Variation in Mating Dynamics across Five Species of Leiobunine Harvestmen (Arachnida: Opliones)

The study of mating choices often focuses on correlates of traits to the overall outcome of a mating interaction. However, mating interactions can proceed through a series of stages, with opportunities for assessment at each stage. We compared whether male or female size predicted mating interaction outcome across several stages of mating in five species of North American leiobunine harvestmen (commonly known as daddy longlegs). Leiobunine harvestmen have been previously shown to exhibit incredible morphological diversity consistent with a spectrum of male–female antagonism. Across all of the species, we found a general progression of female size predicting the outcome (success and timing) of early stages of interactions, and male size or male size relative to female size predicting the outcome and timing of later stages of interactions. We also found that size was not a strong predictor of outcome in the two species on the lower end of the antagonism spectrum. The variation in how female and male size predicted outcomes across species and stages of mating suggests that multiple mechanisms may operate to shape mating dynamics within and across species. Given the close relatedness of the species studied, the patterns we uncovered suggest a rapid evolution of the traits and processes predicting the outcome of mating interactions

Observations of Non-radial Pulsations in Radio Pulsars

We introduce a model for pulsars in which non-radial oscillations of high spherical degree (l) aligned to the magnetic axis of a spinning neutron star reproduce the morphological features of pulsar beams. In our model, rotation of the pulsar carries a pattern of pulsation nodes underneath our sightline, reproducing the longitude stationary structure seen in average pulse profiles, while the associated time-like oscillations reproduce "drifting subpulses"--features that change their longitude between successive pulsar spins. We will show that the presence of nodal lines can account for observed 180 degree phase jumps in drifting subpulses and their otherwise poor phase stability, even if the time-like oscillations are strictly periodic. Our model can also account for the "mode changes" and "nulls" observed in some pulsars as quasiperiodic changes between pulsation modes of different l or radial overtone n, analogous to pulsation mode changes observed in oscillating white dwarf stars. We will discuss other definitive and testable requirements of our model and show that they are qualitatively supported by existing data. While reserving judgment until the completion of quantitative tests, we are inspired enough by the existing observational support for our model to speculate about the excitation mechanism of the non-radial pulsations, the physics we can learn from them, and their relationship to the period evolution of pulsars.Comment: 28 pages, 9 figures (as separate png files), Astrophysical Journal, in pres

Relationship between the Social Cognition and Object Relations Scale (SCORS) and attachment style in a clinical sample

This present study examined the relationship between the Social Cognition and Object Relations Scale (SCORS) and two measures of adult attachment: the Relationship Questionnaire (RQ) and the Experiences in Close Relationships Questionnaire‐Revised (ECR‐R). Forty‐five patients (76% female) at a university‐based outpatient treatment clinic participated in this study. We hypothesized that higher levels of attachment security would be associated with higher, more adaptive ratings on the SCORS variables. Results indicated that the SCORS Self‐Esteem (SE) variable was significantly positively related to the RQ's Secure Attachment ratings and negatively related with the ECR‐R's Anxious Attachment scale. Additionally, negative trends were noted between SE and the RQ's Fearful and Preoccupied Attachment scores. The SCORS Emotional Investments in Relationships and Affective Quality of Representations variables were associated with higher Secure scores and lower, more maladaptive Preoccupied scores on the RQ. It was also associated with greater attachment anxiety as measured by the ECR‐R. Using both clinician (SCORS) and participant‐rated measures (ECR‐R and RQ), this study provides further understanding on how object representations and attachment style relate within a clinical sample. Results are discussed in light of prior research examining relationships between object relations and adult attachments, and clinical implications are also reviewed. Copyright © 2010 John Wiley & Sons, Ltd. Key Practitioner Message: • Individuals with higher levels of attachment anxiety may enter therapy with more self‐image problems. • Individuals with higher levels of attachment anxiety may enter therapy with more maladaptive expectations about relationships. • Patients who endorse high levels of attachment anxiety (e.g., fearful and preoccupied) may be more likely to present with Axis II complaints. • Examining a patient's attachment style and object relations using different measures of assessment (e.g., explicit and implicit) can help gain a deeper and more comprehensive understanding of a patient.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88074/1/721_ftp.pd

A Probable Case of Incipient Speciation in Schizocosa Wolf Spiders Driven by Allochrony, Habitat Use, and Female Mate Choice

There is growing evidence that speciation can occur between populations that are not geographically isolated. The emergence of assortative mating is believed to be critical to this process, but how assortative mating arises in diverging populations is poorly understood. The wolf spider genus Schizocosa has become a model system for studying mechanisms of assortative mating. We conducted a series of experiments to identify the factors that control mate-pair formation in a Schizocosa population that includes both ornamented and nonornamented males. We show that the population also includes two previously unrecognized female phenotypes. One female phenotype mates mostly or exclusively with ornamented males, and the other mates mostly or exclusively with unornamented males. Assortative mating within these groups is maintained by differences in maturation time, microhabitat use, and female mate preference. We conclude that the population is not a single species, as previously believed, but rather an incipient species pair with multiple overlapping mechanisms of reproductive isolation. The identification of a new incipient species pair in the well-studied and rapidly speciating Schizocosa clade presents new opportunities for the study of speciation without geographic isolation

Demonstrating mate choice copying in spiders requires further research

Mate choice copying—when individuals learn to prefer mates or mate types that have been chosen by others—can influence trait evo-lution and speciation (Varela et al. 2018; Dion et al. 2019). Most examples of mate choice copying are from fish, birds, and mammals including humans (Varela et al. 2018). However, 2 invertebrate examples—fruit flies and wolf spiders—have been used to argue that the phenomenon may be phylogenetically widespread, and perhaps the rule rather than the exception in nature (Varela et al. 2018). Here, we revisit the evidence for mate choice copying in wolf spiders (Fowler-Finn et al. 2015) in light of new data (Gilman et al. 2018). Then, we discuss why mate choice copying is a phenomenon that is likely to occur in wolf spiders, and why this deserves attention

Comparing Two Species: Historical Phylogeography and Species Delimitation of Myiarchus Flycatchers in the West Indies.

In a recent expedition to the Bahamas, the morphological observations of many of the individuals captured bore plumage with coloration that was characteristic of M. stolidus. A species that has up to this point, been considered allopatric. Documented distributions in the West Indies for Myiarchus flycatchers are indicative that while the M. stolidus inhabits Hispaniola and Jamaica, the Bahamas are the native habitat of M. sagrae. In a report from Joseph et al., questionable boundaries were discussed between the two species by highlighting that within a comprehensive Myiarchus phylogeny, M. sagrae is shown as paraphyletic, yet M. stolidus forms a polyphyletic grouping by sharing the most recent common ancestor with M. sagrae. Preliminary analyses here further support these questionable boundaries between M. stolidus and M. sagrae, both genetically and morphologically. Our objective is resolving this taxonomic discrepancy and in doing so, allowing for a better understanding of the demographic history and distributions of these species to assess comprehensively, the avian phylogeography in the West Indies. Morphological variation found among specimens from the same region measured and sampled at the Field Museum of Natural History in Chicago, along with sequence data at one mitochondrial marker procured from recent field work form the basis for the preliminary analyses. Proposed analyses include sequence capture of ultra-conserved elements (UCEs) both of contemporary and historical specimens, along with results in data from many loci across the genome. Furthermore, recordings acquired from the Macaulay audio library at Cornell University will be included as well so as to provide an assessment of vocal variation

Female mate choice of male signals is unlikely to promote ecological adaptation in Enchenopa treehoppers (Hemiptera: Membracidae)

A key question in speciation research is how ecological and sexual divergence arise and interact. We tested the hypothesis that mate choice causes local adaptation and ecological divergence using the rationale that the performance~signal trait relationship should parallel the attractiveness~signal trait relationship. We used female fecundity as a measure of ecological performance. We used a species in the Enchenopa binotata treehopper complex, wherein speciation involves adaptation to novel environments and divergence in sexual communication. We used a full-sibling, split-family rearing design to estimate genetic correlations (rG) between fecundity and signal traits, and compared those relationships against population-level mate preferences for the signal traits. Animal model estimates for rG between female fecundity and male signal traits overlapped zero—rejecting the hypothesis—but could reflect sample size limitations. The magnitude of rG correlated with the strength of the mate preferences for the corresponding signal traits, especially for signal frequency, which has the strongest mate preference and the most divergence in the complex. However, signal frequencies favored by the population-level mate preference are not associated with high fecundity. Therefore, mate preferences do not appear to have been selected to favor high-performance genotypes. Our findings suggest that ecological and sexual divergence may arise separately, but reinforce each other, during speciation

