Maternal body size affects sex allocation in a gregarious parasitoid.

In parasitoid wasps, body size is a key predictor of reproductive success, as size is often correlated with increased gamete production. In Hymenoptera, due to haplodiploid sex determination, sperm are required to produce daughters but not sons, so sex allocation relies on a female's ability to obtain and manage a finite supply of sperm. Body size may, therefore, affect sex allocation if smaller males provide fewer sperm, or if larger, more fertile females deplete their sperm supplies by fertilizing more eggs.

Simulating selection and evolution at the community level using common garden data.

A key issue in evolutionary biology is whether selection acting at levels higher than the individual can cause evolutionary change. If it can, then conceptual and empirical studies must consider how selection operates at multiple levels of biological organization. Here, we test the hypothesis that estimates of broad-sense community heritability, , can be used to predict the evolutionary response by community-level phenotypes when community-level selection is imposed.

Local adaptation and rapid evolution of aphids in response to genetic interactions with their cottonwood hosts.

Several studies have demonstrated the ecological consequences of genetic variation within a single plant species. For example, these studies show that individual plant genotypes support unique composition of the plants' associated arthropod community. By contrast, fewer studies have explored how plant genetic variation may influence evolutionary dynamics in the plant's associated species.

Dialects in the alarm calls of black- tailed prairie dogs (Cynomys ludovicianus): A case of cultural diffusion?

Prairie dogs (Cynomys spp.) produce an alarm call when a predator appears. Gunnison's prairie dogs (Cynomys gunnisoni) produce calls that vary in spectral structure according to predator type and specific characteristics unique to the individual predator, such as color and shape.

The opportunity for sexual selection and the evolution of non-responsiveness to pesticides, sterility inducers and contraceptives.

We illustrate a method for delaying and possibly eliminating the evolution of non-responsiveness to the treatments now used to control pest populations. Using simulations and estimates of the variance in relative fitness, i.e.

Population survey and management strategies of free-roaming dogs (Canis familiaris) on Saipan, Commonwealth of the Northern Mariana Islands.

The island of Saipan, Commonwealth of the Northern Mariana Islands, is populated by free-roaming dogs who were introduced during World War II. The local nonhuman animal control agency manages this population; however, the demographic information and public perception of this population remain unknown. To characterize the free-roaming dog population, an island-wide survey on Saipan was conducted.

sp. n. (Hirudinida, Glossiphoniidae) a new species inhabiting Montezuma Well, Arizona, USA.

A new leech species , is described from Montezuma Well, an isolated travertine spring mound located in central Arizona, USA. In its native habitat, had been previously identified as (Linnaeus, 1758), which was later reclassified to (Verrill, 1872). Similar to the European and North American , has six pairs of testisacs, five pairs of smooth crop caecae, one lobed pair of posteriorly-directed crop caecae, one pair of eyes, a nuchal scute, and diffuse salivary glands.

Climate change perils for dioecious plant species.

Climate change, particularly increased aridity, poses a significant threat to plants and the biotic communities they support. Dioecious species may be especially vulnerable to climate change given that they often exhibit spatial segregation of the sexes, reinforced by physiological and morphological specialization of each sex to different microhabitats. In dimorphic species, the overexpression of a trait by one gender versus the other may become suppressed in future climates.

Genetically informed ecological niche models improve climate change predictions.

We examined the hypothesis that ecological niche models (ENMs) more accurately predict species distributions when they incorporate information on population genetic structure, and concomitantly, local adaptation. Local adaptation is common in species that span a range of environmental gradients (e.g.

Genotypic variation in foundation species generates network structure that may drive community dynamics and evolution.

Although genetics in a single species is known to impact whole communities, little is known about how genetic variation influences species interaction networks in complex ecosystems. Here, we examine the interactions in a community of arthropod species on replicated genotypes (clones) of a foundation tree species, Populus angustifolia James (narrowleaf cottonwood), in a long-term, common garden experiment using a bipartite "genotype-species" network perspective. We combine this empirical work with a simulation experiment designed to further investigate how variation among individual tree genotypes can impact network structure.

The Opportunity for Post-Copulatory Sexual Selection in the Ectoparasitic Pea Crab, Dissodactylus primitivus (Brachyura: Pinnotheridae).

Pea crabs, Dissodactylus primitivus, inhabit multiple echinoid (heart urchin) hosts. Male and female crabs move among hosts in search for mates, and both sexes mate multiple times, creating opportunities for post-copulatory sexual selection. For such selection to occur, only a fraction of the males who succeed in mating can also succeed in siring progeny.

Rapid plant evolution in the presence of an introduced species alters community composition.

Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities.

Incorporating climate change and exotic species into forecasts of riparian forest distribution.

We examined the impact climate change (CC) will have on the availability of climatically suitable habitat for three native and one exotic riparian species. Due to its increasing prevalence in arid regions throughout the western US, we predicted that an exotic species, Tamarix, would have the greatest increase in suitable habitat relative to native counterparts under CC. We used an ecological niche model to predict range shifts of Populus fremontii, Salix gooddingii, Salix exigua and Tamarix, from present day to 2080s, under five general circulation models and one climate change scenario (A1B).

