Honest Signal Research Articles

Impact of Honest Signal, Cues, Prey’s Experience Rate and Environmental Toxicity in a Predator–Prey Interaction Model

Biological signaling plays a crucial role in predator–prey interaction systems, serving both intraspecific and interspecific communication purposes. Prey populations utilize signaling internally, employing honest signals among themselves to enhance their defense capabilities. Conversely, they also use signaling for interspecific communication, emitting cues to predators to increase their own chances of survival. Recently, Al-Salman et al. [Appl. Math. Modell. 89, 1405 (2021)] proposed a two-species interaction model incorporating Holling Type II predation along with honest signals and cues. In this paper, we extend and modify their study by incorporating factors such as prey’s experience rate and environmental toxicity in prey populations. We conduct a comprehensive mathematical and numerical analysis of the model. We investigate the positive invariance and dissipativeness of the model, discuss the existence of equilibrium points and analyze the behavior of the system around all equilibrium points. Particularly, we determine conditions for local stability and Hopf bifurcation of the system. Furthermore, we perform a detailed numerical analysis to study periodic solutions through Hopf bifurcations in the proposed system. We plot two-parameter bifurcation diagrams to examine changes in the system with combined effects, identifying critical values for stability switching. There is no chaotic dynamics seen in our investigation. Numerical results indicate that the system tends to stabilize when the experience rate is high, and the rate of error-prone honest signals regulates system stability. Additionally, we analyze how environmental toxicity affects the stability of the system.

Spread of yellow-bill-color alleles favored by selection in the long-tailed finch hybrid system

Carotenoid pigments produce the yellow and red colors of birds and other vertebrates. Despite their importance in social signaling and sexual selection, our understanding of how carotenoid ornamentation evolves in nature remains limited. Here, we examine the long-tailed finch Poephila acuticauda, an Australian songbird with a yellow-billed western subspecies acuticauda and a red-billed eastern subspecies hecki, which hybridize where their ranges overlap. We found that yellow bills can be explained by the loss of C(4)-oxidation, thus preventing yellow dietary carotenoids from being converted to red. Combining linked-read genomic sequencing and reflectance spectrophotometry measurements of bill color collected from wild-sampled finches and laboratory crosses, we identify four loci that together explain 53% of variance in this trait. The two loci of largest effect contain the genes CYP2J19, an essential enzyme for producing red carotenoids, and TTC39B, an enhancer of carotenoid metabolism. A paucity of protein-coding changes and an enrichment of associated upstream variants suggest that the loss of C(4)-oxidation results from cis-regulatory evolution. Evolutionary genealogy reconstruction indicates that the red-billed phenotype is ancestral and that yellow alleles at CYP2J19 and TTC39B first arose and fixed in acuticauda approximately 100 kya. Yellow alleles subsequently introgressed into hecki less than 5 kya. Across all color loci, acuticauda-derived variants show evidence of selective sweeps, implying that yellow bill coloration has been favored by natural selection. Our study illustrates how evolutionary transitions between yellow and red coloration can be achieved by successive selective events acting on regulatory changes at a few interacting genes.

Costly Signaling as an Integral Part of the Systemic Approach to Religion

In this commentary on Purzycki and Sosis’ book Religion Evolving: Cultural, Cognitive, and Ecological Dynamics (2022), I subject their central assumption, namely that religious costs function as honest signals of commitment to systematic scrutiny. Many studies show that people who partake in (costlier) rituals cooperate (to a larger extent), but these studies are often non-experimental and say only a little about the causal relationship between signals and signaled quality, i.e., willingness to cooperate. Reviewing the existing literature on religious costly signaling, I argue that the core costly signaling model originally developed in evolutionary biology (and economics) is only partially supported when applied to religious signaling. At the same time, I show that little is known about the interactions between costly signals and supernatural beliefs. I discuss the results of the recent experimental work that tested basic assumptions of human costly signaling within the religious context.

Plant-to-plant defence induction in cotton is mediated by delayed release of volatiles upon herbivory.

