Scent Marking Research Articles

Symbiotic bacteria mediate volatile chemical signal synthesis in a large solitary mammal species

Mammalian chemosignals—or scent marks—are characterized by astounding chemical diversity, reflecting both complex biochemical pathways that produce them and rich information exchange with conspecifics. The microbiome of scent glands was thought to play prominent role in the chemical signal synthesis, with diverse microbiota metabolizing glandular products to produce odorants that may be used as chemosignals. Here, we use gas chromatography–mass spectrometry and metagenomic shotgun sequencing to explore this phenomenon in the anogenital gland secretions (AGS) of the giant panda (Ailuropoda melanoleuca). We find that this gland contains a diverse community of fermentative bacteria with enzymes that support metabolic pathways (e.g., lipid degradation) for the productions of volatile odorants specialized for chemical communication. We found quantitative and qualitative differences in the microbiota between AGS and digestive tract, a finding which was mirrored by differences among chemical compounds that could be used for olfactory communication. Volatile chemical compounds were more diverse and abundant in AGS than fecal samples, and our evidence suggests that metabolic pathways have been specialized for the synthesis of chemosignals for communication. The panda’s microbiome is rich with genes coding for enzymes that participate in the fermentation pathways producing chemical compounds commonly deployed in mammalian chemosignals. These findings illuminate the poorly understood phenomena involved in the role of symbiotic bacteria in the production of chemosignals.

Scent communication behavior by giant pandas

Behavioral strategies used in scent communication can reflect the adaptive capacity of animals. Signal detection theory and the principle of least effort posit that scent marking must be efficient and energy maximizing. The giant panda (Ailuropoda melanoleuca) is a solitary species that relies heavily on scent communication. There have been few studies on scent communication of wild pandas due to their elusive nature. To deepen the understanding of scent communication in this vulnerable species, we analyze a novel dataset obtained from integrating transect surveys on scent marked trees with infrared camera trapping of wild giant pandas performing scent marking and scent investigation behaviors. We found that pandas selected large coniferous trees for scent marking relative to what was available. Of the scent marked trees, trees that were more frequently marked than others were those of preferred species, high elevation, at topographical aspects conducive for odor transmission, with larger surrounding trees, and at gentle slopes. There were three peaks in the frequency of scent communication throughout the year in October, December, and March, the third period overlapping with the mating season. Scent communication occurred mainly during daytime hours, peaking at dusk (18:00–20:00). Frequency of anogenital gland secretion (AGS) markings were significantly greater than urine markings during the mating season but not during other times of year, which may reflect their stronger capacity to convey estrus state of females during mating season. The findings enrich the understanding of giant panda scent communication, and more broadly emphasize the importance of considering scent communication for conservation efforts such as corridor design for this vulnerable species.

Scent Marks Signal Species, Sex, and Reproductive Status in Tamarins (Saguinus spp., Neotropical Primates).

Olfactory communication is an important mediator of social interactions in mammals, thought to provide information about an individual’s identity and current social, reproductive, and health status. In comparison with other taxa such as carnivores and rodents, few studies have examined primate olfactory communication. Tamarins (Callitrichidae) conspicuously deposit odorous secretions, produced by specialized scent glands, in their environment. In this study, we combined behavioral and chemical data on captive cotton-top tamarins, Saguinus oedipus, and bearded emperor tamarins, S. imperator subgrisescens, to examine the role of olfactory communication in the advertisement of species, sex, and reproductive status. We observed no difference in scent-marking behavior between species; however, females marked more frequently than males, and reproductive individuals more than non-reproductive ones. In addition, tamarins predominantly used their anogenital gland when scent-marking, followed by the suprapubic gland. We collected swabs of naturally deposited tamarin anogenital scent marks, and analyzed these samples using headspace gas chromatography-mass spectrometry. Despite a limited sample size, we established differences in tamarin anogenital mark chemical composition between species, sex and reproductive status, and identified 41 compounds. The compounds identified, many of which have been reported in previous work on mammalian semiochemistry, form targets for future bioassay studies to identify semiochemicals. Our non-invasive method for collecting deposited scent marks makes it a promising method for the study of olfactory communication in scent-marking animal species, applicable to field settings and for the study of elusive animals.

