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All animals harbor beneficial microbes. One way these microbes can benefit their animal hosts is by increasing the diversity and efficacy of communication signals available to the hosts. The fermentation hypothesis for mammalian chemical communication posits that bacteria in the scent glands of mammals generate odorous metabolites used by their hosts for communication and that variation in host chemical signals is a product of underlying variation in the bacterial communities inhabiting the scent glands. An effective test of this hypothesis would require accurate surveys of the bacterial communities in mammals' scent glands and complementary data on the odorant profiles of scent secretions--both of which have been historically lacking. Here we use next-generation sequencing to survey deeply the bacterial communities in the scent glands of wild spotted and striped hyenas. We show that these communities are dominated by fermentative bacteria and that the structures of these communities covary with the volatile fatty acid profiles of scent secretions in both hyena species. The bacterial and volatile fatty acid profiles of secretions differ between spotted and striped hyenas, and both profiles vary with sex and reproductive state among spotted hyenas within a single social group. Our results strongly support the fermentation hypothesis for chemical communication, suggesting that symbiotic bacteria underlie species-specific odors in both spotted and striped hyenas and further underlie sex and reproductive state-specific odors among spotted hyenas. We anticipate that the fermentation hypothesis for chemical communication will prove broadly applicable among scent-marking mammals as others use the technical and analytical approaches used here.

Four species of gonyleptid harvestmen, Acanthogonyleptes pulcher, Gonyleptes saprophilus (Gonyleptinae), Sodreana barbiellini, and Sodreana leprevosti (Sodreaninae), were examined by GC-MS and ¹³H NMR. All of these species release vinyl ketones, and three of them produce the corresponding pyranyl ketones, which are presumed hetero-Diels-Alder (HDA) dimers. The vinyl ketones 5-methyl-1-hexen-3-one, rac-4-methyl-1-hexen-3-one, and (S)-4-methyl-1-hexen-3-one were synthesized. Natural 4-methyl-1-hexen-3-one is present as a single stereoisomer and has the R-configuration. Vinyl ketone dimers (HDA dimers) were also observed in the scent gland exudate and characterized by HRMS, ¹³C NMR, and ¹H NMR chemical shifts of the pyranyl moiety.

Acoustic and, to a lesser degree, visual signals are the predominant means of signaling in frogs. Nevertheless, certain lineages such as the mantelline frogs from Madagascar use the chemical communication channel as well. Males possess femoral glands on the hind legs, which recently have been shown to contain volatile compounds used in communication as pheromones. Many mantelline species occur in sympatry, and so far species recognition is regarded to occur mainly by acoustic signals. The analysis of the gland constituents of Mantidactylus femoralis by GC/MS revealed the presence of volatile macrolides and secondary alcohols. The new natural products mantidactolides A (4) and B (6), as well as several methyl carbinols, were identified, and their structures were confirmed by synthesis. The analysis of individuals from different locations of Madagascar revealed the presence of two groups characterized by specific patterns of compounds. While one group contained the alcohols and mantidactolide B, the other showed specific presence of the macrolides phoracantholide I (1) and mantidactolide A (4). Genetic analysis of some individuals showed no congruence between genetic relatedness and gland constituents. Several other individuals from related species had different gland compositions. This suggests that a basic set of biosynthetic machinery might be available to a broader group of related species.

Most empirical and theoretical papers on prey-predator interactions are for animals with long-range detection, animals that can detect and react to predators long before these touch the prey. Heavy-bodied and chemically defended harvestmen (Arachnida, Opiliones) are an exception to this general pattern and rely on contact to detect arthropod predators. We examined the interactions between the Brazilian wandering spider Ctenus ornatus with harvestmen (Mischonyx cuspidatus) or control prey (Gryllus sp. and M. cuspidatus immature, both with soft integuments). Considering a prey-predator system in which fleeing from or reacting to a predator at a distance is not possible, we predicted both a high survival value of near-range defense mechanisms and that mortality would be higher in the absence of such defense mechanisms. We also expected the predator to behave differently when interacting with harvestmen or with a control prey without such defense mechanisms. Our results from laboratory experiments partially matched our predictions: First of all, histological sections showed that the integument of adult harvestmen is thicker than that of immature harvestmen and that of crickets. Adult harvestmen were less preyed upon than the control prey; the heavy armature increases the survival rate but the secretions from the scent glands do not. The predator did behave differently when attacking harvestmen compared to crickets. Despite the large size difference between predator and harvestmen, the protection provided by the armature allowed some of the harvestmen to survive encounters without pre-contact detection, thus greatly reducing the reliance on long-range detection to survive encounters with predators. Harvestmen call for theoretical and empirical work on prey-predator interactions that take into account the possibility that prey may not detect the predator before contact is established., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Benzo[a]pyrene (BaP) is a prototypical polycyclic aromatic hydrocarbon (PAH) found in combustion processes. Cytochrome P450 1A1 and 1B1 enzymes (CYP1A1, CYP1B1) and other enzymes can activate PAHs to reactive oxygenated intermediates involved in mutagenesis and tumor initiation; also, CYP1 enzymes can detoxify PAHs. Cyp1(+/+) wild-type (WT) and Cyp1b1(-/-) knockout mice receiving oral BaP (12.5 mg/kg/day) remain healthy for >12 months. In contrast, we found that global knockout of the Cyp1a1 gene (1a1KO) results in proximal small intestine (PSI) adenocarcinoma within 8-12 weeks on this BaP regimen; striking compensatory increases in PSI CYP1B1 likely participate in initiation of adenocarcinoma in 1a1KO mice. Cyp1a1/1b1(-/-) double-knockout (DKO) mice on this BaP regimen show no PSI adenocarcinoma, but instead preputial gland duct (PGD) squamous cell carcinoma (SCC) occurs by 12 weeks. Herein, we compare microarray expression of PGD genes in WT, 1a1KO and DKO mice at 0, 4, 8, 12 and 16 weeks of oral BaP; about four dozen genes up- or down-regulated during most critical time-points were further verified by qRT-PCR. In DKO mice, CYP3A59 was unequivocally identified as the BaP-inducible and BaP-metabolizing best candidate responsible for initiation of BaP-induced SCC. Striking increases or decreases were found in 26 cancer-related genes plus eight Serpin genes in DKO, but not in 1a1KO or WT, mice on this BaP regimen; of the 26, 8 were RAS-related oncogenes. The mechanism by which cancer-related genes are responsible for SCC tumor progression in the PGD remains to be elucidated., (Copyright © 2012 UICC.)

The metathoracic scent gland of 25-day-old adults of both sexes of the leaf-footed bug, Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), are described based on optical microscopy analysis. No sexual dimorphism was observed in the glandular composition of this species. The gland is located in the anteroventral corner of the metathoracic pleura between the middle and posterior coxal pits. The opening to the outside of the gland is very wide and permanently open as it lacks a protective membrane. In the internal part, there is a pair of metathoracic glands that consist of piles of intertwined and occasionally bifurcated cellular tubes or columns. These glands discharge their pheromonal contents into the reservoir through a narrow cuticular tube. The reservoir connects with the vestibule via two opposite and assembled cuticular folds that can separate muscularly in order to allow the flow of liquid away from the insect. The external part consists of an ostiole from which the pheromone is emitted. The ostiole is surrounded by a peritreme, a structure that aids optimum pheromone dispersion. The described gland is of the omphalien type.

