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Species interactions shape the evolution of traits, life histories, and the pattern of speciation. What is less clear is whether certain types of species interaction are more or less likely to lead to phenotypic divergence among species. We used the brood pollination mutualism between yuccas and yucca moths to test how mutualistic (pollination) and antagonistic (oviposition) traits differ in the propensity to increase phenotypic divergence among pollinator moths. We measured traits of the tentacular mouthparts, structures used by females to actively pollinate flowers, as well as ovipositor traits to examine differences in the rate of evolution of these two suites of traits among pollinator species. Morphological analyses revealed two distinct groups of moths based on ovipositor morphology, but no such groupings were identified for tentacle morphology, even for moths that pollinated distantly related yuccas. In addition, ovipositor traits evolved at significantly faster rates than tentacular traits. These results support theoretical work suggesting that antagonism is more likely than mutualism to lead to phenotypic divergence.

Insect mutualisms are essential for reproduction of many plants, protection of plants and other insects, and provisioning of nutrients for insects. Disruption of these mutualisms by global change can have important implications for ecosystem processes. Here, we assess the general effects of global change on insect mutualisms, including the possible impacts on mutualistic networks. We find that the effects of global change on mutualisms are extremely variable, making broad patterns difficult to detect. We require studies focusing on changes in cost-benefit ratios, effects of partner dependency, and degree of specialization to further understand how global change will influence insect mutualism dynamics. We propose that rapid coevolution is one avenue by which mutualists can ameliorate the effects of global change.

The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur at night when Yucca flowers are open and strongly scented. Thus, floral volatiles have been suggested as key sensory signals attracting yucca moths to their host plants, but no bioactive compounds have yet been identified. In this study, we showed that both sexes of the pollinator moth Tegeticula yuccasella are attracted to the floral scent of the host Yucca filamentosa. Chemical analysis of the floral headspace from six Yucca species in sections Chaenocarpa and Sarcocarpa revealed a set of novel tetranorsesquiterpenoids putatively derived from (E)-4,8-dimethyl-1,3,7-nonatriene. Their structure elucidation was accomplished by NMR analysis of the crude floral scent sample of Yucca treculeana along with GC/MS analysis and confirmed by total synthesis. Since all these volatiles are included in the floral scent of Y. filamentosa, which has been an important model species for understanding the pollination mutualism, we name these compounds filamentolide, filamentol, filamental, and filamentone. Several of these compounds elicited antennal responses in pollinating (Tegeticula) and non-pollinating (Prodoxus) moth species upon stimulation in electrophysiological recordings. In addition, synthetic (Z)-filamentolide attracted significant numbers of both sexes of two associated Prodoxus species in a field trapping experiment. Highly specialized insect-plant interactions, such as obligate pollination mutualisms, are predicted to be maintained through "private channels" dictated by specific compounds. The identification of novel bioactive tetranorsesquiterpenoids is a first step in testing such a hypothesis in the Yucca-yucca moth interaction.

Mutualisms, or reciprocally beneficial interspecific interactions, constitute the foundation of many ecological communities and agricultural systems. Mutualisms come in different forms, from pairwise interactions to extremely diverse communities, and they are continually challenged with exploitation by nonmutualistic community members (exploiters). Thus, understanding how mutualisms persist remains an essential question in ecology. Theory suggests that high species richness and functional redundancy could promote mutualism persistence in complex mutualistic communities. Using a yeast system (Saccharomyces cerevisiae), we experimentally show that communities with the greatest mutualist richness and functional redundancy are nearly two times more likely to survive exploitation than are simple communities. Persistence increased because diverse communities were better able to mitigate the negative effects of competition with exploiters. Thus, large mutualistic networks may be inherently buffered from exploitation.

Wang and Althoff (2019) explored the capacity of Drosophila melanogaster to exhibit adaptive plasticity in a novel environment. In a full-sib, half-sib design, they scored the activity of the enzyme alcohol dehydrogenase (ADH) and plastic responses, measured as changes in ADH activity across ethanol concentrations in the range of 0-10% (natural variation) and 16% (the novel environment). ADH activity increased with alcohol concentration, and there was a positive association between larval viability and ADH activity in the novel environment. They also reported that families exhibiting greater plasticity had higher larval survival in the novel environment, concluding that ADH plasticity is adaptive. However, the four authors now concur that, since the study estimated plasticity from phenotypic differences across environments using full-sib families, it is not possible to disentangle the contributions of allele frequency changes at the Adh locus from regulatory control at loci known to influence ADH activity. Selective changes in allele frequencies may thus conflate estimates of plasticity; any type of "plasticity" (adaptive, neutral, or maladaptive) could be inferred depending on allele frequencies. The problem of scoring sib-groups after selection should be considered in any plasticity study that cannot use replicated genotypes. Researchers should monitor changes in allele frequencies as one mechanism to deal with this issue.

Premise of the study Polyploidy, or whole genome duplication (WGD), is common in plants despite theory suggesting that polyploid establishment is challenging and polyploids should be evolutionarily transitory. There is renewed interest in understanding the mechanisms that could facilitate polyploid establishment and explain their pervasiveness in nature. In particular, premating isolation from their diploid progenitors is suggested to be a crucial factor. To evaluate how changes in assortative mating occur, we need to understand the phenotypic effects of WGD on reproductive traits. Methods We used literature surveys and a meta-analysis to assess how WGD affects floral morphology, flowering phenology, and reproductive output in plants. We focused specifically on comparisons of newly generated polyploids (neopolyploids) and their parents to mitigate potential confounding effects of adaptation and drift that may be present in ancient polyploids. Key results The results indicated that across a broad representation of angiosperms, floral morphology traits increased in size, reproductive output decreased, and flowering phenology was unaffected by WGD. Additionally, we found that increased trait variation after WGD was uncommon for the phenotypic traits examined. Conclusions Our results suggest that the phenotypic effects on traits important to premating isolation of neopolyploids are small, in general. Changes in flowering phenology, reproductive output, and phenotypic variation resulting from WGD may be less critical in facilitating premating isolation and neopolyploid establishment. However, floral traits for which size is an important component of function (e.g., pollen transfer) could be strongly influenced by WGD.