A Semivolatile Floral Scent Marks the Shift to a Novel Pollination System in Bromeliads

Perfume flowers (sensu Vogel1) produce intense scents that function both as attractants and as the sole rewards for pollinators. The scent is collected exclusively by male euglossine bees and used during pre-mating behavior.2-5 Perfume flowers have evolved independently in 15 angiosperm families, with over 1,000 reported species across the Neotropical region.6 Members of Cryptanthus (Bromeliaceae) represent a puzzling exception among perfume flowers, as flowers produce nectar and do not emit a noticeable scent yet still attract euglossine males.7 Here, we studied the pollination ecology of Cryptanthus burle-marxii and decode the chemical communication between its flowers and euglossine males. Field observations revealed euglossine males and hummingbirds as potential pollinators. The bees always contacted anthers/stigma of C.burle-marxii while scraping the petals to obtain chemicals, whereas nectar-seeking hummingbirds normally only contacted the anthers. Based on gas chromatography-mass spectrometry/nuclear magnetic resonance analyses of flower scent samples and bioassays, we identified the diterpene copalol as the only floral scent compound triggering scent-gathering behavior in euglossine males. Unlike euglossine-bee-mediated pollination, hummingbird pollination is ancestral in the Cryptanthus clade, suggesting a case of an ongoing pollinator shift8-10 mediated by the evolution of perfume as a reward. Copalol was previously unknown as a floral scent constituent and represents the heaviest and least-volatile compound known to attract euglossine males. Our study provides the first experimental evidence that semivolatile floral compounds can mediate euglossine bee interactions. Male euglossine pollination in other plant species lacking noticeable floral scents11-13 suggests that semivolatile-mediated pollinator attraction is more widespread than currently appreciated.

The long-term impact of infant rearing background on the behavioural and physiological stress response of adult common marmosets (Callithrix jacchus)

Although triplet litters are increasing in captive colonies of common marmosets, parents can rarely rear more than two infants without human intervention. There is however much evidence that early life experience, including separation from the family, can influence both vulnerability and resilience to stress. The current study investigated the behavioural and hypothalamic pituitary adrenal (HPA) axis response to the routine stressor of capture and weighing in adult common marmosets (Callithrix jacchus), reared as infants under 3 different conditions: family reared twins (n = 6 individuals), family reared animals from triplet litters where only 2 remain (2stays: n = 8) and triplets receiving supplementary feeding from humans (n = 7). In the supplementary feeding condition, infants remained in contact with each other when they were removed from the family. There were no significant differences (P > 0.5) in cortisol level or behaviour between the rearing conditions. In all conditions, salivary cortisol decreased from baseline to post capture, which was accompanied by increases in agitated locomotion. Familyreared 2stays demonstrated significant cortisol decreases from baseline to post capture (post 5 min.: P = 0.005; post 30 min.: P = 0.018), compared to the other conditions. Family reared twins displayed significantly more behavioural changes following the stressor than the other conditions, including significant increases in scent marking (post 5 min. and post 30 min.: P = 0.028) and significant decreases in inactive alert (post 5 min.: P = 0.042), calm locomotion (post 5 min.: P = 0.028; post 30 min.: P = 0.046) and proximity to partner (post 5 min.: P = 0.046). There were increases in behaviour suggesting reduced anxiety, including significantly more exploration post capture in supplementary fed triplets (post 5 min.: P = 0.041), and significantly more foraging post capture in family reared 2stays (post 5 min. .: P = 0.039). However, as differences between rearing conditions were minimal, supplementary feeding of large litters of marmosets at this facility did not have a major effect on stress vulnerability, suggesting that this rearing practice may be the preferred option if human intervention is necessary to improve the survival of large litters.