Chemical defense is one of the most important traits, which endow insects the ability to conquer a most diverse set of ecological environments. Chemical secretions are used for defense against anything from vertebrate or invertebrate predators to prokaryotic or eukaryotic parasites or food competitors. Tenebrionid beetles are especially prolific in this category, producing several varieties of substituted benzoquinone compounds. In order to get a better understanding of the genetic and molecular basis of defensive secretions, we performed RNA sequencing in a newly emerging insect model, the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae). To detect genes that are highly and specifically expressed in the odoriferous gland tissues that secret defensive chemical compounds, we compared them to a control tissue, the anterior abdomen. 511 genes were identified in different subtraction groups. Of these, 77 genes were functionally analyzed by RNA interference (RNAi) to recognize induced gland alterations morphologically or changes in gland volatiles by gas chromatography-mass spectrometry. 29 genes (38%) presented strong visible phenotypes, while 67 genes (87%) showed alterations of at least one gland content. Three of these genes showing quinone-less (ql) phenotypes - Tcas-ql VTGl; Tcas-ql ARSB; Tcas-ql MRP - were isolated, molecularly characterized, their expression identified in both types of the secretory glandular cells, and their function determined by quantification of all main components after RNAi. In addition, microbe inhibition assays revealed that a quinone-free status is unable to impede bacterial or fungal growth. Phylogenetic analyses of these three genes indicate that they have evolved independently and specifically for chemical defense in beetles., Competing Interests: The authors have declared that no competing interests exist.

Insects use pheromones as a means of chemical communication. Pheromones act on individual receptors and produce specific behavioral or physiological responses that are fundamental to intra- and interspecific recognition. The objective of this study was to evaluate the interspecific differences among the linear hydrocarbon profiles of the cuticles of 3 wasp species of the genus Mischocyttarus. The chemical strategy that permits an interaction among 2 of these species was also examined about their hydrocarbon profiles. The cuticular hydrocarbons present on the abdomen of each individual were extracted with hexane in an ultrasonic bath and analyzed using gas chromatography with a flame ionization detector. The results suggested that the wasp species have distinct chemical signatures as the linear hydrocarbons of their cuticles. However, these signatures are more alike in those with similar morphological and behavioral aspects. These similarities facilitate an interaction of facultative parasitism observed among these species, in which the invaders acquire parts of the chemical signature of the host colony, possibly as a chemical strategy to increase the likelihood that an invader will be accepted by the females of a host colony. Both invader and host have their own chemical signature changed by the first contact between the species.

Many mammals possess specialized scent glands, which convey information about the marking individual. As the chemical profile of scent marks is likely to be affected by bacteria metabolizing the primary gland products, the variation in bacterial communities between different individuals has been proposed to underpin olfactory communication. However, few studies have investigated the dependency of microbiota residing in the scent organs on the host's individual-specific parameters. Here, we used terminal restriction fragment length polymorphism analysis of the PCR-amplified 16S rRNA gene and clone library construction to investigate the microbial communities in the subcaudal gland secretion of the European badger (Meles meles). As the secretion has been shown to encode individual-specific information, we investigated the correlation of the microbiota with different individual-specific parameters (age, sex, body condition, reproductive status, and season). We discovered a high number of bacterial species (56 operational taxonomic units from four phyla: Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes), dominated by Actinobacteria (76.0%). The bacterial communities of cubs and adults differed significantly. Cubs possessed considerably more diverse communities dominated by Firmicutes, while in adults the communities were less diverse and dominated by Actinobacteria, suggesting that the acquisition of a 'mature bacterial community' is an ontogenetic process related to physiological changes during maturation., (© 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae) is a serious insect pest of litchi and longan in South China. When disturbed, this insect could release large quantities of disagreeable odorous volatiles from its scent gland. Knowledge on the scent gland and its secretion is crucial for developing the semiochemical methods to manage this pest. Morphology and ultrastructure of the metathoracic scent glands (MTGs) were studied under stereo and scanning electron microscopy, and the volatile compounds of MTGs from both male and female T. papillosa were analyzed with coupled gas chromatography-mass spectrometry (GC-MS). The MTG complex is located between the metathorax and the first abdominal segment at the ventral surface of the insect, which has a well-developed single double valve cystic-shaped orange median reservoir, paired colorless lateral glands in both sides, and a long and wavy tubular accessory gland that inlays tightly into the ventral edge around the median reservoir. The MTG opens to the body surface through paired ostioles located between the meso- and metacoxae of the evaporatorium with mushroom bodies. The GC-MS analyses showed that female and male adults have nine major volatile components in common. Tridecane is the most abundant in both females and males, reaching up to 47.1% and 51.8% of relative amount, respectively. The minor component is benzophenone with only 0.28% and 0.14%. Furthermore, undecane, tetradecane, 3-methyl-tridecane, and cyclopentadecane were found only in males. The possible function of volatile compounds of MTG contents in T. papillosa is addressed.

The scent gland secretion of Austropurcellia forsteri was analyzed by gas chromatography-mass spectrometry, providing the first description of the secretion chemistry in the cyphophthalmid family Pettalidae. The secretion contained a total of 21 compounds: About 60% of the whole secretion consisted of a series of saturated, mono-unsaturated and doubly unsaturated methylketones, from C11 to C15, with a cluster of saturated and mono-unsaturated C13-methylketones dominating. A second fraction included several naphthoquinones such as 1,4-naphthoquinone (ca. 20% of secretion), 6-methyl-1,4-naphthoquinone (ca. 17%), and minor amounts of chloronaphthoquinones (ca. 2%). When compared with scent gland compositions of other representatives of cyphophthalmids (e.g. from families Sironidae and Stylocellidae), a highly conservative chemistry of cyphophthalmid secretions is apparent, based on a restricted number of methylketones and naphthoquinones.

In order to elucidate the relationship between androgens and the function of the muskrat (Ondatra zibethicus) scented glands during the breeding season, we investigated immunolocalization of steroidogenic enzymes P450scc, 3βHSD and P450c17 in the muskrat testes and scented glands. Nine adult muskrats were obtained in March (n=3), May (n=3) and July (n=3) 2010. Steroidogenic enzymes were immunolocalized using polyclonal antisera raised against bovine adrenal P450scc, human placental 3βHSD and porcine testicular P450c17. Histologically, all types of spermatogenic cells including mature-phase spermatozoa in seminiferous tubules were observed in all testes. Glandular cells, interstitial cells, epithelial cells and excretory tubules were identified in scented glands during the breeding season. P450scc, 3βHSD and P450c17 were only identified in Leydig cells during the breeding season; P450scc and P450c17 were observed in glandular cells of scented glands, however, 3βHSD was not found in scented glands during the breeding season. These novel findings provide the first evidence showing that scented glands of the muskrats are capable of locally synthesizing androgens and androgens acting via an endocrine, autocrine or paracrine manner may play an important role in scented gland function during the breeding season.

