Lipophilic compounds in femoral secretions of males and females of the El Hierro giant lizard Gallotia simonyi (Lacertidae)

Many lizards use femoral gland secretions in reliable intraspecific communication. Based on mass spectra, obtained by GC–MS, we found 57 lipophilic compounds in femoral secretions of males and females of El Hierro giant lizards, Gallotia simonyi (fam. Lacertidae). Compounds included steroids (mainly cholesterol) and fatty acids ranging between n-C₁₆ and n-C₂₂ (mainly hexadecanoic and octadecanoic acids), followed by aldehydes, alcohols, ketones, squalene and waxy esters. There were important intersexual differences in the presence, abundance and number of compounds (more numerous in males). Males had higher proportions of the most odoriferous compounds (fatty acids and aldehydes), while females had higher proportions of more stable compounds (steroids, waxy alcohols, waxy esters and terpenoids). This suggests sexual differences in function of femoral secretions. In addition, some compounds could reflect the physiological state, allowing monitoring health of lizards from secretions samples, which is especially important given the critical conservation status of this lizard.     

Lipids in femoral gland secretions of male lizards, Psammodromus hispanicus

Many lizards produce chemical secretions that may be used as pheromones in reproductive behavior, but only a few studies have identified chemical compounds in secretions. By using GC–MS, we found only 20 lipophilic compounds in femoral glands secretion of male lizards, Psammodromus hispanicus. Main compounds were six steroids (mainly cholesterol and campesterol) and seven n-C₉ to n-C₁₈ carboxylic acids (especially dodecanoic acid), and minor components were six alcohols between C₁₆ and C₂₉ and squalene. We compared these chemicals with those previously found in secretions of the closely related sister species Psammodromus algirus and other lizard species.     

Chemical composition of femoral secretions of oviparous and viviparous types of male common lizards Lacerta vivipara

In spite of the importance of chemoreception in intraspecific communication of lizards, only a few studies have examined chemical composition of secretions of lizards. The secretion of the femoral glands of adult male lizards Lacerta vivipara contains a relatively low number (18) of lipophilic compounds in comparison with other related lacertid lizards. These compounds were identified on the basis of mass spectra, obtained by GC-MS. Chemicals included ten steroids (mainly cholesterol) and four carboxylic acids between n-C₁₂ and n-C₁₈, and minor components such as squalene, α-tocopherol, and two waxy esters, which may contribute to avoid oxidation of other lipophilic components in the fairly humid environments occupied by this lizard. Secretions of adult males from oviparous and viviparous populations did not differ in the numbers and quality of chemical compounds, but there were some differences in the relative proportion of some compounds. Males from oviparous populations had lower proportions of hexadecanoic acid and cholestan-3-one, and higher proportions of squalene than viviparous males. These differences might be explained by either small genetic differences between types or due to different microclimatic conditions in the original populations.     

Age related differences in lipophilic compounds found in femoral gland secretions of male spiny-footed lizards, Acanthodactylus erythrurus

Although chemoreception plays an important role in social organization of many lizards, only a few studies have examined the chemicals found in secretions used for intraspecific communication. We report the composition of the secretion of the femoral glands of males of the spiny-footed lizard (Acanthodactylus erythrurus). On the basis of mass spectra, obtained by GC/MS, we identified 45 lipophilic compounds, including several alcohols ranging from 10 to 29 carbon atoms (mainly hexacosanol and tetracosanol), steroids (mainly cholesterol and dehydrocholesterol), n-C9 to n-C20 carboxylic acids, esters of carboxylic acids, and minor components such as lactones, ketones, squalene and a-tocopherol. Some of these compounds are reported for the first time in lizards. Adult and subadult males differed in the composition of secretions, with C9 to C15 carboxylic acids being more abundant in younger than in older lizards, whereas C16 to C20 carboxylic acids were more abundant in older lizards. Also, older lizards had significant lower proportions of cholesterol and campesterol but higher proportions of dehydrocholesterol.     