Phenotypic plasticity can allow organisms to respond to environmental changes by producing better matching phenotypes without any genetic change. Because of this, plasticity is predicted to be a major mechanism by which a population can survive the initial stage of colonizing a novel environment. We tested this prediction by challenging wild Drosophila melanogaster with increasingly extreme larval environments and then examining expression of alcohol dehydrogenase (ADH) and its relationship to larval survival in the first generation of encountering a novel environment. We found that most families responded in the adaptive direction of increased ADH activity in higher alcohol environments and families with higher plasticity were also more likely to survive in the highest alcohol environment. Thus, plasticity of ADH activity was positively selected in the most extreme environment and was a key trait influencing fitness. Furthermore, there was significant heritability of ADH plasticity that can allow plasticity to evolve in subsequent generations after initial colonization. The adaptive value of plasticity, however, was only evident in the most extreme environment and had little impact on fitness in less extreme environments. The results provide one of the first direct tests of the adaptive role of phenotypic plasticity in colonizing a novel environment.

The hydrocarbon pattern in the floral scent of Yucca species was found to comprise a group of unbranched, mid-chain alkanes, alkenes, and an alkadiene. In Y. reverchonii, highly dominant (Z)-8-heptadecene is accompanied by (6Z,9Z)-6,9-heptadecadiene and heptadecane as minor components and by traces of other saturated and unsaturated hydrocarbons with similar chain length. Some of these volatiles proved to be perceived by the antennae of Tegeticula cassandra (pollinating seed-eater of Yucca) and Prodoxus decipiens (herbivore on Yucca). The possible biosynthesis of the compounds is discussed.

Phenotypic plasticity is known to enhance population persistence, facilitate adaptive evolution and initiate novel phenotypes in novel environments. How plasticity can contribute or hinder adaptation to different environments hinges on its genetic architecture. Even though plasticity in many traits is genetically controlled, whether and how plasticity's genetic architecture might change in novel environments is still unclear. Because much of gene expression can be environmentally influenced, each environment may trigger different sets of genes that influence a trait. Using a quantitative trait loci (QTL) approach, we investigated the genetic basis of plasticity in a classic functional trait, alcohol dehydrogenase (ADH) activity in D. melanogaster, across both historical and novel alcohol environments. Previous research in D. melanogaster has also demonstrated that ADH activity is plastic in response to alcohol concentration in substrates used by both adult flies and larvae. We found that across all environments tested, ADH activity was largely influenced by a single QTL encompassing the Adh-coding gene and its known regulatory locus, delta-1. After controlling for the allelic variation of the Adh and delta-1 loci, we found additional but different minor QTLs in the 0 and 14% alcohol environments. In contrast, we discovered no major QTL for plasticity itself, including the Adh locus, regardless of the environmental gradients. This suggests that plasticity in ADH activity is likely influenced by many loci with small effects, and that the Adh locus is not environmentally sensitive to dietary alcohol.

Aim The determinants of species’ geographical ranges are the result of both abiotic and biotic factors. Among co-occurring closely related species, some degree of differentiation in niche characteristics is assumed necessary to allow continued coexistence. As niche requirements are likely to show similarity or overlap, competition among such species may also restrict range limits and help maintain species boundaries. We examined the roles of niche compartmentalization and competition to assess their relative contributions in determining geographical distributions of four closely related species of Yucca co-occurring across a large region of Texas. These species are pollinated by the same moth species, but each yucca is a distinct biological species. Location Texas, USA. Methods We used species distribution modelling and niche evaluation methods based on extensive field surveys to evaluate the roles of abiotic factors and competition. We also conducted surveys of flowering activity to determine if species boundaries may be maintained by species-specific shifts in flowering phenology that would limit interspecific gene flow. Results Niche evaluation methods demonstrate unique niches mostly consistent with the defined ecological regions of Texas. Geographical distributions of yuccas are mostly parapatric with some regions of sympatry. Species distribution models indicate that most species pairings display a region of potential sympatry where one of the species is numerically dominant, suggesting that competitive exclusion is delineating species ranges at parapatric margins. Flowering activity data indicate the potential for cross-pollination among these species. Nevertheless, there is little evidence for hybridization, suggesting that strong selection due to niche requirements is mediating species boundaries. Main conclusions Results suggest that adaptation to abiotic conditions has been a major force underpinning diversification in these plants. However, competition at the edge of species’ ranges likely limits the spread of any one species, leading to uncharacteristically high species diversity over a relatively small geographical area.

Brood pollination mutualisms-interactions in which specialized insects are both the pollinators (as adults) and seed predators (as larvae) of their host plants-have been influential study systems for coevolutionary biology. These mutualisms include those between figs and fig wasps, yuccas and yucca moths, leafflowers and leafflower moths, globeflowers and globeflower flies, Silene plants and Hadena and Perizoma moths, saxifrages and Greya moths, and senita cacti and senita moths. The high reciprocal diversity and species-specificity of some of these mutualisms have been cited as evidence that coevolution between plants and pollinators drives their mutual diversification. However, the mechanisms by which these mutualisms diversify have received less attention. In this paper, we review key hypotheses about how these mutualisms diversify and what role coevolution between plants and pollinators may play in this process. We find that most species-rich brood pollination mutualisms show significant phylogenetic congruence at high taxonomic scales, but there is limited evidence for the processes of both cospeciation and duplication, and there are no unambiguous examples known of strict-sense contemporaneous cospeciation. Allopatric speciation appears important across multiple systems, particularly in the insects. Host-shifts appear to be common, and widespread host-shifts by pollinators may displace other pollinator lineages. There is relatively little evidence for a "coevolution through cospeciation" model or that coevolution promotes speciation in these systems. Although we have made great progress in understanding the mechanisms by which brood pollination mutualisms diversify, many opportunities remain to use these intriguing symbioses to understand the role of biotic interactions in generating biological diversity.

