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We demonstrated a novel tandem-column micro-gas chromatography (microGC) based on optofluidic ring resonator (OFRR). The OFRR is a thin-walled fused silica capillary whose interior surface is coated with a polymeric stationary phase. The circular cross section of the OFRR forms the micro-ring resonator and supports whispering gallery modes (WGMs). Via tapered optical fibers in contact with the OFRR, the WGM can be excited externally at any positions along the OFRR capillary, thus enabling multi-point, on-column, real-time detection of vapor molecules flowing through the OFRR. In the present OFRR-based tandem-column-based microGC implementation, a 180 cm long conventional GC column coated with a nonpolar stationary phase was followed by a relatively short OFRR column coated with a polar phase. Two detection positions, one at the inlet of the OFRR and the other a few centimeters downstream, were used to monitor the separation achieved by the first and the second column, respectively. Owing to the multi-point on-column detection that provides complementary retention time information on each chemical compound, co-eluted analytes can be well separated and identified on at least one detection channel and no modulation is needed at the interface of tandem columns. Separation and detection of twelve analytes with various volatilities and polarities within four minutes were demonstrated. In addition, the chromatograms obtained from three different locations along the OFRR column demonstrated the system's capability of on-column monitoring of the separation process for the target analyte in a vapor mixture. Our results will lead to the development of a rapid, simple, and portable microGC system with significantly improved selectivity and chemical identification capabilities.

We demonstrate the utility of the opto-fluidic ring resonator (OFRR) sensor for the purpose of analyzing the degree of methylation in sample oligonucleotides. Cytosine methylation, a regular epigenetic function in cellular growth and metabolism, is prone to abnormal behavior that may lead to uncontrolled suppression of key genes involved with cellular proliferation. Such behavior is suspected to be strongly related to the occurrence of several types of cancers. The OFRR is demonstrated as a tool to explore and monitor the degree of methylation in DNA. Two different approaches are explored, using either bisulfite modification or immunoprecipitation. The methods are compared and the signal response for both methods is characterized.

Publisher Summary There is general recognition among evolutionists that no matter how one defines a species, the boundaries between distinct, sexually reproducing species are maintained by barriers to gene flow at individual loci. Isolating barriers have typically been categorized into those operating before fertilization (prezygotic) and after fertilization (postzygotic). Prezygotic reproductive barriers can arise due to the evolution of habitat utilization differences, mating behavior differences, and/or phenological differences between incipient species. Postzygotic isolating barriers encompass hybrid inviability, hybrid sterility and hybrid breakdown. This chapter is concerned with the set of prezygotic barriers that occur in closely related animal species after ejaculation or spawning and before fertilization, resulting in postmating, prezygotic (PMPZ) isolation. The transfer or spawning of sperm sets the stage for the operation of PMPZ barriers to gene exchange. The environment of the female reproductive tract eliminates or kills many male gametes, even conspecific ones, in a variety of ways. These barriers to fertilization by conspecific sperm may also serve as barriers to fertilization by heterospecific sperm. Moreover, in heterospecific pairings, sperm may fail to move appropriately in the female reproductive tract. The importance of chemotaxis in mediating PMPZ isolation varies among major taxonomic groups and appears to be related to whether fertilization occurs internally or externally. In insects, the proteins in the seminal fluid can influence the fertilization process in a number of ways including: the storage and capacitation of sperm; the induction of peristalsis in the female reproductive tract; and the induction of ovulation.

Two closely related species of ground crickets, Allonemobius fasciatus and A. socius, overlap and hybridize in a contact zone in the eastern United States. In earlier work, Howard (1986) described geographic variation in the width of the zone and in the strength of reproductive isolation between the two ground crickets. The zone was wider in the hills and mountains of southeastern Ohio and West Virginia than along the eastern coastal plain, and reproductive isolation appeared to be stronger where the zone was wider. Howard attributed the greater width in the mountains to the wide intermingling and patchy distribution of habitats appropriate for a species adapted to a northern climate and for a species adapted to a southern climate. He also pointed out that the mosaicism and the increased breadth of the zone in the mountains enhanced the probability of occurrence of reinforcement. We tested three predictions that emerged from Howard's hypothesized links among topographic diversity, zone width, and the strength of reproductive isolation. The first two predictions were fulfilled. The northern cricket, A. fasciatus, occurred in the high mountains south of its previously known distributional limit; and the zone narrowed considerably in Illinois, an area of low topographic diversity. These results provide further evidence for the importance of the environment in determining the structure of the zone. The third prediction was falsified. Contrary to the prediction, the strength of reproductive isolation between the two species was as strong in Illinois as in the Appalachian Mountains. This result suggests that if reinforcement has occurred in the zone, the width of the zone has not been a major factor in the process.