Behavioral responses of Japanese macaques to playback-simulated intergroup encounters

Group-living animals gain fitness benefits from intergroup aggression, but also incur costs. Advertisement behaviors, such as long-distance calls and scent marking, help animals avoid disadvantageous, or less rewarding, fights. However, it remains unclear how species that lack advertisement behaviors respond to auditory information from other groups. We hypothesized that such species use auditory information prior to visual contact with the opponent group to determine its relative resource holding potential. Here, we aimed to identify the behavioral responses of Japanese macaques to simulated intergroup encounters. We conducted a vocal playback experiment and behavioral observations of 11 adult males and females from two groups intermittently from October 2015 to June 2017. In response to vocalizations of other groups, the macaques stopped feeding, decreased contact calling, and increased visual scanning, which could enable them to make timely and accurate decisions as to whether to fight or flee. The spatial cohesion of the group did not change. These results partly support our hypothesis and suggest that the onset of increased vigilance to opponents is prior to visual contact with them. The present study highlights the importance of investigating early phases of intergroup encounters in species lacking advertisement behaviors to obtain new insights on intergroup conflicts in animals.

Sociality and signaling activity modulate information flow in river otter communication networks

Abstract Animal communication networks are built from interactions between senders and receivers of signals. The drivers of signaling decisions, which are the building blocks of such networks, are not well understood. Theory predicts that conditions which ensure information spread to the largest possible number of receivers should be favored. Several carnivores use latrine sites for visual, olfactory, and auditory signaling. We tested the hypotheses that signaling behavior at latrine sites is influenced by social structure and locally acquired information on the presence of conspecifics, using coastal river otters (Lontra canadensis), in Alaska. River otters exhibit a flexible social system of mostly males that communicate through scent marking at latrines. During scent marking, river otters also perform feet stomping, which may add a visual component to their signal. Using trail camera footage, we found that solitary otters were more likely to perform both sniffing and scent marking compared with otters in groups. Feet stomping was more intense for solitary otters but less pronounced during overmarking. Signalers demonstrated a greater tendency to scent mark when in smaller groups at highly active latrines, whereas feet stomping was more intense in recently visited sites. When in groups, scent-marking frequency increased when other individuals were signaling, suggesting a positive feedback, possibly driven by feet stomping. In concert, our results suggest that in river otters, scent-marking decisions minimize signal dilution by being performed in small groups and maximize the receivers through preferential signaling at latrines with higher, more recent activity. Because signaling decisions in social animals are linked to key life-history events such as mating and group membership shifts, understanding their individual and population-level drivers can be crucial.

The scent world of cats: where to place a urine scent mark to increase signal persistence?

Abstract Scent-marking is a predominant form of communication among felids, with urine spraying having a key role. Detectability and longevity of scent marks are recognized as crucial for efficiency of scent-marking, but there is limited research that has tested scent persistence with respect to various environmental factors. We used an experimental framework to measure human-perceived strength of felid urine smell and determine the effects of substrate, tilt and aspect of marked surfaces on persistence of the simulated scent marks. We used area under the curve (AUC), calculated for the scent strength of each scent-marked surface over time, as a proxy for urine scent preservation. Thereafter, we used ANOVA, followed by analysis of differences of interest between the marking sites, to assess the effect of environmental factors on human-perceived scent mark persistence. Odour persisted significantly better on rough surfaces, surfaces covered with moss and on surfaces with overhanging tilts, while there was no significant difference between the northerly- and southerly-oriented surfaces. The results are generally in accordance with the use and selection of marking sites previously reported for wild felids throughout the world, confirming that in their marking behaviour felids strive to prolong the persistence of scent marks. This knowledge will help researchers in interpretation of data on scent-marking and to evaluate the adaptive significance of this behaviour.

Female-Based Patterns and Social Function in Avian Chemical Communication.

