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The Atlantic sand fiddler crab Uca pugilator, is an extremely abundant crab found along the eastern coast of the United States. Fiddler crabs have a life cycle with an obligatory planktonic larval phase of 30–90 days, which might be expected to lead to widespread larval dispersal and consequent genetic homogeneity over considerable distances. However, a large amount of morphological and behavioral variation is found between northern and southern populations along the eastern coast. This study was undertaken to determine the population genetic structure of U.pugilator and to determine whether these differences may have a genetic basis. The population structure of the fiddler crab was analyzed using 472 individuals collected from 12 sites along the eastern coast. PCR-based single stand conformation polymorphism (SSCP) was used to investigate between-site variation in the mitochondrial 16S rRNA gene of these individuals. Analysis of genetic variation indicated frequent gene flow between nearby localities, but much reduced levels between populations separated by larger geographic distances. Thus, despite the potential for high dispersal by planktonic larvae, population differentiation and isolation by distance is evident between northern and southern populations of U.pugilator. A high amount of genetic differentiation (FST = 0.3468) was found between northern and southern regions suggesting that the morphological and behavioral differences between these two regions have a genetic basis and may represent subspecies.

At four sites in Texas, the density of the clown weevil, Eudiagogus pulcher, in stands of rattlebox, Sesbania drummondii, increased with proximity to water. Size-assortative mating (SAM) was negative at high density, positive at intermediate density, and absent at low density. Only at intermediate density were relatively small potential mates frequently rejected. Females rejected males via resistance to attempts to mount while males rejected females by abandoning them soon after mounting. A laboratory experiment showed that mate rejection is more likely when individuals experience intermediate densities, but not low or high densities, prior to courtship. In the field, rival males displaced mounting males that were small relative to either the female or rival. Rates of rivalry increased with density. At high density, low rates of mate rejection and high rates of rivalry resulted in the formation of displacement-resistant pairs consisting of large males and small females. This left small males to vie for large females and resulted in negative SAM. At intermediate density, low rates of rivalry coupled with rejection of small individuals favored the formation of pairs consisting of similarly sized males and females, causing positive SAM. At low density, low rates of both mate rejection and rivalry resulted in random mating by size and the absence of SAM. [ABSTRACT FROM AUTHOR]

In fields of the coastal plain of Georgia (USA), the seed bug, Neacoryphus bicrucis, feeds and mates exclusively on ragwort. The distribution of ragwort, Senecio tomentosus, is either dispersed, with small numbers of plants spread over large areas, or clustered, with large numbers of plants concentrated into relatively small areas. In dispersed habitat, the density of seed bugs is always low (< 20/0.25 m2) as is the proportion of adults who are mating (20%). In clustered habitat, adult densities are occasionally high (30–75/0.25 m2) as are mating rates (> 67%). In both habitats, mating males are in better condition (= mass – mass expected from length) than non-mating males. In clustered habitats, aggression between males occurs frequently and determines residency in areas of high ragwort abundance to which females are especially attracted for mating and oviposition. A mark-recapture study revealed that males move about more in dispersed than clustered habitats, possibly searching for mates. Variance in male mating efficiency (copulations/sightings) matches random expectations in dispersed habitats but is significantly higher than that in clustered habitats, suggesting greater opportunity for sexual selection. A multivariate analysis of selection intensity using mark-recapture data revealed that longer wings and shorter bodies are favored in dispersed habitat, suggesting selection on ability to search for mates. In clustered habitat, selection favors a longer body, antennae, and legs. This finding suggests selection favoring dominance in aggressive interactions, as legs and antennae are used to grapple with opponents and to seize females during aggressive courtship. [ABSTRACT FROM AUTHOR]

The Medical College of Wisconsin (MCW) and the Wisconsin Geriatric Education Center (WGEC) are committed to developing educational materials for primary care physicians in training. In response to the opportunity created by the Accreditation Council for Graduate Medical Education (ACGME) competency mandate, an MCW-led interdisciplinary working group has developed competency-linked video-based assessment tools for use in primary care residency training programs. Modeled after the Objective Structured Clinical Examinations (OSCE), used as part of the medical licensing examination process, we created geriatric-focused Objective Structured Video Examinations (OSVEs) as a strategy to infuse geriatrics into residency training. Each OSVE tool contains a 1-3 minute video trigger that is associated with a series of multiple choice and/or constructed response questions (e.g., fill in the blank). These questions assess residents' understanding of video-demonstrated ACGME competencies including professionalism, systems-based practice, communication, and practice-based learning. An instructor's guide and scoring key are provided for each tool. Response to the OSVEs has been overwhelmingly enthusiastic including greater than 90% commitment by statewide faculty to use the tools in residency training. [ABSTRACT FROM AUTHOR]