This research examines the use of questions in advertising through a content analysis of magazine print ads. Three variables are examined: question type (rhetorical vs. non-rhetorical), position (pre-argument vs. post-argument) and self-referencing (present vs. absent). Results reveal that rhetorical (non-rhetorical) questions tend to be used after (before) the arguments to which they refer. Further, self-referencing tends to be used with rhetorical questions in the post-argument position. The findings are discussed illustrating how theoretically-based empirical research can be used to guide decisions in ad practice, and how the practice of advertising can provide support for testable ideas in the conduct of future research.

In this work we present a method for creating an integrated optofluidic ring resonator (OFRR) laser system by embedding it in a low index polymer, polydimethylsiloxane (PDMS). Packaging the OFRR inside PDMS enhances portability, mechanical stability, and the ability to connect it to chip-based microfluidics. The OFRR retains high Q-factors even in the polymer (> 106) and exhibits a low lasing threshold (

An intriguing aspect of the current renaissance in investigations of the genetics of reproductive isolation is that it has been dominated by studies that resemble work done in the 1930s, 1940s, and 1950s. The dominant model organism (Drosophila), research approaches, and traits of interest (sterility and inviability of hybrids) all harken back to this earlier era. Herein, we explore the factors that led to a rebirth of interest in the genetics of reproductive isolation and to the adoption of the approaches of an earlier generation of biologists. At the same time, we appeal for more intensive investigations of traits that reproductively isolate closely related species, inclusion of a greater range of organisms in studies of reproductive isolation, and focus on a broader range of questions surrounding speciation. We end with a description of ongoing quantitative trait loci (QTL) studies of conspecific sperm precedence in the ground crickets Allonemobius fasciatus and Allonemobius socius. We have found several QTL with large effects on variance in patterns of sperm utilization in backcross females. Moreover, some QTL have an antagonistic effect on conspecific sperm, a finding that lends support to the hypothesis that rapid evolution of conspecific sperm precedence is a by-product of sexual conflict.

Opto-fluidic ring resonator (OFRR) dye lasers are embedded in low index polydimethylsiloxane (PDMS) to achieve enhanced portability, mechanical stability, and potential integration with conventional soft lithography based microfluidics for development of micro total analysis systems. The OFRR retains high Q-factors (10(6)) and exhibits low lasing threshold (1 microJ/mm(2)). Fiber prisms and tapered optical fibers are used to directionally couple out the laser emission. At 2.2 microJ/mm(2) pump intensity, the laser output from the fiber prism is 80 nW, corresponding to 50% power extraction efficiency. A microarray structure of parallel OFRRs is also demonstrated, allowing simultaneous multi-color emissions.

This research reports the results of a study in which pre-questions and post-questions are employed in a radio commercial. Responses of subjects exposed to questions are compared to responses of other subjects exposed to content equivalent statements. Also manipulated in this research is the length of a pause after commercial arguments. Post-questions were found to be more effective in facilitating information processing than post-statements. However, pre-questions and combined (both pre- and post-) questions were not more effective than pre-statements and combined statements respectively. Further, the length of the pause did not affect outcomes. Results are discussed in terms of the conditions under which questions may and may not be expected to increase message processing. Different theoretical views are presented in explaining the pattern of results observed.

Eurosta solidaginis, a gallmaking tephritid (Diptera), infests at least two species of Solidago in the eastern United States. We used horizontal starch gel electrophoresis of enzymes to examine whether populations on the two principal host plant species, Solidago altissima and S. gigantea, have diverged genetically. At the d-β-hydroxybutyrate dehydrogenase (HBDH) locus, the predominant allele in all nine populations from S. altissima (HBDH1.00 ) was absent or uncommon in all but 1 of the 12 populations from S. gigantea. At the phosphoglucomutase locus (PGM), the most common allele in all populations was PGM1.00 , but the frequency of this allele was, with one exception, higher in populations from S. gigantea than in populations from S. altissima. Genetic heterozygosity was usually greater in populations from S. altissima (H = 0.028) than in populations from S. gigantea (H = 0.009). A phylogenetic tree derived from a genetic distance matrix clustered gallmaker populations from the same host plant together.