Much of the growing interest in avian chemical signals has focused on the role of kin recognition or mate attraction, often with an emphasis on males, with uropygial gland secretions perhaps providing information about an individual's identity and quality. Yet, data collected to date suggest sexual dimorphism in uropygial glands and secretions are often emphasized in female, rather than in male birds. That is, when a sexual difference occurs (often during the breeding season only), it is the female that typically exhibits one of three patterns: (1) a larger uropygial gland, (2) a greater abundance of volatile or semi-volatile preen oil compounds and/or (3) greater diversity of preen oil compounds or associated microbes. These patterns fit a majority of birds studied to date (23 of 30 chemically dimorphic species exhibit a female emphasis). Multiple species that do not fit are confounded by a lack of data for seasonal effects or proper quantitative measures of chemical compounds. We propose several social functions for these secretions in female-based patterns, similar to those reported in mammals, but which are largely unstudied in birds. These include: (1) intersexual advertisement of female receptivity or quality, including priming effects on male physiology, (2) intrasexual competition, including scent marking and reproductive suppression or (3) parental behaviors, such as parent-offspring recognition and chemical protection of eggs and nestlings. Revisiting the gaps of chemical studies to quantify the existence of female social chemosignals and any fitness benefit(s) during breeding are potentially fruitful but overlooked areas of future research.

Conspecific recognition of pedal scent in domestic dogs

Carnivores rely heavily on scent to communicate with conspecifics. Scent glands located on the underside of the feet provide an especially efficient way of leaving a scent trail. Although domestic dogs (Canis familiaris) are well-known for their olfactory abilities and scent marking behaviours, their use of pedal scent for communication remains unknown. We studied the reaction of intact dogs of both sexes to male and female pedal scent as well as a control sample of scent taken from the ground, using sniffing time and nostril usage as an indicator of interest level and emotional valence. In male subjects, only the sniffing duration for other males differed from the control samples, with no clear difference detected between male and female scent. Females showed no difference in the sniffing duration for any sample type. Conversely, male nostril use did not differ between the sample types, whereas females demonstrated a right nostril bias when sniffing the scent from other females and a left nostril bias when sniffing the control. We have shown that dogs recognize scent taken from the pedal glands from other dogs, although the extent to which they use this information to determine the sex of the scent depositor remains unclear.

The effect of social odour context on the amount of time male meadow voles, Microtus pennsylvanicus, self-groom

Abstract Communicational behaviours by individuals provide information for not only the intended target(s) of the signal but any non-target individual(s) that may be nearby. For terrestrial mammals a major form of communication and social information is through odours via scent marking and self-grooming. Self-grooming is a ubiquitous behaviour in mammals with the function thought to primarily be centred on personal care. But it has been found in rodents that self-grooming will occur in the presence of social odours thus potentially serving a communicative role. For example, male meadow voles (Microtus pennsylvanicus) self-groom in the presence of a female conspecific odour but not a male conspecific odour. Most studies examining self-grooming as a form of olfactory communication have used single odour donors but in a natural environment individuals will come across complex social odour situations. Therefore, we examined how male meadow voles respond to complex social odours with regards to their self-grooming behaviour. We tested the hypothesis that self-grooming can act as a form of olfactory communication and that male meadow voles will control this behaviour measured by differences in self-grooming rates based on social contexts. Male meadow voles did not show differences in the amount of time spent self-grooming to social odours that contained a female and varying number of rival males (0, 1, 3, or 5) or if the social odour contained an acquainted or novel male. Male meadow voles did self-groom more to a social odour that contained a female and a younger male compared to when the social odour contained a female and older male. Male meadow voles appear to adjust their self-grooming behaviour based on the context of the social information. This may be a strategy that can maximize that individual’s fitness by adjusting how much information is provided to potential rivals and mates.