Aromatase cytochrome P450 (P450arom) is an enzyme that catalyzes the conversion of androgen to estrogen. Expression of P450arom in extra-gonadal sites and locally-synthesized estrogen play an important role in physiological conditions. The purpose of this study was to investigate the cellular immunolocalization of androgen receptor (AR), P450arom, estrogen receptor alpha (ERa) and estrogen receptor beta (ERβ) in muskrat scent glands during the breeding season. Histological observation and immunohistochemistry of AR, P450arom, ERa and ERβ were performed in the muskrat scent glands. In addition, total proteins were extracted from scent glandular tissues in the breeding season and were used for Western blotting analysis for AR, P450arom, ERα and ERβ. Histologically, glandular cells, interstitial cells, epithelial cells of the excretory duct and the excretory tubules were identified in the muskrat scent glands during the breeding season. AR was only observed in glandular cells of scent glands; P450arom was expressed in glandular cells and epithelial cells of the excretory duct; ERα was found in glandular cells, interstitial cells and epithelial cells of the excretory duct, whereas ERβ was present in glandular cells and epithelial cells of the excretory duct. Also, the positive signals of AR, P450arom, ERα and ERβ by Western blotting were all observed in scent glandular tissues. These results suggested that the scent gland is the target organ of androgens and estrogens, and that estrogens may play an important autocrine or paracrine role in glandular function of the muskrats.

The morphological organization and functional anatomy of prosomal defensive (scent) glands in Paranemastoma quadripunctatum, a representative of the dyspnoid harvestmen, was investigated by means of histological semithin sections, software-based 3D-reconstruction and scanning electron microscopy. Scent glands comprise large, hollow sacs on either side of the prosoma, each of these opening to the outside via one orifice (ozopore) immediately above coxa I. In contrast to the situation known from laniatorean, cyphophthalmid and some eupnoid Opiliones, ozopores are not exposed but hidden in a depression (atrium), formed by a dorsal integumental fold of the carapace and the dorsal parts of coxae I. Glandular sacs are connected to ozopores via a short duct which is equipped with a specific closing mechanism in its distal part: A layer of modified epidermal cells forms a kind of pad-like tissue, surrounding the duct like a valve. Several muscles attached to the anterior parts of the glandular reservoir and to the epithelial pad may be associated with ozopore-opening. The actual mechanism of secretion discharge seems to be highly unusual and may be hypothesized on the basis of corroborating data from behavioral observations, scent gland anatomy and secretion chemistry as follows: Enteric fluid is considered to be directed towards the ozopores via cuticular grooves in the surface of the coxapophyses of legs I. Then, the fluid is sucked into the anterior part of the scent gland reservoirs by the action of dorsal dilator muscles that widen the reservoir and produce a short-term negative pressure. After dilution/solution of the naphthoquinone-rich scent gland contents, a secretion-loaded fluid is thought to be discharged with the help of transversal compressor muscles. This is the first detailed study on the functional anatomy of scent glands and the mechanisms of secretion discharge in the Dyspnoi., (Copyright © 2011 Wiley-Liss, Inc.)

The objective of this study was to investigate the cellular immunolocalization of inhibin a and inhibin/activin (β(A) and β(B)) subunits in the muskrat testes and scented glands during the breeding season. Inhibin α and inhibin/activin (β(A) and β(B)) subunits were expressed in Sertoli cells and Leydig cells of testes and glandular cells of scented glands, respectively. Also, positive signals of inhibin α and inhibin/activin (β(A) and β(B)) subunits by Western blotting were both observed in testicular and scented glandular tissues. These results suggested that the testes and scented glands of the muskrats had the ability to synthesize inhibins and activins and that activins and inhibins might play an important role in testicular and scented glandular function in muskrats.

The importance of olfaction in birds' social behavior has long been denied. Avian chemical signaling has thus been relatively unexplored. The black-legged kittiwake provides a particularly appropriate model for investigating this topic. Kittiwakes preferentially mate with genetically dissimilar individuals, but the cues used to assess genetic characteristics remain unknown. As in other vertebrates, their body odors may carry individual and sexual signatures thus potentially reliably signaling individual genetic makeup. Here, we test whether body odors in preen gland secretion and preen down feathers in kittiwakes may provide a sex and an individual signature. Using gas chromatography and mass spectrometry, we found that male and female odors differ quantitatively, suggesting that scent may be one of the multiple cues used by birds to discriminate between sexes. We further detected an individual signature in the volatile and nonvolatile fractions of preen secretion and preen down feathers. These results suggest that kittiwake body odor may function as a signal associated with mate recognition. It further suggests that preen odor might broadcast the genetic makeup of individuals, and could be used in mate choice to assess the genetic compatibility of potential mates.

Scent is used across taxa to communicate information about signaler identity. Eurasian otters Lutra lutra are mainly solitary and thought to use scent as their primary means of communication. Little is known, however, about what information otters communicate through scent or what social function this performs. Headspace solid-phase microextraction and gas chromatography-mass spectrometry were used to sample and analyze volatile organic compounds from anal scent gland secretion from 158 otters of differing sex, age, and female reproductive status. Univariate and multivariate differences were clear between adult and juvenile otters. Complex sex differences were apparent in adult otters but not in younger individuals, suggesting the use of this scent secretion in mate attraction. The scent of pregnant and lactating females was highly differentiated from male and juvenile scent, but anecdotal reports suggest females avoid communication during these times., (© The Author 2011. Published by Oxford University Press. All rights reserved.)

The desert gerbil, M. hurrianae scent marks the general substratum in its territory with the sebum exudation of mid abdominal gland and urine. Having assessed number of functions, which scent marking plays in the social life of these rodents, the scent marking behaviour was studied in animals, in which the gland was surgically removed and was compared with that of intact rodents. After recovery from the operation, the scent marking frequency of both male and female M. hurrianae declined significantly and was maintained at a low level. Surprisingly, scent marking with urine also declined considerable with time. After 5 months of the operation, desert gerbils were given a choice to respond to male and female sebum odours. The frequency of their scent marking with either sebum or urine did not show any significant enhancement as compared to their initial marking rate. However, the duration of their stay and scent marking frequency near the source of the sebum odour was more that in the clean side of the cage. The role of such altering behaviors of M. hurrianae and their impact on social organization are discussed.

The defensive secretions of five neotropical species of harvestmen (Opiliones: Gonyleptidae) from the Brazilian Atlantic Forest were analyzed and chemically characterized by GC-MS and NMR methods. Three of the species, Cobania picea, Roweria virescens, and Serracutisoma proximum, secrete a mixture of 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone. The secretions produced by the other two species, Iporangaia pustulosa and Neosadocus maximus, contain 1-hepten-3-one, 5-methyl-1-hexen-3-one, and 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) as major components, as well as 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone as minor constituents. The dihydropyran 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) is a new natural product, composed of two 1-hepten-3-one subunits formally linked in a hetero-Diels-Alder reaction. The natural product was proven to be racemic, and its biogenetic origin is discussed.