The interaction between yucca plants and yucca moths has been one of the focal model systems investigated in the study of pollination mutualism and coevolution, especially in terms of understanding the prevention of overexploitation by mutualist partners. Yuccas have the ability to assess the number of eggs placed by pollinators into their ovaries, and can preferentially abort those flowers that would have many moth larvae consuming yucca seeds. Previous phylogenetic research identified a rapid radiation of moth species that corresponded with shifts in the interaction with their host plants. These shifts led to the evolution of moth species that circumvent the egg detection method used by yuccas to limit seed damage. In particular, some pollinator species deposit their eggs so that they are undetectable by the plants, whereas other species are ‘cheaters’ that have lost the ability to pollinate, yet deposit eggs into developing fruit rather than flowers. The evolution of these new species happened so quickly that the phylogeny of the moths has remained unresolved despite repeated attempts with standard Sanger sequencing of mtDNA loci and AFLP marker generation. Here, we use extensive analyses of RAD-seq data to determine the phylogenetic relationships among yucca moth species. The results provide a robust phylogenetic framework that identifies the evolutionary relationships among shifts in egg-laying strategies, as well as determining the closest pollinating relatives to the cheater species. Based on the obtained phylogeny, a shift in egg-laying strategy that avoided the overexploitation regulatory mechanism used by yucca plants was a precursor for the evolution of two species with cheating behaviour.

The determinants of a species' geographic distribution are a combination of both abiotic and biotic factors. Environmental niche modeling of climatic factors has been instrumental in documenting the role of abiotic factors in a species' niche. Integrating this approach with data from species interactions provides a means to assess the relative roles of abiotic and biotic components. Here, we examine whether the high host specificity typically exhibited in the active pollination mutualism between yuccas and yucca moths is the result of differences in climatic niche requirements that limit yucca moth distributions or the result of competition among mutualistic moths that would co-occur on the same yucca species. We compared the species distribution models of two Tegeticula pollinator moths that use the geographically widespread plant Yucca filamentosa. Tegeticula yuccasella occurs throughout eastern North America whereas T. cassandra is restricted to the southeastern portion of the range, primarily occurring in Florida. Species distribution models demonstrate that T. cassandra is restricted climatically to the southeastern United States and T. yuccasella is predicted to be able to live across all of eastern North America. Data on moth abundances in Florida demonstrate that both moth species are present on Y. filamentosa; however, T. cassandra is numerically dominant. Taken together, the results suggest that moth geographic distributions are heavily influenced by climate, but competition among pollinating congeners will act to restrict populations of moth species that co-occur.

International audience; PREMISE: Variation in pollen-ovule ratios is thought to reflect the degree of pollen transfer efficiency—the more efficient the process, the fewer pollen grains needed. Few studies have directly examined the relationship between pollen-ovule ratio and pollen transfer efficiency. For active pollination in the pollination brood mutualisms of yuccas and yucca moths, figs and fig wasps, senita and senita moths, and leafflowers and leafflower moths, pollinators purposefully collect pollen and place it directly on the stigmatic surface of conspecific flowers. The tight coupling of insect reproductive interests with pollination of the flowers in which larvae develop ensures that pollination is highly efficient.METHODS: We used the multiple evolutionary transitions between passive pollination and more efficient active pollination to test if increased pollen transfer efficiency leads to reduced pollen-ovule ratios. We collected pollen and ovule data from a suite of plant species from each of the pollination brood mutualisms and used phylogenetically controlled tests and sister-group comparisons to examine whether the shift to active pollination resulted in reduced pollen-ovule ratios.RESULTS: Across all transitions between passive and active pollination in plants, actively pollinated plants had significantly lower pollen-ovule ratios than closely related passively pollinated taxa. Phylogenetically corrected comparisons demonstrated that actively pollinated plant species had an average 76% reduction in the pollen-ovule ratio.CONCLUSIONS: The results for active pollination systems support the general utility of pollen-ovule ratios as indicators of pollination efficiency and the central importance of pollen transfer efficiency in the evolution of pollen-ovule ratio.

One of the major issues in phylogenetic analysis is that gene genealogies from different gene regions may not reflect the true species tree or history of speciation. This has led to considerable debate about whether concatenation of loci is the best approach for phylogenetic analysis. The application of Next-generation sequencing techniques such as RAD-seq generates thousands of relatively short sequence reads from across the genomes of the sampled taxa. These data sets are typically concatenated for phylogenetic analysis leading to data sets that contain millions of base pairs per taxon. The influence of gene region conflict among so many loci in determining the phylogenetic relationships among taxa is unclear. We simulated RAD-seq data by sampling 100 and 500 base pairs from alignments of over 6000 coding regions that each produce one of three highly supported alternative phylogenies of seven species of Drosophila. We conducted phylogenetic analyses on different sets of these regions to vary the sampling of loci with alternative gene trees to examine the effect on detecting the species tree. Irrespective of sequence length sampled per region and which subset of regions was used, phylogenetic analyses of the concatenated data always recovered the species tree. The results suggest that concatenated alignments of Next-generation data that consist of many short sequences are robust to gene tree/species tree conflict when the goal is to determine the phylogenetic relationships among taxa.