Lanostane triterpenes of Canscora decussata

From the aerial parts of Canscora decussata Schult (Gentianaceae), five triterpenes, viz. gluanone, canscoradione, friedelin, fridelan-3-β-ol, and β-amyrin, three sterols, viz. sitosterol, stigmasterol, and campesterol, besides liberal amount of a mixtures of n-alkanes (C₂₇-C₃₁) and n-alkanols (C₂₆-C₃₂) have been isolated. The identity of the compounds has been established by chemical transformations, spectral evidence, and by direct comparison, where possible, with authentic reference materials. Gluanone and canscoradione have not been encountered before in nature.     

Chemical scent constituents in feces of wild Iberian wolves (Canis lupus signatus)

In spite of the importance of feces in scent marking and intraspecific chemical communication of many mammals, only a few studies have examined the chemical constituents of feces that could have a signaling function. We described here the chemicals found in feces recently deposited in the wild by adult and pup Iberian wolves (Canis lupus signatus). By means of analyses using gas chromatography–mass spectrometry (GC–MS), we identified 77 compounds in feces of adult wolves, mainly heterocyclic aromatic organic compounds, such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C₃ and n-C₁₈, aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. Some of the odoriferous compounds are very likely originated in the anal-sac secretions, and later incorporated onto feces during defecation. However, the abundance of the main odoriferous compounds in feces could be explained by the result of the bacterial action on food components. Feces of pups only had 26 compounds, most of these were also found in adults’ feces, but four compounds were only found in pups’ feces, and there were also age-related differences respect to the proportions of shared chemicals. These differences could be partly due to the absence of anal-sac glands in pups, which would not need to scent mark substrates.     

Lipophilic compounds in femoral secretions of male collared lizards,Crotaphytus bicinctores (Iguania,Crotaphytidae)

In many lizards, chemical compounds from the femoral gland secretions are used in intraspecific communication, but most studies describing these chemicals are for lizard species included in the Scleroglossa clade, whereas lizards within the Iguanian clade have been much less studied, probably because these lizards were considered to rely more on visual cues. However, many iguanian lizards have abundant femoral secretions and are able of chemosensory conspecific recognition, which might be based on compounds secreted by femoral glands. By using GC–MS analyses, we found 58 lipophilic compounds in femoral gland secretions of male Great Basin collared lizard, Crotaphytus bicinctores (Iguania, Crotaphytidae). Main compounds were steroids (mainly two triunsaturated steroids and cholesterol), carboxylic acids (mainly hexadecanoic acid), waxy esters of long chain fatty acids, alcohols (mainly hexadecanol), aldehydes and other minor compounds. We compared these compounds with those found in other lizard species and discussed the potential signaling function of some compounds and how the xeric habitat of this lizard could have conditioned the composition of secretions.     

Chemosensory exploration of male scent by female rock lizards result from multiple chemical signals of males

Multiple sexual signals may convey information on males' quality. However, most research focused on visual signals, ignoring chemical signals. In vertebrates, chemical signals are probably often a multicomponent mixture of several active compounds, but they are not well known. We examined the potential additive and interactive effects of 2 compounds (oleic acid and ergosterol) naturally found in femoral gland secretions of male rock lizards on chemosensory exploration behavior of females. Tongue-flick (TF) rates of females to male secretions may result from the combination of responses to multiple compounds. There may be an additive or synergetic effect because male secretions with the highest proportions of both compounds received the highest TF rates, suggesting that their scents were more intriguing. However, there might be an interactive effect too; female TF rates were higher to males' scent with high proportions of ergosterol alone, even if proportions of oleic acid were low, than to high proportions of oleic acid but with low proportions of ergosterol. Further bioassays testing TF behavior of females to standard compounds, presented alone or combined in different concentrations confirmed these findings. Variations in female TF behavior might be explained because different compounds signal different male traits of different importance for females. Our study suggested that femoral secretion of male rock lizards may act as a multicomponent chemical signal.     

