Influence of mustelid scent-gland compounds on suppression of feeding by snowshoe hares (Lepus americanus)

This study investigated the influence of mustelid anal-gland compounds in suppressing feeding by snowshoe hares on coniferous tree seedlings. Pen and field bioassays indicated that 3-propyl-1,2-dithiolane from the stoat (Mustela erminea), and secondarily, 2,2-dimethylthietane from the mink (M. vison) had a very negative effect on feeding behavior of hares. The major component of stoat anal gland secretions, 2-propylthietane, and the related compounds, thietane and 2-methylthietane, were not effective. 3,3-Dimethyl-1,2-dithiolane from the least weasel (M. nivalis) and ferret (M. putorius) and di-n-propyldisulfide (acyclic analog of 3-propyl-1,2-dithiolane) similarly did not affect hare feeding. 3-Propyl-1,2-dithiolane and 2,2-dimethylthietane (also found inM. erminea) may act as interspecific chemical signals which induce a fear or avoidance response in hares. Such compounds have outstanding potential as area repellents to reduce crop and livestock depredations. Our study reports one of the first practical utilizations of mammalian semiochemicals in crop protection and wildlife management.     

Volatile compounds from interdigital gland of male white-tailed deer (Odocoileus virginianus)

Interdigital secretions were collected from eight male white-tailed deer of various ages. Analysis of volatiles was performed by gas chromatography-mass spectrometry with a modified headspace technique. Forty-six volatile compounds were found including alkanes, arenes, aldehydes, ketones, aliphatic acids, esters, pyrroles, furans, and sulfur compounds. Eleven occurred in higher concentrations (P0.10) in dominant (3.5-year-old) than in subordinate (1.5-year-old) animals. Dominant males typically have higher serum testosterone levels, and fatty acids and esters fluctuate with sebum production, which is under hormonal control. Therefore, these compounds may reflect testosterone levels and act as chemical signals indicating the presence of a dominant male. Interdigital volatiles also may act as generalized scent trail markers.     

Effects of monoterpene odors on food selection by red deer calves (Cervus elaphus)

The response of red deer calves (Cervus elaphus) to the odors of Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus conforta) needles and five monoterpene constituents of their essential oils was measured by simple two-choice feeding trials. All odors were significantly rejected (P < 0.05) except Sitka spruce and lodgepole pine by females and Sitka spruce and alpha-terpineol by males. Females had a stronger dislike of all odors except lodgepole pine than males. Rejection of monoterpene odors weakened slightly with time. A strong logarithmic relationship between the strength of the rejection response and vapor pressure of the compounds tested suggested that the odors were rejected on the basis of concentration rather than quality.Research supported by the Natural Environment Research Council and the Forestry Commission.     

A comparison of the effectiveness of predator odor and plant antifeedant in deterring small mammal feeding damage on lodgepole pine seedlings

The influence of mustelid (weasel) anal-gland compounds (semiochemicals) and a plant antifeedant (pinosylvin) on snowshoe hare (Lepus americanus) and meadow vole (Microtus pennsylvanicus) feeding damage was investigated. This study has shown conclusively that when applied to spring-planted lodgepole pine seedlings, pinosylvin is effective in significantly reducing feeding damage. Seedlings treated with pinosylvin suffered damage levels of 2.3% and 21.2% compared to the controls with damage levels of 24.5% and 41.0%. Weasel scent was found to reduce damage levels, but the reduction was not statistically significant in all blocks.     

Pheromone specificity inEriocrania semipurpurella (Stephens) andE. sangii (Wood) (Lepidoptera: Eriocraniidae) based on chirality of semiochemicals

The fifth abdominal segment of femaleEriocrania semipurpurella (Stephens) andE. sangii (Wood) contains a pair of exocrine glands. Hexane extracts of this segment were prepared from both species and analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). For both species, the EAD active peaks were identified as nonan-2-one, (Z)-6-nonen-2-one, and (Z)-6-nonen-2-ol by means of mass spectrometry and comparison of retention indices with those of synthetic standards. Enantiomeric separation of chiral alcohols from the female extracts was achieved by gas chromatographic analysis on a cyclodextrin column. InE. semipurpurella, a mixture of (2S,6Z)-nonen-2-ol and (2R,6Z)-nonen-2-ol (2: I) was found, whereas inE. sangii (2S,6Z)-nonen-2-ol was the predominant enantiomer and only traces of theR enantiomer were indicated by the antennal response. In field tests, a blend of the three compounds was not attractive to conspecific males. A subtractive assay showed that the alcohol in various enantiomeric mixtures was the only attractive compound, whereas addition of (Z)-6-nonen-2-one to the alcohol completely inhibited the attraction of both species. A trapping experiment including a wide range of ratios between theR andS enantiomers showed that baits containing 95–100% of theS enantiomer were attractive to maleE. sangii, whereas males ofE. semipurpurella were attracted to all tested ratios of the enantiomers. However, the response profiles of maleE. semipurpurella differed between populations from southern Sweden, south Finland, and the Kola Peninsula in Russia. In south Sweden males were maximally attracted to a racemic mixture of the alcohols. At the Kola PeninsulaE. semipurpurella was attracted to baits containing 95–100% of theR enantiomer. In south Finland all tested ratios between 0 and 100%R enantiomer trappedE. semipurpurella, but the trap catches appeared to be bimodally distributed with peaks around 15 and 70%R enantiomer. The trapping results suggest the existence of pheromone races or sibling species among the specimens identified asE. semipurpurella.Dedicated to Prof. H. J. Bestmann on the occasion of his 70th birthday.     

Species discrimination in five species of winter-flying geometrids (Lepidoptera) based on chirality of semiochemicals and flight season

Enantiomer separation of (6Z,9Z)-cis-3,4-epoxynonadecadiene and (3Z,9Z)-cis-6,7-epoxynonadecadiene could be achieved using chiral high-resolution gas chromatography and a cyclodextrin-bond column. (3Z,9Z)-(6R,7S)-Epoxynonadecadiene was identified from ovipositor extracts ofColotois pen-Naria, while inErannis defoliaria the 6S,7R-enantiomer was found. In field trapping tests pure synthetic enantiomers caught only conspecific males of these species. (3Z,6Z,9Z)-Nonadecatriene was found in both species, while the presence of (3Z,6Z,9Z)-heneicosatriene was indicated inC. Pennaria only. A 10103 blend of (3Z,9Z)-(6R,7S)-epoxynonadecadiene, (3Z,6Z,9Z)-heneicosatriene, and (3Z,6Z,9Z)-nonadecatriene was found to be optimal for catchingC. Pennaria, whileE. Defoliaria males were optimally caught by a 11 mixture of (3Z,9Z)-(6S,7R)-epoxynonadecadiene and (3Z,6Z,9Z)-nona-decatriene. (6Z,9Z)-(3S,4R)-Epoxynonadecadiene was identified from ovipositor extracts ofAgriopis (Erannis) aurantiaria. In field tests the pure enantiomer proved to be a highly specific sex attractant for both the late autumn/early winter flyingA. Aurantiaria and the late winter/early spring flyingA. Leucophearia. Males ofAgriopis marginaria, which fly in late winter/early spring, were attracted to (3Z,9Z)-(6S,7R)-epoxynonadecadiene. The addition of (3Z,6Z,9Z)-nonadecatriene to theS,R-enantiomer increased captures. Optimal catches were recorded with a 103 epoxide-hydrocarbon blend. Enantiomer specificity in all species was confirmed in EAG measurements.     

Comparison of release devices for stoat (Mustela ermined) semiochemicals used as montane vole (Microtus montanus) repellents

Fenced enclosures were used to simulate peak populations of montane voles (Microtus montanus) for field bioassays of a stoat (Mustela erminea) scent mixture in various controlled-release devices. A 1 1 mixture of 2-propylthietane and 3-propyl-1,2-dithiolane was dispensed in capillary tubes, clay pellets (activated alumina), rubber septa, and plastic rope. Release devices were placed near, or attached to, young apple trees planted in blocks in two enclosures containing high populations of voles. The stoat scent mixture in rubber septa and plastic rope significantly reduced vole attack of trees compared with a control, pellets, and capillary tubes. In terms of complete girdling (tree mortality), this odor in septa and rope also significantly reduced feeding compared with the control, and the rubber septa formulation was more effective than either the pellets or capillary tubes. Fenced populations of voles may be used effectively to conduct field bioassays during low years in vole cycles. Variations of release devices (with this stoat scent mixture) based on rubber septa for broadcast application to depress vole population density and survival, and plastic rope attached to individual trees to generate an avoidance response, should be used for forest and agricultural crop protection.     