Abstinence-only sexuality education (AOSE); is required in the public school systems of many states, raising public health concerns and perpetuating health disparities through school systems. This study aimed to determine the correlations between state-mandated AOSE and the rates of adolescent HIV and teen pregnancy.Using publicly available data on all 50 United States' laws and policies on AOSE, states were ranked according to their level of abstinence emphasis on sexuality education (Level 0 - Level 3);. We calculated the relative proportion of Black students in public schools and the proportion of families below the federal poverty line then ranked them by state. We compared the states' ranks to the incidence of adolescent HIV and teen pregnancy in those states to identify associations between variables.The majority of states (~44 percent ); have legally mandated AOSE policies (Level 3); and adolescent HIV and teen pregnancy rates were highest in these Level 3 states. There were significant, positive correlations between HIV incidence rates of 13-19 year olds, HIV rates of 20-24 year olds, teen pregnancy rates, and AOSE level, with the proportion of the population that lives below the federal poverty level, and whether they attended schools that had a greater than 50 percent of an African American population.These data show a clear association between state sexuality education policies and adolescent HIV and teen pregnancy rates not previously demonstrated. Our data further show that states that have higher proportions of at-risk populations, with higher adolescent HIV and teen pregnancy rates, are more likely to also have restrictive AOSE policies. These populations may be more likely to attend public schools where AOSE is taught, increasing their risk for HIV and teen pregnancy. The World Health Organization considers fact-based Comprehensive Sexuality Education a human right, and the authors believe it is past time to end harmful, discriminatory sexuality education policies in US public schools.

1. Specialisation in host plant use is strongly correlated with speciation in many plant-feeding insects. Specialised taxa, however, could be restricted in host range due to limits in ecological availability of host plant species rather than trade-offs in using alternate host species. 2. Moths in the genus Prodoxus are extreme specialists on Yucca and speciation is closely tied to host plant shifts. However, many Yucca ranges are allopatric. This study examined whether the bogus yucca moth Prodoxus decipiens is limited in host range because of biogeographic factors or due to differences in the characteristics of host plant species. 3. In a common garden, local P. decipiens moths that use Yucca filamentosa were exposed to individuals of five Yucca species, two that are known hosts of P. decipiens in other parts of its range and three that are used by its sister species, Prodoxus quinquepunctellus. 4. Local moths were attracted to flowers of all Yucca species and females attempted oviposition in the flowering stalks of all species. However, larvae successfully completed development to diapause in only one of the five host plant species. Larval development on non-natal Yucca species was significantly reduced compared with the local host. 5. The results suggest that differences in host plant characteristics among Yucca species would result in strong natural selection during a host shift. Thus, specialisation in host plant use is probably due to trade-offs involved with using novel host plant species as well as ecological availability.

Through the process of ecological speciation, insect populations that adapt to new host plant species or to different plant tissues could speciate if such adaptations cause reproductive isolation. One of the key issues in this process is identifying the mechanisms by which adaptation in ecological traits leads directly to reproductive isolation. Here I show that within a radiation of specialist moths that pollinate and feed on yuccas, shifts in egg placement resulted in changes in female moth egg-laying structures that led to concomitant changes in male reproductive morphology. As pollinator moths evolved to circumvent the ability of yuccas to selectively abscise flowers that contain pollinator eggs, ovipositor length became shorter. Because mating occurs through the ovipositor, shortening of the ovipositor also led to significantly shorter and wider male intromittent organs. In instances where two pollinator moth species occur in sympatry and on the same host plant species, there is one short and one long ovipositor species that are reproductively isolated. Given that many plant-feeding insects lay eggs into plant tissues, changes in ovipositor morphology that lead to correlated changes in reproductive morphology may be a mechanism that maintains reproductive isolation among closely related species using the same host plant species.

Florivores are present in many pollination systems and can have direct and indirect effects on both plants and pollinators. Although the impact of florivores are commonly examined in facultative pollination mutualisms, their effects on obligate mutualism remain relatively unstudied. Here, we used experimental manipulations and surveys of naturally occurring plants to assess the effect of florivory on the obligate pollination mutualism between yuccas and yucca moths. Yucca filamentosa (Agavaceae) is pollinated by the moth Tegeticula cassandra (Lepidoptera: Prodoxidae), and the mutualism also attracts two florivores: a generalist, the leaf-footed bug Leptoglossus phyllopus (Hemiptera: Coreidae), and a specialist, the beetle Hymenorus densus (Coleoptera: Tenebrionidae). Experimental manipulations of leaf-footed bug densities on side branches of Y. filamentosa inflorescences demonstrated that feeding causes floral abscission but does not reduce pollen or seed production in the remaining flowers. Similar to the leaf-footed bugs, experimental manipulations of beetle densities within individual flowers demonstrated that beetle feeding also causes floral abscission, but, in addition, the beetles also cause a significant reduction in pollen availability. Path analyses of phenotypic selection based on surveys of naturally occurring plants revealed temporal variation in the plant traits important to plant fitness and the effects of the florivores on fitness. Leaf-footed bugs negatively impacted fitness when fewer plants were flowering and leaf-footed bug density was high, whereas beetles had a positive effect on fitness when there were many plants flowering and their densities were low. This positive effect was likely due to adult beetles consuming yucca moth eggs while having a negligible effect on floral abscission. Together, the actions of both florivores either augmented the relationship of plant traits and fitness or slightly weakened the relationship. Overall, the results suggest that, although florivores are always present during flowering, the impact of florivores on phenotypic selection in yuccas is strongly mitigated by changes in their densities on plants from year to year. In contrast, both florivores consistently influenced pollinator larval mortality through floral abscission, and H. densus beetles additionally via the consumption of pollinator eggs.