Inter-island variation in femoral secretions of the Balearic lizard,Podarcis lilfordi (Lacertidae)

Many lizards use femoral gland secretions in intraspecific communication. Although there is a consistent interspecific variation in chemical composition of secretions, considerable variation is also often found between populations, which may affect conspecifc recognition and lead to speciation processes. Balearic lizards (Podarcis lilfordi) are currently distributed only in several isolated islets offshore of the main islands with different environmental conditions (vegetation, diet, density of population, etc). Also, there is a high genetic variability between populations. We examined whether there was a similar variation in the composition of the femoral secretions of male lizards, and which could be the causes of such variation. By using GC–MS analyses, we found 75 lipophilic compounds in femoral gland secretions of male P. lilfordi from three representative island populations. Main compounds were steroids (94.4%), mainly cholesterol, but we also found alkanes, ketones, waxy esters, squalene, carboxylic acids and their ethyl esters, alcohols and other minor compounds. However, there were clear differences between populations with respect to the number and relative proportions of compounds. Using the patterns of presence and abundance of compounds in secretions it is possible to predict the population of origin of a lizard. We discuss how these differences could be explained considering genetic and environmental differences between populations.     

A new sexual signal in rutting male red deer: Age related chemical scent constituents in the belly black spot

Rutting behaviour of red deer stags (Cervus elaphus) includes an extensive repertoire of visual and acoustic signals directed either to rival males or to females. As in other mammals, olfactory communication is expected to play a central role in these rutting interactions too, but this has rarely been investigated. Only during the rutting season, red deer males show a conspicuous black spot area throughout most of their underbelly produced by the impregnation of substances with a strong scent. Here, we examined the origin of these compounds and their potential role as chemical signals. By using gas chromatography–mass spectrometry (GC–MS), we identified 67 compounds in the hair from the belly black spot of red deer stags, mainly heterocyclic aromatic organic compounds, such as m-cresol, benzoic acid, cyclohexanecarboxylic acid and ethylphenol, but we also found steroids, such as cholesterol and androstane-3,17-dione, carboxylic acids and their esters between n-C₆ and n-C₂₂, alcohols, squalene and other minor compounds. Many of these compounds are found in the belly black spot but not in other hair areas, and may have originated from several sources, such as the urine or the sebaceous glands of the skin, which impregnated the belly. Moreover, we found differences in chemical profiles depending on age, with older males having higher proportions of benzoic acid and androstane-3,17-dione, but lower proportions of m-cresol. Because most of these compounds are strongly odoriferous, and appear related to male characteristics, our data indicate that scent from the hairs forming the black spot of the belly may be regarded as an overlooked new sexual chemical signal in red deer in the context of competition for mates during the rutting season.     

Resorcinol and m-guaiacol alkylated derivatives and asymmetrical secondary alcohols in the leaves from Tamarix canariensis

We have discovered that leaves from the halotolerant plant saltcedar (Tamarix canariensis [Willd.]) are a source of resorcinols and guaiacols. Specifically, the waxes of the saltcedar leaves contained high amounts of 5-n-alkylresorcinols (ARs; 17 g/kg dry weight), 5-n-alkyl-m-guaiacols (AGs; 14 g/kg dw) and secondary alcohols (44 g/kg dw). Herein we provide the report of 5-n-alkylresorcinols with long side-alkyl chains as natural compounds in Tamaricaceae. These compounds are homologous to ones previously reported almost exclusively in cereals. The ARs span the formulas n-C₁₄ to n-C₂₇, the most abundant of which is n-C₂₁. Although the odd-C-numbered compounds dominate, there are non-negligible amounts of the even-numbered homologs. We also provide, the first-ever report of 11 homologs of 5-n-alkyl-m-guaiacols (AGs) as natural compounds from the sample plant, which we characterized as the corresponding trimethylsilyl (TMS)-ether derivatives. The AGs contain a hydroxyl group at carbon 1 of the phenolic nucleus, a methoxy group at position 3, and a (predominantly odd-C-numbered) linear alkyl chain linked to the benzene ring at position 5. They span the formulas n-C₁₃ to n-C₂₇, the most abundant of which is n-C₂₁. Finally, we also isolated from saltcedar a series of eight asymmetric secondary alcohols, whose formulas range from n-C₂₅ to n-C₃₅ and whose major homolog is n-hentriacontan-12-ol.     

Flavanone and other constituents from Onychium siliculosum

Two new compounds, onitinoside and onysilin along with the known compounds, pinostrobin, onitin, onitisin, campesterol, sitosterol and n-alkanes (C₂₅-C₃₃) were isolated from Onychium siliculosum. Onitinoside and onysilin were identified by spectral and chemical methods as 4-O-glucosyl-6-(2′-hydroxyethyl)-2,2,5,7-tetramethylindan-1-one and 5-hydroxy-6,7-dimethoxyflavanone, respectively.     

