Demonstration of an odorous intramale primer effect in short-tailed vole,Microtus agrestis L.

Anal (proctodeal) glands of maleMicrotus agrestis housed in social isolation undergo severe atrophy. Their weight and volume is significantly lower than those of the stock control males. The atrophied glands can be revived by subjecting deprived voles to various social odors. Atrophied glands of isolated males do not respond to the odors of male and female urine, voided feces of females, and unvoided feces of males. Atrophied anal glands of males exposed to voided male feces (which have passed the orifice of the anal gland) and soiled bedding from adult males show strong recrudescence. The mean weight and volume of the glands and plasma testosterone level are significantly higher than of males maintained in complete social isolation, although they are significantly less than those of stock control males. Atrophied glands of socially deprived males strongly respond to the odor of ethereal extract of gland secretion. In males exposed daily to anal gland secretion extract, the weight and volume of the gland and plasma testosterone level increase and are not significantly different from those of stock controls. They enjoy higher plasma testosterone levels and consequently larger and more active anal glands than complete isolates.     

Odor of the muskox

The behavior of captive male muskoxen was observed closely during their characteristic superiority display, the anatomy of the preputial region was studied in two adults and three calves, and preputial washings and preorbital gland secretion were subjected to gas chromatography and mass spectroscopy. During the superiority display, the prepuce was everted to form a pendulous tube tipped with a fringe of matted hair. Owing to the movement of the animal, the urine that dribbled from the preputial opening was liberally applied to the long guard hairs of the belly. The superiority display was almost exclusively confined to dominant males and apparently accounted for their odor. In the quiescent state, the hair seen around the preputial opening was drawn inside and formed an 8 cm-wide band on the lining of the prepuce. The preputial washings contained large amounts of benzoic acid andp-cresol. The infraorbital gland secretion contained cholesterol, benzaldehyde, and a homologous series of saturated -lactones ranging from 8 to 12 carbons. The latter compounds and the natural secretion smell similar to the human nose.     

Reproduction and Urine Marking in Laboratory Groups of Female Common Voles Microtus arvalis

In laboratory groups of common voles, Microtus arvalis, consisting of one mother, two of her daughters and one male, mainly the mother reproduced. The three females spent most of the time in close body contact. By using a modified method of coloring the urine of the three females by nonmetabolizable, nontoxic dyes, we found that mothers display a higher urine marking intensity than their daughters, and urine marks from the mother were distributed more frequently than those from the daughters. The results suggest that both pheromonal and behavioral mechanisms are involved in the regulation of reproduction in matriarchal groups of common voles.     

Morphology and chemistry of brown rat,Rattus norvegicus,preputial and clitoral glands

In contrast to previous results from laboratory rats, when sexual dimorphism occurred, clitoral glands from wild female rats were heavier and accounted for a greater proportion of body mass than preputial glands from wild males. Gland length and weight increased with body weight, but gland weight as a proportion of body weight did not. Preputial and clitoral glands showed seasonal differences in size: at one site glands were smaller in December than in April. Maturity, estrus, and pregnancy had no significant effect on clitoral gland size, but immature males had proportionally smaller preputial glands than mature males, and the absolute gland weight, but not gland weight as a proportion of body weight, increased with testes weight. There were no differences between the sexes in lipid production, which increased with preputial or clitoral gland weight. An homologous series of aliphatic acids and their methyl and ethyl esters, plus squalene, cholesterol and lanosterol, was revealed by GC-MS study of the trimethyl silyl derivatized lipid extract. Males and females could be distinguished by principal component analysis of chromatogram peaks.     

A Two-Component Female-Produced Pheromone of the Spider Pholcus beijingensis

Chemical signaling plays an important role in spider sexual communication, yet the chemistry of spider sex pheromones remains poorly understood. Unlike insects and mammals, the identification of spider pheromones has seldom been attempted, and no multicomponent pheromones have been found. Empty webs of sexually receptive females of Pholcus beijingensis were more attractive to male conspecifics as compared to webs of sexually unreceptive females or to mature males. Coincidently, chemical analysis revealed that (E,E)-farnesyl acetate, diisobutyl phthalate, and hexadecyl acetate of the spider webs exhibited higher relative abundances in sexually receptive females than in sexually unreceptive females or males, indicative of possible pheromone components. Two-choice behavioral assays verified that the blend of (E,E)-farnesyl acetate and hexadecyl acetate (w/w: 2:1) attracted males at a dosage equivalent to the amounts of these compounds in one spider web, whereas neither compound alone aroused males. In addition, diisobutyl phthalate (a likely contaminant from contact with plastic) alone or in combination with either of the acetates did not evoke the males’ attraction. The behavioral data suggest that (E,E)-farnesyl acetate and hexadecyl acetate comprise a two-component female-produced sex pheromone in P. beijingensis, the first multicomponent pheromone found in spiders.     