D∗± production via e+e−→D∗±X has been measured at an average CM energy of 34.4 GeV. The D∗± energy spectrum is hard, with a maximum near χ = 0.6. The size of the D∗ cross section, R D ∗ = σ( e + e − → D ∗ X ) σ μμ = 2.50 ± 0.64 ± 0.88 (assuming R D ∗0 = R D ∗+ ) indicates that a large fraction of charm quark production yields D∗ mesons. The D∗± angular distribution exhibits a forward—backward asymmetry, A = −0.28 ± 0.13. This is consistent with that expected in the standard theory for weak neutral currents and leads to |gAc| = 0.89 ± 0.44 for the axial vector coupling of the charm quark.

We present an analysis of electroweak leptonic couplings from high statistics experiments on Bhabha scattering and μ pair production at an energy of 34.5 GeV. The forward-backward charge asymmetry of the μ pairs was measured to be −0.098±0.023±0.005. The data were found to agree well with the standard theory of electroweak interaction giving sin2θW=0.27±0.07. The leptonic weak couplings were determined to begv=0.000±0.170 andgA=−0.481±0.055. The data were also used to investigate a class of composite models for leptons.

Three-jet events produced by e+e- annihilation into hadrons at 34.6 GeV c.m. energy were studied by comparing them with 2nd order QCD and two different models of fragmentation. The distribution of low energy particles in the 3-jet plane is found to be better described by the LUND color string model than by the independent jet model. The opposite is true for more energetic particles flowing between the 3 jets. The average transverse momenta in jets can be described with values of σq between 350 and 500 MeV/c for the gluon jet. © 1985 Springer-Verlag.

We present an analysis of ρ0ρ0 production by two photons in the ρ0ρ0 invariant mass range from 1.2 to 2.0 GeV. From a study of the angular correlations in the process γγ→ρ0ρ0→π- π+π- we exclude a dominant contribution from JP=0- or 2- states. The data indicate sizeable contributions from JP=0+ for four pion masses M4π1.7 GeV. The data are also well described by a model with isotropic production and uncorrelated isotropic decay of the ρ0,s. The cross section stays high below the nominal ρ0ρ0 threshold, i.e. M4π

We have measured the processe + e −→e + e −+hadrons, where one of the scattered electrons was detected at large angles, withQ 2 ranging from 7 to 70 (VeV/c)2. The photon structure functionF 2 γ (x, Q2) was determined at an averageQ 2 of 23 (GeV/c)2. The measurements were compared to theoretical predictions of the Quark Parton Model and Quantum Chromodynamics. In both models a hadronic part was added. Within the errors the data are in agreement with the QPM using quark masses of 300 MeV/c2 for the light quarks. The data also agree with a QCD calculation including higher order corrections. A fit yielded a $$\Lambda _{\overline {MS} } $$ value of 140 −65 +190 MeV, where the errors include statistical and systematic uncertainties.

Questions How does spatial scale (extent and grain) influence the relative importance of different environmental factors as determinants of plant community composition? Are there general scale thresholds that mark the transition from primarily edaphic to primarily climatic control of plant communities? Location Global. Methods We surveyed the empirical literature and identified 89 analyses from 63 published studies that analysed vegetation–environment relationships involving at least two categories of predictor variables (edaphic, climatic, topographic, biotic, spatial or disturbance-related). For each analysis, we identified the primary predictor variable (i.e. the variable that explained the most variation in community composition) and the relative effect size of the best predictor variable from each category. We defined ‘primacy’ as the proportion of times a variable category was primary when it was measured, and analysed primacy and the relative effect size of each category as a function of spatial extent and grain. We also analysed the subset of studies that measured both edaphic and climatic variables to identify spatial extent and grain thresholds for the primacy of these factors. We surveyed the empirical literature and identified 89 analyses from 63 published studies that analysed vegetation–environment relationships involving at least two categories of predictor variables (edaphic, climatic, topographic, biotic, spatial or disturbance-related). For each analysis, we identified the primary predictor variable (i.e. the variable that explained the most variation in community composition) and the relative effect size of the best predictor variable from each category. We defined ‘primacy’ as the proportion of times a variable category was primary when it was measured, and analysed primacy and the relative effect size of each category as a function of spatial extent and grain. We also analysed the subset of studies that measured both edaphic and climatic variables to identify spatial extent and grain thresholds for the primacy of these factors. Results Edaphic variables had the highest primacy in the overall data set and at fine grain sizes (

Review of: Butlin, R., Bridle, J. and Schluter, D. 2009. Speciation and Patterns of Diversity. Cambridge University Press. 346 pp. ISBN 978-0-521-70963-7 Paper. The fields of adaptive speciation and macroecology have made many significant advances in recent years. Research in adaptive speciation has elucidated the mechanisms of ecological speciation and sought to explain how selection can divide a single lineage into multiple independent lineages (e.g., Schluter 2000; Rundle and Nosil 2005; Nosil et al. 2009). Concomitantly, macroecologists have characterized the large-scale distributional patterns of the earth’s biodiversity and advanced theory to explain the turnover of taxa within space and time (e.g., Gaston and Blackburn 2000; Blackburn and Gaston 2003; Smith et al. 2008). Although seemingly directed at the same goal, understanding the origin and maintenance of diversity, these two fields have developed along somewhat independent lines. There is an obvious connection between the two and no evolutionary biologist would doubt the importance of ecology in facilitating speciation and no ecologist would doubt the importance of speciation in facilitating diversity. Beyond that, however, there has been little dialogue about how these two fields can integrate and form a much stronger understanding of the genesis of biodiversity. Butlin, Bridle, and Schluter designed the book, Speciation and Patterns of Diversity, to stimulate thought and discussion about the interconnectedness of macroecology and evolutionary biology. The book is a result of the 2007 Annual Symposium of the British Ecological Society entitled Speciation and Ecology. The goal of the symposium was to foster ties between the fields of macroecology and adaptive speciation. The resulting edited volume goes a long way toward enlightening the reader of the importance of blending evolution with macroecology. The main thesis of the book is to take the evolutionary mechanisms that are responsible for generating species and examine their consequences for patterns of diversity—a melding of mechanism and pattern that will lead to an understanding of process. The editors assembled leaders in the fields of macroecology and adaptive speciation to provide perspectives of where we are both ecologically and evolutionarily with regards to patterns of diversity. This is no small feat given that the topic encompasses all of the earth’s biodiversity—past and present. These leaders have offered their views and challenges for understanding the evolutionary ecology of speciation and how mechanisms of speciation may determine patterns of diversity. The result is a careful examination of the key issues currently being studied with regards to speciation and its role in generating patterns of diversity. This book is not an in-depth look at one particular aspect of diversity, nor is it a cursory look at all topics. Instead, it is a well-balanced book that explores mechanisms of speciation and the consequences for the patterns of diversity that we observe. The taxa discussed in the book range from microbes to mammals. If I have one complaint about the breadth of taxa, it is that plants are sorely missing. They are featured on the cover, but are only mentioned in passing in one of the chapters. As has historically been the case in the development of speciation theory, plant speciation mechanisms and patterns have rarely been integrated with animal speciation. Perhaps one day that will be remedied.

