pheromone in the anterior reproductive tract of partially fed femaleDermacentor variabilis was demonstrated by extraction and bioassay. A new type of bioassay, the neutered female assay, was developed to test the potency of extracts or chemically defined fractions to stimulate males to copulate. Electrophysiological tests confirmed the ability of males to detect the pheromone with sensilla on their cheliceral digits. Males of bothD. variabilis andD. andersoni exhibited neuronal excitation when stimulated with extracts of theD. variabilis reproductive tissues. The pheromone, which is soluble in methanol, was fractionated and found to contain at least two fractions that stimulated copulation by sexually excited males. Evidently, the pheromone is a mixture of two or more compounds. Histologic, ultrastructural, and histochemical studies suggest the vestibular vagina as the site of genital sex pheromone occurrence, presumably from secretions of the surrounding lobular accessory gland. The identity of the compounds that comprise the pheromone remains unknown.Supported by grants AI10986 and AI10987 from the National Institute of Allergy and Infectious Diseases, National Institute of Health, U.S. Public Health Service, Bethesda, Maryland 20205.     

Evidence for occurrence of mounting sex pheromone on body surface of femaleDermacentor variabilis (Say) AndDermacentor andersoni (Stiles) (Acari: Ixodidae)

MaleDermacentor variabilis andD. andersoni respond to an unknown chemical or chemicals present on the body surfaces of partially engorged conspecific female ticks. Following contact, the males mount the females and apply their mouthparts and legs against the female dorsal body surface. Then, the males turn with these appendages still in close contact and crawl to the female's venter, whereupon they locate the gonopore, probe the vulva, and copulate. Similar responses are elicited by heterospecific as well as conspecific females. However, the response is lost when the female cuticle is cleaned (delipidized) with organic solvents. It can be restored by applying hexane extracts prepared from female cuticle to the previously cleaned females. Males do not use surface texture as the primary stimulus for mate recognition. Male ticks also respond to hexane extracts applied to spherical inanimate objects, (dummy female), suggesting that a chemical or chemicals soluble in organic solvents has been transferred to these objects. These findings suggest the existence of a previously undescribed pheromone, the mounting sex pheromone (MSP). This contact sex pheromone enables males excited and attracted by 2,6-dichlorophenol to identify the female as a potential mating partner. The MSP is the second in the series of three sex pheromones guiding the hierarchy of behavioral responses which constitute tick courtship behavior.Supported by grant AI 10,986 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health and Human Services, Bethesda, Maryland 20205.     

Chemically mediated behavior in Acari: Adapations for finding hosts and mates

Ticks and mites respond to a limited spectrum of stimuli in their search for hosts and mates. Airborne chemical signals include carbon dioxide, ammonia, organic acids, terpenoids, 2,6-dichlorophenol, and other phenolic compounds. These are detected primarily by sensilla in and adjacent to Haller's organ. Most ixodid species examined have one or more multiporose sensilla that detect such volatiles. These olfactoreceptors enable the ticks to respond to remote volatile chemicals from hosts and from the other ticks, e.g., sex pheromones. Other sensilla, probably mechanogustatory in function, also occur on the tarsi. Gustatory sensilla on the palps detect assembly pheromones that enable ticks and mites to respond to conspecific or heterospecific chemical stimuli in their environment. Responses to those stimuli in ticks result in clustering, i.e., arrestant behavior. Arrestant behavior also occurs in certain mites. Finally, cheliceral chemosensilla enable ticks to recognize specific phagostimulants in host blood, e.g., ATP and glutathione, that stimulate feeding. InDennacentor variabilis andD. andersoni, these same cheliceral chemosensilla recognize species-specific genital sex pheromones in the vulvae of conspecific mates, without which they do not copulate.     

Salivary glands and preputial glands of males as source of estrus-stimulating pheromone in female mice

Male mice produce pheromones that induce estrus in adult female mice. The synthesis of these chemosignals is controlled by testosterone. Male tissues abundant in testosterone-binding receptors were tested for their ability to stimulate estrus in grouped females. The percentage of females that showed estrus during two days following exposure to male tissues was used as the indicator of biological activity of tested samples. Homogenates of salivary glands and preputial glands induced estrus; other tested organs (liver, testes, coagulation and vesicular glands or kidneys) did not stimulate estrus in female mice. These results indicate that estrus-stimulating pheromone has multiple sources.     

