Blueprint for a high-performance biomaterial: full-length spider dragline silk genes.

Spider dragline (major ampullate) silk outperforms virtually all other natural and manmade materials in terms of tensile strength and toughness. For this reason, the mass-production of artificial spider silks through transgenic technologies has been a major goal of biomimetics research. Although all known arthropod silk proteins are extremely large (>200 kiloDaltons), recombinant spider silks have been designed from short and incomplete cDNAs, the only available sequences. Here we describe the first full-length spider silk gene sequences and their flanking regions. These genes encode the MaSp1 and MaSp2 proteins that compose the black widow's high-performance dragline silk. Each gene includes a single enormous exon (>9000 base pairs) that translates into a highly repetitive polypeptide. Patterns of variation among sequence repeats at the amino acid and nucleotide levels indicate that the interaction of selection, intergenic recombination, and intragenic recombination governs the evolution of these highly unusual, modular proteins. Phylogenetic footprinting revealed putative regulatory elements in non-coding flanking sequences. Conservation of both upstream and downstream flanking sequences was especially striking between the two paralogous black widow major ampullate silk genes. Because these genes are co-expressed within the same silk gland, there may have been selection for similarity in regulatory regions. Our new data provide complete templates for synthesis of recombinant silk proteins that significantly improve the degree to which artificial silks mimic natural spider dragline fibers

Females sample more males at high nesting densities, but ultimately obtain less attractive mates

Background: Sexual selection is largely driven by the availability of mates. Theory predicts that male competition and female choice should be density-dependent, with males competing more intensely at relatively high density, and females becoming increasingly discriminating when there are more males from whom to choose. Evidence for flexible mating decisions is growing, but we do not understand how environmental variation is incorporated into mate sampling strategies. We mimicked threespine stickleback (Gasterosteus aculeatus) breeding conditions in pools with high and low densities of nesting males and allowed females to search for mates to determine whether 1) mate search strategies change with the density of breeding males and 2) pre-copulatory components of mate choice (signalling, competition, search patterns, and mating decisions) are modified in parallel. Results: While females sampled more males at high male density, suggesting greater opportunity for sexual selection, the expanded search did not result in females choosing males with more attractive sexual signals. This is likely because red throat colouration was twice as great when half as many males competed. Instead, females chose similarly at high and low male density, using a relative strategy to compare male traits amongst potential suitors. Reduced throat colour could reflect a trade-off with costly male competition. However, we did not observe more intense competition at higher relative density. Density-dependent signalling appears largely responsible for females associating with males who have more attractive signals at low density. If we lacked knowledge of plasticity in signalling, we might have concluded that females are more discriminating at low male density. Conclusions: To understand interactions between mate choice and population dynamics, we should consider how components of mate choice that precede the mating decision interact

Females sample more males at high nesting densities, but ultimately obtain less attractive mates

Background: Sexual selection is largely driven by the availability of mates. Theory predicts that male competition and female choice should be density-dependent, with males competing more intensely at relatively high density, and females becoming increasingly discriminating when there are more males from whom to choose. Evidence for flexible mating decisions is growing, but we do not understand how environmental variation is incorporated into mate sampling strategies. We mimicked threespine stickleback (Gasterosteus aculeatus) breeding conditions in pools with high and low densities of nesting males and allowed females to search for mates to determine whether 1) mate search strategies change with the density of breeding males and 2) pre-copulatory components of mate choice (signalling, competition, search patterns, and mating decisions) are modified in parallel. Results: While females sampled more males at high male density, suggesting greater opportunity for sexual selection, the expanded search did not result in females choosing males with more attractive sexual signals. This is likely because red throat colouration was twice as great when half as many males competed. Instead, females chose similarly at high and low male density, using a relative strategy to compare male traits amongst potential suitors. Reduced throat colour could reflect a trade-off with costly male competition. However, we did not observe more intense competition at higher relative density. Density-dependent signalling appears largely responsible for females associating with males who have more attractive signals at low density. If we lacked knowledge of plasticity in signalling, we might have concluded that females are more discriminating at low male density. Conclusions: To understand interactions between mate choice and population dynamics, we should consider how components of mate choice that precede the mating decision interact

