Kin Recognition Research Articles

The effects of genetic distance, nutrient conditions, and recognition ways on outcomes of kin recognition in Glechoma longituba.

Kin recognition might help plants decrease competitive cost and improve inclusive fitness with close genes; thus it might interact with environmental factors to affect communities. Whether and how various factors, such as the genetic distance of neighbors, environmental stressors, or the way a plant recognizes its neighbors, might modify plant growth strategies remains unclear. To answer these questions, we conducted experiments in which ramets of a clonal plant, Glechoma longituba, were grown adjacent to different genetically related neighbors (clone kin / close kin / distant kin) in different nutrient conditions (high / medium / low), or with only root exudates from pre-treatment in culture solution. By comparing competitive traits, we found that: (1) kin recognition in G. longituba was enhanced with closer genetic distance; (2) the outcomes of kin recognition were influenced by the extent of nutrient shortage; (3) kin recognition helped to alleviate the nutrient shortage effect; (4) kin recognition via root exudates affected only below-ground growth. Our results provide new insights on the potential for manipulating the outcome of kin recognition by altering neighbor genetic distance, nutrient conditions and recognition ways. Moreover, kin recognition can help plants mitigate the effects of nutrient shortage, with potential implications in agricultural research.

Plasticity for the kin and conspecific preferences in the frog tadpoles (Rana ornativentris).

In vertebrates, little is known of kin recognition systems and their plasticity. Even in well-studied anuran larvae (tadpoles), the determinants and effects of prior experience have not been clarified. This study evaluates the plasticity of kin and conspecific discrimination in tadpoles of the Japanese montane brown frog Rana ornativentris. We raised tadpoles under two different sibship conditions: the pure line, comprising only siblings, and the mixed line, comprising both siblings and non-siblings. The association preference by a subject tadpole to unfamiliar ("stimulus") tadpoles was assessed through binary-choice tests using a 2 × 2 × 2 factorial design among each kinship line (pure and mix), subject ontogeny/size (early stage/small and late-stage/large), and stimuli ontogeny/size. Contrary to our expectations, kin preference was confirmed only in early developmental small tadpoles from mixed line, and only with a small stimulus. Furthermore, tadpoles from mixed line did not exhibit size preference for unrelated conspecifics. These results suggest that different prior associations have modulated kin templates along tadpole ontogeny and that the presence of non-kin would enhance the learning of kin/non-kin. This study provides the first example that plasticity of kin recognition affects not only kin-biased association but also conspecific recognition along ontogeny in tadpoles.

Multiple social encounters can eliminate Crozier’s paradox and stabilise genetic kin recognition

Crozier’s paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognised and helped. This causes common tags to increase in frequency, and hence eliminates the genetic variability that is required for genetic kin recognition. It has therefore been assumed that genetic kin recognition can only be stable if there is some other factor maintaining tag diversity, such as the advantage of rare alleles in host-parasite interactions. We show that allowing for multiple social encounters before each social interaction can eliminate Crozier’s paradox, because it allows individuals with rare tags to find others with the same tag. We also show that rare tags are better indicators of relatedness, and hence better at helping individuals avoid interactions with non-cooperative cheats. Consequently, genetic kin recognition provides an advantage to rare tags that maintains tag diversity, and stabilises itself.

Permissive aggregative group formation favors coexistence between cooperators and defectors in yeast.

In Saccharomyces cerevisiae, the FLO1 gene encodes flocculins that lead to formation of multicellular flocs, that offer protection to the constituent cells. Flo1p was found to preferentially bind to fellow cooperators compared to defectors lacking FLO1 expression, enriching cooperators within the flocs. Given this dual function in cooperation and kin recognition, FLO1 has been termed a "green beard gene". Because of the heterophilic nature of the Flo1p bond however, we hypothesize that kin recognition is permissive and depends on the relative stability of the FLO1+/flo1- versus FLO1+/FLO1+ detachment force F. We combine single-cell measurements of adhesion, individual cell-based simulations of cluster formation, and in vitro flocculation to study the impact of relative bond stability on the evolutionary stability of cooperation. We identify a trade-off between both aspects of the green beard mechanism, with reduced relative bond stability leading to increased kin recognition at the expense of cooperative benefits. We show that the fitness of FLO1 cooperators decreases as their frequency in the population increases, arising from the observed permissive character (F+- = 0.5 F++) of the Flo1p bond. Considering the costs associated with FLO1 expression, this asymmetric selection often results in a stable coexistence between cooperators and defectors.

