Minimizing the cost of competition in the black-crested titmouse: status signaling, dominance, and foraging behavior

Status signals allow senders and receivers to minimize the costs of competition by minimizing the need for costly physical fights. While much research has focused on demonstrating that individuals respond to status signals in both breeding and non-breeding contexts, less is known about how the function of status signals may change as resource availability changes seasonally. In this thesis, I provide a basic review of status signaling in birds and report the results of an investigation on status signaling in the black-crested titmouse during different environmental conditions. The black-crested titmouse is a socially monogamous passerine that defends territories throughout the year. This species forms small family groups during the breeding and post-breeding season, which dissolve into mated pairs during the non-breeding and pre-breeding seasons. Using an array of supplemental seed-feeders outfitted with RFID technology, I investigated the relationship between the crest size of adult male titmice and their foraging behavior during the post- and pre-breeding seasons. I also investigated the effect of both crest size and dominance on an individual’s ability to maintain baseline foraging behavior after approximately half of the feeders were removed. I found that birds with larger crests had greater access and monopolization of feeders during the post-breeding season, but not the pre-breeding season. When the number of available feeders were reduced during the pre-breeding season, males that monopolized their most-used feeder the most during baseline, and males that had longer crests, reduced their access to the feeders relatively less than other birds. Taken together, these findings indicate that the crest is used to signal status, particularly during times of increased competition (i.e. due to seasonal fluctuation in resources or increased competition between family groups)

Theory of Inclusive Fitness

A review of Social Evolution and Inclusive Fitness Theory: An Introduction. By James A. R. Marshall. Princeton (New Jersey): Princeton University Press. $39.95. xix + 195 p.; ill.; index. ISBN: 978-0-691-16156-3. 2015

Kin Selection and Its Discontents

Kin selection is a core aspect of social evolution theory, but a small number of critics have recently challenged it. Here I address these criticisms and show that kin selection remains an important explanation for much (though not all) social evolution. I show how many of the criticisms rest on historical idiosyncrasies of the way the field happened to develop, rather than on the real logic and evidence

Pollen‐Ovule Ratios And Hermaphrodite Sexual Allocation Strategies

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137413/1/evo00383.pd

Patrones de diversidad de especies leñosas en los bosques españoles a diferentes escalas espaciales: efectos de las perturbaciones selvícolas y otros factores ambientales y de paisaje