Identification of a Small Regulatory RNA UspS Associated with the Universal Stress Protein in Lactobacillus Species

The gut microbiome is a complex habitat with many bacterial species, each playing crucial roles in regulating various physiological processes in the body. As the use of probiotics to combat human disease continues to increase, it is important to understand the mechanisms by which probiotic bacteria regulate their interactions with other bacteria and their host. Our exploration of the physiological functions of probiotic bacteria hopes to elucidate the role of small regulatory RNA (sRNA) in regulating gene expression within the microbiome. The goal of this project was to characterize the structure and function of the sRNA, UspS, which is found in probiotic, lactic acid bacteria. In Lactobacillus, UspS is closely associated with a downstream universal stress protein and contains an orphaned Lacto-usp RNA motif of unknown function. Computational methods have been used to study the UspS sRNA sequences from two Lactobacillus species in order to predict the secondary structures, generate 3D models, and search for potential mRNA interactions. Comparative sequence alignments and covariance analysis within the secondary structures predict a pseudoknot structure. The UspS sequence was isolated from two Lactobacillus species and sRNAs were synthesized by in vitro transcription with a T7 RNA polymerase. In preliminary studies, differential scanning fluorimetry of the UspS sRNA was able to confirm the presence of stable secondary structures. Future work will be focused on the structure of the pseudoknot region of UspS and its role in regulating the expression of the downstream universal stress protein

The complexities of female mate choice and male polymorphisms: Elucidating the role of genetics, age, and mate-choice copying

Genetic, life history, and environmental factors dictate patterns of variation in sexual traits within and across populations, and thus the action and outcome of sexual selection. This study explores patterns of inheritance, diet, age, and mate-choice copying on the expression of male sexual signals and associated female mate choice in a phenotypically diverse group of Schizocosa wolf spiders. Focal spiders exhibit one of two male phenotypes: ‘ornamented’ males possess large black brushes on their forelegs, and ‘non-ornamented’ males possess no brushes. Using a quantitative genetics breeding design in a mixed population of ornamented/non-ornamented males, we found a strong genetic basis to male phenotype and female choice. We also found that some ornamented males produced some sons with large brushes and others with barely visible brushes. Results of diet manipulations and behavioral mating trials showed no influence of diet on male phenotype or female mate choice. Age post maturation, however, influenced mate choice, with younger females being more likely to mate with ornamented males. A mate-choice copying experiment found that, following observations of another female’s mate choice/copulation, virgin mature females tended to match the mate choice (ornamented vs. non-ornamented males) of the females they observed. Finally, analyses of genetic variation across phenotypically pure (only one male phenotype present) vs. mixed (both phenotypes present) populations revealed genetic distinction between phenotypes in phenotypically-pure populations, but no distinction in phenotypically-mixed populations. The difference in patterns of genetic differentiation and mating across geographic locations suggests a complex network of factors contributing to the outcome of sexual selection

The complexities of female mate choice and male polymorphisms: Elucidating the role of genetics, age, and mate-choice copying

Genetic, life history, and environmental factors dictate patterns of variation in sexual traits within and across populations, and thus the action and outcome of sexual selection. This study explores patterns of inheritance, diet, age, and mate-choice copying on the expression of male sexual signals and associated female mate choice in a phenotypically diverse group of Schizocosa wolf spiders. Focal spiders exhibit one of two male phenotypes: ‘ornamented’ males possess large black brushes on their forelegs, and ‘non-ornamented’ males possess no brushes. Using a quantitative genetics breeding design in a mixed population of ornamented/non-ornamented males, we found a strong genetic basis to male phenotype and female choice. We also found that some ornamented males produced some sons with large brushes and others with barely visible brushes. Results of diet manipulations and behavioral mating trials showed no influence of diet on male phenotype or female mate choice. Age post maturation, however, influenced mate choice, with younger females being more likely to mate with ornamented males. A mate-choice copying experiment found that, following observations of another female’s mate choice/copulation, virgin mature females tended to match the mate choice (ornamented vs. non-ornamented males) of the females they observed. Finally, analyses of genetic variation across phenotypically pure (only one male phenotype present) vs. mixed (both phenotypes present) populations revealed genetic distinction between phenotypes in phenotypically-pure populations, but no distinction in phenotypically-mixed populations. The difference in patterns of genetic differentiation and mating across geographic locations suggests a complex network of factors contributing to the outcome of sexual selection