Human-mediated disturbances have altered every ecosystem on the planet and these changes may have important consequences for biodiversity and community structure. We tested how the degree of urbanization impacts a tri-trophic interaction among the Florida scrub endemic plant Palafoxia feayi, a gallmaking midge, and the associated parasitoid wasps. A combination of field surveys and laboratory rearings were used to determine whether habitat disturbance associated with housing development (e.g., land clearing, fire suppression) was correlated with changes in plant architecture, gallmaker abundance, or parasitoid diversity. We found significant differences in the number of side branches of plants at urban sites, and that the number of galls per plant increased with both the number of side branches and plant height. More parasitoids were found in galls collected from urban sites, but parasitoid diversity was unchanged by urbanization. We conclude that although urbanization influenced plant architectu...

Premise of the study Specialized brood pollination systems involve both mutualism and antagonism in the overall interaction and have led to diversification in both plants and insects. Although largely known for mutualism, the role of the antagonistic side of the interaction in these systems has been overlooked. Specialization may be driven by plant defenses to feeding by the insect larvae that consume and kill developing plant ovules. The interaction among yuccas and yucca moths is cited as a classic example of the importance of mutualism in specialization and diversification. Pollinators moths are very host specific, but whether this specificity is due to adult pollination ability or larval feeding ability is unclear. Here, I test the potential role of antagonism in driving specialization among yuccas and yucca moths. Methods I examined the ability of the most-polyphagous yucca moth pollinator, Tegeticula yuccasella, to pollinate and develop on five Yucca species used across its range. Yucca species endemic to the Great Plains and Texas were transplanted to a common garden in Syracuse, New York and exposed to the local pollinator moth population over 3 years. Key results Local moths visited all but one of the Yucca species, but had drastically lower rates of successful larval development on non-natal Yucca species in comparison to the local host species. Conclusion Specialization in many brood pollination systems may be strongly influenced by the antagonistic rather than the mutualistic side of the overall interaction, suggesting that antagonistic coevolution is a possible source of diversification.

Mutualisms are interactions among species in which the participants receive a fitness benefit. Almost all organisms are engaged in at least one mutualistic interaction and mutualisms forms the basis of many, if not all, communities and ecosystems. This article provides an overview of how these important interactions originate, remain stable, and are influenced by the presence of other species.

The yucca–yucca moth interaction is one of the most well-known and remarkable obligate pollination mutualisms, and is an important study system for understanding coevolution. Previous research suggests that specialist pollinators can promote rapid diversification in plants, and theoretical work has predicted that obligate pollination mutualism promotes cospeciation between plants and their pollinators, resulting in contemporaneous, parallel diversification. However, a lack of information about the age of Yucca has impeded efforts to test these hypotheses. We used analyses of 4322 AFLP markers and cpDNA sequence data representing six non-protein-coding regions (trnT–trnL, trnL, trnL intron, trnL–trnF, rps16 and clpP intron 2) from all 34 species to recover a consensus organismal phylogeny, and used penalized likelihood to estimate divergence times and speciation rates in Yucca . The results indicate that the pollination mutualism did not accelerate diversification, as Yucca diversity (34 species) is not significantly greater than that of its non-moth-pollinated sister group, Agave sensu latissimus (240 species). The new phylogenetic estimates also corroborate the suggestion that the plant–moth pollination mutualism has at least two origins within the Agavaceae. Finally, age estimates show significant discord between the age of Yucca ( ca 6–10 Myr) and the current best estimates for the age of their pollinators (32–40 Myr).

The genus Yucca is widely recognized for its pollination mutualism with yucca moths. Analysis of diversification in this interaction has been hampered by the lack of a robust phylogeny for the genus. Here we attempt the first extensive nuclear DNA based assessment of the phylogenetic relationships of Yucca. We used AFLP markers to recover the phylogeny of 87 samples representing 38 Yucca taxa. An analysis based on 4322 markers strongly supported a topology consistent with morphological classification at the section level (capsular-fruited Chaenocarpa, fleshy-fruited Sarcocarpa, and spongy-fruited Clistocarpa). Within Sarcocarpa, all but two of the traditional species were monophyletic. Within Chaenocarpa, the morphologically distinct series Rupicolae was strongly supported. In the remaining Chaenocarpa, a western group (Colorado Plateau southward) and an eastern group (Great Plains, central Texas east to Florida) were recovered. Within these groups, where taxonomic circumscriptions are narrow and historically contested, there was at most limited monophyly of traditional taxa, suggesting rapid recent diversification, introgression, or non-monophyletically circumscribed taxa.

The interactions between herbivorous insects and their host plants have been central in generating diversification in both groups. We used a community of four yucca moth species, monophagous on the host plant Hesperoyucca whipplei (Agavaceae), to examine how the type of interaction and where insects feed within a plant influence phylogeographic structure of herbivorous insects. These four species included two fruit-feeders, one mutualistic and one commensalistic, and two commensalistic stalk-feeders. Surveys based on mtDNA cytochrome oxidase I sequence data demonstrated that the moth species differed in phylogeographic history. Populations of the mutualist pollinator, Tegeticula maculata, exhibited the most subdivision in comparison to the three commensal Prodoxus species (both genera in Lepidoptera, Prodoxidae). Feeding location was also correlated with differences in phylogeographic history through its influence on population sizes and the probability of gene flow. The results suggest that both the outcome of interactions and where insects feed may influence population structure.

Integrated research across disciplines is required to address many of the pressing environmental problems facing human societies. Often the integration involves disparate disciplines, including those in the biological sciences, and demands collaboration from problem formulation through hypothesis development, data analysis, interpretation, and application. Such projects raise conceptual and methodological challenges that are new to many researchers in the biological sciences and to their collaborators in other disciplines. In this article, we develop the theme that many of these challenges are fundamentally philosophical, a dimension that has been largely overlooked in the extensive literature on cross-disciplinary research and education. We present a “toolbox for philosophical dialogue,” consisting of a set of questions for self-examination that cross-disciplinary collaborators can use to identify and address their philosophical disparities and commonalities. We provide a brief user's manual for...

The interaction between yuccas and yucca moths has been central to understanding the origin and loss of obligate mutualism and mutualism reversal. Previous systematic research using mtDNA sequence data and characters associated with genitalic morphology revealed that a widespread pollinator species in the genus Tegeticula was in fact a complex of pollinator species that differed in host use and the placement of eggs into yucca flowers. Within this mutualistic clade two nonpollinating "cheater" species evolved. Cheaters feed on yucca seeds but lack the tentacular mouthparts necessary for yucca pollination. Previous work suggested that the species complex formed via a rapid radiation within the last several million years. In this study, we use an expanded mtDNA sequence data set and AFLP markers to examine the phylogenetic relationships among this rapidly diverging clade of moths and compare these relationships to patterns in genitalic morphology. Topologies obtained from analyses of the mtDNA and AFLP data differed significantly. Both data sets, however, corroborated the hypothesis of a rapid species radiation and suggested that there were likely two independent species radiations. Morphological analyses based on oviposition habit produced species groupings more similar to the AFLP topology than the mtDNA topology and suggested the two radiations coincided with differences in oviposition habit. The evolution of cheating was reaffirmed to have evolved twice and the closest pollinating relative for one cheater species was identified by both mtDNA and AFLP markers. For the other cheater species, however, the closest pollinating relative remains ambiguous, and mtDNA, AFLP, and morphological data suggest this cheater species may be diverged based on host use. Much of the divergence in the species complex can be explained by geographic isolation associated with the evolution of two oviposition habits.

Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such ‘cheaters’ may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca–yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.

Obligate pollination mutualisms have been central to our understanding of the ecology and evolution of mutualisms. Although usually viewed as pairwise interactions, obligate mutualists also interact with other community members that may impact the mu- tualism. In this study, we examined the community context of the obligate mutualism between the plant Yucca filamentosaand its yucca moth pollinator Tegeticula cassandra to determine the relationships among plant traits, the community assemblage, and fruit set. In addition to attracting its pollinator, Y. filamentosain central Florida also attracts two insect florivores: the hemipteran Leptoglossus phyllopusand the beetle Hymenorus densus. We surveyed flowering Y. filamentosain 2001 and 2002 to determine the abundance of the three insect species throughout the flowering period. We also measured fruit set and four plant traits thought to be important in attracting the moth pollinator. Path analysis revealed that T. cassandra was the most important determinant of relative fruit set for both years. Peak pollinator abundance was significantly earlier than peak flowering. Consequently, we found a negative relationship between plant flowering date and pollinator abundance. Fur- thermore, taller plants also attracted more pollinators. Leptoglossus phyllopus had a sig- nificantly negative impact on relative fruit set in 2001 but not in 2002, whereas H. densus had no effect in either year. Abundance of the two florivores was more closely tied to peak flowering of Y. filamentosathan was the peak abundance of the pollinator moths. Although both florivore species reached high densities on Y. filamentosa , their effect on relative fruit set through floral abscission may be partially masked by the characteristically high ab- scission rates found in yuccas. As a result, florivores may be feeding on flowers that are already destined to be abscised. Similarly, pollinator moths may be preadapted to handle the effects of florivores because females lay eggs across multiple plants and flowers. Hence, the obligate mutualism between yuccas and yucca moths may be somewhat buffered from the effects of local community members depending on whether florivores substantially increase floral abscission rates from year to year.

Yucca moths (Lep., Prodoxidae) are well-known for their obligate pollination mutualism with yuccas. In addition to the pollinators, yuccas also host many non-pollinating yucca moths. Here the genus Prodoxus, the non- pollinating sister group of the pollinators, is revised using morphological and molecular data, their phylogenetic relationships are analysed, and the evolution of host tissue specialization explored. Twenty-two species are recognized, includ- ing nine new species: Prodoxus gypsicolor sp.n., P. sonorensis sp.n., P. carnerosa- nellus sp.n., P. tamaulipellus sp.n., P. weethumpi sp.n., P. tehuacanensis sp.n., P. californicus sp.n., P. mapimiensis sp.n. and P. atascosanellus sp.n. Prodoxus y-inversus Riley, P. coloradensis Riley and P. sordidus Riley are redescribed. The genus Agavenema is synonymized with Prodoxus. Phylogenetic analyses indicated that stalk-feeding is basal within the group, that there are three separate origins of fruit-feeding, and one origin of leaf-mining from a stalk-feeding ancestor. Although species with different feeding habits often coexist within hosts, the analyses suggest that ecological specialization and diversification within a host only may have occurred within one or possibly two hosts.