Las Agtech en Argentina

The development and diffusion of digital technologies has been massively transforming economic and social relations at a global level. The value chain around the production of food and other products of biological origin was not aside from these transformations, which led to the emergence and consolidation of the “Agtech” sector. Although there is no established definition, in this study we consider Agtech companies as those that provide knowledge-intensive services based on digital technologies for the various stages of the agri-food chains –from field production to the industrialization, logistics, and commercialization phases–. In this document, we present the results of a survey that covered 63 companies operating in Argentina (59 of them with Agtech as the main line of business), carried out between August 2019 and March 2020 (continuing the effort initiated in 2017, when the first survey in the country for this sector was carried out by the same research team). The work is a joint effort from IIEP and CREA researchers. We address multiple aspects that contribute to the understanding of the current situation and perspectives of these companies. The report discusses the economic performance of Agtech firms, their origin, their experiences in the incubation and acceleration processes, the main funding sources, the value proposals, the most frequent routines for innovation activities, their international experiences, as well as their commercialization strategies and the obstacles they face for growth.El desarrollo de las tecnologías digitales ha venido transformando masivamente las relaciones económicas y sociales a nivel global. La cadena que involucra la producción de alimentos y demás productos de origen biológico no fue ajena a estas transformaciones, lo cual dio lugar a la emergencia y consolidación del sector “Agtech”. Si bien no hay una definición establecida, en este trabajo entendemos por empresas Agtech a aquellas que proveen servicios intensivos en conocimiento basados en tecnologías digitales para las diversas etapas de las cadenas agroalimentarias –desde la producción a campo hasta las fases de industrialización, logística y comercialización–. En el presente documento de trabajo presentamos los resultados de una encuesta que cubrió a 63 empresas que operan en Argentina (59 de ellas con Agtech como línea principal de negocio), llevada a cabo entre agosto de 2019 y marzo de 2020 (encuesta que tuvo como antecedente a otra realizada en 2017, la primera llevada adelante en el país para este sector). El trabajo corresponde a un esfuerzo conjunto realizado por investigadores del IIEP y de CREA, en el cual se abordan múltiples aspectos que contribuyen a entender la situación actual y perspectivas de estas empresas. De forma estilizada, el informe presenta los resultados sobre la performance económica de las firmas Agtech, el origen y conformación de esos emprendimientos, sus experiencias en los procesos de incubación y aceleración, las principales fuentes de financiamiento, las diversas propuestas de valor, las rutinas más frecuentes a la hora de encarar actividades de innovación, sus experiencias en el exterior, así como también sus estrategias de comercialización y los obstáculos que enfrentan para su crecimiento

Las Agtech en Argentina desarrollo reciente, situación actual y perspectivas

El desarrollo de las tecnologías digitales ha venido transformando masivamente las relaciones económicas y sociales a nivel global. La cadena que involucra la producción de alimentos y demás productos de origen biológico no fue ajena a estas transformaciones, lo cual dio lugar a la emergencia y consolidación del sector “Agtech”. Si bien no hay una definición establecida, en este trabajo entendemos por empresas Agtech a aquellas que proveen servicios intensivos en conocimiento basados en tecnologías digitales para las diversas etapas de las cadenas agroalimentarias –desde la producción a campo hasta las fases de industrialización, logística y comercialización–. En el presente documento de trabajo presentamos los resultados de una encuesta que cubrió a 63 empresas que operan en Argentina (59 de ellas con Agtech como línea principal de negocio), llevada a cabo entre agosto de 2019 y marzo de 2020 (encuesta que tuvo como antecedente a otra realizada en 2017, la primera llevada adelante en el país para este sector). El trabajo corresponde a un esfuerzo conjunto realizado por investigadores del IIEP y de CREA, en el cual se abordan múltiples aspectos que contribuyen a entender la situación actual y perspectivas de estas empresas. De forma estilizada, el informe presenta los resultados sobre la performance económica de las firmas Agtech, el origen y conformación de esos emprendimientos, sus experiencias en los procesos de incubación y aceleración, las principales fuentes de financiamiento, las diversas propuestas de valor, las rutinas más frecuentes a la hora de encarar actividades de innovación, sus experiencias en el exterior, así como también sus estrategias de comercialización y los obstáculos que enfrentan para su crecimiento.Fil: Lachman, Jeremías. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Departamento de EconomíaFil: López, Andrés. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Departamento de EconomíaFil: Tinghitella, Gabriel . Asociación Argentina de Consorcios Regionales de Experimentación AgrícolaFil: Gómez-Roca, Sebastián. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Departamento de Economí