Real power loss reduction by hyena optimizer algorithm

<p><span>To solve optimal reactive power problem this paper projects Hyena Optimizer (HO) algorithm and it inspired from the behaviour of Hyena. Collaborative behaviour & Social relationship between Hyenas is the key conception in this algorithm. Hyenas a form of carnivoran mammal & deeds are analogous to canines in several elements of convergent evolution. Hyenas catch the prey with their teeth rather than claws – possess hardened skin feet with large, blunt, no retractable claws are adapted for running and make sharp turns. However, the hyenas' grooming, scent marking, defecating habits, mating and parental behaviour are constant with the deeds of other feliforms. Mathematical modelling is formulated for the basic attributes of Hyena. Standard IEEE 14,300 bus test systems used to analyze the performance of Hyena Optimizer (HO) algorithm. Loss has been reduced with control variables are within the limits.</span></p>

How to maintain underground social relationships? Chemosensory sex, partner and self recognition in a fossorial amphisbaenian.

Maintaining social relationships depends on the ability to recognize partners or group members against other individuals. This is especially important in animals with relatively stable social groups. The amphisbaenian Trogonophis wiegmanni is a semi blind fossorial reptile that spends its entire life underground where it interacts with mates and social partners. In this environment, visual cues are limited. Chemosensory cues may rather allow conspecific social and partner recognition. We recorded the number of tongue-flick (TF) rates of T. wiegmanni amphisbaenians to scents of both sexes with different pairing social bonds (familiar vs. unfamiliar) presented on cotton swabs to test discrimination of social groups. As seen from a rise in the number of TFs, males discriminated unfamiliar females from unfamiliar males. This suggests that chemical cues may be used by males to locate new mates. In contrast, females detected scent of unfamiliar conspecifics, but did not show sex discrimination. Both males and females discriminated the scent of an individual with which they had formed a pair bond from an unfamiliar individual of the same sex as the partner. Also, males, but not females, were capable of self-recognition, suggesting that scent marks of males in home ranges may provide individual information in intrasexual relationships. We conclude that conspecific discrimination based on chemical cues may allow the maintenance of social relationships and relatively stable pairs in fossorial reptiles inhabiting visually restricted environments.

Agonistic behaviors and neuronal activation in sexually naïve female Mongolian gerbils

Agonistic interaction is important for establishing social hierarchy and determining access to limited resources. Although there are substantial studies investigating the neural mechanisms of aggressive or defensive behavior in male rodents, little attention has been paid to the mechanisms underlying agonistic behaviors in females. In the present study, we depicted patterns of agonistic behaviors in sexually naïve female Mongolian gerbils (Meriones unguiculatus) and examined the neuronal activation in the brain by Fos-immunoreactive (Fos-ir) staining. We found that the winner-loser relationship was established rapidly. Winners displayed higher levels of aggression, environmental exploration, scent marking, and self-grooming, but less defensive behavior, in comparison to losers. Several patterns of Fos-ir expression emerged following agonistic interactions. Winners had the number of Fos-ir cells in the ventrolateral subnucleus of the ventromedial hypothalamus (VMHvl) and dorsal periaqueductal grey (PAGd) more than the controls but less than the losers. Losers also had more Fos-ir cells in the paraventricular nucleus of the hypothalamus (PVN), anterior medial (BSTam) and anteriolateral (BSTal) subnuclei of the bed nucleus of the stria terminalis (BST), and the ventral subnucleus of the lateral septum (LSv), as well as less Fos-ir cells in the dentate gyrus of the hippocampus (DG), compared to the controls. In addition, the number of Fos-ir cells showed similar increases in the principal nucleus (BSTpr) and interfascicular nucleus (BSTif) of the BST and amygdala (AMYG) in both the winners and losers, compared to the controls. Together, these data illustrate the patterns of altered neuronal activation in a behavior-, social status-, and brain region-specific manner, implicating potential roles of the brain neural circuit in mediating agonistic interactions in female Mongolian gerbils.

Experimental Evaluation of Spontaneous Olfactory Discrimination in Two Nocturnal Primates (Microcebus murinus and M. lehilahytsara).