Signal Transduction Network Principles Underlying Bacterial Collective Behaviors.

Bacteria orchestrate collective behaviors and accomplish feats that would be unsuccessful if carried out by a lone bacterium. Processes undertaken by groups of bacteria include bioluminescence, biofilm formation, virulence factor production, and release of public goods that are shared by the community. Collective behaviors are controlled by signal transduction networks that integrate sensory information and transduce the information internally. Here, we discuss network features and mechanisms that, even in the face of dramatically changing environments, drive precise execution of bacterial group behaviors. We focus on representative quorum-sensing and second-messenger cyclic dimeric GMP (c-di-GMP) signal relays. We highlight ligand specificity versus sensitivity, how small-molecule ligands drive discrimination of kin versus nonkin, signal integration mechanisms, single-input sensory systems versus coincidence detectors, and tuning of input-output dynamics via feedback regulation. We summarize how different features of signal transduction systems allow groups of bacteria to successfully interpret and collectively react to dynamically changing environments.

Early social experience, rather than kinship affecting aggression in an egg parasitoid wasp, Anastatus disparis (Hymenoptera: Eupelmidae), that exhibits extreme male–male combat behaviour

Fighting behaviour is important for acquiring crucial resources and is widely observed in the animal kingdom. Based on the conflict consequence, fighting behaviour is usually classified into non-extreme and extreme fighting patterns. Numerous factors that influence aggression, such as resource value, resource-holding potential, kinship, and prior experience, have been extensively studied, resulting in the emergence of many important theories. To secure mating opportunities, males of the quasi-gregarious parasitoid, Anastatus disparis (Hymenoptera: Eupelmidae), exhibit extreme fighting behaviour. Inconsistent with the general kin selection theory prediction, there is no evidence that male A. disparis competitors alter their fighting behaviour in response to relatedness with resource presence or interacted with altering resource value. The results of our current study do not clearly indicate whether unchanged kin-based aggression is caused by a lack of kin recognition ability or overriding by competition for resources, which A. disparis males rarely exhibit fighting behaviour under condition of resource female absence in the environment. However, significant decreases in the fighting frequency and intensity in A. disparis were shown in males with early social experience, which was also not influenced by the kinship between the contestants. Our result suggests that in A. disparis, male aggression was likely mediated by early social experience rather than kinship.

Kin recognition benefits clonal offspring performance of historically grazed Leymus chinensis: insights for grassland management

BackgroundIndividual plants can identify their neighbors and adjust their biomass investment to avoid competing with their relatives or jointly cope with external stresses. Maternal effects can improve their offspring adaptability under external stresses. However, how grazing-induced maternal effects influence plant kin interactions remain unknown.MethodsClonal offspring of Leymus chinensis grown under multi-year grazing and non-grazing conditions were used for this study. A greenhouse experiment was conducted to evaluate the performance of focal plants in the presence of kin and stranger neighbors, with the aim of analyzing the interaction between maternal effect and kin relatedness.ResultsKin relatedness of neighboring plants affected the biomass production and allocation of focal plants, demonstrating the presence of kin recognition in L. chinensis. Moreover, grazing-induced maternal effects significantly enhanced kin recognition in the species. Consequently, the presence of stranger neighbors significantly improved the growth potential of grazed offspring. Specifically, the total biomass of clonal offspring increased by 73.1% compared to the kin group, potentially buffering grazing-induced plant productivity declines.ConclusionsThis study shows that historical grazing enhances kin recognition in L. chinensis. Thus, introducing multi-genotypic plants can increase the productivity of grasslands. The findings of this study enhance our understanding of intraspecific plant–plant interactions in clonal species and provide new insights into sustainable grassland management.

Comparison of competitive behaviours between native and invasive ecotypes of garlic mustard under different density conditions, presence and identity of neighbours

Invasive species in monocultures in introduced habitats experience different competitive conditions compared with their native habitats. Invasive monospecific stands can be composed of highly related individuals, creating high opportunity for kin selection in invaded habitats. We investigated the responses of North American and European ecotypes of the invasive species garlic mustard ( Alliaria petiolata (M. Bieb.) Cavara & Grande) to aspects of the competitive environment including density, presence and identity of conspecific neighbors. Several aboveground morphological and performance traits responded to density independent of the origin of the plants. Belowground, however, North American ecotypes allocated more resources to roots and particularly to the taproot portion of their root system, while petiole elongation was density-dependent with North American ecotypes showing reduced elongation in high density compared to European ecotypes. These results were consistent with the evolution of reduced competitive ability in garlic mustard and indicated better resource storage in the introduced environment. Differential responses to neighbour identity indicated the ability for kin recognition in this species. Thus, a combination of natural and kin selection favouring better resource storage and less intraspecific competition, aided by the ability for kin recognition, may be responsible for the success of garlic mustard as an invasive species in North America.

Shift in beneficial interactions during crop evolution.

Plant domestication can be viewed as a form of co‐evolved interspecific mutualism between humans and crops for the benefit of the two partners. Here, we ask how this plant–human mutualism has, in turn, impacted beneficial interactions within crop species, between crop species, and between crops and their associated microbial partners. We focus on beneficial interactions resulting from three main mechanisms that can be promoted by manipulating genetic diversity in agrosystems: niche partitioning, facilitation, and kin selection. We show that a combination of factors has impacted either directly or indirectly plant–plant interactions during domestication and breeding, with a trend toward reduced benefits arising from niche partitioning and facilitation. Such factors include marked decrease of molecular and functional diversity of crops and other organisms present in the agroecosystem, mass selection, and increased use of chemical inputs. For example, the latter has likely contributed to the relaxation of selection pressures on nutrient‐mobilizing traits such as those associated to root exudation and plant nutrient exchanges via microbial partners. In contrast, we show that beneficial interactions arising from kin selection have likely been promoted since the advent of modern breeding. We highlight several issues that need further investigation such as whether crop phenotypic plasticity has evolved and could trigger beneficial interactions in crops, and whether human‐mediated selection has impacted cooperation via kin recognition. Finally, we discuss how plant breeding and agricultural practices can help promoting beneficial interactions within and between species in the context of agroecology where the mobilization of diversity and complexity of crop interactions is viewed as a keystone of agroecosystem sustainability.

No evidence that relatedness or familiarity modulates male harm in Drosophila melanogaster flies from a wild population.

Sexual selection frequently promotes the evolution of aggressive behaviors that help males compete against their rivals, but which may harm females and hamper their fitness. Kin selection theory predicts that optimal male–male competition levels can be reduced when competitors are more genetically related to each other than to the population average, contributing to resolve this sexual conflict. Work in Drosophila melanogaster has spearheaded empirical tests of this idea, but studies so far have been conducted in laboratory‐adapted populations in homogeneous rearing environments that may hamper kin recognition, and used highly skewed sex ratios that may fail to reflect average natural conditions. Here, we performed a fully factorial design with the aim of exploring how rearing environment (i.e., familiarity) and relatedness affect male–male aggression, male harassment, and overall male harm levels in flies from a wild population of Drosophila melanogaster, under more natural conditions. Namely, we (a) manipulated relatedness and familiarity so that larvae reared apart were raised in different environments, as is common in the wild, and (b) studied the effects of relatedness and familiarity under average levels of male–male competition in the field. We show that, contrary to previous findings, groups of unrelated‐unfamiliar males were as likely to fight with each other and harass females than related‐familiar males and that overall levels of male harm to females were similar across treatments. Our results suggest that the role of kin selection in modulating sexual conflict is yet unclear in Drosophila melanogaster, and call for further studies that focus on natural populations and realistic socio‐sexual and ecological environments.

Size-dependent aggression towards kin in a cannibalistic species.