Olfactory Responses of Neotropical Short-Tailed Singing Mice, <Emphasis Type="Italic">Scotinomys teguina</Emphasis>, to Odors of the Mid-Ventral Sebaceous Gland: Discrimination of Conspecifics,Gender, and Female Reproductive Condition

We examined the olfactory communication of the Neotropical short-tailed singing mouse, Scotinomys teguina, by investigating whether S. teguina responded to odors produced by the mid-ventral sebaceous gland of conspecifics. Females spent significantly more time investigating male odor than an odorless stimulus or a female odor. Males spent significantly more time investigating female odor than an odorless stimulus, but not that of a male odor. This latter result does not seem to be explained by differences in age or sexual experience of test subjects, but may be influenced by reproductive condition of the female odor donor. Male S. teguina spent significantly more time (1) investigating and (2) in total proximity to odors of estrous than non-estrous females. Males spent more time (1) investigating and (2) in total proximity to odors of males than non-estrous females. Finally, given the choice between odor of males vs proestrous females, males showed no preference. Thus, the mid-ventral gland in S. teguina seems to convey information about conspecifics, sex, and female reproductive condition. Male odor, compared with proestrous female odor, is equally interesting to males, suggesting that the gland also plays an important role in male–male communication. Sexual dimorphism in the size of the gland and in the amount of secretion produced by the gland may be related to either male–male competition or female choice.     

Chemical signals involved in spacing behavior of breeding female bank voles (Clethrionomys glareolus Schreber 1780, Microtidae,Rodentia)

In order to study the mechanism involved in the seasonal territoriality of breeding bank voles, the social behavior and scent marking of paired females were observed throughout a reproductive cycle. Initially unfamiliar females were kept in large laboratory pens provided with individual burrows. After a brief period of hostility, females behaved in a friendly manner towards each other, sharing the same nest even in the presence of a male and until the middle of pregnancy. They scarcely marked with urine. Continuous olfactory assessment appeared to play an important role in maintaining the friendly interactions. In late pregnant and lactating females, on the contrary, the odor of a familiar female triggered aggressiveness and scent marking with urine and probably with flank glands. These reactions may be interpreted as spacing behavior. Moreover, the interaction between females may inhibit reproduction in one of them. These results are discussed in relation with the available ecological data.     

Identification of Volatiles from the Secretions and Excretions of African Wild Dogs (Lycaon pictus)

Gas chromatography/mass spectrometry was used to identify 103 organic compounds from urine, feces, anal glands, and preputial glands of free-ranging African wild dogs, Lycaon pictus. Aliphatic acids were the dominant class of compound in all materials. In addition to aliphatic acids, urine contained dimethyl sulfone, 1,3-propanediol, benzoic acid, 1-methyl-2,4-imidazolidinedione, and squalene as major components: feces contained indole and cholesterol; and both contained 2-piperidone, phenol, 4-methyl phenol, benzeneacetic acid, and benzenepropanoic acid and other compounds. Anal gland secretion was particularly rich in cholesterol and fatty acids, and preputial gland secretion rich in squalene. A large majority of the identified compounds have been reported from other mammals, including species sympatric with African wild dogs. Eleven of the African wild dog components have not been reported previously from mammals and have not been found in sympatric species; one component, 1-methylimidazole-5-carboxaldehyde has not been reported previously as a natural product. In the chemical profiles of their urine, feces, and anal gland secretion African wild dogs differ markedly from other canids.     

Chemical Defense in the Stink Bug Cosmopepla bimaculata

Adult Cosmopepla bimaculata discharge a volatile secretion from paired ventral metathoracic glands (MTG) when disturbed. Collected volatiles were similar in both sexes and consisted of n-tridecane (67%), (E)-2-decenal (12%), (E)-2-decenyl acetate (12%), (E)-2-hexenal (3%), hexyl acetate (2%), n-dodecane (2%), a tridecene isomer (1%), and n-undecane, n-tetradecane, and n-pentadecane (all <1%). In addition, undisturbed males produced a novel insect compound, (E)-8-heneicosene, whose function is unknown. The MTG secretion emerges as an enlarging droplet, which is held in place by a cuticular projection and a pleural scent area consisting of specialized rough cuticle surrounding the gland opening. Insects can selectively discharge from either the right or left gland or both glands simultaneously, can control the amount of fluid ejected, and can resorb the ejected secretion droplet back into the gland reservoir. In feeding trials, killdeer (Charadrius vociferous), starlings (Sturnus vulgaris), robins (Turdus migratorius), and anole lizards (Anolis carolinensis) rejected or demonstrated aversion to feeding on the bugs. Furthermore, bugs that lacked the secretion were more susceptible to predation than bugs with secretion, suggesting that the secretion functions in defense against predators.     