Chemical compounds from femoral gland secretions of male Iberian rock lizards, Lacerta monticola cyreni

In spite of the importance of chemoreception and chemical signals in the social organization of lizards, there are only a few studies examining the chemical composition of secretions of lizards used for scent marking. The secretion of the femoral glands of male Iberian rock lizards (Lacerta monticola cyreni) contains 44 lipophilic compounds, including several steroids (mainly cholesterol), and n-C6 to n-C22 carboxylic acids, and minor components such as esters of carboxylic acids, alcohols, squalene, and one lactone. These compounds were identified on the basis of mass spectra, obtained by GC-MS. Most lipids were detected in all individuals, although relative proportions of each chemical show a high interindividual variability. This variability might be related to the characteristics or physical and health condition of males and might be the basis of female choice based on chemical cues observed in this lizard species.     

Supplementation of male pheromone on rock substrates attracts female rock lizards to the territories of males: a field experiment

Background

Many animals produce elaborated sexual signals to attract mates, among them are common chemical sexual signals (pheromones) with an attracting function. Lizards produce chemical secretions for scent marking that may have a role in sexual selection. In the laboratory, female rock lizards (Iberolacerta cyreni) prefer the scent of males with more ergosterol in their femoral secretions. However, it is not known whether the scent-marks of male rock lizards may actually attract females to male territories in the field.

Methodology/Principal Findings

In the field, we added ergosterol to rocks inside the territories of male lizards, and found that this manipulation resulted in increased relative densities of females in these territories. Furthermore, a higher number of females were observed associated to males in manipulated plots, which probably increased mating opportunities for males in these areas.

Conclusions/Significance

These and previous laboratory results suggest that female rock lizards may select to settle in home ranges based on the characteristics of scent-marks from conspecific males. Therefore, male rock lizards might attract more females and obtain more matings by increasing the proportion of ergosterol when scent-marking their territories. However, previous studies suggest that the allocation of ergosterol to secretions may be costly and only high quality males could afford it, thus, allowing the evolution of scent-marks as an honest sexual display.     

Sterols from Candida lipolytica yeast grown on n-alkanes

The sterols of Candida lipolytica grown on n-alkanes were isolated by reverse phase HPLC and found to be mainly ergosterol, with small quantities of ergost-7-en-3β-ol, ergosta-7,22-dien-3β-ol, ergosta-7,24(28)-dien-3β-ol and ergosta-5,7,9(11),22-tetraen-3β-ol.     

New compounds, sexual differences, and age-related variations in the femoral gland secretions of the lacertid lizard Acanthodactylus boskianus

Integumental gland secretions in lizards have been postulated to play a role as semiochemicals, but few studies have analysed the chemical nature of the gland secretions used in communication. We analysed the femoral gland secretions of Acanthodactylus boskianus using GC–MS, compared secretions of both sexes and different ages of males. For the first time in reptiles monoglycerides of fatty acids and glycerol monoethers of long chain alcohols were identified. In addition, alcohols, steroids, carboxylic acids, alkanes, amides, aldehydes, carboxylic acid esters, and squalene occurred. Sexual differences and age correlation in the amount of all major groups of compounds occurred, as such these results strengthen the theory that these secretions are used as semiochemicals. This work lays the foundations to test in future the role of chemical cues in mate choice and dominance hierarchies in lizards and to test the activity of compounds in behavioural assays to eventually identify the pheromones.     

Chemical constituents of the femoral gland secretions of male tegu lizards (Tupinambis merianae) (Family teiidae)

In spite of the importance of chemical signals (pheromones) in the reproductive behaviour of lizards, the chemical compounds secreted by their femoral glands, which may be used as sexual signals, are only known for a few lizard species. Based on mass spectra, obtained by GC-MS, we found 49 lipophilic compounds in femoral gland secretions of male tegu lizards (Tupinambis merianae) (fam. Teiidae), including a very high proportion of carboxylic acids and their esters ranging between n-C8 and n-C20 (mainly octadecanoic and 9,12-octadecadienoic acids), with much less proportions of steroids, tocopherol, aldehydes, and squalene. We discuss the potential function of these compounds in secretions, and compare the compounds found here with those documented for other lizard species.     