Sex pheromones of moths are largely classified into two types based on the presence (Type I) or absence (Type II) of a terminal functional group. While Type-I sex pheromones are synthesized from common fatty acids in the pheromone gland (PG), Type-II sex pheromones are derived from hydrocarbons produced presumably in the oenocytes and transported to the PG via the hemolymph. Recently, a fatty acid transport protein (BmFATP) was identified from the PG of the silkworm Bombyx mori, which produces a Type-I sex pheromone (bombykol). BmFATP was shown to facilitate the uptake of extracellular fatty acids into PG cells for the synthesis of bombykol. To elucidate the presence and function of FATP in the PG of moths that produce Type-II sex pheromones, we explored fatp homologues expressed in the PG of a lichen moth, Eilema japonica, which secretes an alkenyl sex pheromone (Type II). A fatp homologue cloned from E. japonica (Ejfatp) was predominantly expressed in the PG, and its expression is upregulated shortly after eclosion. Functional expression of EjFATP in Escherichia coli enhanced the uptake of long chain fatty acids (C₁₈ and C₂₀), but not pheromone precursor hydrocarbons. To the best of our knowledge, this is the first report of the cloning and functional characterization of a FATP in the PG of a moth producing a Type-II sex pheromone. Although EjFATP is not likely to be involved in the uptake of pheromone precursors in E. japonica, the expression pattern of Ejfatp suggests a role for EjFATP in the PG not directly linked to pheromone biosynthesis., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Preen glands exist in almost every bird species and several non-exclusive functions have been proposed for this gland and the oils that it produces. One function generally admitted is that the oily secretions of the preen gland would provide a waterproofing layer when spread over feathers. Alternatively, several authors have proposed that plumage waterproofness is mostly due to the spatial micro-structure of feathers. The purpose of this study was to examine, by manipulating the access to the preen gland, the effect of the preen oil on the plumage waterproofness and condition. To explore this question, we carried out two independent experiments where we temporarily blocked access to the preen gland secretions with a removable mechanism in one group of captive mallards (Anas platyrhynchos), whilst a second group of birds had access to gland secretions. In a long-term experiment (3 months of treatment) and a short-term experiment (10 days), we measured plumage water retention and condition. After 3 months without access to preen glands, we found a significant decrease of plumage condition and an associated increase in plumage water retention. Moreover, we found a significant correlation between plumage condition and water retention ability. In contrast, after 10 days of treatment, no significant effect was found on plumage condition and water retention. Our study shows that preen oil acts to maintain plumage condition and suggests that feather microstructure is essential to maintain plumage waterproofness.

Preputial gland is one of the best known and most odour-producing organs in many non-primate mammals. It is generally believed that the development of this gland and functions are regulated by testosterone. To substantiate this point, the present study was aimed to evaluate the testosterone-dependent volatile compounds and proteins in the preputial gland of rat adopting castration and testosterone supplementation. The results revealed that four compounds, geranyl linalool isomer, oxirane, farnesol and lanosterol, are testosterone-dependent. Similarly, a low molecular mass protein with molecular weight 18kDa, supposed to be a pheromone carrier, also is shown to be testosterone-dependent. This study leads to the conclusion that testosterone-dependent compounds and sex-associated protein are present in the preputial gland of rat which may act as a sex pheromone and pheromone carrier, respectively., (Copyright 2010 Elsevier Inc. All rights reserved.)

Primates are traditionally considered to be microsmatic, with decreased reliance on olfactory senses in comparison to other sensory modalities such as vision. This is particularly the case for Old World monkeys and apes (catarrhines). However, various lines of evidence suggest that chemical communication may be important in these species, including the presence of a sternal scent-gland in the mandrill. We investigated the volatile components of mandrill odor using gas chromatography-mass spectrometry. We identified a total of 97 volatile components in 88 swabs of the sternal gland secretion and 95 samples of sternal gland hair saturated with scent-gland secretion collected from 27 males and 18 females. We compared odor profiles with features of the signaler using principle components and discriminant function analyses and found that volatile profiles convey both variable (age, dominance rank in males) and fixed (sex, possibly individual identity) information about the signaler. The combination of an odor profile that signals sex, age, and rank with increased motivation to scent-mark and increased production of secretion in high-ranking males leads to a potent signal of the presence of a dominant, adult male with high testosterone levels. This may be particularly relevant in the dense Central African rain forest which mandrills inhabit. By contrast, we were unable to differentiate between either female cycle stage or female rank based on odor profiles, which accords with behavioral studies suggesting that odor signals are not as important in female mandrills as they are in males. The similarity of our findings to those for other mammals and in primates that are more distantly related to humans suggests a broader role for odor in primate communication than is currently recognized.

The gray short-tailed opossum is one of the most widely studied of all marsupials and an important model for study of olfactory communication, particularly as it relates to pheromonal activation of reproduction. Males respond to differentially to female skin gland secretions and urine from anestrous females, while females respond only skin gland secretions, particularly that of the suprasternal gland. Divergent responses by male and female opossums to odors from these different body sources are most likely related to sex-specific production and deposition of chemical signals in this species. Female opossums do not have an estrous cycle but are stimulated to estrus by male pheromone. Females nuzzle scent marks from male suprasternal gland secretions, and thereby facilitate delivery of a nonvolatile estrus-inducing pheromone to the chemosensory epithelium of vomeronasal organ. Neuroendocrine correlates of pheromonal induction of estrus include elevated plasma estradiol and upregulation of progesterone receptors in hypothalamic regions that control reproductive behavior., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Rabbits use a variety of olfactory signals to transmit information related with reproduction. Such cues are produced in skin glands (submandibular, anal, Harder's, lachrymal, preputial) and the mammary gland-nipple complex. Some signals are transmitted by active behaviors, for example, chin-marking, urination, and defecation, while others are transmitted passively (e.g., mammary pheromone (MP) and inguinal gland secretions). We show that sex steroids regulate: chinning frequency and the chin gland's size, weight and secretory activity in bucks and does by acting on specific brain regions or on the chin gland, respectively. The "mammary pheromone," identified in milk as 2-methyl-but-2-enal, is essential for guiding the pups to the nipples, but its origin (mammary gland, ventral skin, nipple) remains to be determined. Estradiol, progesterone, and prolactin regulate the emission of an olfactory cue that also triggers nipple-search behavior in the pups, but its chemical identity and relation with the MP are unclear., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Studies over the past three decades have demonstrated that female moths usually produce sex pheromones as multicomponent blends in which the ratios of the individual components are precisely controlled, making it possible to generate species-specific pheromone blends. Most moth pheromone components are de novo synthesized from acetyl-CoA in the pheromone gland (PG) through modifications of fatty acid biosynthetic pathways. Pheromone biosynthesis activating neuropeptide (PBAN), a neurohormone produced by a cephalic organ (subesophageal ganglion) stimulates sex pheromone biosynthesis in the PG via an influx of extracellular Ca(2+). In recent years, we have expanded our knowledge of the precise mechanisms underlying silkmoth (Bombyx mori) sex pheromone production by characterizing a number of key molecules. In this review, we want to highlight our efforts in elucidating these mechanisms in B. mori and to understand how they relate more broadly to lepidopteran sex pheromone production in general., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Elevated testosterone levels can lower condition and increase parasites. We analysed testosterone in 84 blood samples of wild European badgers Meles meles collected at regular intervals (winter = mating season; spring = end of mating season; summer = minor mating peak; autumn = reproductive quiescence), and related variation to body condition, subcaudal gland secretion, parasite burden, and bite wounding. All males showed elevated levels in winter and low levels in autumn. In neither season did testosterone correlate with fitness-related parameters. However, two different endocrinological phenotypes existed in spring and summer. Whilst some males lowered their testosterone to levels comparable to autumnal quiescence (Type 1), others maintained elevated levels comparable to those during winter (Type 2). In spring and summer high levels were correlated with lower body condition and increased parasite burden, and Type 2 males tended to suffer higher mortality rates than Type 1. No animals older than 6 years adopted phenotype 2, indicating that males either switch phenotypes with age or that Type 2 results in lower life expectancy, evidencing the costs of male reproduction in badgers.

