The cost of self-promotion: ecological and demographic implications of the mentor effect in natural plant populations.

Under the mentor effect, compatible heterospecific pollen transfer induces self-pollen germination in otherwise self-incompatible plants. The mentor effect could be considered a novel mode of reproductive interference if it negatively impacts fitness. Yet to date, this phenomenon has predominately been investigated under experimental conditions rather than in situ. We address this gap in natural populations of the self-incompatible native dandelion, Taraxacum ceratophorum, where selfing only occurs in association with hybridization from exotic Taraxacum officinale. We tested whether self-fertilization rate increases in the hybrid zone, as predicted due to the mentor effect. Using results from these investigations, we created an exponential growth model to estimate the potential demographic impacts of the mentor effect on T. ceratophorum population growth. Our results demonstrate that the strength of the mentor effect in Taraxacum depends on the prevalence of pollinator-mediated outcross pollen deposition rather than self-pollination. Demographic models suggest that reduced outcrossing in T. ceratophorum under exotic invasion could negatively impact population growth through inbreeding depression. We demonstrate the mentor effect is rare in natural populations of T. ceratophorum due to masking by early life cycle inbreeding depression, prevalent outcrossing, and ovule usurpation by heterospecific pollen.

Psychotherapy session frequency: A naturalistic examination in a university counseling center.

With increasing demand for psychotherapy services, clinicians are carrying increasingly large caseloads (Bailey et al., 2020). As the number of new intakes exceeds the number of clinical hours available each week in some settings, psychotherapy is delivered on an attenuated schedule for returning clients (rather than the traditional weekly frequency); there is, however, little support for the efficacy of this practice. The present study explored the effect of session frequency on psychotherapy outcomes using a quasi-randomized controlled design. In a working university counseling center, we assigned therapists to either a treatment-as-usual (TAU) group (attenuated session frequency) or an experimental group (weekly session frequency). Clients were randomly assigned to a therapist in either condition. Using hierarchical linear modeling and survival analyses, we examined psychotherapy outcomes (measured by session-by-session Outcome Questionnaire 45 scores) for 1,322 clients (3,919 individual sessions). We found no differences between groups when examining the full sample, but also found limited fidelity in the experimental group. When identifying individuals who were seen weekly in at least the first three sessions after intake (sensitivity analysis), we found the following: (a) weekly therapy resulted in faster trajectories of change over time, (b) weekly therapy resulted in a greater likelihood of achieving recovery, and (c) weekly therapy resulted in a greater likelihood of achieving recovery sooner. We discuss the importance of including session frequency when considering the dose of therapy, as well as the implication that prioritizing weekly therapy may increase therapy efficacy and efficiency in routine practice. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Functional mismatch in a bumble bee pollination mutualism under climate change.

Ecological partnerships, or mutualisms, are globally widespread, sustaining agriculture and biodiversity. Mutualisms evolve through the matching of functional traits between partners, such as tongue length of pollinators and flower tube depth of plants. Long-tongued pollinators specialize on flowers with deep corolla tubes, whereas shorter-tongued pollinators generalize across tube lengths. Losses of functional guilds because of shifts in global climate may disrupt mutualisms and threaten partner species. We found that in two alpine bumble bee species, decreases in tongue length have evolved over 40 years. Co-occurring flowers have not become shallower, nor are small-flowered plants more prolific. We argue that declining floral resources because of warmer summers have favored generalist foraging, leading to a mismatch between shorter-tongued bees and the longer-tubed plants they once pollinated.