Production and release of (Z,E)-9,12-tetradecadienal by sex pheromone glands of females ofPlodia interpunctella (lepidoptera: pyralidae)

Extracts of sex pheromone glands obtained from females ofPloida interpunctella contained detectable amounts of (Z,E,)-9,12-tetradecadien-1-ol acetate (Z9,E12–14:Ac) and (Z,E.)-9,12-tetradecadien-1-ol (Z9,E12–14:OH) 4 hr prior to the first scotophase after adult emergence. The amount of pheromone increased during the first 4 hr of the scotophase and then declined to low levels during the subsequent photophase. Decapitation of females immediately after emergence, prior to expansion of the wings, inhibited production of pheromone during the subsequent 48 hr. Injection of extracts of the heads of 1-day-old females ofP. interpunctella of partially purified extracts of the cephalic ganglia of females of the corn earworm moth into decapitated females stimulated production of bothZ9,E12–14:Ac andZ9,E12–14:OH as well as production of (Z,E)-9,12-tetradecadienal (Z9,E12–14:Al). This aldehyde was subsequently identified from extracts of pheromone glands obtained from naturally calling females as well as from volatiles emitted by calling females. Studies on the terminal steps in biosynthesis of the pheromone showed thatZ9,E12–14:OH was produced from the corresponding acetate and thatZ9,E12–14:Al was produced from the alcohol via the action of an oxidase(s).     

Effects of sex pheromone on locomotion in the male American cockroach,Periplaneta americana

The locomotory activities of individual males ofPeriplaneta americana in a circular arena 2.5 m in diameter were investigated during the portion of the photocycle in which the cockroaches are most active. Control animals ran at an average speed of 10.86 cm/sec but remained immobile 68 % of the time. Pauses in locomotion occurred frequently and at fairly regular intervals (x=0.88 sec). Males showed a strong tendency to remain near the sides of the arena. Sex pheromone presented in the center of the arena produced a reduction in immobility time and a slight increase in running speed. The frequency of pauses decreased, and the time between pauses became less regular. The proportion of time spent near the sides of the arena was greatly reduced also.     

Unusual periodicity of sex pheromone production in the large black chaferHolotrichia parallela

(R)-(–)-Linalool was identified as a minor component sex pheromone of the scarab beetleHolotrichia parallela (Coleoptera: Scarabaeidae). Field evaluations revealed that, although not attractive per se, (R)-(–)-linalool enhances the attractiveness of the major sex pheromone,L-isoleucine methyl ester (LIME). Analyses of the pheromone titers in the glands of field-collected females demonstrated the occurrence of peak levels of 48-hr (circabidian) periodicity. The levels of LIME in the glands of 45-day-old virgin females increased over three times from the scototo the photophase of a calling day, but the amounts of (R)-(–)-linalool did not significantly change. Virgin females had in average two times more LIME and 3.6 times more (R)-(–)-linalool than the average amount found in the field-captured beetles throughout the season.     

Male sternal pheromone glands in Acanthosomatid shield bugs from Britain

Pheromone glands are present in the abdominal sternites of the pregenital region in the male adults in all British species of Acanthosomatidae. Secretory units are most numerous in the hawthorn bugAcanthosoma haemorrhoidale and maternal bugElasmucha grisea, next most numerous in the birch bugElasmostethus interstinctus, and least numerous in the juniper bugCyphostethus tristriatus. The largest dorsal abdominal scent glands were found inCyphostetheus. Ordinary dermal glands are also present. They are most numerous along the lateral margins of the abdomen. It is possible that Pendergrast's organ is the source of a female-produced pheromone. Secretory units were numerous in this organ inC. tristriatus female adults.     

A sex pheromone for male boll weevils from females

Steam distillation of frass of the female boll weevil,Anthonomus grandis Boheman, yielded an extract that was more attractive to males than to females in the laboratory. Extracts purified by TLC were attractive to males only. The active components appear to be alcohols and hydrocarbons.Coleoptera: Curculionidae.In cooperation with the Mississippi Agricultural and Forestry Experiment Station, Mississippi State, Mississippi 39762.Mention of proprietary products does not constitute an endorsement by the USDA.     

Filbertworm sex pheromone

(E,E)- and (E,Z)-8,10-Dodecadien-1-ol acetates were identified in a 14.3 ratio in the extract of abdominal tips of female filbert-worm moths,Melissopus latiferreanus (Walsingham). The identifications were based on electroantennogram (EAG) analysis, gas chromatography, mass spectrometry, ozonolysis, and synthesis. TheE,Z isomer produced the stronger EAG response. In the field tests of various ratios ofE,EE,Z, the ratio found in the extract captured the most males. The pureE,E isomer initially was not attractive by itself (<0.1%E,Z) but became attractive after a few days, presumably because of isomerization. TheE, Z isomer (<0.1%E,E) was attractive initially, but this compound might have isomerized faster than theE,E isomer. A study of the isomerization showed that regardless of the initial mixture of 8,10-dodecadien-1-ol acetate isomers, almost complete equilibration existed after one month. The equilibrium mixture consisted of 9%Z8,E10, 65%E8,E10, 23%E8,Z10, and 3%Z8,Z10. Concentrations in rubber septa (14 ratio ofE,E toE,Z) of 0.03–3.0 mg/septum produced equivalent trap catches.This paper reports the results of research only. Mention of a commercial product in this paper does not constitute a recommendation by the U.S. Department of Agriculture.     