This study reports the results of three field experiments which demonstrate that asking someone how they feel, having them verbally respond, and then acknowledging that response, facilitates compliance with a charitable request. The findings are discussed with respect to the influence of public commitments on behavioral consistency. Before you ask anyone for a donation, you first ask them how they're feeling. After they tell you they're feeling good, and you tell them you're glad they're feeling good, the/11 be more likely to contribute to helping someone who isn't.

Starch gel electrophoresis was used to study patterns of genetic variation within and among seven species of North American Chauliognathus . All species displayed levels of genetic variation lower than are usually found in insects. Geographic variation in allele frequencies within a species appeared to be limited, whereas differentiation among species was substantial. The differences among species often involved loci monomorphic within populations. Despite the abrupt genetic discontinuities separating species, the sharing by five species of a polymorphism at the PGI locus suggests that variation at PGI might be maintained by some form of diversifying selection. Finally, phylogenetic trees constructed from electrophoretic evidence for the seven species are consistent with phylogenies based on morphology and ecology.

Four experiments were conducted examining the effects of asking rhetorical questions on message processing and persuasion utilizing a radio commercial. Subjects exposed to questions were compared to other subjects exposed to content-equivalent statements across different message positions. The expectations of two different theoretical models of question effects are contrasted and compared. The results of all four experiments are consistent with the view that rhetorical questions elicit judgments on the topic of the request when they are received and that the availability of relevant information when a judgment is first requested is a critical factor determining whether or not message persuasion occurs. The pattern of results predicted by viewing rhetorical questions as elicitors of judgments is differentiated from previous views.

Industry practitioners and social scientists throughout the world have long sought to determine the effectiveness of advertising in this multi-billion dollar industry. For close to a century, many social scientists have debated just how advertising works. One suggested explanation is the hierarchy of effects—that body of literature that posits that audiences go through a variety of stages, namely cognitive, affective, and conative, in responding to advertising, and other persuasive marketing messages. This paper reviews the hierarchy of effects from its beginning at the turn of this century to present-day developments. The paper also examines the controversies surrounding hierarchy models and provides a critique of the evidence supporting its position as an advertising model.

The evolution of barriers to gene exchange is centrally important to speciation. We used the crickets Allonemobius fasciatus and A. socius to investigate the genetic architecture of conspecific sperm precedence (CSP), a postinsemination prezygotic reproductive barrier. With amplified fragment-length polymorphism (AFLP) markers and controlled crosses we constructed linkage maps and estimated positions of QTL associated with CSP. The majority of QTL have low to moderate effects, although a few QTL exist in A. socius with large effects, and the numbers of QTL are comparable to numbers of genes accounting for species differences in other studies. The QTL are spread across many unlinked markers, yet QTL placed with linked markers are on a small number of linkage groups that could reflect the role of the large Allonemobius sex chromosome in prezygotic isolation. Although many QTL had positive effects on conspecific sperm utilization several QTL also exerted negative effects, which could be explained by intraspecific sexual conflict, sperm competition, or epistasis of introgressed genes on novel backgrounds. One unexpected outcome was that A. socius CSP alleles have a stronger effect than those from A. fasciatus in hybrid females, causing hybrids to behave like A. socius with regard to sperm utilization. Implications of this asymmetry in the Allonemobius hybrid zone are discussed.

Accessory reproductive gland proteins (Acps) in Drosophila evolve quickly and appear to play an important role in ensuring the fertilization success of males. Moreover, Acps are thought to be involved in establishing barriers to fertilization between closely related species. While accessory glands are known to occur in the males of many insect groups, the proteins that are passed on to females by males during mating have not been well characterized outside of Drosophila. To gain a better understanding of these proteins, we characterized ESTs from the accessory glands of two cricket species, Allonemobius fasciatus and Gryllus firmus. Using an expressed sequence tag (EST) approach, followed by bioinformatic and evolutionary analyses, we found that many proteins are secreted and, therefore, available for transfer to the female during mating. Further, we found that most ESTs are novel, showing little sequence similarity between taxa. Evolutionary analyses suggest that cricket proteins are subject to diversifying selection and indicate that Allonemobius is much less polymorphic than Gryllus. Despite rapid nucleotide sequence divergence, there appears to be functional conser- vation of protein classes among Drosophila and cricket taxa. Resume´ : Les proteines des glandes reproductives accessoires chez le genre Drosophila evoluent rapidement et semblent jouer un role important dans le succes des males en matiere de fecondation. De plus, ces proteines sont soupconnees d'une implication dans l'etablissement de barrieres ala fecondation entre especes proches. Tandis que des glandes accessoires sont presentes chez les males de nombreux groupes d'insectes, les proteines transmises des males aux femelles lors de l'accouplement n'ont pas etebien caracterisees a l'exterieur du genre Drosophila. Afin de mieux connaoˆtre ces proteines, les auteurs ont caracterisedes EST des glandes accessoires chez deux especes de grillons, Allonemobius fasciatus et Gryl- lus firmus .Al'aide d'une approche EST, suivie d'analyses bioinformatiques et evolutives, les auteurs ont trouveque plu- sieurs proteines etaient secretees et ainsi disponibles pour transfert a la femelle lors de l'accouplement. De plus, la plupart des EST etaient inedits puisqu'ils montraient peu de similariteentre taxons. Des analyses evolutives suggerent que les pro- teines de grillons sont sujettes aune selection divergente et indiquent que l'Allonemobius est beaucoup moins polymorphe que le Gryllus .E n depit d'une rapide divergence de la sequence nucleotidique, il semble y avoir une conservation fonc- tionnelle des classes de proteines chez le genre Drosophila et les grillons. Mots cles : Allonemobius, Gryllus ,evolution rapide, isolement reproductif, fluide seminal. (Traduit par la Redaction)