Exposure to novel adult males and their urine can hasten the onset of sexual maturity in female mice. Some evidence implicates chemosignals from males' preputial glands, while other evidence suggests that male urinary steroids, especially 17beta-oestradiol, contribute to this effect. The present experiment was designed to determine whether preputial gland removal would influence the capacity of males to accelerate female sexual development, and to measure male urinary oestradiol and testosterone in the presence or absence of these glands. Juvenile females aged 28 days were housed for two weeks in isolation or underneath two outbred males that had undergone preputialectomy or sham surgery. Urine samples were collected non-invasively from males that were isolated or exposed to females, then assayed for oestradiol, testosterone and creatinine. Combined uterine and ovarian mass from females sacrificed at 43 days of age was increased by exposure to males, regardless of whether or not these males had been preputialectomised. Male urinary creatinine was reduced by exposure to developing females. Creatinine-adjusted oestradiol and testosterone were significantly greater in female-exposed than in isolated males, in both preputialectomised and intact males. These data suggest that the preputials are not necessary for the capacity of males to hasten female uterine and ovarian growth. As exogenous oestrogens can promote uterine growth and other parameters of female reproductive maturation, oestradiol in males' urine may contribute to earlier sexual maturity in male-exposed females.

Pheromones are volatile chemical cues that in rodents originate in large part from the preputial glands and influence various behavioral and physiological processes. We have examined the effect of psychosocial stress on volatile compound composition of preputial glands of male rats. Rats were housed three per cage or singly for 70 days. Dominants had heavier preputials compared to subdominant and subordinate rats. Capillary gas chromatographic mass spectrometry identified 55 volatile preputial compounds: 17 did not differ between groups, while 26 compounds were higher in single-housed compared to triad-housed rats. Six compounds were higher in dominant, while another six were higher in both dominant and single-housed rats. We conclude that both housing condition and rank status have significant differential effects on the preputial volatile compounds.

Chinning consists of rubbing the chin against an object, thereby depositing secretions from the submandibular glands. As mating, chinning is stimulated in male and female rabbits by testosterone and estradiol, respectively. To investigate the brain sites where steroids act to stimulate chinning and mating we implanted into the ventromedial hypothalamus (VMH) or the medial preoptic area (MPOA) of gonadectomized male and female rabbits testosterone propionate (TP; males) or estradiol benzoate (EB; females) and quantified chinning and sexual behavior. EB implants into the VMH or MPOA reliably stimulated chinning in females. Most of those implanted into the VMH and around half of the ones receiving EB into MPOA or diagonal band of Broca (DBB) showed lordosis. Chinning, but not sexual behavior, was stimulated in males by TP implants into the MPOA or DBB. Neither chinning nor mounting were reliably displayed by males following TP implants into the VMH. Results indicate that, in females, the VMH is an estrogen-sensitive brain area that stimulates both chinning and lordosis while the MPOA seems to contain subpopulations of neurons involved in either behavior. In males, androgen-sensitive neurons of the MPOA, but not the VMH, are involved in chinning stimulation but it is unclear if these areas also participate in the regulation of copulatory behavior.

Female gray short-tailed opossums (Monodelphis domestica) lack an estrous cycle and are induced into estrus by exposure to a pheromone in male scent marks. Behavioral and physiological responses of females to the volatile and nonvolatile components of scent marks were examined in two experiments. Young females (n=9) were tested prior to and during their first estrus for behavioral responses to scent marks, collected on a 7-ml glass vial rubbed over the suprasternal gland of a mature male. The response to volatile components of the scent mark, recorded when marked and unmarked vials were covered with a perforated shield, was compared to the response to these vials when unshielded. Estrous females nuzzled the shields over marked vials (55.8+/-8.5 nuzzles/10 min) more than the shielded clean vial (10.9+/-2.4) (P<0.05); a similar response was observed in anestrous females. Nuzzling of unshielded, scent-marked vials was higher (P<0.05) during anestrus than in the same females when in estrus. The role of nonvolatile pheromones in reproductive activation was tested in adult females (n=11) exposed for up to 14 days to a shielded, marked vial or to an unshielded, marked vial in a crossover design. All females exposed to unshielded vials expressed estrus, and 10 copulated. Only 2 females expressed estrus (significantly fewer, P<0.05), when exposed to shielded marked vials, and neither copulated. These results demonstrate that females detect and respond behaviorally to both volatile and nonvolatile components of male suprasternal gland secretion, but the estrus-inducing pheromone in these secretions is nonvolatile.

This study was aimed at validating the sexual attractiveness of hexadecanol and hexadecyl acetate, two putative pheromone compounds, from preputial gland secretion of mice. These two compounds have been reported to be among the major components of preputial gland secretion in both sexes but higher in quantity in males than females. In this study, we show that castration suppressed the production of the two compounds, further suggesting their association with maleness. Adding preputial gland secretion and the synthetic analogs of the two compounds to castrated male urine at their physiological levels in intact males increased the attractiveness of castrated male urine to female mice, showing that the two compounds were indeed male pheromones. Furthermore, their sexual attractiveness disappeared upon removing the vomeronasal organs (VNOs) from female recipients. Replenishing castrated male urine with preputial gland secretion and the two compounds at their physiological levels in females increased the attractiveness of castrated male urine to males. Such a reversal of sexual attractiveness for hexadecanol and hexadecyl acetate suggests that they had opposing dual effects in sexual attractiveness in a dosage-dependent manner.

This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography-mass spectrometry (GC-MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.