In juveniles extreme intraspecies aggression can seem counter-intuitive, as it might endanger their developmental goal of surviving until reproductive stage. Ultimately, aggression can be vital for survival, although the factors (e.g., genetic or environmental) leading to the expression and intensity of this behavior vary across taxa. Attacking (and sometimes killing) related individuals may reduce inclusive fitness; as a solution to this problem, some species exhibit kin discrimination and preferentially attack unrelated individuals. Here, we used both experimental and modeling approaches to consider how physical traits (e.g., size in relation to opponent) and genetic relatedness mediate aggression in dyads of cannibalistic Dendrobates tinctorius tadpoles. We paired full-sibling, half-sibling, and non-sibling tadpoles of different sizes together in an arena and recorded their aggression and activity. We found that the interaction between relative size and relatedness predicts aggressive behavior: large individuals in non-sibling dyads are significantly more aggressive than large individuals in sibling dyads. Unexpectedly, although siblings tended to attack less overall, in size-mismatched pairs they attacked faster than in non-sibling treatments. Using a theoretical model to complement these empirical findings, we propose that larval aggression reflects a balance between relatedness and size where individuals trade-off their own fitness with that of their relatives.

Population viscosity promotes altruism under density-dependent dispersal.

A basic mechanism of kin selection is population viscosity, whereby individuals do not move far from their place of birth and hence tend to be surrounded by relatives. In such circumstances, even indiscriminate altruism among neighbours will often involve interactions between kin, which has a promoting effect on the evolution of altruism. This has the potential to explain altruistic behaviour across the whole tree of life, including in taxa for which recognition of kin is implausible. However, population viscosity may also intensify resource competition among kin, which has an inhibitory effect on altruism. Indeed, in the simplest scenario, in which individuals disperse with a fixed probability, these two effects have been shown to exactly cancel such that there is no net impact of viscosity on altruism. Here, we show that if individuals are able to disperse conditionally upon local density, they are favoured to do so, with more altruistic neighbourhoods exhibiting a higher rate of dispersal and concomitant relaxation of kin competition. Comparing across different populations or species, this leads to a negative correlation between overall levels of dispersal and altruism. We demonstrate both analytically and using individual-based simulations that population viscosity promotes the evolution of altruism under density-dependent dispersal.

Evidence of low within-pair genetic relatedness in a relict population of Thorn-tailed Rayadito despite long-term isolation.

Investigating whether mating patterns are biased in relation to kinship in isolated populations can provide a better understanding of the occurrence of inbreeding avoidance mechanisms in wild populations. Here, we report on the genetic relatedness (r) among breeding pairs in a relict population of Thorn‐tailed Rayadito (Aphrastura spinicauda) in north‐central Chile that has experienced a long‐term history of isolation. We used simulations based on 8 years of data to assess whether mating is random with respect to relatedness. We found that mean and median population values of pair relatedness tended to be lower than randomly generated values, suggesting that mating is not random with respect to kinship. We hypothesize that female‐biased dispersal is the main mechanism reducing the likelihood of mating among kin, and that the proportion of related pairs (i.e., r > 0.125) in the study population (25%) would presumably be higher in the absence of sex‐biased dispersal. The occurrence of other mechanisms such as extra‐pair copulations, delayed breeding, and active inbreeding avoidance through kin discrimination cannot be dismissed and require further study.

Mechanisms of inbreeding avoidance in a wild primate

Inbreeding often imposes net fitness costs,1-5 leading to the expectation that animals will engage in inbreeding avoidance when the costs of doing so are not prohibitive.4-9 However, one recent meta-analysis indicates that animals of many species do not avoid mating with kin in experimental settings,6 and another reports that behavioral inbreeding avoidance generally evolves only when kin regularly encounter each other and inbreeding costs are high.9 These results raise questions about the processes that separate kin, how these processes depend on kin class and context, and whether kin classes differ in how effectively they avoid inbreeding via mate choice-in turn, demanding detailed demographic and behavioral data within individual populations. Here, we address these questions in a wild mammal population, the baboons of the Amboseli ecosystem in Kenya. We find that death and dispersal are very effective at separating opposite-sex pairs of close adult kin. Nonetheless, adult kin pairs do sometimes co-reside, and we find strong evidence for inbreeding avoidance via mate choice in kin classes with relatedness ≥0.25. Notably, maternal kin avoid inbreeding more effectively than paternal kin despite having identical coefficients of relatedness, pointing to kin discrimination as a potential constraint on effective inbreeding avoidance. Overall, demographic and behavioral processes ensure that inbred offspring are rare in undisturbed social groups (1% of offspring). However, in an anthropogenically disturbed social group with reduced male dispersal, we find inbreeding rates 10× higher. Our study reinforces the importance of demographic and behavioral contexts for understanding the evolution of inbreeding avoidance.9.