Caterpillar feeding immediately triggers the release of volatile compounds stored in the leaves of cotton plants. Additionally, after 1 d of herbivory, the leaves release other newly synthesised volatiles. We investigated whether these volatiles affect chemical defences in neighbouring plants and whether such temporal shifts in emissions matter for signalling between plants. Undamaged receiver plants were exposed to volatiles from plants infested with Spodoptera caterpillars. For receiver plants, we measured changes in defence-related traits such as volatile emissions, secondary metabolites, phytohormones, gene expression, and caterpillar feeding preference. Then, we compared the effects of volatiles emitted before and after 24 h of damage on neighbouring plant defences. Genes that were upregulated in receiver plants following exposure to volatiles from damaged plants were the same as those activated directly by herbivory on a plant. Only volatiles emitted after 24 h of damage, including newly produced volatiles, were found to increase phytohormone levels, upregulate defence genes, and enhance resistance to caterpillars. These results indicate that the defence induction by volatiles is a specific response to de novo synthesised volatiles, suggesting that these compounds are honest signals of herbivore attack. These findings point to an adaptive origin of airborne signalling between plants.

Pterin-Based Red Coloration Predicts the Outcome of Male-Male Competition in Guinan Toad-Headed Lizard.

Animal coloration offers a unique opportunity to explore the evolutionary mechanisms underlying phenotypic diversity. Conspicuous coloration caused by pigments plays a crucial role in social signaling across multiple species by conveying information about individual quality, social ranks, or reproductive condition. Nevertheless, most previous studies have focused predominantly on colors produced by the exogenous pigments-carotenoids. Pterins are another prevalent group of conspicuous pigments, which can be produced endogenously and have received comparatively little attention. Whether pterin-based colors represent reliable signals remains elusive. The remarkable red ventrolateral coloration exhibited by males of the Guinan toad-headed lizard (Phrynocephalus guinanensis) in the Mugetan Desert presents an ideal model for investigating pterin-based coloration. Through electron microscopy and metabolomic identification, we discovered three types of pterin pigments within xanthophores. Integrating a series of morphological measurements and behavioral experiments, we found that this red coloration was not correlated with body size, bite force, and testosterone level, nor did females show a preference bias toward it. However, the red intensity predicted male-male competition outcomes, with deeper red males being more likely to emerge as winners. Our results indicated that the pterin-based coloration could convey information about male quality, suggesting its potential role in honest signaling, given the vital importance of pterin metabolism in physiological processes. This study provides a novel case into the understanding of pterin-based colors in animals.

Sexual selection for single song repertoires.

Despite birdsong being one of the most studied models of sexual selection, how it operates in birds that sing only one song remains poorly understood. A recent study using a big data approach reveals a novel aspect of song that may potentially function as an honest signal of male quality and a way to maintain listener attention.

Differences in honeybee queen pheromones revealed by LC-MS/MS: Reassessing the honest signal hypothesis

The honest signal hypothesis posits that social insect queens emit pheromonal signals that convey information about fecundity, which workers use to make decisions around investing in direct or indirect fitness. We used liquid chromatography-tandem mass spectrometry to measure honeybee (Apis mellifera) queen retinue pheromone (QRP) in relation to age, laying status, and acceptance using a protocol that enables concurrent metabolomic and lipidomic analyses. Older queens produced higher levels of the QRP components 9-R-hydroxydec-2(E)-enoic acid (9(R)-HDA), linolenic acid (LEA), and 4-hydroxy-3-methoxyphenylethanol (HVA) compared to younger queens, with HVA also correlating with ovary mass. However, ovary mass was not an influential metric for worker decision-making around queen acceptance; therefore, the relationship between HVA and ovary mass is merely an "honest signal" of a non-influential metric. Parallel metabolomic and lipidomic analyses showed that samples cluster according to queen age and mating status, but not ovary mass, revealing many other physiological changes occurring in the queen's early life.

What Makes Peer Fundraisers Successful? Examining Peer‐to‐Peer Fundraising Success in the Context of Peer‐to‐Peer Nonprofit–Business Collaboration

ABSTRACTTo advance the conceptual understanding of what drives peer‐to‐peer fundraising success, this study takes a first step toward conceptualizing antecedents of peer fundraiser success based on a real‐world nonprofit–business collaboration. Drawing on social network and signaling theories, combined with knowledge from peer‐to‐peer fundraising literature, the authors developed and tested a mid‐range theory‐driven framework of peer fundraising success. The study collected observable data from a peer‐to‐peer collaboration between UNICEF and Les Mills, labeled “Workout for Water” campaign, and analyzed a unique dataset of 1899 fitness instructors who were engaged in the campaign as peer fundraisers. By contrasting characteristics and actions of successful and unsuccessful peer fundraisers, the empirical evidence from the two‐part model affirms several antecedents distinguishing between those peer fundraisers who achieve fundraising success and those who do not. The personal efforts to initiate additional actions and peer fundraiser's professional reputation within the peer community are particularly important. Furthermore, personalizing the individual's online fundraising page is important for overcoming the barrier of receiving no donations. As a key implication for practice, we present how to better realize peer‐to‐peer fundraising campaigns within a nonprofit–business collaboration setting.

