Social runaway : fisherian elaboration (or reduction) of socially selected traits via indirect genetic effects

NWB was funded by fellowships from the UK Natural Environment Research Council [NE/G014906/1 and NE/L011255/1].Our understanding of the evolutionary stability of socially‐selected traits is dominated by sexual selection models originating with R. A. Fisher, in which genetic covariance arising through assortative mating can trigger exponential, runaway trait evolution. To examine whether non‐reproductive, socially‐selected traits experience similar dynamics—social runaway—when assortative mating does not automatically generate a covariance, we modelled the evolution of socially‐selected badge and donation phenotypes incorporating indirect genetic effects (IGEs) arising from the social environment. We establish a social runaway criterion based on the interaction coefficient, ψ, which describes social effects on badge and donation traits. Our models make several predictions. (1) IGEs can drive the original evolution of altruistic interactions that depend on receiver badges. (2) Donation traits are more likely to be susceptible to IGEs than badge traits. (3) Runaway dynamics in non‐sexual, social contexts can occur in the absence of a genetic covariance. (4) Traits elaborated by social runaway are more likely to involve reciprocal, but non‐symmetrical, social plasticity. Models incorporating plasticity to the social environment via IGEs illustrate conditions favouring social runaway, describe a mechanism underlying the origins of costly traits such as altruism, and support a fundamental role for phenotypic plasticity in rapid social evolution.PostprintPeer reviewe

Within-generation and transgenerational social plasticity interact during rapid adaptive evolution

Funding: We are grateful for support from the Natural Environment Research Council to NWB (NE/L011255/1 and NE/T000619/1).The effects of within-generation plasticity vs. transgenerational plasticity on trait expression are poorly understood, but important for evaluating plasticity's evolutionary consequences. We tested how genetics, within-generation plasticity, and transgenerational plasticity jointly shape traits influencing rapid evolution in the field cricket Teleogryllus oceanicus. In Hawaiian populations attacked by acoustically orienting parasitoid flies, a protective, X-linked variant ("flatwing") eliminates male acoustic sexual signals. Silent males rapidly spread to fixation, dramatically changing the acoustic environment. First, we found evidence supporting flatwing-associated pleiotropy in juveniles: pure-breeding flatwing males and females exhibit greater locomotion than those with normal-wing genotypes. Second, within-generation plasticity caused homozygous-flatwing females developing in silence, which mimics all-flatwing populations, to attain lower adult body condition and reproductive investment than those experimentally exposed to song. Third, maternal song exposure caused transgenerational plasticity in offspring, affecting adult, but not juvenile, size, condition, and reproductive investment. This contrasted with behavioral traits, which were only influenced by within-generation plasticity. Fourth, we matched and mismatched maternal and offspring social environments and found that transgenerational plasticity sometimes interacted with within-generation plasticity and sometimes opposed it. Our findings stress the importance of evaluating plasticity of different traits and stages across generations when evaluating its fitness consequences and role in adaptation.Publisher PDFPeer reviewe

Intrasexual aggression reduces mating success in field crickets

This work was supported by the UK Natural Environment Research Council (NE/L011255/1 and NE/T000619/1).Aggressive behaviour is thought to have significant consequences for fitness, sexual selection and the evolution of social interactions, but studies measuring its expression across successive encounters?both intra- and intersexual?are limited. We used the field cricket Teleogryllus oceanicus to evaluate factors affecting repeatability of male aggression and its association with mating success. We quantified focal male aggression expressed towards partners and received from partners in three successive, paired trials, each involving a different male partner. We then measured a proxy of focal male fitness in mating trials with females. The likelihood and extent of aggressive behaviour varied across trials, but repeatability was negligible, and we found no evidence that patterns of focal aggression resulted from interacting partner identity or prior experience. Males who consistently experienced aggression in previous trials showed decreased male mating ?efficiency??determined by the number of females a male encountered before successfully mating, but the effect was weak and we found no other evidence that intrasexual aggression was associated with later mating success. During mating trials, however, we observed unexpected male aggression towards females, and this was associated with markedly decreased male mating efficiency and success. Our findings suggest that nonadaptive aggressive spillover in intersexual mating contexts could be an important but underappreciated factor influencing the evolution of intrasexual aggression.Publisher PDFPeer reviewe

Ancestral sex-role plasticity facilitates the evolution of same-sex sexual behavior