Pheromone differences between sibling taxaDiachrysia chrysitis (linnaeus, 1758) andD. tutti (Kostrowicki, 1961) (Lepidoptera: Noctuidae)

The noctuid sibling taxaDiachrysia chrysitis s. str. andD. tutti, of yet uncertain taxonomic status, have previously been shown to possess differences in morphology and to be attracted to different mixtures of the two presumed pheromone components (Z)-5-decenyl acetate and (Z)-7-decenyl acetate. TypicalD. tutti males (clearly broken forewing marking) are known to respond to a 2: 100 mixture of the two isomers, whereasD. chrysitis males (unbroken marking) are attracted to a 100: 10 mixture. We investigated female pheromone production and male electroantennographic (EAG) response inDiachrysia families raised in the laboratory from field-collected gravid females. Extracts of individual females from typicalD. tutti andD. chrysitis families were subjected to gas chromatography with simultaneous flame ionization and electroantennographic detection. All females produced mixtures of Z5- and Z7-10:OAc, but femaleD. chrysitis produced predominantly Z5-10:OAc and the antennae of their brothers responded more strongly to the Z5 peak than to the Z7-10:OAc peak, whereas the opposite was true forD. tutti families. The pheromone components were shown to be biosynthesized from hexadecanoic and tetradecanoic acid, respectively by Z11-desaturation followed by chain shortening, reduction, and acetylation. The EAG responses of males trapped with the typicalD. tutti andD. chrysitis blends, as well as with an intermediate blend, were investigated. Males trapped with theD. tutti mixture almost exclusively had a clearly broken wing marking and showed strongest EAG response to Z7-10:OAc. The intermediate blend and theD. chrysitis mixture gave more mixed catches, but with a prevalence of males with an unbroken (or almost unbroken) wing marking and with a higher mean response to Z5-10:OAc. Some males with typicalD. tutti EAG responses were attracted in the field to theD. chrysitis pheromone. In the flight tunnel someD. chrysitis males were attracted also to theD. tutti mixture. This indicates that cross attraction may take place between the two taxa under natural conditions.     

Urine-marking and the response to fresh vs. aged urine in wild and domestic Norway rats

Wild and domestic Norway rats (Rattus norvegiens) were compared in regard to their tendency to investigate the odors of fresh vs. aged rat urine and to urine-mark metal rods and wooden blocks placed in their home cages. Castration, sex, and domestication had no effect on the tendency to investigate sources of fresh vs. aged urine odors, but the odor of aged urine was more attractive than fresh urine for most subjects tested. The frequency of urine marking was lower for females and castrated males but generally did not differ between wild and domestic stocks. The implications of these findings for the ecology of the species are discussed.     

Increased scent marking in male Mongolian gerbils by urinary polypeptides of female conspecifics

Male Mongolian gerbils scent mark during a standardized openfield test on an individually different but more-or-less constant level in the absence of females. The presence of females in the same room but without direct contact to the males increases the marking frequencies of the males to an individually different higher level. A similar increase in marking frequency is obtained by application of female urine directly to the nostrils of the males, but not by male gerbil urine or female laboratory mouse urine. This indicates that substances present in female gerbil urine are responsible for the increase in male marking behavior. Using this bioassay, various fractions of female urine were tested for their influence on marking behavior. Our results to date show that the component increasing male scent-marking behavior is hydrophilic and nonvolatile and is contained in the nondialyzable, high-molecular-weight polypeptide fraction of female gerbil urine.     

A comparison of the effectiveness of the odors of rabbits,Oryctolagus cuniculus,in enhancing territorial confidence

In 14 series, each of 100 tests, involving 350 individual animals it has been shown that odors derived from the anal, inguinal and chin glands and urine strengthen to different degrees the confidence of European wild rabbits,Oryctolagus cuniculus. In the tests, two rabbits were put together on otherwise neutral ground previously treated with the odor from one of the contestants. The confidence of the rabbits was determined from an assessment of the record of the time to first physical contact, the frequencies of approaches and aggression, the number of attempts to escape, and also by making a subjective assessment of their general deportment. The results confirm earlier conclusions on the territorial functions of the anal and chin glands, the role of inguinal glands in individual identification, and the behavioral role of urine. On otherwise neutral ground the rabbits' own chin secretions were found to be the most effective in stimulating the confidence of males and that of their female partners. The odor of the anal gland secretions of males stimulated a similar but slightly weaker effect. The anal gland secretions of females influenced their own confidence but not that of males. Urine seemed to play a more important role in affecting the confidence of females than of males. Inguinal gland secretions had least effect. Odor from this source generally did not influence the confidence of the experimental animals; secretion from the inguinal glands of males had a slight effect on the behavior of their female partners.     