Hybrid zones havc been invertigated for more than 70 yean, yet the fascination that they hold for srplutionists shorw no rign of diminirhing. Thir hscination is easy to undersand; not only are hybrid zones common evolutionary phenomena (Hewitt 1988) worthy of undentanding on their own righg their snrdy can provide inright into the nature of specier (Harrfuon l9$)), the genetic architecturc of species differenceg (Harrison lgg0, Riereberg d ol lggg), the role of nanrral selection in mainaining species boundarier (Bigelow lg6i, Barton and Hewitt l98la) and the evolution of reprodrrctive icolation (Howard 1993, Nooa 1999). Although studies of hybrid zones have a rich hirtory shrdents entcring the 6eld have a suong tendency to focur on the molt recent utcrahrre, with the consequence that through time the older literature becomes neglectcd and io findings lost This is not a problerr unique to the field of hybrid zone snrdier; ir amice all of biology. The following chapar provides a bridintroduction o hybrid zones and the anolutionary questions theyprercnu It is writrcn in the spirit ttrat rtre old hy,brid zone literanrre is worthwhile and many of itr condusions relevant to issue! of current intcresL we hopc that it stimulatcs errclutionists to delve further into a body of work that desenes wider recognition.

Patterns of reproductive isolation between two sympatric species of oaks, Quercus gambelii and Q. grisea, that exhibit strong ecological differentiation were examined. A full diallel cross using four trees of each species (i.e. all possible pollinations among eight trees) was performed. This design was repeated at two sites that represent different outcomes of sympatry: (1) a xeric mountain ridge where many hybrids are established (HZ); and (2) a mesic valley bottom where virtually no hybrids are established (MOCYN). By measuring fruit survival at several developmental stages, both the timing and strength of reproductive barriers within and between sites, species, cross types, and pollen dosage levels were examined. In three of four cases, heterospecific fruit set was significantly reduced compared to conspecific fruit set. This reduction occurred after the time of fertilization, but before the onset of embryo growth. Increasing the dose of pollen from an average of 9–194 grains/stigma did not affect this result. Thus, early postfertilization processes play a strong role in species fidelity in these oaks. Quercus gambelii experienced a five-fold decrease in conspecific fruit set at HZ relative to MOCYN. In contrast, heterospecific fruit set of Q. gambelii was the same at both sites. Poor Q. gambelii pollen performance is implicated as playing the major role in this result. One Q. gambelii individual at HZ was highly fecund, and had higher heterospecific than conspecific fruit set; slight introgression in this tree was detected uisng RAPD markers. The Environmental Emasculation Hypothesis that posits that environmental stress can increase the probability of hybrid formation by reducing the competitive ability of male gametes of one species is proposed.

Predictions using quantitative genetic models generally assume that the variance-covariance matrices remain constant over time. This assumption is based on the supposition that selection is generally weak and hence variation lost through selection can be replaced by new mutations. Whether this is generally true can only be ascertained from empirical studies. Ideally for such a study we should be able to make a prediction concerning the relative strength of selection versus genetic drift. If the latter force is prevalent then the variance-covariances matrices should be proportional to each other. Previous studies have indicated that females in the two sibling cricket species Allonemobius socius and A. fasciatus do not discriminate between males of the two species by their calling song. Therefore, differences between the calling song of the two males most likely result from drift rather than sexual selection. We test this hypothesis by comparing the genetic architecture of calling song of three populations of A. fasciatus with two populations of A. socius. We found no differences among populations within species, but significant differences in the G (genetic) and P (phenotypic) matrices between species, with the matrices being proportional as predicted under the hypothesis of genetic drift. Because of the proportional change in the (co)variances no differences between species are evident in the heritabilities or genetic correlations. Comparison of the two species with a hybrid population from a zone of overlap showed highly significant nonproportional variation in genetic architecture. This variation is consistent with a general mixture of two separate genomes or selection. Qualitative conclusions reached using the phenotypic matrices are the same as those reached using the genetic matrices supporting the hypothesis that the former may be used as surrogate measures of the latter.

