Philopatry of male marine turtles inferred from mitochondrial DNA markers

Recent studies of mitochondrial DNA (mtDNA) variation among marine turtle populations are consistent with the hypothesis that females return to beaches in their natal region to nest as adults. In contrast, less is known about breeding migrations of male marine turtles and whether they too are philopatric to natal regions. Studies of geographic structuring of restriction fragment and microsatellite polymorphisms at anonymous nuclear loci in green turtle (Chelonia mydas) populations indicate that nuclear gene flow is higher than estimates from mtDNA analyses. Regional populations from the northern and southern Great Barrier Reef were distinct for mtDNA but indistinguishable at nuclear loci, whereas the Gulf of Carpentaria (northern Australia) population was distinct for both types of marker. To assess whether this result was due to reduced philopatry of males across the Great Barrier Reef, we determined the mtDNA haplotypes of breeding males at courtship areas for comparison with breeding females from the same three locations. We used a PCR-restriction fragment length polymorphism approach to determine control region haplotypes and designed mismatch primers for the identification of specific haplotypes. The mtDNA haplotype frequencies were not significantly different between males and females at any of the three areas and estimates of Fst among the regions were similar for males and females (Fst = 0.78 and 0.73, respectively). We conclude that breeding males, like females, are philopatric to courtship areas within their natal region. Nuclear gene flow between populations is most likely occurring through matings during migrations of both males and females through nonnatal courtship areas.

Experimental evidence for a behavior-mediated trophic cascade in a terrestrial food chain

Predators of herbivorous animals can affect plant populations by altering herbivore density, behavior, or both. To test whether the indirect effect of predators on plants arises from density or behavioral responses in a herbivore population, we experimentally examined the dynamics of terrestrial food chains comprised of old field plants, leaf-chewing grasshoppers, and spider predators in Northeast Connecticut. To separate the effects of predators on herbivore density from the effects on herbivore behavior, we created two classes of spiders: (i) risk spiders that had their feeding mouth parts glued to render them incapable of killing prey and (ii) predator spiders that remained unmanipulated. We found that the effect of predators on plants resulted from predator-induced changes in herbivore behavior (shifts in activity time and diet selection) rather than from predator-induced changes in grasshopper density. Neither predator nor risk spiders had a significant effect on grasshopper density relative to a control. This demonstrates that the behavioral response of prey to predators can have a strong impact on the dynamics of terrestrial food chains. The results make a compelling case to examine behavioral as well as density effects in theoretical and empirical research on food chain dynamics.

Raising the bar: the importance of hospital library standards in the continuing medical education accreditation process*

The Connecticut State Medical Society (CSMS) reviews and accredits the continuing medical education (CME) programs offered by Connecticut's hospitals. As part of the survey process, the CSMS assesses the quality of the hospitals' libraries. In 1987, the CSMS adopted the Medical Library Association's (MLA's) “Minimum Standards for Health Sciences Libraries in Hospitals.” In 1990, professional librarians were added to the survey team and, later, to the CSMS CME Committee. Librarians participating in this effort are recruited from the membership of the Connecticut Association of Health Sciences Librarians (CAHSL). The positive results of having a qualified librarian on the survey team and the invaluable impact of adherence to the MLA standards are outlined. As a direct result of this process, hospitals throughout the state have added staffing, increased space, and added funding for resources during an era of cutbacks. Some hospital libraries have been able to maintain a healthy status quo, while others have had proposed cuts reconsidered by administrators for fear of losing valuable CME accreditation status. Creating a relationship with an accrediting agency is one method by which hospital librarians elsewhere may strengthen their efforts to ensure adequate library resources in an era of downsizing. In addition, this collaboration has provided a new and important role for librarians to play on an accreditation team.