No evidence for the evolution of mating behavior in spider mites due to Wolbachia-induced cytoplasmic incompatibility.

Arthropods are often infected with Wolbachia inducing cytoplasmic incompatibility (CI), whereby crosses between uninfected females and infected males yield unviable fertilized offspring. Although uninfected females benefit from avoiding mating with Wolbachia-infected males, this behavior is not always present in host populations and its evolution may hinge upon various factors. Here, we used spider mites to test whether CI could select for mate preference in uninfected females in absence of kin recognition. We found that uninfected females from several field-derived populations showed no preference for infected or uninfected males, nor evolved a preference after being exposed to CI for 12-15 generations by maintaining uninfected females with both infected and uninfected males (i.e., stable "infection polymorphism"). This suggests that Wolbachia-mediated mate choice evolution may require very specific conditions in spider mites. However, after experimental evolution, the copulation duration of Wolbachia-infected control males was significantly higher than that of uninfected control males, but not than that of uninfected males from the "infection polymorphism" regime. This result illustrates how gene flow may oppose Wolbachia-driven divergence between infected and uninfected hosts in natural populations.

Distinct kin strategies of the legume soybean and the non-legume balsam by accomplishing different nitrogen acquisition and rhizosphere microbiome composition.

SUMMARYKin selection has been proposed vvto be an important mechanism for plant relatives growing together. To reveal kin recognition, we used15N labeling to assess the short‐term nitrogen (N) acquisition (uptake of nitrate and ammonium), long‐term N utilization (recovery of added urea), N‐use efficiency (NUE) and rhizosphere microbiome in leguminousGlycine maxand non‐leguminousImpatiens balsamina. Individuals of each species were planted pairwise with either a sibling or a stranger. Enzyme activity and soil microbial composition were compared between kinship groups. Compared with strangers,G. maxsiblings increased aboveground biomass, NUE, and nitrogenase activity, whereasI. balsaminasiblings decreased root biomass and increased uptake rate of nitrate and potential nitrification rate. Plant kinship affected soil bacterial communities by enriching specific groups possessing explicit eco‐functions (Rhizobiales forG. maxandNitrospiraforI. balsamina). Kinship‐sensitive operational taxonomic units formed independent modules in the bacterial co‐occurrence network and were positively correlated with plant growth performance, N acquisition and enzymatic activity. Plant kin recognition may depend on the growth strategies of the plant species. Kin selection was dominant inG. maxby enhancing biological N fixation through the enrichment of symbiotic rhizobia (demonstrated by aboveground growth and NUE superiority among siblings). Kin selection and niche partitioning occurred simultaneously inI. balsamina, expressed through reduced root allocation but increased nitrate uptake, and enhanced soil N nitrification, by enriching functional microbial groups. Kin recognition responses are the consequence of complex interactions among the host plant, the microbiome, and soil nutrient cycling and utilization processes.

Deficiency of nde1 in zebrafish induces brain inflammatory responses and autism-like behavior

SummaryThe cytoskeletal protein NDE1 plays an important role in chromosome segregation, neural precursor differentiation, and neuronal migration. Clinical studies have shown that NDE1 deficiency is associated with several neuropsychiatric disorders including autism. Here, we generated nde1 homologous deficiency zebrafish (nde1−/−) to elucidate the cellular molecular mechanisms behind it. nde1−/− exhibit increased neurological apoptotic responses at early infancy, enlarged ventricles, and shrank valvula cerebelli in adult brain tissue. Behavioral analysis revealed that nde1−/− displayed autism-like behavior traits such as increased locomotor activity and repetitive stereotype behaviors and impaired social and kin recognition behaviors. Furthermore, nde1 mRNA injection rescued apoptosis in early development, and minocycline treatment rescued impaired social behavior and overactive motor activity by inhibiting inflammatory cytokines. In this study, we revealed that nde1 homozygous deletion leads to abnormal neurological development with autism-related behavioral phenotypes and that inflammatory responses in the brain are an important molecular basis behind it.