Conspecific sperm precedence is widespread in animals, appears to evolve rapidly, and is thought to have the potential to prevent hybridization between closely related species. However, to date no study has tested the isolating potential of such a barrier in mixed populations of two taxa under conditions in which other potential barriers to gene flow are controlled for or are prevented from operating. We tested the isolating potential of conspecific sperm precedence in the ground crickets Allonemobius fasciatus and A. socius in population cage experiments in which the frequency of the two species was varied. Despite the observation of abundant interspecific matings, the proportions of hybrid progeny were low and differed statistically from the proportions expected in the absence of conspecific sperm pre- cedence. The results demonstrate that conspecific sperm precedence can severely limit gene flow between closely related species, even when one species is less abundant than the other.

This paper introduces the use of nonlinear jump phenomena in the frequency response of a quartz crystal resonator for mass detection. In contrast to recent studies that exploit parametric excitation for mass detection, our device exhibits nonlinear behavior modeled by the directly forced Duffing equation. In addition, internal resonance due to modal coupling is demonstrated for sufficiently large forcing amplitudes. A system of coupled Duffing equations based on a Galerkin expansion of the von Karman plate equations is used to model these higher order effects.

The white oaks Quercus gambelii and Q. grisea overlap in distribution in New Mexico and Arizona. Within the region of overlap, there are numerous instances of contact between the two taxa. In some areas of contact morphologically, intermediate trees are common, whereas in others, morphologically intermediate trees are rare or absent. We describe a set of RAPD markers that distinguish between the two species and use these markers to examine patterns of gene exchange in an area of contact in the San Mateo Mountains of New Mexico. The markers are highly coincident with morphology and confirm that hybridization between the two species takes place. Despite the occurrence of hybrids, both species remain distinct, even in areas of sympatry, and marker exchange appears to be limited.

Thorough examinations of purported cases of reproductive character displacement are critical for reaching an understanding of the role of reinforcement in the evolution of reproductive barriers between closely related species. In this paper, we report the results of an extensive investigation of male calling song variation in the ground crickets, Allonemobius fasciatus and A. socius. Contrary to the results of an earlier study, we uncovered little evidence of displacement of songs in areas of overlap. We discuss explanations for the lack of displacement as well as for the discrepancies between the results of the current study and those of the earlier study.

The ground crickets Allonemobius fasciatus and A. socius meet in a mosaic zone of overlap and hybridization stretching from the East Coast to at least Illinois. To test whether male calling song differences were enhanced in sympatry, we analyzed the songs of crickets from inside and outside the zone of overlap along two transects. No evidence of calling song displacement was found in A. socius males from populations within the zone of overlap. On the other hand, A. fasciatus displayed calling song displacement in three populations. Our results are consistent with the hypothesis that the selective pressure exerted by the challenge from a related species is frequency dependent. While not a conclusive demonstration, the observed shifts in calling song are strongly suggestive of reproductive character displacement.

Remington (1968) argued that 13 suture zones exist in North America. Remington defined a suture zone as, ''a band of geographic overlap between major biotic assemblages, including some pairs of species or semispecies which hybridize in the zone'' (p. 322). Although initially controversial, the idea that suture zones exist has picked up momentum over the past decade, due largely to the phylogeographic work of Hewitt, Avise, and their colleagues. Nevertheless, the reality of suture zones has not yet been subjected to rigorous analysis using statistical and geographic information system (GIS) approaches. To test for the existence of Remington's suture zones, we first identified 117 terrestrial hybrid zones in Canada and the United States through a literature search for the key words ''cline,'' ''contact zone,'' ''hybrid zone,'' and ''hybridization'' in articles published between 1970 and 2002. The 117 hybrid zones were mapped using a GIS approach and compared with a digitized version of Remington's original suture zone map. Overall, there does appear to be an association between hybrid zones and suture zones, but this association is largely attributable to clustering of hybrid zones in only two of the 13 suture zones recognized by Remington. The results suggest that evolutionary biologists should retain some skepticism toward Remington's suture zones.