Release of ethylene from pruned olive logs: Influence on attack by bark beetles (Coleoptera,Scolytidae)

In recently pruned olive logs, an increase in ethylene release has been observed between 48 and 72 hr after pruning. The values reached, as well as the duration of ethylene release, varied greatly from one log to another. PioneerPhloeotribus scarabaeoides females have shown a preference for logs in which ethylene emission was higher. In logs treated with ethrel, a significant increase in ethylene emission was observed, together with a greater period of release. Therefore, the use of logs treated with ethrel could be of great importance in the control of this pest of olive trees.     

The annual cycle of Flehmen in black-tailed deer (Odocoileus hemionus columbianus)

Flehmen is a stereotyped response of ungulates and other mammals to urine. In black-tailed deer, Flehmen occurs typically in males (rarely in females), and its frequency shows an annual cycle. Flehmen in response to female urine was most frequent in November, and to male urine in January. The response minimum to both types of urine occurred in May. Fifty-five to 100% of initial responses to female urine resulted in Flehmen. The deer responded more often to female urine, and the difference between the responses to female and male urine increased from May to November. A male's own urine released Flehmen more often than did urine of other males. The response intensity varied with the spatial orientation of the male to the urinating female, and responses were usually limited to distances of 15 m or less.     

Electroantennogram responses of the southern pine beetle parasitoidDinotiscus dendroctoni (Ashmead) (Hymenoptera: Pteromalidae) to potential semiochemicals

In two studies using the electroantennogram (EAG) technique, bark beetle- and tree-produced semiochemicals were presented toDinotiscus dendroctoni (Ashmead), a larval parasitoid ofDendroctonus frontalis Zimm. In the first study, 20 test compounds and a standard mixture of oxygenated monoterpenes were presented individually at one concentration to the parasitoids. In the second study, the nine compounds that elicited the greatest EAGs in study 1 were then tested as serial dilutions of 10 to 0.0001g/ul. The individual compounds did not elicit responses greater than the standard mixture of oxygenated monoterpenes. Males and females exhibited similar dose responses, although females showed lower thresholds of response than males to frontalin, terpinen-4-ol,E,Z-chalcogran, andexo-brevicomin. In both studies, pino-/isopinocamphone elicited the greatest responses at high concentrations. Tests of different ratios of the camphone mixture indicated that pinocamphone elicited the greatest response. Most of the test compounds elicited similar responses which suggests that several of the compounds may be used together byD. dendroctoni in habitat and/or host community location.     

Variations in mouse (Mus musculus) urinary volatiles during different periods of pregnancy and lactation

Mouse urine samples from different pregnancy and lactation periods were examined by capillary gas chromatography to assess variations in the volatile signals that may affect the endocrine function of other females. Statistically significant changes in the excretion of certain urinary volatiles were observed; from 26 readily quantifiable constituents, 14 appear to be under the endocrine control. These selected components, positively identified through mass spectrometry and retention data, and the synthetic standards are ketones, unsaturated alcohols, esters, and cyclic vinyl ethers.     

Beneficial arthropod behavior mediated by airborne semiochemicals. II. Olfactometric studies of host location by the parasitoidMicroplitis croceipes (Cresson) (Hymenoptera: Braconidae)

The response ofMicroplitis croceipes (Cresson) to odors from a plant-host complex was investigated using a four-choice olfactometer. Female, but not male, parasitoids responded in a dose-dependent fashion to volatiles from the plant-host complex and oviposition experience enhanced this response. Female age had no apparent effect on the response. Both artificially damaged leaves and frass elicited positive responses but of lower magnitude than those elicited by the plant-host complex. Volatiles collected from the plant-host complex placed on filter paper also elicited positive responses by female parasitoids.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Volatile compounds from crabapple (Malus spp.) cultivars differing in susceptibility to the Japanese beetle (Popillia japonica Newman)