Kin recognition by cannibals is modulated by hunger level in a generalist predatory mite Amblyseius herbicolus (Chant) (Acari: Phytoseiidae)

AbstractCannibalism is a commonly found behaviour in the animal kingdom. The biggest concern of cannibalism is that it reduces the inclusive fitness of the cannibals by eliminating close relatives. Kin recognition is a strategy used by many cannibals to benefit from cannibalism without the cost of reducing their inclusive fitness by eating close relatives. Most members of the family Phytoseiidae are cannibalistic. Previous studies suggest that specialist phytoseiids practice kin recognition, while generalists use species recognition or discrimination due to the diet specification and frequent intraspecific interactions. We examined whether kin recognition is used by a type‐III generalist phytoseiid, Amblyseius herbicolus (Chant) (Acari: Phytoseiidae). The cannibalistic adults with different hunger levels (0‐, 24‐ and 48‐hr starvation) were given a choice of kin and a non‐kin larva. Kin recognition of A. herbicolus was affected by the hunger level. Adults not starved before the test significantly preferred cannibalizing non‐kin larva. Conversely, adults starved for 24 and 48 hr showed no statistically significant preference between kin and non‐kin larvae. Furthermore, the latency reflected hunger level, where not starved adults had the most prolonged latency, while adults starved for 24 and 48 hr had intermediate and shortest latency. This study suggests A. herbicolus use innate recognition mechanisms to avoid kin cannibalism since the adults and larvae had no prior association before the experiment. The effect of familiarization on kin recognition in A. herbicolus should be further investigated.

Evidence of aggregation behavior in Erythrolamprus poecilogyrus caesius (Cope, 1862) (Serpentes: Dipsadidae) in the Dry Chaco

Aggregation among individuals of the same species is a common spatial pattern in nature, and has been well studied in insects, mammals, birds, and fishes. Among vertebrates, mammals, birds, and fishes are considered the most social. Among reptiles, snakes also form aggregations for mating, defense, or communal shedding, and this behavior can be associated to kin and conspecific recognition. Here, we report information on the aggregation behavior in Erythrolamprus poecilogyrus caesius. We made two observations in the Dry Chaco of Paraguay. In the first observation (2016) we found three adults of E. p. caesius under a fallen trunk. The second observation occurred in three temporary ponds (2020), where E. p. caesius aggregated in groups of five (juveniles), ten (juveniles and sub-adults), and two (juveniles). Aggregation can reduce predation risk, increase the survival or the reproductive success, and could occur in response to external cues. Future research must focus on aggregation context and define experimentally the factors that trigger it, and whether it depends on environmental resources, or if it is part of a social interaction.

Kin recognition in Drosophila: rearing environment and relatedness can modulate gut microbiota and cuticular hydrocarbon odour profiles

From inbreeding avoidance to kin‐selected cooperation, social behaviours are frequently reliant on kin recognition. However, kin recognition mechanisms are costly to evolve and currently not very well understood. Recent evidence suggests that, by altering their host's odour, gut and other host‐associated microorganisms may provide a promising avenue for understanding kin recognition. In Drosophila melanogaster, kin recognition can mediate mate choice, sexual conflict and larval competition/cooperation, underscoring its important functional role. As is commonly the case, kin recognition in this species depends on both familiarity (i.e. shared rearing environment) and relatedness, and seems to rely mainly on body odours determined by cuticular hydrocarbons. Here, we investigated the degree to which larval rearing environment and relatedness (full‐sibs versus unrelated) determine co‐variation between gut microbiota and cuticular hydrocarbons in D. melanogaster. We found that rearing environment strongly determined microbiota composition and cuticular hydrocarbon profiles, but that these effects were independent from each other. In contrast, relatedness did not influence microbiota composition, but had a strong influence on microbiota diversity, which in turn covaried significantly with cuticular hydrocarbon profiles. Our results show that, in D. melanogaster, odours may convey information about both familiarity and relatedness via an interaction between: 1) direct effects of the rearing environment on cuticular hydrocarbons and 2) indirect effects of relatedness on cuticular hydrocarbons via gut microbiota diversity.