Characterization of a composite with enhanced attraction to savannah tsetse flies from constituents or analogues of tsetse refractory waterbuck (Kobus defassa) body odor

Savannah tsetse flies avoid flying toward tsetse fly-refractory waterbuck (Kobus defassa) mediated by a repellent blend of volatile compounds in their body odor comprised of δ-octalactone, geranyl acetone, phenols (guaiacol and carvacrol), and homologues of carboxylic acids (C₅-C₁₀) and 2-alkanones (C₈-C₁₃). However, although the blends of carboxylic acids and that of 2-alkanones contributed incrementally to the repellency of the waterbuck odor to savannah tsetse flies, some waterbuck constituents (particularly, nonanoic acid and 2-nonanone) showed significant attractive properties. In another study, increasing the ring size of δ-octalactone from six to seven membered ring changed the activity of the resulting molecule (ε-nonalactone) on the savannah tsetse flies from repellency to attraction. In the present study, we first compared the effect of blending ε-nonalactone, nonanoic acid and 2-nonanone in 1:1 binary and 1:1:1 ternary combination on responses of Glossina pallidipes and Glossina morsitans morsitans tsetse flies in a two-choice wind tunnel. The compounds showed clear synergistic effects in the blends, with the ternary blend demonstrating higher attraction than the binary blends and individual compounds. Our follow up laboratory comparisons of tsetse fly responses to ternary combinations with different relative proportions of the three components showed that the blend in 1:3:2 proportion was most attractive relative to fermented cow urine (FCU) to both tsetse species. In our field experiments at Shimba Hills game reserve in Kenya, where G. pallidipes are dominant, the pattern of tsetse catches we obtained with different proportions of the three compounds were similar to those we observed in the laboratory. Interestingly, the three-component blend in 1:3:2 proportion when released at optimized rate of 13.71mg/h was 235% more attractive to G. pallidipes than a combination of POCA (3-n-Propylphenol, 1-Octen-3-ol, 4-Cresol, and Acetone) and fermented cattle urine (FCU). This constitutes a novel finding with potential for downstream deployment in bait technologies for more effective control of G. pallidipes, G. m. morsitans, and perhaps other savannah tsetse fly species, in ‘pull’ and ‘pull-push’ tactics.     

Sterols of Xanthoria parietina: Evidence for two sterol ‘pools’ and the identification of a novel C,8 triene,ergosta-5,8,22-trien-3β-ol

Sterols extracted from Xanthoria parietina with organic solvents and released by saponification of the residual lichen tissue were analysed by GC-MS. The main components of the solvent-extractable sterols were two C₂₈ trienes and those of the more tightly bound sterols were ergost-5-en-3β-ol and two C₂₉ compounds. The structures of the C₂₈ compounds were shown to be ergosta-5,7,22-trien-3β-ol, Ia (ergosterol) and the previously unreported ergosta-5,8,22-trien-3β-ol, IIa, for which the name lichesterol is proposed. The main C₂₉ sterol was identified as (24R)-24-ethylcholesta-5,22-dien-3β-ol (poriferasterol).     

Free sterols,steryl esters,glucosides, acylated glucosides and water-soluble complexes in Calendula officinalis

In 3- and 14-day-old seedlings and in the leaves of Calendula officinalis the following sterols were identified: cholestanol, campestanol, stigmastanol, cholest-7-en-3-β-ol, 24-methylcholest-7-en-3β-ol, stigmast-7-en-3β-ol, cholesterol, campesterol, sitosterol, 24-methylcholesta-5,22-dien-3β-ol, 24-methylenecholesterol, stigmasterol and clerosterol. Sitosterol was predominant in young and stigmasterol in old tissues. Young tissues contained relatively more campesterol but in old tissues a C₂₈Δ^5,22 diene was present suggesting transformation of campesterol to its Δ^5,22 analog, similar to that of sitosterol to stigmasterol. All the identified sterols were present as free compounds and also in the steryl esters, glucosides, acylated glucosides and water-soluble complexes. The variations in the amounts of these fractions in the embryo axes and cotyledons of 3- and 14-day-old seedlings and the distribution of individual sterols among the fractions are discussed.