Female Phytocoris calli Knight produce a sex pheromone from metathoracic scent glands. The pheromone consists of hexyl acetate (HA; present in both sexes), with the female-specific compounds (E)-2-hexenyl acetate (E2HA), octyl acetate (OA), and (E)-2-octenyl acetate (E2OA). HA and E2OA are key components of the pheromone, since deletion of either ester from the blend resulted in a total suppression of conspecific male trap catches. However, the binary blend of HA and E2OA was only slightly attractive to males, and was significantly less active than the four-component blend. The two ternary blends, HA/OA/E2OA and HA/E2HA/E2OA, were each as attractive as the full four-component blend. Evidence from previous research on the pheromones of Phytocoris species suggests that the apparent chemical redundancy in the pheromone of P. calli may actually be involved in maintaining reproductive isolation from other sympatric species. The patterns observed for pheromones of the five Phytocoris species whose pheromones have been directly (P. californicus, P. relativus, P. difficilis, and P. calli) or indirectly (P. breviusculus) studied are discussed vis-à-vis the pheromone intractable species of Lygus and Lygocoris plant bugs.

Since the seminal work of Lindauer and Kerr (1958), many stingless bees have been known to effectively recruit nestmates to food sources. Recent research clarified properties of several signals and cues used by stingless bees when exploiting food sources. Thus, the main source of the trail pheromone in Trigona are the labial, not however the mandibular glands. In T. recursa and T. spinipes, the first stingless bee trail pheromones were identified as hexyl decanoate and octyl decanoate, respectively. The attractant footprints left by foragers at the food source are secreted by glandular epithelia of the claw retractor tendon, not however by the tarsal gland. Regarding intranidal communication, the correlation between a forager's jostling rate and recruitment success stresses the importance of agitated running and jostling. There is no evidence for a "dance" indicating food source location, however, whereas the jostling rate depends on food quality. Thoracic vibrations, another intranidal signal well known in Melipona, were analyzed using modern technology and distinguishing substrate vibrations from airborne sound. Quantitative data now permit estimates of signal and potential communication ranges. Airflow jets as described for the honeybee were not found, and thoracic vibrations do not "symbolically" encode visually measured distance in M. seminigra.

Females may be attracted to males genetically resistant to infectious diseases, and one potential mechanism for this mating bias is that such males may be better able to maintain high testosterone. To test these two hypotheses, we collected scent-marks from male house mice (Mus domesticus) genetically resistant and susceptible to Salmonella due to a single locus (Nramp 1, also known as Slc11a1). We tested whether females are more attracted to the scent-marks of resistant males, and whether such males are better able to maintain testosterone concentrations during an experimental Salmonella infection. We found that females preferred the scent-marks of genetically resistant males compared to susceptible ones; but they showed no preferences 5d after males were infected. As predicted, genetically resistant males maintained their testosterone concentrations during the experimental infection, whereas susceptible males showed a significant decline 14 d after inoculation. These differences in the males' ability to modulate testosterone, however, do not explain females' attraction to resistant males. Thus, our results indicate that females sometimes prefer males genetically resistant to infection, and they provide the first evidence that males modulate their testosterone depending upon their genetic resistance to infection; however, we found no evidence to link these two findings.

With a combination of dichloromethane extraction and analysis by gas chromatography-mass spectrometry (GC-MS), we found 39 compounds (corresponding to 38 GC peaks) in the anogenital gland secretion (AGS) of captive adult giant pandas, Ailuropoda melanoleuca, during the non-mating season. In addition to indole, squalene, and some of the straight-chain fatty acids that had been characterized previously from the AGS of giant pandas, we identified several new compounds such as decenal, two isomers of decadienal, phenylacetic acid, 5-methylhydantoin, hydroquinone, phenylpropanoic acid, and erucic acid. Quantitative comparison of the relative abundances of the 20 main GC peaks revealed that 5-methylhydantoin, indole, and erucic acid are putative female pheromones, whereas squalene and hydroquinone are putative male pheromones. In addition to the presence of a few individual-specific compounds, the relative abundances of most of the 21 constituents varied more among individuals than within individuals. This suggests that individual identity might be coded in both digital and analog form. The chemical composition of different AGS samples from the same pandas consistently displayed a minimum cluster distance, much smaller than that between samples from different individuals in a hierarchical linkage cluster (average linkage) dendrogram. Our results indicate that the AGS might contain an "odor fingerprint." Although putative sex pheromones such as squalene and erucic acid should be assessed further by bioassay, our study suggests that synthetic chemosignals might be useful in modulating the behavior and physiology of giant pandas.

Numerous behavioral studies have shown that animals use olfactory cues as inbreeding avoidance or kin avoidance mechanisms, implying that scent is unique to families. However, few studies have analyzed the chemical profile of a scent and ascertained the messages that are conveyed in scent secretions. Owl monkeys (Aotus nancymaae) are socially monogamous primates that utilize scent when interacting with foreign conspecifics. This suggests there is a difference in the chemical composition of scent marks. We chemically analyzed sub-caudal gland samples from three families of captive owl monkeys (Aotus nancymaae). Samples were analyzed by capillary GC-MS and relative retention time and fragment pattern was compared with known standards. Gland samples were high in large plant-based shikikate metabolites and fatty ketones; alcohols, acids, and acetates were virtually absent. Gender, age, and family could be reliably classified using discriminant analysis (92.9, 100, and 100%, respectively). Female scent profiles were greater in concentration of aromatic plant metabolites, possibly the result of a different diet or physiological differences in female metabolism as compared to male. Offspring of adult age still living in their natal group showed a less complex chemical profile than their parents. Finally, each family had its own unique and complex chemical profile. The presence of family scent may play a role in mediating social interactions.

Gilbert (1976) suggested that male-contributed odors of mated females of Heliconius erato could enforce monogamy. We investigated the pheromone system of a relative, Heliconius melpomene, using chemical analysis, behavioral experiments, and feeding experiments with labeled biosynthetic pheromone precursors. The abdominal scent glands of males contained a complex odor bouquet, consisting of the volatile compound (E)-beta-ocimene together with some trace components and a less volatile matrix made up predominately of esters of common C16- and C18-fatty acids with the alcohols ethanol, 2-propanol, 1-butanol, isobutanol, 1-hexanol, and (Z)-3-hexenol. This bouquet is formed during the first days after eclosion, and transferred during copulation to the females. Virgin female scent glands do not contain these compounds. The transfer of ocimene and the esters was shown by analysis of butterflies of both sexes before and after copulation. Additional proof was obtained by males fed with labeled D-13C6- glucose. They produced 13C-labeled ocimene and transferred it to females during copulation. Behavioral tests with ocimene applied to unmated females showed its repellency to males. The esters did not show such activity, but they moderated the evaporation rate of ocimene. Our investigation showed that beta-ocimene is an antiaphrodisiac pheromone of H. melpomene.

The present study investigated urinary scent marking behavior in male C57BL/6J (C57) mice as olfactory social signaling. In Experiment 1, when compared scent marking toward adult males, C57 males showed substantial scent marking toward CD-1 males and even toward the odor alone of CD-1 males, but not toward C57 males. Experiment 2 explored scent marking in C57 males of different ages to males and females, and juveniles and adults of the same strain. C57 males deposited more marks than control conditions only toward an adult C57 female when tested at 100 days of age, but not at 60 days of age. Development of urine marking behavior was investigated in C57 males at the ages of 30, 60, 90, and 120 days in Experiment 3. When tested alone (control) or confronted with a C57 male, C57 males showed diminished scent marks throughout development. Compared to controls, marking toward a CD-1 male increased after the age of 60 days, while marks toward an adult female showed significant increases after the age of 90 days. This difference in scent marking depending on the sex of the stimulus animal is likely to be associated with development of sexual behavior, in which males need to set up territories against other males prior to advertising to females. Although highly inbred strains have similar odor components, C57 males are able to detect and deposit urine marks after puberty as social communication depending on age, sex, and genetic differences in the opponents.

Many lizards have epidermal glands in the cloacal or femoral region with semiochemical function related to sexual behavior and/or territorial demarcation. Externally, these glands are recognized as a row of pores, opening individually in the center of a modified scale. In many species the pores are used as systematic characters. They form a glandular cord or, in some species, a row of glandular beads below the dermis, and are connected to the exterior through the ducts, which continuously liberate a solid secretion. Dead cells, desquamated from the secretory epithelium, constitute the secretion, known as "a secretion plug." The present work focuses on the morphology of the femoral glands of the teiid lizard Ameiva ameiva, correlating it to the way in which the secretion is deposited in the environment. The results here obtained are compared to those available for other lizards and amphisbaenians. We observed that the diameter of the glandular pores did not show significant differences between males and females. The glands comprise germinative and secretory cells, which pass through at least three stages of differentiation, during which an accumulation of cytoplasmic granules, with a glycoprotein content, occurs. The cells eventually die and desquamate from the secretory epithelium, forming a secretory plug mostly constituted by juxtaposed nonfragmented secretory cells. Because of the arrangement of the rosette-like scales surrounding the femoral pores, we suggest that when the animal is in a resting position, with its femoral regions touching the ground, these scales may be involved in the breakage of their respective plugs, depositing tiny portions on the substrate. In this manner, it seems that the method for signal dispersion in this species involves specifically adapted structures and does not simply involve the chance breakage of the plug, as the gland secretes it. Signal dispersion must also be intimately associated with the animal's movement within its territory.

Volatile emissions of adult male Triatoma infestans were collected on non-polar SPME fibers and analyzed by gas chromatography linked to a mass spectrometer. A complex mixture of 16 short-chain esters and acids were identified. The composition of short-chain aliphatic acids (ethanoic to nonanoic acids) was similar to previously reported results. The most abundant aliphatic acid was 2-methylpropanoic acid, constituting 18% of the total volatile content. Also abundant were the esters 2- and 3-methylbutyl 2-methylpropanoate, which constituted 30% and 22%, respectively, of the total volatile content. A similar pattern of compounds was observed in the volatiles secreted by dissected male Brindley's glands; however, in this case, 2- and 3-methylbutan-1-ol were detected which were not found in live insect volatile emissions. Large variability in volatile composition was also observed among the glands excised from different insects. Electroantennographic (EAG) evaluation of the components of Brindley's gland showed significant responses for 2- and 3-methylbutyl 2-methylpropanoate compared to controls. The mixture of volatiles secreted by excised Brindley's glands and the isolated 2- and 3-methylbutyl 2-methylpropanoate had repellent effects on both male and female T. infestans, possibly associated with a defensive strategy.

Chemical communication is an important component of mammalian social behaviors. Gray short-tailed opossums (Monodelphis domestica) communicate by scent marking. The male opossum possesses a prominent suprasternal scent gland, extracts of which strongly attract female opossums. This attractivity remains unaltered following repeated lyophilization. The suprasternal gland secretion functions in a sexually dimorphic manner, i.e., it elicits elevated levels of IP(3) in the vomeronasal (VN) sensory epithelium of female opossums, but suppressed the levels of IP(3) in the VN sensory epithelium of male opossums. The elevated levels of IP(3) induced by suprasternal gland secretion in female vomeronasal sensory epithelium is inhibited by the G(i/o) specific inhibitor, NF023, but not its inactive analogue, NF007. It is also suppressed by specific antibodies to the alpha subunits of G(i) and G(o) proteins, by the phospholipase C inhibitor, U73122, as well as by GDPbetaS. Surprisingly, GDPbetaS itself enhances basal levels of IP(3) in female VN sensory epithelium. This GDPbetaS-induced increase in levels of IP(3) is reduced by the PLC inhibitor, U73122, but not by the G(i/o) inhibitor, NF023. In addition, GDP also enhances basal levels of IP(3). GDPbetaS, a known inhibitor of G-protein activation, thus appears to have dual functions: as both stimulator and inhibitor of IP(3) production in the VN sensory epithelium of opossums. In contrast, this nucleotide analogue functions as an inhibitor in the VN sensory epithelium of mice. The mechanism of signal transduction underlying the suprasternal gland secretion-elicited signals in the VN sensory epithelium of opossums appears to involve signals that are generated through activation of G-protein-coupled receptors and transduced via activation of G(i/o)-proteins and the effector, phospholipase C, resulting in an increased production of the second messenger, IP(3). The extracellular signals are thus amplified.

To explore whether preputial gland secretions and/or urine from the house mouse (Mus musculus) can be used for coding information about sex, individuality, and/or the genetic background of strain [ICR/albino, Kunming (KM), and C57BL/6], we compared the volatile compositions of mouse preputial glands and urine using a combination of dichloromethane extraction and gas chromatography coupled with mass spectrometry (GC-MS). Of the 40 identified compounds in preputial gland secretions, 31 were esters, 2 sesquiterpens, and 7 alcohols. We failed to find any compound unique to a specific sex, individual, or strain. However, many low molecular weight compounds between the sexes, most compounds among individuals, and several compounds among the 3 strains varied significantly in relative ratios. These quantitative differences in preputial gland volatiles (analog coding) are likely to convey information about sex, individual, and the genetic background of mouse strain. We identified 2 new main and male-elevated compounds, 1-hexadecanol (Z=3.676, P=0.000, N=19 in ICR; Z=3.576, P=0.000, N=18) and 1-hexadecanol acetate (Z=3.429, P=0.000, N=19 in ICR; Z=3.225, P=0.001, N=18), which were eluted in GC chromatogram after the 2 sesquiterpens. They might also be potential male pheromones, in addition to the well-known E-beta-farnesene and E,E-alpha-farnesene. Additionally, a few compounds including 1-hexadecanol also varied with strains and might also code for genetic information. Of the 9 identified volatile compounds in male urine, (s)-2-sec-butyl-4,5-dihydrothiazole and R,R-3,4-dehydro-exo-brevicomin are known urine-originated male pheromones from previous studies. We also detected 6-hydroxy-6-methyl-3-heptanone, a male urinary pheromonal compound, which had not been directly detected by GC-MS previously. Chemical analysis shows that the genetically more closely related ICR and KM strains had a higher similarity in the volatile compositions of preputial glands and urine than that between ICR or KM and C57BL/6. R,R-3,4-dehydro-exo-brevicomin, in particular, was sensitive to genetic shifts and differed in relative abundance among the 3 strains, whereas (s)-2-sec-butyl-4,5-dihydrothiazole differed between ICR or Km and C57BL/6. Hence, these 2 compounds might code for information about their genetic background.