A review of plant phenolics and endozoochory.

Phenolic compounds (phenolics) are secondary metabolites ubiquitous across plants. The earliest phenolics are linked to plants' successful transition from an aquatic to a terrestrial environment, serving as protection against damaging ultraviolet (UV) radiation, and as antioxidants to reduce oxidative stress in an atmosphere with an increasingly high O2:CO2 ratio. In modern plants, phenolics are best known for the defense against fungal and bacterial pathogens and as antifeedants that deter herbivory. Phenolics also play a role in seed dormancy, delaying germination, and lengthening viability in the seed bank. Many plants' seeds are endozoochorous - dispersed by animals, like birds, who eat and later excrete the seeds. Plants send visual signals to attract birds with UV-sensitive (UVS) vision for pollination and seed dispersal. As fruits ripen, antioxidant activity and phenolic content decrease. The waxy cuticle of fruits increases in UV reflection as phenolic rings, which absorb UV light, degrade. The UV contrast that birds detect may act as an honest signal, indicating nutritional changes in the fruit. However, there is little evidence to support the evolution of UV coloration during ripening being driven by frugivore selection. Antioxidant properties of fruit phenolics may be dually adaptive in plants and avian frugivores.

Mounting an immune response reduces male attractiveness in a lizard.

Parasites impact host fitness and constitute an important selective pressure on the host's life history. According to parasite-mediated sexual selection, ornaments are presumed to honestly indicate immune capacity or resistance against parasites, and the chooser sex (typically females) obtains an advantage by selecting more ornamented, thus more immunocompetent mates. Therefore, signalers mounting an immune response must allocate resources from the sexual signal to the immune system, hence reducing the expression of the ornament and becoming less attractive to the choosing sex. Here, we test this idea in the lizard Psammodromus algirus. We inoculated a subsample of males with lipopolysaccharide (LPS) of the cell wall of Escherichia coli, while others served as sham controls. The inoculation of LPS decreased the proportion of ergosterol (pro-vitamin D2) in femoral secretions, and chemosensory tests showed that the scent of LPS-inoculated males was less attractive to females than the scent of control males. Given that ergosterol is a precursor of vitamin D, which has physiological functions as an immune modulator, immunocompromised males likely needed to divert vitamin D to the immune system, reducing the allocation of ergosterol to secretions. In this way, females could detect "sick" males, preferring the apparently healthy males. Overall, our study shows that mounting an immune response is costly in terms of reduced attractiveness. Moreover, we disentangle the underlying mechanism, which involves an honest signal based on vitamin D allocation.

Social Signaling and Childhood Immunization: A Field Experiment in Sierra Leone.

This article explores the use of social signaling as a policy tool to sustainably affect childhood immunization. In a 26-month field experiment with public clinics in Sierra Leone, I introduce a verifiable signal-in the form of color-coded bracelets-given to children upon timely completion of the first four or all five required vaccinations. Signals increase parents' belief in the visibility of their actions and knowledge of other children's vaccine status. The impact of signals varies significantly with the cost and perceived benefits of the action. There are no discernible effects on timely and complete immunization when the signal is linked to an easier-to-complete vaccine with low perceived benefits, and large positive effects when the signal is linked to a costlier-to-achieve vaccine with high perceived benefits. Parents adjust their behavior nine months before realizing the social image benefit, demonstrating the motivational strength of signaling incentives. Of substantive policy importance, bracelets increase full immunization at one year of age by 9 percentage points, with impacts persisting at two years of age. At a marginal cost of US$24.7 per fully immunized child, social signals can be as cost-effective as financial or in-kind incentives.

When and why host country nationals give advice to expatriates: A relational work context perspective

This study advances our understanding of how a relational work context can promote host country nationals’ (HCNs’) advice-giving behavior. Drawing from social interdependence theory and relational signalling theory, we develop a multilevel model to demonstrate how task interdependence and expatriate advice seeking can jointly influence HCNs’ advice giving. Using data from 795 HCNs nested within 159 expatriates, we find that at the HCN level (Level 1), task interdependence facilitates HCNs’ prosocial motivation and advice-giving behavior. Also, at the expatriate level (Level 2), task interdependence facilitates expatriates’ advice-seeking behavior, which further has a cross-level interaction effect with HCNs’ task interdependence in predicting HCNs’ prosocial motivation and ultimate advice-seeking behavior. We discuss the implications for theory and practice.