Biodiversity provides many services to humans and influences many ecosystem functions. Among forest biodiversity indicators, species richness is the most frequently used, although all components of biodiversity are important. Patterns of species richness and their drivers are scale-dependent. In Spain most studies analyzing the factors explaining plant species richness at the landscape scale have focused on relatively large grain and extent spatial scales, or on smaller grain sizes but only in particular and relatively small Spanish regions. Other studies have shown that silvicultural disturbances may influence species richness of vascular plants, but most of them have been developed in boreal or temperate forests; our understanding of such influences in Spanish woodlands still remains much limited. Effects of management on Mediterranean forests are expected to be different due to a long lasting human disturbance regime, and to differences in the ecophysiological responses in the understorey to canopy opening as related to the prevalent climatic conditions in Mediterranean areas. In this PhD we evaluate the factors, and potential underlying ecological processes, that explain forest biodiversity patterns in Spain, mainly focusing on the species richness of woody plants in central Spain. In this context, we place special emphasis on the assessment of the role of silvicultural treatments as a potential factor explaining those patterns. The spatial scale is a key transversal element throughout the work, since different processes operate at different scales and potentially influence each other. Intermediate and local grain sizes were analysed covering relatively large regional extents in order to intend to provide broad insights that could be of interest beyond a particular stand type, forest land, or mountainous system. Species richness of woody plants was better explained than other structural indicators of forest biodiversity at the habitat level. In general, environmental factors were more strongly associated to tree and shrub species richness than landscape structure or management factors. Variables representing biotic interactions had also relatively important effects in some cases. While clearcutting treatments had a negative impact on species richness of woody plants both at local and landscape scales, selection cuttings or improvement treatments benefited species richness in some cases. Particularly, landscapes in central Spain were richer in tree and shrub species richness with increasing proportion of forests managed through these treatments. However, above a threshold of 40-60% the tendency was reversed. Forest stands selectively cut had also in general more tree species than unmanaged stands. Although this result was maintained in coniferous and broadleaved forests (either deciduous or sclerophyllous), the response to selection cuttings varied in relation to coarse climatic patterns. Indeed, the increase in tree species after selection harvesting was not observed in most xeric Mediterranean regions. Under summer stressful conditions, canopy facilitation may prevail to competitive exclusion. Species richness of trees also depended on ecological processes operating at intermediate spatial scales. Management practices such as those of dehesas or plantations seemed to be associated to a reduced tree species in neighbouring forest stands. The number of species in a managed stand also depended on the proportion of managed forests in the surrounding landscape. Positive effects on local tree species richness were found when riparian or unmanaged forests were increasingly represented in a landscape. Actually, we showed that an increased diversity of potential seed fluxes colonizing a stand was linked to a proportional increase in the number of tree species in that stand, highlighting the importance of species pools and connectivity patterns in the forest landscape. In general, the results obtained in this PhD point out the necessity to widen the spatial scale at which the forest management plans are usually conducted in order to better achieve the goals of conserving forest biodiversity and related ecosystem services. RESUMEN La biodiversidad proporciona numerosos servicios al hombre e influye sobre muchas funciones de los ecosistemas. Entre los indicadores de biodiversidad forestal, la riqueza de especies es el mas utilizado, si bien todos los componentes de la biodiversidad son importantes. Los patrones de riqueza de especies y los factores que los explican varian en funcion de la escala espacial. En Espana, la mayoria de los estudios que han analizado los factores que explican la riqueza de especies vegetales han utilizado escalas espaciales (grano y extension) relativamente grandes, o bien tamanos de grano menores pero restringiendose a regiones concretas relativamente pequenas. Por otra parte, algunos estudios han demostrado que las perturbaciones selvicolas pueden influir sobre la riqueza de especies vegetales. Sin embargo, muchos de estos estudios se han desarrollado en bosques boreales o templados y por tanto nuestro conocimiento sobre dicha influencia en el caso de los montes espanoles es todavia bastante limitado. Los efectos de la gestion en los bosques mediterraneos son presumiblemente diferentes debido a la larga historia de perturbaciones antropicas a la que han sido sometidos, y a las diferencias en las respuestas ecofisiologicas del sotobosque a la apertura del dosel arboreo bajo climas mediterraneos. En esta tesis se evaluan los factores, y potenciales procesos subyacentes, que explican los patrones de biodiversidad forestal en Espana, centrandonos principalmente en la riqueza de especies de plantas lenosas en el centro de Espana. En este contexto, se hace especial hincapie en evaluar cual es el papel de los tratamientos selvicolas en la explicacion de dichos patrones. La escala espacial es un elemento clave y trasversal a lo largo de este trabajo, dado que diferentes procesos operan a diferentes escalas y potencialmente interactuan unos con otros. En este trabajo se utilizaron tamanos de grano intermedios y locales cubriendo extensiones relativamente grandes con el fin de intentar obtener conclusiones amplias que pudieran ser de interes mas alla de un tipo de rodal o monte concreto. La riqueza de especies lenosas fue explicada en mayor medida que otros indicadores estructurales de biodiversidad forestal a nivel de habitat. Ademas, en general, los factores ambientales se asociaron mas a la riqueza de arboles y arbustos que los factores de estructura de paisaje o de gestion. Por otra parte, las interacciones biologicas tambien tuvieron un efecto relativamente importante en algunos casos. Mientras que las cortas a hecho tuvieron un impacto negativo en la riqueza de lenosas tanto a escala local como de paisaje, la entresaca o los tratamientos de mejora resultaron xii beneficiosos en algunos casos. En concreto, los paisajes del centro de Espana fueron mas ricos en especies arboreas y arbustivas a medida que aumento la proporcion de bosques gestionados mediante dichos tratamientos. Sin embargo, a partir de un umbral de 40-60% dicha tendencia se invirtio. Tambien a escala local los rodales entresacados tuvieron en general mas especies arboreas que los no gestionados. Este resultado se observo en bosques de coniferas y frondosas (caducifolias o esclerofilas), pero vario en funcion de las condiciones climaticas regionales. De hecho, no se observo un aumento de especies arboreas tras la entresaca en las regiones mediterraneas mas xericas. Es posible que bajo las condiciones de estres hidrico estival en estas regiones, las interacciones de facilitacion con el estrato arboreo superen a las de exclusion competitiva. La riqueza de especies arboreas tambien dependio de procesos ecologicos que operan a escalas espaciales intermedias. Por ejemplo, la mayor presencia en el paisaje de las practicas de gestion asociadas a las dehesas o las plantaciones se tradujeron en una reduccion en la riqueza arborea en rodales cercanos. El numero de especies de arboles en los rodales gestionados tambien estuvo influido por la proporcion de bosques gestionados a su alrededor. Asimismo se encontro un efecto positivo del aumento en el paisaje de bosques de ribera o no gestionados sobre la riqueza local. De hecho, los resultados demostraron que un aumento en la diversidad de flujos de semillas que pueden colonizar un rodal esta ligado a un aumento proporcional en el numero de especies arboreas en dicho rodal, lo que subraya la importancia de la riqueza regional de especies y de los patrones de conectividad en el paisaje forestal para explicar estos procesos. En general, los resultados de esta tesis senalan la necesidad de ampliar la escala espacial de monte individual a la que generalmente se plantean los proyectos de ordenacion y planes de gestion forestal con el fin de contribuir a una mejor consecucion de los objetivos de conservacion y fomento de la biodiversidad forestal y de los servicios ecosistemicos asociados