The volatile compounds emitted by leaves of four crabapple cultivars susceptible to damage by Japanese beetles and four relatively resistant cultivars were examined. Twelve compounds, mostly terpene hydrocarbons, were identified from intact leaves. The terpenes (E)--ocimene, caryophylene, germacrene D and (E,E)--farnesene occurred in significantly higher levels in susceptible cultivars, whereas resistant cultivars produced greater amounts of (E)-4,8-dimethyl 1,3,7-nonatriene and linalool. The relative attractiveness of the cultivars as determined in a pitfall bioassay, however, was not related to their susceptibility to the Japanese beetle as previously determined by defoliation sustained in the field. The attractiveness of individual cultivars was found to be positiviely correlated with linalool as a percent of the total volatile blend emitted by leaves. This study and previous work suggest that variation in susceptibility of crabapple cultivars to defoliation by Japanese beetles is not due to the attractiveness of the individual cultivars but rather to nonvolatile components of susceptibility and/or resistance. A scenario for host location by the Japanese beetle is presented.     

Musk deer (Moschus moschiferus): Reinvestigation of main lipid components from preputial gland secretion

The qualitative and quantitative composition of the principal lipid constituents of Siberian musk deer (Moschus moschiferus) preputial gland secretion, main odor carriers and potential precursors of odorous substances, was investigated by means of high-performance liquid chromatography. Free fatty acids and phenols (10%), waxes (38%), and steroids (38%) were found to be the main groups of the secretion lipids. Cholestanol (I), cholesterol (II), androsterone (III), ⁴-3-hydroxy-17-ketoandrostene (IV), 5, 3-hydroxy-17-ketoandrostane (V), 5, 3, 17-dihydroxyandrostane (VI), 5, 3, 17-dihydroxyandrostane (VII), and 5, 3, 17-dihydroxyandrostane (VIII) were isolated from the steroid fraction and their structures confirmed by IR, PMR, and mass spectra. 3-Methylpentadecanone (muscone) was not identified among the secretion lipids. Preputial gland secretion stimulated sex behavior of musk deer females.     

Quantification of cantharidin in canthariphilous ceratopogonidae (Diptera), anthomyiidae (Diptera) and cantharidin-producing oedemeridae (Coleoptera)

Cantharidin contents were determined in several canthariphilous insects by means of quantitative gas chromatography. Usually the ceratopogonidsAtrichopogon oedemerarum andA. trifasciatus caught in the field contained low concentrations of cantharidin, with concentrations in males, in most cases, being lower than in females. When fed in the laboratory with synthetic cantharidin, these species concentrated cantharidin by as much as 100-fold (males) and 40-fold (females). Accumulation in the different body tagmata (head, thorax, abdomen) of these species is similar. Maximal concentrations of cantharidin in tissues ofAtrichopogon are comparable to those known from oedemerid and meloid beetles. InA. trifasciatus about 90% of total cantharidin content is bound in tissues. Investigations using the canthariphilous anthomyiid flyAnthomyia pluvialis and three cantharidin-producing oedemerid species revealed the same pattern of distribution in different body tagmata as inAtrichopogon.     

Putative Chemical Signals from White-Tailed Deer (Odocoileus virginianus): Social and Seasonal Effects on Urinary Volatile Excretion in Males

Urine samples collected from dominant and subordinate male white-tailed deer during the breeding and nonbreeding season were analyzed by combined gas chromatography–mass spectrometry (GC-MS). Fifty-five volatiles were found in measurable quantities. Ketones were most numerous, followed by alcohols and alkanes. Nine compounds were common to both dominants and subordinates during the breeding season. Of these nine, three were present in higher concentrations in dominants, and six were higher in subordinates. During the breeding season, nine compounds were found exclusively in the urine of dominants, whereas 19 compounds were found exclusively in the urine of subordinates. Concentrations of several compounds were dependent on the time of year (breeding vs. nonbreeding season). Differences in compound presence and concentration may produce a rank-specific odor, although we suggest that differing concentrations of these suites of compounds may be more important for the identification of social status than the presence of individual compounds. Since mature male white-tailed deer urinate on their tarsal glands frequently during the breeding season, this behavior may allow a deer to simultaneously scent-mark its environment and carry intraspecific cues indicative of social status.     