In our recent article in TREE [1xReinforcement: the road not taken. Marshall, J.L. et al. Trends Ecol. Evol. 2002; 17: 558–563Abstract | Full Text | Full Text PDF | Scopus (79)See all References[1], we suggested that the cost of mating with a heterospecific, and thus the strength of selection against hybridization acting upon the individual, is reduced for those individuals that mate multiply and with at least one conspecific relative to individuals that mate once and with a heterospecific. Given the above and assuming that, in multiple mating systems, individuals always mate with at least one conspecific, we inferred that reinforcement would be less likely to occur in promiscuous systems than in monogamous systems. Under this scenario, our inferences about the role of multiple mating, per se, are correct.However, if the above assumption is removed and heterospecific matings are allowed to occur at a given frequency, as in Kisdi's model [2xReinforcement with multiple mating. Kisdi, E. Trends Ecol. Evol. 2003; See all References[2], then there is no a priori reason to predict that reinforcement would be less likely to occur in promiscuous systems. Nevertheless, the individual cost of mating with a heterospecific is reduced if it is preceded, or followed by a conspecific mating. Kisdi's model helps resolve the apparent disconnect between costs at the individual level and the spread of a ‘reinforcement’ allele (e.g. a preference or assortative mating allele) through a population.Kisdi's model and letter [2xReinforcement with multiple mating. Kisdi, E. Trends Ecol. Evol. 2003; See all References[2] also serve to underscore a major inference of our paper; that the interaction between the mating system and pattern of gamete utilization will influence the potential for reinforcement when there is selection against hybridization [1xReinforcement: the road not taken. Marshall, J.L. et al. Trends Ecol. Evol. 2002; 17: 558–563Abstract | Full Text | Full Text PDF | Scopus (79)See all References[1]. In particular, any deviation, regardless of how small, from equal utilization of gametes will affect the possibility of reinforcement under a multiple mating system. If conspecific gamete preference exists (the possibility explored in our paper [1xReinforcement: the road not taken. Marshall, J.L. et al. Trends Ecol. Evol. 2002; 17: 558–563Abstract | Full Text | Full Text PDF | Scopus (79)See all References[1]), reinforcement is less likely to occur. However, if hetero-population sperm precedence occurs (a possibility supported by recent experimental evidence [3xHeteropopulation males have a fertilization advantage during sperm competition in the yellow dung fly (Scatophaga stercoraria). Hosken, D.J. et al. Proc. R. Soc. Lond. Ser. B. 2002; 269: 1701–1707Crossref | PubMed | Scopus (43)See all References[3]), then reinforcement is more likely to occur.

80 undergraduates were exposed to arguments advocating supplemental vitamin use. Ending arguments with rhetorical questions (when compared with statements) resulted in more favorable attitudes towards vitamin use and a more favorable profile of questions generated about the message topic. The question profile, principally reflecting uncertainty concerning personal nutrition, mediated the attitudinal effect.

The study of speciation has recently undergone a revival, with much controversy centering on whether new species can originate quickly and within the geographic range of their ancestor. Hendry et al . ([1][1]) described a case of reproductive isolation arising between two sockeye salmon populations

Many hybrid zones have a mosaic structure, yet we know of no theoretical work that examines the impact of mosaicism on the outcome of evolution. We developed a computer simulation model designed to test whether the outcome of reinforcing selection differs in a mosaic and a clinal hybrid zone. Our model was a one-dimensional stepping-stone model. The mosaic and clinal hybrid zones that we modeled were, respectively, a mosaic maintained by differential fitness of the interacting taxa in patchy habitats and a tension zone. We modeled changes in gene frequency at two biallelic loci, A and B. Hybrids at the A locus were selected against. An allele at the B locus caused assortative mating at the A locus, which promoted reinforcement; there was a selective cost to this allele. In a mosaic hybrid zone, spatial variation in the fitness of A-locus homozygotes in different patches caused gene and genotype frequencies at the A and B loci to differ greatly from those in a tension zone. Compared to a tension zone, a mosaic hybrid zone had a broader region in which hybrids could be formed and, thus, a broader region in which the assortative- mating allele provided a net selective advantage (via decreased production of the less fit A-locus hybrids). This caused the assortative-mating allele to be favored under a broader set of conditions in a mosaic hybrid zone than in a tension zone. In mosaic and tension hybrid zones, both low and high levels of migration could prevent the establishment of the allele that promoted reinforcement, but the allele could establish under a wider range of migration rates in a mosaic than in a tension zone. In a tension zone, both low and high levels of selection against A-locus hybrids could prevent the establishment of the assortative-mating allele. In a mosaic hybrid zone, the assortative-mating allele established under lower levels of selection against hybrids than in a tension zone, and high levels of selection did not impede the establishment of this allele. Overall, our work illustrates how the structure of a hybrid zone can alter the outcome of an important evolutionary process, in this case, reinforcement.