Sexual selection and population divergence I. The influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus)

Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here we examined social flexibility in a sexually selected male trait – cuticular hydrocarbon (CHC) profiles – in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets’ social environments during rearing and then characterised CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene-by-social-environment interactions occur.PostprintPeer reviewe

Behavioral Responses of a Parasitoid Fly to Rapidly Evolving Host Signals

Animals eavesdrop on signals and cues generated by prey, predators, hosts, parasites, competing species, and conspecifics, and the conspicuousness of sexual signals makes them particularly susceptible. Yet, when sexual signals evolve, most attention is paid to impacts on intended receivers (potential mates) rather than fitness consequences for eavesdroppers. Using the rapidly evolving interaction between the Pacific field cricket, Teleogryllus oceanicus, and the parasitoid fly, Ormia ochracea, we asked how parasitoids initially respond to novel changes in host signals. We recently discovered a novel sexual signal, purring song, in Hawaiian populations of T. oceanicus that appears to have evolved because it protects the cricket from the parasitoid while still allowing males to attract female crickets for mating. In Hawaii, there are no known alternative hosts for the parasitoid, so we would expect flies to be under selection to detect and attend to the new purring song. We used complementary field and laboratory phonotaxis experiments to test fly responses to purring songs that varied in many dimensions, as well as to ancestral song. We found that flies strongly prefer ancestral song over purring songs in both the field and the lab, but we caught more flies to purring songs in the field than reported in previous work, indicating that flies may be exerting some selective pressure on the novel song. When played at realistic amplitudes, we found no preferences–flies responded equally to all purrs that varied in frequency, broadbandedness, and temporal measures. However, our lab experiment did reveal the first evidence of preference for purring song amplitude, as flies were more attracted to purrs played at amplitudes greater than naturally occurring purring songs. As purring becomes more common throughout Hawaii, flies that can use purring song to locate hosts should be favored by selection and increase in frequency

Sexual selection and population divergence I. the influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus).

This is the peer reviewed version of the article which has been published in final form at DOI: 10.1111/evo.12839.© 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here we examined social flexibility in a sexually selected male trait - cuticular hydrocarbon (CHC) profiles - in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets' social environments during rearing and then characterised CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene-by-social-environment interactions occur. This article is protected by copyright. All rights reserved.Natural Environment Research Council (NERC)University of California Pacific Rim Research GrantRoyal SocietyBiotechnology and Biological Sciences Research Council (BBSRC)Erasmus Exchang

Testing the role of trait reversal in evolutionary diversification using song loss in wild crickets

The mechanisms underlying rapid macro evolution are controversial.One largely untested hypothesis that could inform this debate is that evolutionary reversals might release variation in vestigial traits, which then facilitate subsequent diversification. We evaluated this idea by testing key predictions about vestigial traits arising from sexual trait reversal in wild field crickets. In Hawaiian Teleogryllus oceanicus, the recent genetic loss of sound producing and amplifying structures on male wings eliminates their acoustic signals.Silence protects these ‘flatwing’ males from an acoustically orienting parasitoid and appears to have evolved independently more than once.Here we report that flatwing males show enhanced variation in vestigial resonator morphology under varied genetic backgrounds. Using laser Doppler vibrometry, we found that these vestigial sound-producing wing features resonate at highly variable acoustic frequencies well outside the normal range for this species. These results satisfy two important criteria for a mechanism driving rapid evolutionary diversification: sexual signal loss was accompanied by a release of vestigial morphological variants, and these could facilitate the rapid evolution of novel signal values. Widespread secondary trait losses have been inferred from fossil and phylogenetic evidence across numerous taxa, and our results suggest that such reversals could play a role in shaping historical patterns of diversification

Global urban environmental change drives adaptation in white clover.

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale