Deer do not affect short‐term rates of vegetation recovery in overwash fans on Fire Island after Hurricane Sandy

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The effects of grazing by gastropods and physical factors on the upper limits of distribution of intertidal macroalgae

Summary The cover of foliose algae is sparse to non-existent above a low-level algal zone on many shores in N.S.W., except in rock-pools. Above this algal zone, encrusting algae, mostly Hildenbrandia prototypus, occupy most of the primary substratum on sheltered shores. Experimental manipulations at midtidal levels were used to test hypotheses about the effects of grazing by molluses and of physical factors during low tide on this pattern of algal community structure.Fences and cages were used to exclude grazers: molluscs grazed under roofs and in open areas. Cages and roofs provided shade, and decreased the harshness of the environment during low tide: fences and open areas had the normal environmental regime.In the absence of grazers, rapid colonization of Ulva and slower colonization by other foliose algae occurred in all experimental areas. The rate of colonization by Ulva sporelings was initially retarded on existing encrusting algae, but after a few months, cover of Ulva equalled that on cleared rock.Most species of algae only grew to maturity inside cages, and remained as a turf of sporelings inside fences. No foliose algae grew to a visible size in open, grazed areas. Grazing thus prevents the establishment of foliose algae above their normal upper limit on the shore, but the effects of physical factors during low tide prevent the growth of algae which become established when grazers are removed. Physical factors thus limit the abundance of foliose algae at mid-tidal levels.The recolonization of cleared areas by Hildenbrandia was not affected by the presence of a turf of sporelings, nor by the shade cast by roofs, but was retarded in cages where mature algae formed a canopy. Even under such a canopy, Hildenbrandia eventually covered as much primary substratum as in open, grazed areas. This encrusting alga is able to escape from the effects of grazing by having a tough thallus, and by its vegetative growth which allows individual plants to cover a lot of substratum, and by the tendency for new individuals to start growing from small cracks and pits in the rock, which are apparently inaccessible to the grazers.Mature foliose algae are removed from the substratum by waves, and many individual plants died during periods of hot weather. Sporelings in a turf were eliminated, after experimental fences were removed, by the combined effects of macroalgal grazers, which invaded the areas, and microalgal grarers which ate the turt from the edges inwards.The results obtained here are discussed with respect to other studies on limits to distribution of intertidal macroalgae, and the role of grazing in the diversity and structure of intertidal algal communities. Some problems of these experimental treatments are also discussed.     

Comparing oxalic acid and sucrocide treatments for Varroa destructor (Acari: Varroidae) control under desert conditions

The effectiveness of oxalic acid (OA) and Sucrocide (S) (AVA Chemical Ventures, L.L.C., Portsmouth, NH) in reducing populations of the varroa mite Varroa destructor Anderson & Trueman (Acari: Varroidae) in honey bee, Apis mellifera L. (Hymenoptera: Apidae) colonies was measured under the desert conditions of Arizona, USA. OA and S were applied three times 7 d apart. A 3.2% solution of OA was applied in sugar syrup via a large volume syringe, trickling 5 ml per space between frames in the colony. S was applied at a concentration of 0.625% (mixed with water), according to the label directions, using a compressed air Chapin sprayer at 20 psi to apply 59 ml per frame space. Varroa mites, collected on a sticky board before, during, and after the treatments, were counted to assess the effectiveness of the treatments. This study showed that a desert climate zone did not confer any positive or negative results on the acaricidal properties of OA. Even with brood present in colonies, significant varroa mite mortality occurred in the OA colonies. In contrast, we found that Sucrocide was not effective as a mite control technique. Despite its ability to increase mite mortality in the short-term, varroa mite populations measured posttreatment were not affected any more by Sucrocide than by no treatment at all.     

A continental scale evaluation of the role of limpet grazing on rocky shores

It is critical for our knowledge of biodiversity and ecosystem processes to understand how individual species contribute to ecosystem processes and how these contributions vary in space and time. We used a manipulative field experiment in five locations over 17° of latitude [from southern Portugal to the Isle of Man (British Isles)] to determine the relative response of rocky intertidal algal assemblages released from control by the grazing of limpets. Response ratios showed that when limpets were removed there was a trend of effects from north to south. In the north, grazing had a strong effect on algal assemblages, but removing grazers reduced spatial variability in assemblages. In the south, the effect of limpet grazing was far weaker and removal of grazers had a much reduced impact on spatial variability. Here we show a clear trophic control of an ecosystem in that grazing by limpets not only determines macroalgal abundance overall but also modifies ecosystem stability via variability in cover of algae.     