Evidence of honest signalling in a suboscine bird: Southwestern willow flycatcher song frequency is positively related to apparent reproductive success

Evidence of honest signalling in a suboscine bird: Southwestern willow flycatcher song frequency is positively related to apparent reproductive success

Glimpses into the social mind: Decoding messages from faces and eyes.

The human brain is fundamentally a social brain, with its perceptual and cognitive systems evolved to support a diverse set of processes aimed at enabling our complex social function. And while in the last decades the field has advanced considerably in understanding the mechanisms by which the perceptual and cognitive faculties support human social behaviour, there remains a lack of knowledge about how social information is communicated between individuals. In my work, I have studied nonverbal visual social signalling via faces and eyes. In this article, I summarize the results from three lines of my research which show that (a) limiting face visibility decreases its social value, (b) eyes transmit key social messages, and (c) group size modulates social messages. Together, these data show that visual signals from faces and eyes convey complex social messages and represent an important vehicle for the communication of social information. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Young Consumers’ Price Perceptions in Purchasing Foods: Evidence from Greece

The recent consecutive economic and social crises impose sustainable “from farm to fork” food chain management to feed the global population. In this study, we investigated the price perceptions of young consumers (Gen Z) in purchasing foods in Greece to find out the determinants ensuring sustainable, future food consumption. We used eight overall price perception determinants, five with negative roles, namely value and price consciousness, coupon and sales proneness, and price mavenism, and three with positive roles, namely price–quality, price–value, and prestige–sensitivity for the formation of the study’s questionnaire. A total of 514 students (Gen Z, 85%) answered the questionnaire, promoted through the Google platform during September and October 2023. The data were analyzed with statistical tools, combining cross and chi-square tests. Between the negative determinants, the “value consciousness” price perceptions (71.02%) were the most important parameters in purchasing food, followed by “price consciousness” (55.02%) parameters. “Coupon proneness”, 48.4%, and “sales proneness”, 49%, were equally lower, while “price mavenism” parameters were minimally preferred by only 26.4% of the participants. Participants exhibited a major preference for the “value to price” interconnection (66.7%), such as good value for money, value exceeding a product’s price, and overvalued low-priced foods, while their preference for the “quality to price” interconnection was significantly lower (48.8%), such as in terms of getting what you pay for, more money for better quality, and priced, quality foods. The “prestige–sensitivity” price perception was outside of their preferences in terms of food purchasing (only 7.1%). Our findings indicate that young consumers (Gen Z) pay more attention to the values of negative and positive parameters concerning price perceptions when purchasing food rather than quality, coupons and sales, low prices, and mavenism, or even the prestige of the foods. This means that value issues such as the perceived environmental impact (green value), the climate crisis, the social signaling potential, and others are significant concerns, including their price perceptions for food purchases.

The modelling of flower colour: spectral purity or colour contrast as biologically relevant descriptors of flower colour signals for bees depending upon the perceptual task.

Flower colour is an important mediator of plant-pollinator interactions. While the reflectance of light from the flower surface and background are governed by physical properties, the perceptual interpretation of such information is generated by complex multilayered visual processing. Should quantitative modelling of flower signals strive for repeatable consistency enabled by parameter simplification, or should modelling reflect the dynamic way in which bees are known to process signals? We discuss why colour is an interpretation of spectral information by the brain of an animal. Different species, or individuals within a species, may respond differently to colour signals depending on sensory apparatus and/or individual experience. Humans and bees have different spectral ranges, but colour theory is strongly rooted in human colour perception and many principles of colour vision appear to be common. We discuss bee colour perception based on physiological, neuroanatomical and behavioural evidence to provide a pathway for modelling flower colours. We examine whether flower petals and floral guides as viewed against spectrally different backgrounds should be considered as a simple colour contrast problem or require a more dynamic consideration of how bees make perceptual decisions. We discuss that plants such as deceptive orchids may present signals to exploit bee perception, whilst many plants do provide honest signalling where perceived saturation indicates the probability of collecting nutritional rewards towards the centre of a flower that then facilitates effective pollination.