Theory of genomic imprinting conflict in social insects

BACKGROUND: Genomic imprinting refers to the differential expression of genes inherited from the mother and father (matrigenes and patrigenes). The kinship theory of genomic imprinting treats parent-specific gene expression as products of within-genome conflict. Specifically, matrigenes and patrigenes will be in conflict over treatment of relatives to which they are differently related. Haplodiploid females have many such relatives, and social insects have many contexts in which they affect relatives, so haplodiploid social insects are prime candidates for tests of the kinship theory of imprinting. RESULTS: Matrigenic and patrigenic relatednesses are derived for individuals affected in a variety of contexts, including queen competition, sex ratio, worker laying of male eggs and policing, colony fission, and adoption of new queens. Numerous predictions emerge for what contexts should elicit imprinting, which individuals and tissues will show it, and the direction of imprinting effects. The predictions often vary for different genetic structures (varying queen and mate number) and often contrast with predictions for diploids. CONCLUSION: Because the contexts differ from the normal imprinting case, and because nothing is currently known about imprinting in social insects, these predictions can serve as a strong a priori test of the kinship theory of imprinting. If the predictions are correct, then social insects, which have long served as exemplars of cooperation between individuals, will also be shown to be extraordinary examples of competition within individual genomes

Fundamental Theorems of Evolution

Evolutionary biology is undergirded by an extensive and impressive set of mathematical models. Yet only one result, Fisher’s theorem about selection and fitness, is generally accorded the status of a fundamental theorem. I argue that although its fundamental status is justified by its simplicity and scope, there are additional results that seem similarly fundamental. I suggest that the most fundamental theorem of evolution is the Price equation, both because of its simplicity and broad scope and because it can be used to derive four other familiar results that are similarly fundamental: Fisher’s average-excess equation, Robertson’s secondary theorem of natural selection, the breeder’s equation, and Fisher’s fundamental theorem. These derivations clarify both the relationships behind these results and their assumptions. Slightly less fundamental results include those for multivariate evolution and social selection. A key feature of fundamental theorems is that they have great simplicity and scope, which are often achieved by sacrificing perfect accuracy. Quantitative genetics has been more productive of fundamental theorems than population genetics, probably because its empirical focus on unknown genotypes freed it from the tyranny of detail and allowed it to focus on general issues

[Book review of] Adaptation in Metapopulations: How Interaction Changes Evolution, by Michael J. Wade.

Adaptation in Metapopulations: How Interaction Changes Evolution. By Michael J. Wade. Chicago (Illinois): University of Chicago Press . $120.00 (hardcover);$40.00 (paper). vii + 260 p.; ill.; index. ISBN: 978-0-226-12956-3 (hc); 978-0-226-12973-0 (pb); 978-0-226-12987-7 (eb). 2016

Painted Bunting (\u3cem\u3ePasserina ciris\u3c/em\u3e) Caught in the Web of a Giant Lichen Orb-Weaver Spider (\u3cem\u3eAraneus bicentenarius\u3c/em\u3e)

Orb-weaver spiders weave large webs that are capable of entrapping various species of birds. We report a case of a male Painted Bunting (Passerina ciris) caught in the web of a giant lichen orb-weaver (Araneus bicentenarius). Most cases of bird entrapment in spider webs involve spiders with larger webs (often Nephila sp.) and very small birds, usually hummingbirds. Our case is noteworthy because we report a relatively large bird caught in a relatively small web. Furthermore, the geographic distribution of A. bicentenarius extends beyond the tropics and subtropics, which is where most reported cases of bird entrapment occur. This observation suggests that even small orb-weaver webs may pose a threat to relatively large birds, and that this risk may extend well beyond the regions most commonly associated with entrapment