Solitary species often employ chemocommunication to facilitate mate localization. In the solitarily foraging, nocturnal mouse lemurs (Microcebus spp.), females advertise their short period of estrus acoustically and by increased scent marking, whereas males search widely for receptive females. Both sexes can be trained by operant conditioning to discriminate conspecific from heterospecific urine scent. However, it is not known, if males during and outside the reproductive season show different spontaneous interest in conspecific female urine, and if urine from estrous females elicits a higher investigation response than that from diestrous females. We established a spontaneous discrimination paradigm and quantified olfactory investigation responses of 21 captive male mouse lemurs of M. lehilahytsara and M. murinus when presenting 1 conspecific and 1 heterospecific female urine odor sample simultaneously. Overall, M. murinus investigated stimuli significantly longer than M. lehilahytsara. Moreover, males of M. murinus showed significantly longer olfactory investigation at conspecific urine samples during but not outside the reproductive season. This indicates that female urinary cues are spontaneously discriminated by male M. murinus and that this discrimination is more relevant during the reproductive season. However, males of both species did not show different responses toward urine samples from estrous versus diestrous females. Finally, male age did not correlate with the overall duration of olfactory investigation, and investigation levels were similar when testing with fresh or frozen urine samples. In conclusion, this new spontaneous discrimination paradigm provides a useful additional tool to study olfactory communication of nocturnal primates from the receiver's perspective.

Sex differences in olfactory social recognition memory in meadow voles, Microtus pennsylvanicus

AbstractTerrestrial mammals, like rodents, use odors, and scent marks to indicate their presence in an area to conspecifics. These odors convey information about the scent donor's genotype, sex, condition, and age. The ability to discriminate among the scent marks of conspecifics and later recollect the identity of the donor is essential for choosing between familiar and unfamiliar mates. We tested the hypothesis that the promiscuous meadow vole (Microtus pennsylvanicus) can recollect the odor of a familiar, opposite‐sex conspecific and distinguish it from that of an unfamiliar, opposite‐sex conspecific. We also hypothesized that because reproductive success is highly skewed among male meadow voles and competition for mates is intense, males will be more likely than females to recollect the odor of a familiar, opposite‐sex conspecific and distinguish it from that of an unfamiliar, opposite‐sex conspecific, for a longer period of time. Using a habituation task, we first exposed the voles, 4 times successively, to the anogenital area scent of an opposite‐sex conspecific. Then, 1 hr, 24 hrs, 72 hrs, or 96 hrs after the fourth exposure, voles were presented with the odor of the donor from the exposure phase (familiar donor) and that of an unfamiliar, opposite‐sex conspecific. Female meadow voles spent similar amounts of time investigating the scent of the familiar male donor and that of an unfamiliar male donor after the 1‐hr and 24‐hr intervals. Male meadow voles, however, spent more time with the scent of an unfamiliar female donor than that of the familiar female donor after the 1‐hr, 24‐hr, and 72‐hr intervals, suggesting that male voles could recollect the scent mark of a familiar female for at least three days. The implications of these sex differences in social memory may reflect the different strategies male and female meadow voles use in the recognition of previous and potential mates. Recognition of an individual's scents may enhance fitness by allowing animals to direct appropriate behaviors toward those individuals.

Contextual complexity of chemical signals in callitrichids.

In nearly four decades our research and that of others on chemical signaling in callitrichid primates suggest a high degree of contextual complexity in both the use of signals and the response to these signals. We describe our research including observational field studies, behavioral bioassays ("playbacks"), functional imaging, and conditioning studies. Scent marking in both captivity and the wild is used for more than just territorial marking. Social contextual effects are seen in responses by subordinate females responding with ovulatory inhibition only to chemical signals from familiar dominant reproductive females. Males detect ovulation through changes in scent marks. Males responded behaviorally and hormonally to chemical signals of novel ovulating females as a function of their reproductive status (fathers, males paired with a female but not fathers, and single males). Multiple brain areas are activated in males by female chemical signals of ovulation including areas relating to memory, evaluation, and motivation. Furthermore, males can be conditioned to respond sexually to a nonsexual odor demonstrating that learning plays an important role in response to chemical signals. Male androgen and estrone levels changed significantly in response to infant chemical signals as a function of whether the males were fathers or not, whether the odors were from their own versus other infants, as well as the infant's stage of development. Chemical signals in callitrichids are providing a rich source of understanding the context and function of the chemical sensory system and its stimulation of neural, behavioral, and hormonal actions in the recipients.