Patterns of scent-mounding in a population of beaver (Castor canadensis)

The frequency and pattern of distribution of scent-mound construction were studied in a population of beaver in southeast Ohio from 1975 through 1977. The study addressed the questions of whether or not the frequency of scent-mound construction varied with season, site, year, and degree of contact with other family groups, and whether the pattern of scent-mounding activity was parsimonious with the idea of territorial marking. The number of scent-mounds constructed was determined weekly for each site throughout the ice-free season. Scent-mounding activity was highest in spring and declined and remained low during summer and fall. Significant differences were found amoung sites and over years. Contact with other resident family groups altered both frequency and pattern of scent-mound construction. Scent-mounds did not conform to a scent-fence model. The most parsimonious interpretation of function of odor cues deposited on scent-mounds is the effect on the motivational state of residents and nonresidents, increasing the confidence and reducing anxiety in residents smelling their own scent-mound and decreasing the confidence and increasing the readiness to flee in trespassers encountering a strange scent-mound.     

Allelopathic potentials of alfalfa (Medicago sativa) saponins: Their relation to antifungal and hemolytic activities

A wheat seedling bioassay was used to indicate the relationship between the chemical structure of alfalfa saponins and their allelopathic activity. None of the tested saponins significantly influenced wheat germination. Seedling growth bioassays indicated significant differences among the activities of individual glycosides. The most active were medicagenic acid, its glycosides substituted at the C-3 position with glucose, and hederagenin monoglycoside. Medicagenic acid glycosides, substituted at the C-3 position with glucuronic acid, and zahnic acid tridesmoside were less active. No significant correlation was found among the allelopathic, hemolytic, and antifungal activities of the individual glycosides.     

Characterization of and male adaptation to pheromone of femaleTrichostrongylus colubriformis (Nematoda)

Males of the ruminant nematodeTrichostrongylus colubriformis were significantly attracted to an incubate from their females during in vitro assay. Exposure of males to sera from uninfected and infected animals or selected neurotransmitters had no effect on their subsequent responsiveness to the female's pheromone. In contrast, exposure to 1500 female-hours of pheromone decreased male responsiveness after moderate rinsing prior to bioassay. Rinsing of the males with larger volumes of Tyrode's solution prior to in vitro assay increased their subsequent response to the female's pheromone. High-performance liquid chromatography yielded a presumptive pheromone peak with a fivefold increase in biological activity. This peak was soluble in alcohols and tetrahydrofuran, based on elution from reverse-phase Sep-Pak cartridges. Stability of the peak was increased by EDTA or ascorbic acid (10 mM). Storage for six weeks in ascorbic acid at 4 °C allowed recovery of 47.3% of the original material.Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable.     

Flight Tunnel Responses of Female Grape Berry Moth (<Emphasis Type="Italic">Paralobesia viteana</Emphasis>) to Host Plants

Semiochemicals play important roles in mate and host recognition of herbivorous insects, such as moths, and flight tunnels have been an effective tool in the identification of these bioactive compounds. However, more work has been carried out on pheromones than on host plant cues, and few examples exist where flight tunnel evaluations of host cues have resulted in a lure that is attractive under field conditions. Our goal was to determine whether the flight tunnel could be used to evaluate the response of a specialist moth, grape berry moth (GBM), to its host plant (grapevines), by incorporating ecological and physiological aspects of GBM biology. We found grape shoot tips and mature leaves were more attractive to female GBM than unripe and ripe berries or flowers. Under optimized flight tunnel conditions, approximately 80% of tested females flew upwind and closely approached or landed on the most preferred target. Mating status, wind speed, the time of day, and the presence/absence of patterns that resemble grape tissues on the top of the flight tunnel all significantly affected the responses of female GBM. Consideration of these factors in flight tunnel assays will aid in the development of a synthetic lure that can be used to monitor female moths in the field.