Scent Marking in Male Premating Behavior of Bombus confusus

Premating behavior in the species Bombus confusus Schenck, 1859 was studied. The marking habits of bumblebee males were revealed and the use of their labial gland secretion in scent marks was proved chemically. Identical compounds were present both in the labial gland secretion and on male-marked objects. This chemical proof is reported for the first time from natural conditions of a B. confusus locality. Males' flight activities, site tenacity, and male–male interactions are described in detail. Contrary to literature reports, male B. confusus behavior does not basically differ from that of already known perching bumblebee species.     

Alert odor from skin gland in deer

Black-tailed deer (Odocoileus hemionus columbianus) discharge an odor from the metatarsal (MT) gland, located on the hindleg, when disturbed or alarmed. Freely moving, captive deer were exposed to the MT odor by means of a remote-release apparatus. Responses by males and females to MT odor from both sexes were recorded with a coding system and a video camera. When the odor was present, females became more alert and left the site more often than in the presence of control odors, odorless air, or deer urine. It is concluded that the MT secretion provides an alert signal, placing the odor into the class of alarm pheromones. There is no evidence that the closely related white-tailed deer,O. virginianus, possesses this alert (or alarm) odor system to the same degree.     

Alarm pheromone of pentatomid bug,Erthesina fullo Thunberg (Hemiptera: Pentatomidae)

In the pentatomid bug,Erthesina fullo Thunberg, the odor of male metathoracic scent gland elicits an alarm response, making the male individuals of the same species alert and disperse; the alarm response of males is more obvious than that of females. Chemical composition of the glandular secretion was identified by gas chromatography and mass spectrometry data in comparison with authentic compounds. No sexual dimorphism exists in the glandular composition in this species. A total of 9 compounds [(E)-2-hexenal, (E)-4-keto-2-hexenal, (E)-2-hexenyl acetate,n-undecane,n-dodecane, (E)-2-decenal,n-tridecane, (E)-2-decenyl acetate, andn-pentadecane] are identified, among whichn-tridecane and (E)-4-keto-2-hexenal comprised nearly 70% of the total secretion in both females and males.     

Aldehydic contact poisons and alarm pheromone of the antCrematogaster scutellaris (Hymenoptera: Myrmicinae)

The Dufour gland ofCrematogaster scutellaris stores a mixture of long-chain primary acetates bearing a cross-conjugated dienone (Scheme 1, la-c). The poison gland contains two highly active enzymes: an acetate esterase and an alcohol oxidase. During venom emission, the constituents of both glands mix and accumulate on the sting, where the formation of the highly electrophilic aldehydes (Scheme 1, 2a-c) from their acetate precursors is initiated. Acetic acid, produced during the reaction, acts as alarm pheromone. The toxicity of the acetates (Scheme 1, la-c) and of the crude secretion has been assessed by topical application onMyrmica rubra. The acetatecontaining secretion from the Dufour gland was less toxic than the enzymatically altered secretion that was rich in aldehydes. The production of acids (Scheme 1, 3a-c) was an artifact resulting from the nonenzymatic oxidation of the unstable aldehydes.     

Olfactory recognition of individuals by male cavies (Cavia aperea)

In one study, using a habituation procedure, male South American cavies,Cavia aperea, distinguished individual differences in odors collected from three sources: perineal gland secretions, urine, and supracaudal gland secretions. In a second study, male cavies spent more noninvestigatory time and rested more on the side of a cage containing the odor of a familiar subordinate male as compared to the cage side containing the odor of a familiar dominant male. Since the odor source was a glass plate which had been left in the home cage of the donor males for three days, the actual odorous cue to which the test males responded is not known. These studies demonstrate that male cavies distinguish odors of individuals, that individual differences in odors are found in at least three different sources, and that cavies use chemical cues to distinguish between known individuals.     

Sex pheromone of lucerne leafroller,Merophyas divulsana (Walker) (Lepidoptera: Tortricidae): Evidence for two distinct populations

When specimens of the lucerne leafroller,Merophyas divulsana, were sampled from an area with a history of crop damage, they were found to have (E)-11-tetradecenyl acetate, hexadecyl acetate, and tetradecyl acetate as principal components of the pheromone gland. A synthetic mixture of these compounds proved to be a successful lure in delta traps. On the other hand, apparently identical moths collected in areas with no history of crop damage were found to have (Z)-11-tetradecenyl acetate as the major component of the sex pheromone gland. The distribution of the two moths provides the basis for a plausible explanation of the regional pest activity reported forM. divulsana.