This study was supported by JSPS Research Fellowships for Young Scientists CPD Grant 20J00660 (to N.M.), Grant-in-Aid for Early-Career Scientists 21K15168 (to N.M.), and Okanawa Institute of Science and Technology core funding. N.W.B. gratefully acknowledges funding from the UK Natural Environment Research Council (NE/T000619/1).Recent attempts to explain the evolutionary prevalence of same-sex sexual behavior (SSB) have focused on the role of indiscriminate mating. However, in many cases, SSB may be more complex than simple mistaken identity, instead involving mutual interactions and successful pairing between partners who can detect each other?s sex. Behavioral plasticity is essential for the expression of SSB in such circumstances. To test behavioral plasticity?s role in the evolution of SSB, we used termites to study how females and males modify their behavior in same-sex versus heterosexual pairs. Male termites follow females in paired ?tandems? before mating, and movement patterns are sexually dimorphic. Previous studies observed that adaptive same-sex tandems also occur in both sexes. Here we found that stable same-sex tandems are achieved by behavioral plasticity when one partner adopts the other sex?s movements, resulting in behavioral dimorphism. Simulations based on empirically obtained parameters indicated that this socially cued plasticity contributes to pair maintenance, because dimorphic movements improve reunion success upon accidental separation. A systematic literature survey and phylogenetic comparative analysis suggest that the ancestors of modern termites lack consistent sex roles during pairing, indicating that plasticity is inherited from the ancestor. Socioenvironmental induction of ancestral behavioral potential may be of widespread importance to the expression of SSB. Our findings challenge recent arguments for a prominent role of indiscriminate mating behavior in the evolutionary origin and maintenance of SSB across diverse taxa.Publisher PDFPeer reviewe

Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades

BACKGROUND: In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive sex (sex-role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. RESULTS: Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. CONCLUSION: The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status (the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries

Rapid parallel adaptation despite gene flow in silent crickets

The work was funded by Natural Environment Research Council awards to N.W.B. [NE/I027800/1, NE/L011255/1]. Bioinformatics support was provided by a Wellcome Trust ISSF award [105621/Z/14/Z]. X.Z. was supported by a China Scholarship Council PhD studentship [201703780018].Gene flow is predicted to impede parallel adaptation via de novo mutation, because it can introduce pre-existing adaptive alleles from population to population. We test this using Hawaiian crickets (Teleogryllus oceanicus) in which ‘flatwing’ males that lack sound-producing wing structures recently arose and spread under selection from an acoustically-orienting parasitoid. Morphometric and genetic comparisons identify distinct flatwing phenotypes in populations on three islands, localized to different loci. Nevertheless, we detect strong, recent and ongoing gene flow among the populations. Using genome scans and gene expression analysis we find that parallel evolution of flatwing on different islands is associated with shared genomic hotspots of adaptation that contain the gene doublesex, but the form of selection differs among islands and corresponds to known flatwing demographics in the wild. We thus show how parallel adaptation can occur on contemporary timescales despite gene flow, indicating that it could be less constrained than previously appreciated.Publisher PDFPeer reviewe

MANAGEMENT STRATEGIES TO AID STRUCTURAL CHANGE IN LIVESTOCK SYSTEMS. TIM CASE OF POLAND

Dominacija malih gospodarstava i prenapučenost stare su značajke poljoprivrede u Poljskoj. Nagle političke i ekonomske promjene 1989/90. uvođenjem slobodnog tržišta i slobodne konkurencije, prestankom subvencioniranja i smanjenjem broja zaposlenih u industriji dovele su poljoprivredu i seljačko stanovništvo u Poljskoj u nov i težak položaj. Zbog tih promjena životni standard stianovništva je pao a potrošnja hrane se smanjila. Cijene sredstrava za poljoprivrednu proizvodnju nesrazmjerno su se povećale a većina seljaka (farmera) zaposlenih u industriji izgubila je posao. Realni prihod farmera smanjio se između 1989. i 1992. za 64%. Tako su se i populacija životinja na gospodarstvu i proizvodnja mlijeka i mesa u prosjeku smanjili za 30%. Zadnje dvije godine primijenjena je određena ekonomska stabilizacija, ali budućnost poljske poljoprivrede ima nekoliko problema. Koncentracija zemlje općenito se smatra poželjnom ali bez mnogo nade za velike promjene u sljedećem desetljeću. Stoga je potrebno graditi takvu infrastrukturu u seoskim područjima koja će apsorbirati njezino nezaposleno pučanstvo. Gospodarstva za uzgoj životinja, posebna prerada životinjskih proizvoda, seoski turizam morali bi igrati važnu ulogu u takvom planiranju. Vjerojatno će u Poljskoj doći do koncentracije životinja na gospodarstvu, ali još će dugo prevladavati gospodarstva s 3-5 mliječnih krava i nekoliko krmača za proizvodnju mlijeka i svinjetine. Koje bi sisteme proizvodnje trebalo razraditi da bi ta proizvodnja donosila dobit, kako organizirati rad na uzgoju, kako prilagoditi istraživačke i obrazovne programe novoj situaciji i kako naći poljoprivredi u Poljskoj prikladno mjesto u budućoj Europi, glavna su pitanja na koja treba odgovoriti.The domination of small farms and overpopulation are old phenomena of the Polish agriculture. Political and economic sudden changes in 1989/90 by introducing free market and free competition, by removing subsidies and redusing employment in the industry put the Polish agriculture and rural population in a new and difficult position. Due to the transformation the standard of living of the population went down reducing food demand. Prices for agriculture production means went unproportionaly up and majority of part time farmer lost their industrial employment. As a result the profitability of agriculture including animal production went seriously down. Real income of farmers was reduced between 1989 to 1992 by 64 percent. Consequently population of farm animals and the production of milk and meat has been reduced by 30 percent in average. During the last two years some kind of economic stabilization has been observed but the future of Polish agriculture presents several problems. Concentration of land is generaly recognised as desirable but without much hope for great change during the next decade. Therefore it is necessary to build such infrastructure in the rural areas to absorbe the unemployed part of their population. Animal husbandry, special processing of animal products, agroturism should play important role in such planing. The concentration of farm animal population will undautably take place but for the long time farms with 3-5 dairy cows and few sows may predominate milk and pork production scene in Poland. Which production systems should be elaborated to make such animal production profitable, how to organize the breeding work how to adopt research and education programes to the new situation and how to find a suitable place for the Polish agriculture in the future Europe are the main questions to be answered