Biosynthesis,production site,and emission rates of aggregation-attachment pheromone in males of twoAmblyomma ticks

The aggregation-attachment pheromone componentso-nitrophenol (ONP) and methyl salicylate (MS) in maleAmblyomma variegatum ticks appeared after three days of feeding on the host and reached high values after about six days. Variable quantities of 1.3–7.3 g ONP and about 0.6 g MS were present within ticks. ONP and MS were released at the high rates of 300–1800 ng/hr and 20–600 ng/hr per male tick, respectively. After a temporary decrease, males continued to emit at high rates after nearby attachment of females. InA. hebraeum, ONP showed a similar pattern, but with a delay of about a day. A male, which had fed during 14 days, contained about 2 g and released 225–280 ng/hr. Emission in forcibly detached males of both species dropped rapidly to low levels of less than 10 ng/hr per tick. Host skin and tick feces in the vicinity of feeding males were pheromoneimpregnated. The very high emission rates are consistent with the observations that the pheromone is an important component of the host-location mechanism of conspecifics. ONP and MS are produced in the dermal glands type 2 associated with the ventrolateral cuticle.     

Neral and geranial: Components of the sex pheromone of the parasitic wasp,Itoplectis conquisitor

A laboratory investigation of theItoplectis conquisitor sex pheromone was initiated to elucidate the structure(s) of the active component(s) of the system. Functional group tests performed on crude virgin female extract classified the pheromone as unsaturated aldehyde(s) and/or ketone(s). Isolation of active fractions by gas-liquid chromatography (GLC) suggested the existence of a multicomponent pheromone system. Analysis by gas chromatography-mass spectrometry indicated the presence of saturated and unsaturated aldehydes including neral and geranial. When mixtures of neral and geranial were bioassayed independently and in combination with other active GLC fractions, they elicited male sexual activity of intensity comparable to that released by the GLC fraction (DEGS E) from which they were isolated. The authors conclude that neral and/or geranial are components of the sex pheromone system of this species.     

A high-efficiency collection device for quantifying sex pheromone volatilized from female glands and synthetic sources

A high-efficiency collection device for sex pheromones volatized from forcibly extruded female glands is described. Filtered nitrogen gas is the carrier and glass wool the adsorbent. Small quantities of distilled carbon disulfide are used to rinse the glass wool. Recovery efficiency of synthetic compounds was usually 90–100%, and a mean of 2.4 ± 0.65 SD ng/min of (Z)-7-dodecenyl acetate was recovered in emissions from individualTrichoplusia ni (Hubner) glands.     

Identification of the major components in the secretion from the rectal pheromone glands of the queensland fruit fliesDacus tryoni andDacus neohumeralis (Diptera: Tephritidae)

The secretion from the rectal pheromone glands of maleDacus tryoni andDacus neohumeralis is largely a mixture of six aliphatic amides. In order of decreasing quantity these areN-3-methylbutylpropanamide,N-3-methylbutylacetamide,N-(3-methylbutyl-2-methylpropanamide,N-2-methylbutylpropanamide,N-2-methylbutylacetamide, andN-(2-methylbutyl)-2-methylpropanamide. The proportions of the various amides in the two species are similar.     

Population-density-dependent mating frequency amongPlodia interpunctella (Lepidoptera: Phycitidae) in the presence of synthetic sex pheromone with behavioral observations

Mating frequency amongPlodia interpunctella (Hübner) held in enclosed environments was reduced in the presence of the synthetic sex pheromone, (Z,E)-9,12-tetradecadien-l-ol acetate. The effectiveness of any dose of pheromone was markedly increased as population densities were decreased from 10 to 0.1 pairs/m² of wall and ceiling surface. Mating behaviors of the insect are described.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of the product by the U.S. Department of Agriculture.Florida employed under a cooperative agreement with the USDA.     

A chiral sex pheromone system in the pea midge, Contarinia pisi

The sex pheromone of the pea midge consists of 2-acetoxytridecane, (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane. The responses of male pea midges to the corresponding stereoisomers of (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane were tested in field trapping experiments and by electroantennographic recordings. When added at 20% of the pheromone component to the sex pheromone blend, the (2S,11R)- and (2R,11S)-stereoisomers of (2S,11S)-diacetoxytridecane, were shown to have a strong inhibitory effect on male attraction in the field. At the same dose, (2R,11R)-diacetoxytridecane, (2R,12R)-diacetoxytridecane, and meso-2,12-diacetoxytridecane, did not have a significant effect on male behavior. It was also shown that substitution of either (2S,11S)-diacetoxytridecane or (2S,12S)-diacetoxytridecane with the related stereoisomers reduced trap catches to the level of blank traps. The electroantennographic recordings showed similar dose–response curves for the pheromone components and the stereoisomers shown to have an inhibitory effect. It seems likely that male antennae have receptors for both pheromone components and for inhibitory stereoisomers. Scanning electron microscopy and transmission electron microscopy of the antennae revealed three types of sensilla involved in chemoreception: sensilla circumfila, sensilla trichodea, and sensilla coeloconica. The sensilla circumfila and trichodea are both innervated by two sensory cells, whereas the sensilla coeloconica are innervated by four to five cells.