Three experiments demonstrate that remembering someone's name facilitates their compliance with a purchase request made by the rememberer. Experiment 1 shows that name remembrance increases request compliance, but name forgetting does not cause a decrease in compliance. Experiments 2 and 3 show that name remembrance is perceived as a compliment by the person remembered, which mediates compliance with the purchase request. Experimental manipulations of the likelihood of name remembrance (experiment 2) and need for self-enhancement (experiment 3) provide results consistent with a complimentary explanation for the findings. Copyright 1995 by the University of Chicago.

The authors examine the effects of a sweepstakes on evaluation of a prize. Participants were entered in a sweepstakes with a high or low probability of winning a prize (a product), which they subsequently won or lost, and then reviewed an ad for the same product that did or did not credibly support claims of product quality. When participants believed they were the winners of a prize they did not expect to win, their evaluations of that prize were based more on their favorable reactions to the sweepstakes per se than on a careful appraisal of the available information on the product. These findings seem useful in explaining why sweepstakes operators often are able to convince consumers of the value of a “prize” when its claims of quality lack credibility. Theoretical implications of alternative model predictions and results are discussed.

In this paper I describe a zone of overlap and hybridization between the ground crickets, Allonemobius fasciatus and A. socius (Orthoptera: Gryllidae). The former occurs in the northeastern United States, the latter is found in the southeastern United States. They meet in a contact zone of variable width that extends from the East Coast to at least Ohio. In the Allegheny Mountains, where appropriate habitats for a species adapted to a northern climate and a species adapted to a southern climate are patchily distributed and widely intermingled, the zone is broad-at least 200 km. Along the coastal plain of New Jersey, where appropriate habitats are not as widely intermingled, the zone is comparatively narrow (5-100 km). Levels of hybridization were assessed by analyzing electrophoretic data, using population genetic models and a character index approach. Both methods of data analysis agreed-where the zone is broader, levels of hybridization appear reduced.

The effect of the bacterium Klebsiella oxytoca on the fitness of Rhagoletis pomonella (Walsh) and R. suavis (Loew) was tested by removal and reinfection experiments in the laboratory. The absence of the bacterium did not positively or negatively affect most components of fitness studied. These results suggest that larvae of Rhagoletis do not depend on gut microflora to provide essential nutrients or to detoxify plant secondary compounds.

Habitat segregation of closely related species has been well documented among insects, but the factors responsible are poorly understood. We have examined the influence of habitat selection and interspecific competition on the habitat associations of the closely related ground crickets Allo- nemobius allardi and A. Ja'sciatus. Allonemobius fasciatus is found in wet pastures and low-lying grassy areas; A. allardi occurs primarily in dry pastures and grasslands. In a large-scale field exper- iment, crickets were introduced into the centers of runways that extended from wet pasture at the edge of a pond to dry pasture on a south-facing slope. Each runway had been sprayed with insecticide, so that no Allonemobius were present prior to the introduction. We stocked the runways with either A. Ja'sciatus alone, A. allardi alone, or a mixture of the two species. Twenty-four days after release, we collected from each of 15 segments within all runways. Analysis of distribution patterns in mixed- and single-species runways showed that neither species' distribution was influenced by the presence of the other. Thus there is no evidence that current interspecific competition is important in deter- mining distributions. In single-species runways, A. ftJsciatus moved into wetter areas, whereas A. allardi displayed no clear tendency to move either up or down the runways. It appears that habitat selection by A. fasciatuts can account for its association with wet pasture. We discuss several scenari- os for the evolution of habitat selection and its relationship to the processes of adaptation and spe- ciation.

Six biotype bulk populations and two geographic populations of the Hessian fly, Mayetiola destructor (Say), were analyzed at 15 presumptive genetic loci using starch gel electrophoresis. Fourteen of the 15 loci appeared monomorphic. One locus, Pgi, varied in biotypes B, E, and a population from Mason, Mich. The level of genetic variation among Hessian fly populations is among the lowest reported for insects. Genetic differentiation among Hessian fly biotypes and populations is also low, ranging from a Nei's D of 0.000 to 0.002. Protein electrophoresis does not appear to provide a quick procedure to identify Hessian fly biotypes.