Scent marking in wolves Canis lupus inhabiting managed lowland forests in Poland

In wolves Canis lupus, scent marking plays an important role in territory defence. In Europe, studies on patterns of scent marking in wolves have mostly been conducted in mountains or primeval forests, but since these areas are characterised by low human activity, the impact of people on this behaviour has been neglected. We conducted a study that combined genetic methods with an analysis of the spatial distribution of wolf territory markings in lowland managed forests with high human activity. We found that scent markings are deposited by all members of wolf family groups. Wolves most intensively marked crossroads and their vicinity, especially on roads only accessible for four-wheel drive cars. Our study provides further evidence that crossroads of forest roads play a crucial role in wolf scent marking. The results of our study may be useful during inventories of wolf populations based on collecting indirect signs of their presence or non-invasive genetic sampling.

A mechanistic, stigmergy model of territory formation in solitary animals: Territorial behavior can dampen disease prevalencebut increase persistence.

Although movement ecology has leveraged models of home range formation to explore the effects of spatial heterogeneity and social cues on movement behavior, disease ecology has yet to integrate these potential drivers and mechanisms of contact behavior into a generalizable disease modeling framework. Here we ask how dynamic territory formation and maintenance might contribute to disease dynamics in a territorial, solitary predator for an indirectly transmitted pathogen. We developed a mechanistic individual-based model where stigmergy-the deposition of signals into the environment (e.g., scent marking, scraping)-dictates local movement choices and long-term territory formation, but also the risk of pathogen transmission. Based on a variable importance analysis, the length of the infectious period was the single most important variable in predicting outbreak success, maximum prevalence, and outbreak duration. Host density and rate of pathogen decay were also key predictors. We found that territoriality best reduced maximum prevalence in conditions where we would otherwise expect outbreaks to be most successful: slower recovery rates (i.e., longer infectious periods) and higher conspecific densities. However, for slower pathogen decay rates, stigmergy-driven movement increased outbreak durations relative to random movement simulations. Our findings therefore support a limited version of the "territoriality benefits" hypothesis-where reduced home range overlap leads to reduced opportunities for pathogen transmission, but with the caveat that reduction in outbreak severity may increase the likelihood of pathogen persistence. For longer infectious periods and higher host densities, key trade-offs emerged between the strength of pathogen load, the strength of the stigmergy cue, and the rate at which those two quantities decayed; this finding raises interesting questions about the evolutionary nature of these competing processes and the role of possible feedbacks between parasitism and territoriality. This work also highlights the importance of considering social cues as part of the movement landscape in order to better understand the consequences of individual behaviors on population level outcomes.

Volatile fatty acid and aldehyde abundances evolve with behavior and habitat temperature in Sceloporus lizards.

Animal signals evolve by striking a balance between the need to convey information through particular habitats and the limitations of what types of signals can most easily be produced and perceived. Here, we present new results from field measures of undisturbed behavior and biochemical analyses of scent marks from 12 species of Sceloporus lizards to explore whether evolutionary changes in chemical composition are better predicted by measures of species behavior, particularly those associated with visual displays, chemoreception, and locomotion, or by measures of habitat climate (precipitation and temperature). We found that more active lizard species used fewer compounds in their volatile scent marks, perhaps conveying less specific information about individual and species identity. Scent marks from more active lizard species also had higher proportions of saturated fatty acids, and the evolution of these compounds has been tracking the phylogeny closely as we would expect for a metabolic byproduct. In contrast, the proportions of unsaturated fatty acids were better explained by evolutionary shifts in habitat temperature (and not precipitation), with species in warmer climates using almost no volatile unsaturated fatty acids. The proportion of aldehydes was explained by both behavior and environment, decreasing with behavioral activity and increasing with habitat temperature. Our results highlight the evolutionary flexibility of complex chemical signals, with different chemical compounds responding to different elements of the selective landscape over evolutionary time.