Estimating Career Benefits from Online Community Leadership: Evidence from Stack Exchange Moderators

Many IT professionals seek to improve their job prospects by engaging as leaders of online communities, for example, by serving as a moderator or admin. We investigate whether such community leadership leads to (causal) improvements in individuals’ careers. We assemble a data set, including job histories of IT professionals who have sought election as moderators (mods) in Stack Exchange question-and-answer communities, between 2010 and 2020. We estimate the career benefits of moderatorship under two complementary identification strategies: difference-in-differences (DID) and regression discontinuity (RD). We observe qualitatively consistent results under each design, finding that election to a moderator role has a significant, causal, positive effect on job mobility. We estimate that moderatorship increases the probability of a job change by between 4.7 and 12.3 percentage points over the two years following the election. We also report a series of secondary analyses that speak to associated salary increases and show evidence consistent with the notion that social capital and signaling play a role. Our findings help us understand the benefits of online community leadership, and they extend our understanding of the motivations for online community engagement. This paper was accepted by Chris Forman, information systems. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2019.03252 .

Responses of Gross's stinkfish, Callionymus grossi (Ogilby 1910) to perceived threats

AbstractPredator avoidance is critical to fish survival and yet multiple types of predator response are rarely recorded at the level of individuals let alone studied in detail. Behaviour of an individual adult male dragonet, Gross's stinkfish Callionymus grossi (Ogilby 1910) (Family Callionymidae) was observed over the course of four consecutive daily snorkelling sessions on high tides in the Maroochy River estuary, Queensland, Australia. On two occasions, the dragonet buried in the sand in the presence of a great barracuda, Sphyraena barracuda, whereas, smaller benthic predators or competitors and the observer sometimes provoked dorsal fin raising and fleeing responses of the dragonet. The dragonet, therefore, demonstrates multiple responses to potential predators and competitors seemingly depending on the likely severity of interaction. Further research of dragonet fishes is recommended to disentangle the functionality of fin display in this group, with the anti‐predator function of fin displays and honest signalling of chemical defence a promising aspect for investigation.

Re-wiring of the bonded brain: Gene expression among pair bonded female prairie voles changes as they transition to motherhood.

Motherhood is a costly life-history transition accompanied by behavioral and neural plasticity necessary for offspring care. Motherhood in the monogamous prairie vole is associated with decreased pair bond strength, suggesting a trade-off between parental investment and pair bond maintenance. Neural mechanisms governing pair bonds and maternal bonds overlap, creating possible competition between the two. We measured mRNA expression of genes encoding receptors for oxytocin (oxtr), dopamine (d1r and d2r), mu-opioids (oprm1a), and kappa-opioids (oprk1a) within three brain areas processing salience of sociosensory cues (anterior cingulate cortex; ACC), pair bonding (nucleus accumbens; NAc), and maternal care (medial preoptic area; MPOA). We compared gene expression differences between pair bonded prairie voles that were never pregnant, pregnant (~day 16 of pregnancy), and recent mothers (day 3 of lactation). We found greater gene expression in the NAc (oxtr, d2r, oprm1a, and oprk1a) and MPOA (oxtr, d1r, d2r, oprm1a, and oprk1a) following the transition to motherhood. Expression for all five genes in the ACC was greatest for females that had been bonded for longer. Gene expression within each region was highly correlated, indicating that oxytocin, dopamine, and opioids comprise a complimentary gene network for social signaling. ACC-NAc gene expression correlations indicated that being a mother (oxtr and d1r) or maintaining long-term pair bonds (oprm1a) relies on the coordination of different signaling systems within the same circuit. Our study suggests the maternal brain undergoes changes that prepare females to face the trade-off associated with increased emotional investment in offspring, while also maintaining a pair bond.

Testing the human superorganism approach tomorality.

Current theories in moral psychology do not agree about the kinds and range of offenses that people should moralize. In this study, a new approach to defining the moral domain, Human Superorganism Theory (HSoT), is presented and tested. HSoT proposes that the primary function of moral action is the suppression of cheaters in the unusually large societies recently established by our species (i.e., human 'superorganisms'). It suggests that a broad range of moral concerns exist beyond traditional notions of harm and fairness, including actions that inhibit functions such as group-level social control, physical and social structuring, reproduction, communication, signaling and memory. Roughly 80,000 respondents completed a web-based experiment hosted by the British Broadcasting Corporation, which elicited a suite of responses to characteristics of a set of 33 short scenarios representing the areas identified by the HSoT perspective. Results indicate that all 13 superorganism functions are moralized, while violations of scenarios falling outside this area (social customs and individual decisions) are not. Several hypotheses derived specifically from HSoT were also supported. Given this evidence, we believe this new approach to defining a broader moral domain has implications for fields ranging from psychology to legal theory.