How multiple mating by females affects sexual selection.

Multiple mating by females is widely thought to encourage post-mating sexual selection and enhance female fitness. We show that whether polyandrous mating has these effects depends on two conditions. Condition 1 is the pattern of sperm utilization by females; specifically, whether, among females, male mating number, m (i.

Differences in relative fitness among alternative mating tactics might be more apparent than real.

Two theoretical frameworks guide research on multiple male phenotypes within natural populations. Each scheme recognizes that male polymorphisms vary in the degree to which genotype and environment influence trait expression. Consensus remains elusive, however, on whether average fitnesses must be equivalent and whether genetic differences need exist for polymorphism to persist over time.

Sexual selection and mating systems.

Sexual selection is among the most powerful of all evolutionary forces. It occurs when individuals within one sex secure mates and produce offspring at the expense of other individuals within the same sex. Darwin was first to recognize the power of sexual selection to change male and female phenotypes, and, in noting that sexual selection is nonubiquitous, Darwin was also first to recognize the importance of mating system--the "special circumstances" in which reproduction occurs within species.

Tree hybridization and genotypic variation drive cryptic speciation of a specialist mite herbivore.

Few studies have investigated the roles that plant hybridization and individual plant genotype play in promoting population divergence within arthropod species. Using nrDNA sequence information and reciprocal transfer experiments, we examined how tree cross type (i.e.

The evolution of parental care in the context of sexual selection: a critical reassessment of parental investment theory.

Males and females are often defined by differences in their energetic investment in gametes. In most sexual species, females produce few large ova, whereas males produce many tiny sperm. This difference in initial parental investment is presumed to exert a fundamental influence on sex differences in mating and parental behavior, resulting in a taxonomic bias toward parental care in females and away from parental care in males.

Extending genomics to natural communities and ecosystems.

An important step in the integration of ecology and genomics is the progression from molecular studies of relatively simple model systems to complex field systems. The recent availability of sequenced genomes from key plants is leading to a new understanding of the molecular drivers of community composition and ecosystem processes. As genome sequences accumulate for species that form intimate associations in nature, a detailed view may emerge as to how these associations cause changes among species at the nucleotide level.

A framework for community and ecosystem genetics: from genes to ecosystems.

Can heritable traits in a single species affect an entire ecosystem? Recent studies show that such traits in a common tree have predictable effects on community structure and ecosystem processes. Because these 'community and ecosystem phenotypes' have a genetic basis and are heritable, we can begin to apply the principles of population and quantitative genetics to place the study of complex communities and ecosystems within an evolutionary framework. This framework could allow us to understand, for the first time, the genetic basis of ecosystem processes, and the effect of such phenomena as climate change and introduced transgenic organisms on entire communities.

Don'T throw bateman out with the bathwater!

Bateman identified two aspects of sexual selection. The first, called Bateman's principle, is that sexual selection favors increased promiscuity of males but not of females as a result of differences in parental investment in gametes. The second is that the variance in mate number of males is the fundamental cause of a sex difference in fitness variance.

Fractal geometry is heritable in trees.

Understanding the genetic basis to landscape vegetation structure is an important step that will allow us to examine ecological and evolutionary processes at multiple spatial scales. Here for the first time we show that the fractal architecture of a dominant plant on the landscape exhibits high broad-sense heritability and thus has a genetic basis. The fractal architecture of trees is known to influence ecological communities associated with them.

Estimating the strength of sexual selection from Y-chromosome and mitochondrial DNA diversity.

We show that a sex difference in the opportunity for selection results in sex differences in the strength of random genetic drift and thus creates different patterns of genetic diversity for maternally and paternally inherited haploid genes. We derive the effective population size Ne for a male-limited or female-limited haploid gene in terms of I, the "opportunity for selection" or the variance in relative fitness. Because the variance in relative fitness of males can be an order of magnitude larger than that of females, the Ne is much smaller for males than it is for females.

Sexual selection favors female-biased sex ratios: the balance between the opposing forces of sex-ratio selection and sexual selection.

In a verbal model, Trivers and Willard proposed that, whenever there is sexual selection among males, natural selection should favor mothers that produce sons when in good condition but daughters when in poor condition. The predictions of this model have been the subject of recent debate. We present an explicit population genetic model for the evolution of a maternal-effect gene that biases offspring sex ratio.

Microhabitat segregation and cannibalism in an endangered freshwater isopod, Thermosphaeroma thermophilum.

Intraspecific microhabitat segregation is expected to arise when there are age- or sex-specific differences in predation risk. The degree to which conspecific predation (cannibalism) can generate this risk, however, is poorly understood. In this paper, we examine microhabitat use, cannibalism, and individual responses to the presence of conspecifics in Thermosphaeroma thermophilum, an endangered isopod crustacean species that is endemic to a single, thermal spring in Socorro, N.