An evolutionary switch from sibling rivalry to sibling cooperation, caused by a sustained loss of parental care.

Sibling rivalry is commonplace within animal families, yet offspring can also work together to promote each other's fitness. Here we show that the extent of parental care can determine whether siblings evolve to compete or to cooperate. Our experiments focus on the burying beetle Nicrophorus vespilloides, which naturally provides variable levels of care to its larvae. We evolved replicate populations of burying beetles under two different regimes of parental care: Some populations were allowed to supply posthatching care to their young (Full Care), while others were not (No Care). After 22 generations of experimental evolution, we found that No Care larvae had evolved to be more cooperative, whereas Full Care larvae were more competitive. Greater levels of cooperation among larvae compensated for the fitness costs caused by parental absence, whereas parental care fully compensated for the fitness costs of sibling rivalry. We dissected the evolutionary mechanisms underlying these responses by measuring indirect genetic effects (IGEs) that occur when different sibling social environments induce the expression of more cooperative (or more competitive) behavior in focal larvae. We found that indirect genetic effects create a tipping point in the evolution of larval social behavior. Once the majority of offspring in a brood start to express cooperative (or competitive) behavior, they induce greater levels of cooperation (or competition) in their siblings. The resulting positive feedback loops rapidly lock larvae into evolving greater levels of cooperation in the absence of parental care and greater levels of rivalry when parents provide care

Proposing the Interactivity-Stimulus-Attention Model (ISAM) to Explain and Predict the Enjoyment, Immersion, and Adoption of Purely Hedonic Systems

Traditional TAM research primarily focuses on utilitarian systems where extrinsic motivations chiefly explain and predict acceptance. We propose a theoretical model, ISAM, which explains the role of intrinsic motivations in building the user attention that leads to hedonic system acceptance. ISAM combines several theories with TAM to explain how interactivity acts as a stimulus in hedonic contexts—fostering curiosity, enjoyment, and the full immersion of cognitive resources. Two experiments involving over 700 participants validated ISAM as a useful model for explaining and predicting hedonic system acceptance. Immersion and PE are shown to be the primary predictors of behavioral intention to use hedonic systems. Unlike traditional utilitarian adoption research, PEOU does not directly impact BIU, and extrinsic motivations are virtually non-existent. The implications of this study extend beyond hedonic contexts, as users of utilitarian systems continue to demand more hedonic features and enjoyment is often more important than PEOU

Social effects on fruit fly courtship song

LMO was supported by grants from the Swiss National Science Foundation (P2BSP3_158842 and P300PA_171516). NWB and MGR are supported by NERC, UK (NE/L011255/1 and grant NE/J020818/1, respectively).Courtship behavior in Drosophila has often been described as a classic innate behavioral repertoire, but more recently extensive plasticity has been described. In particular, prior exposure to acoustic signals of con‐ or heterspecific males can change courtship traits in both sexes that are liable to be important in reproductive isolation. However, it is unknown whether male courtship song itself is socially plastic. We examined courtship song plasticity of two species in the Drosophila melanogaster subgroup. Sexual isolation between the species is influenced by two male song traits, the interpulse interval (IPI) and sinesong frequency (SSF). Neither of these showed plasticity when males had prior experience of con‐ and heterospecific social partners. However, males of both species produced longer bursts of song during courtship when they were exposed to social partners (either con‐ or heterospecific) than when they were reared in isolation. D. melanogaster carrying mutations affecting short‐ or medium‐term memory showed a similar response to the social environment, not supporting a role for learning. Our results demonstrate that the amount of song a male produces during courtship is plastic depending on the social environment, which might reflect the advantage of being able to respond to variation in intrasexual competition, but that song structure itself is relatively inflexible, perhaps due to strong selection against hybridization.Publisher PDFPeer reviewe