Evidence of hatch-time based growth compensation in the early life history of two salmonid fishes.

Initial body size can indicate quality within-species, with large size increasing the likelihood of survival. However, some populations or individuals may have body size disadvantages due to spatial/temporal differences in temperature, photoperiod, or food. Across-populations, animals often have locally adapted physiology to compensate for relatively poor environmental influences on development and growth, while within-population individual behavioral adjustments can increase food intake after periods of deprivation and provide opportunities to catch up (growth compensation). Previous work has shown that growth compensation should include within-population differences related to short growing seasons due to delayed hatch time. We tested the hypothesis that individual fish that hatch later grow faster than those that hatch earlier. The relative magnitude of such a response was compared with growth variation among populations. We sampled young of the year Arctic charr and brook trout from five rivers in northern Labrador. Daily increments from otoliths were used to back-calculate size to a common age and calculate growth rates. Supporting the hypothesis, older fish were not larger at capture than younger fish because animals that hatched later grew faster, which may indicate age-based growth compensation.

Demonstrating an Analyses of Clinical Data Evaluating Psychotropic Medication Reductions and the ACHIEVE! Program in Adolescents with Severe Problem Behavior.

Researchers report increasing trends in psychotropic medication use to treat problem behavior in individuals with intellectual and developmental disability, despite some controversy regarding its application and treatment efficacy. A substantial evidence base exists supporting behavioral intervention efficacy, however research evaluating separate and combined intervention (i.e., concurrent application of behavioral and psychopharmacological interventions) effects remains scarce. This article demonstrates how a series of analyses on clinical data collected during treatment (i.e., four case studies) may be used to retrospectively explore separate and combined intervention effects on severe problem behavior. First, we calculated individual effect sizes and corresponding confidence intervals. The results indicated larger problem behavior decreases may have coincided more often with behavioral intervention adjustments compared to medication adjustments. Second, a conditional rates analysis indicated surges in problem behavior did not reliably coincide with medication reductions. Spearman correlation analyses indicated a negative relationship between behavioral intervention phase progress and weekly episodes of problem behavior compared to a positive relationship between total medication dosage and weekly episodes of problem behavior. However, a nonparametric partial correlation analyses indicated individualized, complex relationships may exist among total medication dosage, behavioral intervention, and weekly episodes of problem behavior. We discuss potential clinical implications and encourage behavioral researchers and practitioners to consider applying creative analytic strategies to evaluate separate and combined intervention effects on problem behavior to further explore this extremely understudied topic. Supplementary Information: The online version contains supplementary material available at 10.1007/s40614-020-00279-3.

Training Staff to Avoid Problem Behavior Related to Restricting Access to Preferred Activities.

Some training programs for staff working with individuals with intellectual disabilities fail to equip staff with the practical skills necessary to prevent behavioral episodes. The current research describes the results of a staff training program that, following traditional didactic training, used a card game followed by role-play training to increase staff competence in managing problem behavior. The card game and role-play training was based on behavioral episodes that had occurred previously in the research setting. Post-training observations showed that treatment integrity of trained staff improved.

Clinical translation of animal models of treatment relapse.

Behavioral Momentum Theory (BMT) has inspired animal models of treatment relapse. We translated the models of reinstatement and resurgence into clinical procedures to test whether relapse tests would replicate behavior pattern found in basic research. Following multiple schedule baseline reinforcement of a 16-year-old male's problem behavior at equal rates by two therapists, treatment was introduced using a variable-interval, variable-time (VI VT) schedule arrangement with therapists delivering reinforcers at different rates. Despite the differing rates of VI VT reinforcers, the treatment produced comparable reductions in problem behavior. Following successful treatment, the two therapists discontinued treatment and resumed reinforcement of problem behavior at equal rates that constituted a reinstatement of baseline conditions. As predicted by BMT, reinstatement resulted in an immediate return of high rates of problem behavior but was 2.6 times higher for the therapist using the higher rate VI VT treatment. A second treatment phase was implemented followed by a test of resurgence in a single extended extinction session conducted separately for each therapist. The unequal VI VT treatment rates by therapists resulted in 2.1 times greater responding in the resurgence test for the therapist who implemented the higher rate VI VT procedure. These results are consistent with basic research studies and BMT.

The relationship between morphological and behavioral mimicry in hover flies (Diptera: Syrphidae).

Palatable (Batesian) mimics of unprofitable models could use behavioral mimicry to compensate for the ease with which they can be visually discriminated or to augment an already close morphological resemblance. We evaluated these contrasting predictions by assaying the behavior of 57 field-caught species of mimetic hover flies (Diptera: Syrphidae) and quantifying their morphological similarity to a range of potential hymenopteran models. A purpose-built phylogeny for the hover flies was used to control for potential lack of independence due to shared evolutionary history. Those hover fly species that engage in behavioral mimicry (mock stinging, leg waving, wing wagging) were all large wasp mimics within the genera Spilomyia and Temnostoma. While the behavioral mimics assayed were good morphological mimics, not all good mimics were behavioral mimics. Therefore, while the behaviors may have evolved to augment good morphological mimicry, they do not advantage all good mimics.

A comparative analysis of the evolution of imperfect mimicry.

Although exceptional examples of adaptation are frequently celebrated, some outcomes of natural selection seem far from perfect. For example, many hoverflies (Diptera: Syrphidae) are harmless (Batesian) mimics of stinging Hymenoptera. However, although some hoverfly species are considered excellent mimics, other species bear only a superficial resemblance to their models and it is unclear why this is so. To evaluate hypotheses that have been put forward to explain interspecific variation in the mimetic fidelity of Palearctic Syrphidae we use a comparative approach. We show that the most plausible explanation is that predators impose less selection for mimetic fidelity on smaller hoverfly species because they are less profitable prey items. In particular, our findings, in combination with previous results, allow us to reject several key hypotheses for imperfect mimicry: first, human ratings of mimetic fidelity are positively correlated with both morphometric measures and avian rankings, indicating that variation in mimetic fidelity is not simply an illusion based on human perception; second, no species of syrphid maps out in multidimensional space as being intermediate in appearance between several different hymenopteran model species, as the multimodel hypothesis requires; and third, we find no evidence for a negative relationship between mimetic fidelity and abundance, which calls into question the kin-selection hypothesis. By contrast, a strong positive relationship between mimetic fidelity and body size supports the relaxed-selection hypothesis, suggesting that reduced predation pressure on less profitable prey species limits the selection for mimetic perfection.