Cryptic species are common in the singing Orthoptera, and systematists have come to rely heavily on distribution, ecology, life cycle, and especially song characteristics both to recognize species and to work out their evolutionary relationships. Eastern North American ground crickets in the genus Allonemobius have been very well studied in the above manner, and the taxonomy of the group appeared secure. However, electrophoretic evidence presented here indicates that what has been called A. allardi in the past consists of three species and what has been called A. fasciatus consists of two species. The evolutionary history of the eastern North American members of the genus is reconstructed, using three different methods for estimating phylogenetic trees from genetic distance matrices. The two species best suited for speciation studies appear to be A. fasciatus and A. socius .

The Allonemobius fasciatus (De Geer) complex, a group of closely related ground crickets, has proven recalcitrant to analysis by traditional methods of museum taxonomists. Here we formally describe two new species ( A. walkeri and A. fultoni ), reinstate the species status of A. socius (Scudder), and provide an electrophoretic key to the complex. In addition, we describe male calling song, habitat, life cycle, and geographic distribution of each species in the complex, and we compare the species morphometrically.

The study's purpose was to assess the effectiveness of an activity-centered health education curriculum designed for regular students on the general health beliefs of special education students. As part of an entire school system evaluation, 92 ***Learning Disability students and 142 Learning Limitation students were randomly assigned to experimental and control groups. All the students were pretested and subsequently posttested using a 28-item questionnaire based on the Health Belief Model. The analysis of covariance indicated that the activity-centered health education program apparently was effective among the Learning Disability students, but was not effective among students with IQ scores of 80 or below.

Ahstract. The closely related ground crickets Alloneinobiuis allardi and A. fiseciutus provide a striking example of habitat segregation. Both species are abundant in pastures and grasslands in the northeastern United States, but they occupy different parts of these habitats. At a site in northwestern Connecticut, we found nearly pure single-species populations at the extremes of a moisture gradient. Alloenmtohius allaIrdi occurred in dry pasture, A. fiisci'utus in wet pasture. Distribution patterns remained constant from one developmental stage to another and from year to year. We undertook a series of experiments to define the factors that determine habitat associations in these crickets. By introducing single-species and mixed-species populations into enclosures in both wet and dry areas, we could demonstrate no significant differences in adult survival or reproductive success between species. Both A. ullrdli and A. Jufsiiatus can survive and reproduce in wet and dry habitats. Labo- ratory choice experiments indicate that differences in oviposition preference also cannot account for field distribution patterns. Indeed, oviposition preference may be a consequence rather than a cause of habitat association.

All Rhagoletis reportedly establish associations with one or more bacterial species, but the bases for these interactions and their implications for host race formation and speciation are poorly understood. Here we present the results of four studies designed to increase our understanding of these relationships. In the first study, we identify the bacteria associated with seven Rhagoletis taxa by surveying the inhabitants of the esophageal bulb, an organ whose major function appears to be the housing of microorganisms. The results suggest that no bacterium has entered into an obligate symbiotic relationship with any of the Rhagoletis taxa surveyed, although one bacterium, Klebsiella oxytoca, is a very common associate of six of the seven. In the second study we use horizontal starch gel electrophoresis to determine the genetic similarity of K. oxytoca clones isolated from different Rhagoletis populations. This analysis provides a rare look into the genetic structure of natural populations of an enteric bacterium and permits the construction of a dendrogram for the clones-a dendrogram which indicates that there is no clear-cut pattern to the distribution of K. oxytoca genotypes among Rhagoletis. Taken together, the above studies provide indirect evidence that the bacteria associated with Rhagoletis are not important determinants of host plant specificity. The third and fourth studies assess two possible functions associated bacteria may perform for Rhagoletis: pectic substances degradation and nitrogen fixation. Our results do not lend support to either function.

The purpose of this study was to determine the effects of an activity-centered health education curriculum on the attitudes of 4th, 5th and 6th graders in a small, midwest city school system. The program was evaluated in part by a pretest/posttest design in which 10 randomly selected schools received the health curriculum and 10 schools did not. Twenty-eight (28) health belief model questions were used to measure perceived susceptibility, perceived seriousness, perceived preventability and self reported behavior relating to general health problems. The results indicated that the experimental students, compared to their controls, were much more inclined to change their health beliefs and self-reported behavior in a positive direction, regardless of grade level.