There is ample evidence that host shifts in plant-feeding insects have been instrumental in generating the enormous diversity of insects. Changes in host use can cause host-associated differentiation (HAD) among populations that may lead to reproductive isolation and eventual speciation. The importance of geography in facilitating this process remains controversial. We examined the geographic context of HAD in the wide-ranging generalist yucca moth Prodoxus decipiens. Previous work demonstrated HAD among sympatric moth populations feeding on two different Yucca species occurring on the barrier islands of North Carolina, USA. We assessed the genetic structure of P. decipiens across its entire geographic and host range to determine whether HAD is widespread in this generalist herbivore. Population genetic analyses of microsatellite and mtDNA sequence data across the entire range showed genetic structuring with respect to host use and geography. In particular, genetic differentiation was relatively strong between mainland populations and those on the barrier islands of North Carolina. Finer scale analyses, however, among sympatric populations using different host plant species only showed significant clustering based on host use for populations on the barrier islands. Mainland populations did not form population clusters based on host plant use. Reduced genetic diversity in the barrier island populations, especially on the derived host, suggests that founder effects may have been instrumental in facilitating HAD. In general, results suggest that the interplay of local adaptation, geography and demography can determine the tempo of HAD. We argue that future studies should include comprehensive surveys across a wide range of environmental and geographic conditions to elucidate the contribution of various processes to HAD.

The pollination mutualism between yucca moths and yuccas highlights the potential importance of host plant specificity in insect diversification. Historically, one pollinator moth species, Tegeticula yuccasella, was believed to pollinate most yuccas. Recent phylogenetic studies have revealed that it is a complex of at least 13 distinct species, eight of which are specific to one yucca species. Moths in the closely related genus Prodoxus also specialize on yuccas, but they do not pollinate and their larvae feed on different plant parts. Previous research demonstrated that the geographically widespread Prodoxus quinquepunctellus can rapidly specialize to its host plants and may harbor hidden species diversity. We examined the phylogeographic structure of P. quinquepunctellus across its range to compare patterns of diversification with six coexisting pollinator yucca moth species. Morphometric and mtDNA cytochrome oxidase I sequence data indicated that P. quinquepunctellus as currently described contains two species. There was a deep division between moth populations in the eastern and the western United States, with limited sympatry in central Texas; these clades are considered separate species and are redescribed as P. decipiens and P. quinquepunctellus (sensu stricto), respectively. Sequence data also showed a lesser division within P. quinquepunctellus s.s. between the western populations on the Colorado Plateau and those elsewhere. The divergence among the three emerging lineages corresponded with major biogeographic provinces, whereas AMOVA indicated that host plant specialization has been relatively unimportant in diversification. In comparison, the six pollinator species comprise three lineages, one eastern and two western. A pollinator species endemic to the Colorado Plateau has evolved in both of the western lineages. The east-west division and the separate evolution of two Colorado Plateau pollinator species suggest that similar biogeographic factors have influenced diversification in both Tegeticula and Prodoxus. For the pollinators, however, each lineage has produced a monophagous species, a pattern not seen in P. quinquepunctellus.

An increasing number of studies have shown that the traits important to species interactions may differ geographically among populations or groups of populations within a single interacting species. We examined geographic structure in the searching behaviour of a recently discovered parasitoid in the genus Agathis (Hymenoptera: Braconidae) by examining the pattern of population structure obtained from sequence data of mitochondrial DNA cytochrome oxidase I and the pattern of population differentiation in female searching behaviour. Analyses of population structure showed no isolation by distance and suggested long distance dispersal among populations. This pattern is consistent with recent post-glacial expansion of Agathis n. sp. Observations of searching behaviour demonstrated that populations of Agathis n. sp. differed in a subset of the behavioural traits examined and also one morphological trait. These population differences appear to be driven in part by local host plant characteristics, and based on the population structure of Agathis n. sp., have arisen relatively quickly in evolutionary time. This study suggests that the interaction between parasitoids and their host insects may exhibit substantial geographic variation, and studies that focus at the level of single populations or the species-level may be missing much of the evolutionary dynamics of parasitoid‐host interactions.

Recent studies of parasitoid-host interactions have demonstrated that parasitoids and their hosts are geographically structured for traits such as virulence and encapsulation defenses, but no studies have yet compared the geographic structure of parasitoids and hosts using neutral genetic markers. Such studies of geographic structure are needed to evaluate the underlying geographic scale at which these interactions evolve and allow assessment of the relative effects of selection and gene flow on the geographic structure observed in traits under selection. We used sequence data from the mitochondrial DNA cytochrome oxidase I and II subunits to document and compare the geographic structures of the parasitoid Agathis thompsoni and its moth host Greya subalba. We also documented the geographic structure of G. enchrysa and compared it to the geographic structure of its parasitoid Agathis n. sp. The results demonstrated that parasitoids and their hosts may have incongruent patterns of geographic structure as assessed by molecular markers. As a consequence, the geographic scale at which the interaction evolves may be different for each species involved in the interaction. Depending on the interplay of selection and gene flow, there may not be a one-to-one correspondence of traits important in the interaction between parasitoids and their hosts at the level of local populations. The geographic structures of A. thompsoni and G. subalba and Agathis n. sp. and G. enchrysa provide further evidence of the potential importance of the formation of geographic mosaics in coevolving parasitoid-host interactions and evolving interactions in general.