Compounds from the metasternal and Brindley's glands of the blood-sucking bug, Triatoma infestans, were identified by solid phase microextraction (SPME) and gas chromatography-mass spectrometry. Volatile compounds released by adult bugs during copulation or after mechanical disturbance were also characterized. Six compounds were identified and found consistently in all samples from metasternal glands. The most abundant were 3-pentanone, 2-methylbutanol, 3-pentanol, and an unidentified compound. The metasternal gland blends did not differ qualitatively between sexes. Compounds found in Brindley's glands were short chain acids, alcohols, esters, and a ketone with no qualitative differences between sexes. Isobutyric acid was the main component of this blend, and two new confirmed compounds were described as products of these glands: 2-butanone and 2-methylbutyric acid. 3-Pentanone was collected from the headspace over 33% of the copulating pairs of T. infestans. Volatiles found in the headspace of disturbed T. infestans adults included short-chain fatty acids, alcohols, esters, and ketones, with no qualitative differences between sexes. Both types of glands apparently discharge their contents after disturbance. However, most of the volatiles released by bugs after disturbance came from Brindley's glands. The locomotor activity of fourth instars increased significantly after stimulation with the odors emitted by disturbed adults, as compared with larvae stimulated by the odor of undisturbed adults or by clean air. We also studied the directional behavioral response of fifth instars to the disturbance scent in a locomotion compensator. Larvae exposed to volatiles released by disturbed adults walked away from the direction of the odor. The results suggest that this blend or part of it functions as an alarm pheromone for T. infestans. We suggest that the metasternal glands of this species are involved both in the sexual and the alarm contexts, and that the Brindley's glands probably have both alarm and defensive roles.

The cephalic labial gland secretion of Bombus semenoviellus males was analyzed, and its chemical composition is reported for the first time. The secretion functions as sex or marking pheromone. Eighty compounds were identified in the secretion, the main one being all-trans-geranylgeranyl acetate (48%). The same compound was shown to form 87% of the labial gland secretion of B. cullumanus males. Both species are closely related and belong to the subgenus Cullumanobombus.

Foragers of many species of stingless bees guide their nestmates to food sources by means of scent trails deposited on solid substrates between the food and the nest. The corresponding trail pheromones are generally believed to be produced in the mandibular glands, although definitive experimental proof has never been provided. We tested the trail following behavior of recruits of Trigona recursa in field experiments with artificial scent trails branching off from natural scent trails of this stingless bee. First-time recruits (newcomers) did not follow these trails when they were laid with pure solvent or mandibular gland extract. However, they did follow trails made with labial gland extract. Chemical analyses of labial gland secretions revealed that hexyl decanoate was the dominant component (72.4 +/- 1.9% of all volatiles). Newcomers were significantly attracted to artificial trails made with synthetic hexyl decanoate, demonstrating its key function in eliciting scent-following behavior. According to our experiments with T. recursa, the trail pheromone is produced in the labial glands and not in the mandibular glands. Hexyl decanoate is the first component of a trail pheromone identified and proved to be behaviorally active in stingless bees.

Mammalian scent marking is often associated with territorial defense. However, males and females may demonstrate different activity patterns and play different roles. Female mammals nurture the young during lactation, while males purportedly perform other tasks more frequently, such as territorial maintenance and defense. This paper investigates the contribution made by mated pairs of adult males and females to territorial scent-marking in the obligate monogamous Eurasian beavers (Castor fiber). We hypothesized that both sexes should show territorial behavior, and predicted that they deposit a higher proportion of scent marks at borders. We also hypothesized that a sexual dimorphism exists due to reproductive constraints on the females, and predicted that males should invest significantly more in scent-marking behavior than females during summer. We obtained behavioral data by radio tracking six mated pairs of Eurasian beavers during spring and summer 2000-2001 on two rivers in southeastern Norway. Our results showed that both males and females clustered their scent marks near territorial borders, but males deposited a larger number of scent marks than females and spent more time at borders. Males were also found to have a higher scent marking rate and scent marks per night than females during summer, but not during spring. Overall, scent marks per night were higher in males than females. We conclude that both males and females Eurasian beavers carry out territorial behavior by scent marking, but males carry a larger part of the territorial defense during summer when females lactate. Our results are discussed in the light of the codefense hypothesis.

The subsocial tenebrionid Parastizopus armaticeps Pér. is parasitized by the closely related Eremostibes opacus Koch (Coleoptera: Tenebrionidae). We found that the pygidial defensive secretions of both species are similar and contain a mixture of 1,4-benzoquinones, 1-alkenes, and monoterpene hydrocarbons. The 1-alkenes are dominated by 1-undecene, with admixtures of 1-tridecene in both species and 1-pentadecene in P. armaticeps only. Methyl- and ethyl-1,4-benzoquinone are the major quinones of the secretions of both species. The monoterpene fractions consist of (-)-alpha-pinene, (-)-camphene, sabinene, (-)-beta-pinene, and (-)-limonene. Volatiles trapped with Porapak Q at the entrance to the breeding burrows of P. armaticeps were identified as components of the defensive secretion. However, in contrast to the secretion, the 1,4-benzoquinones were almost completely absent in the volatiles. Bioassays investigating attraction showed that the cleptoparasite E. opacus was drawn to the monoterpene hydrocarbons, produced by P. armaticeps, and deterred by the 1,4-benzoquinones. The 1-alkenes had no effect. Among the monoterpenes, only (-)-camphene was attractive to E. opacus. This is one of the rare cases of chemical exploitation of defensive allomones, and the first based on odor homology. We have drawn an evolutionary scenario including various functional changes in the defensive secretion compounds, leading to the kairomonal exploitation.

Although many animals deposit scent marks, previous studies have focused almost entirely on rodents or on the chemical structure of the signal. Here, we study the quantity and temporal pattern of chemical deposition by the territorial sagebrush lizard Sceloporus graciosus, measuring both femoral pore and fecal deposits. Specifically, we tested whether variation in deposition is a good cue of individual and sexual identity and/or whether it is more closely associated with body size and reproductive state, indicators of physiological condition. The results support the latter hypothesis. We found that although the amount of fluid deposited on a single perch (rarely quantified in mammals) carries little information on individual or sexual identity, it reflects the physiological condition and reproductive state of individual lizards and is replenished on a roughly weekly cycle, potentially providing additional information on the producer's activity level. The amount of deposition may thus provide important information to chemical receivers making mate choice and territorial defense decisions. The results further suggest that seasonal increases in gland production allow lizards to mark more sites rather than to influence the quality of the signal on a single perch.