Season-, sex-, and age-specific accumulation of plasma carotenoid pigments in free-ranging white-winged crossbills Loxia leucoptera

Many birds acquire carotenoid pigments from foods and deposit these pigments into feathers and bare‐parts to become sexually attractive, but little work has been done on the interindividual and temporal variability in the types and amounts of carotenoids that free‐ranging individuals have available for use in coloration or other functions (e.g., in immunomodulation). To address this issue, we studied intra‐annual variation in plasma carotenoid profiles of juvenile and adult white‐winged crossbills Loxia leucoptera of both sexes. Adult male crossbills exhibit bright red carotenoid‐based plumage pigmentation, whereas females uniformly display drab yellow feather coloration and juvenile males only occasionally display some orange or pink color. Yellow xanthophylls (e.g., lutein, zeaxanthin) were predominant in plasma of birds from both sexes and age classes throughout the year. Plasma xanthophylls levels tended to be highest in the summer, when crossbills increase seed consumption for breeding as well as supplement their diet with insects. Blood accumulation of three other, less common plasma carotenoids‐β‐cryptoxanthin, rubixanthin, and gazaniaxanthin‐varied in a highly season‐, sex‐, and age‐dependent fashion. These carotenoids were virtually absent in juvenile or adult female plasma at all times of year and were only present in male plasma, at higher concentrations in adults than juveniles, during the period of feather growth (Sept.–Nov.). These pigments have been reported as valuable precursors of the metabolically derived red pigments (e.g., 3‐hydroxy‐echinenone, 4‐oxo‐rubixanthin, and 4‐oxo‐gazaniaxanthin, respectively) that appear in the plumage of male crossbills. These findings suggest that male crossbills either adopt a season‐specific foraging strategy to acquire foods rich in these pigments at the time they are needed to develop red coloration, or have a unique physiological ability to metabolically produce these pigments or absorb them from food during molt, in order to maximize color production.     

A Survey of Honey Bee Colony Losses in the U.S., Fall 2007 to Spring 2008

Background

Honey bees are an essential component of modern agriculture. A recently recognized ailment, Colony Collapse Disorder (CCD), devastates colonies, leaving hives with a complete lack of bees, dead or alive. Up to now, estimates of honey bee population decline have not included losses occurring during the wintering period, thus underestimating actual colony mortality. Our survey quantifies the extent of colony losses in the United States over the winter of 2007–2008.

Methodology/Principal Findings

Surveys were conducted to quantify and identify management factors (e.g. operation size, hive migration) that contribute to high colony losses in general and CCD symptoms in particular. Over 19% of the country''s estimated 2.44 million colonies were surveyed. A total loss of 35.8% of colonies was recorded; an increase of 11.4% compared to last year. Operations that pollinated almonds lost, on average, the same number of colonies as those that did not. The 37.9% of operations that reported having at least some of their colonies die with a complete lack of bees had a total loss of 40.8% of colonies compared to the 17.1% loss reported by beekeepers without this symptom. Large operations were more likely to have this symptom suggesting that a contagious condition may be a causal factor. Sixty percent of all colonies that were reported dead in this survey died without dead bees, and thus possibly suffered from CCD. In PA, losses varied with region, indicating that ambient temperature over winter may be an important factor.

Conclusions/Significance

Of utmost importance to understanding the recent losses and CCD is keeping track of losses over time and on a large geographic scale. Given that our surveys are representative of the losses across all beekeeping operations, between 0.75 and 1.00 million honey bee colonies are estimated to have died in the United States over the winter of 2007–2008. This article is an extensive survey of U.S. beekeepers across the continent, serving as a reference for comparison with future losses as well as providing guidance to future hypothesis-driven research on the causes of colony mortality.     

Validation of a Preclinical Drug Screening Platform for Pharmacoresistant Epilepsy

The successful identification of promising investigational therapies for the treatment of epilepsy can be credited to the use of numerous animal models of seizure and epilepsy for over 80 years. In this time, the maximal electroshock test in mice and rats, the subcutaneous pentylenetetrazol test in mice and rats, and more recently the 6 Hz assay in mice, have been utilized as primary models of electrically or chemically-evoked seizures in neurologically intact rodents. In addition, rodent kindling models, in which chronic network hyperexcitability has developed, have been used to identify new agents. It is clear that this traditional screening approach has greatly expanded the number of marketed drugs available to manage the symptomatic seizures associated with epilepsy. In spite of the numerous antiseizure drugs (ASDs) on the market today, the fact remains that nearly 30% of patients are resistant to these currently available medications. To address this unmet medical need, the National Institute of Neurological Disorders and Stroke (NINDS) Epilepsy Therapy Screening Program (ETSP) revised its approach to the early evaluation of investigational agents for the treatment of epilepsy in 2015 to include a focus on preclinical approaches to model pharmacoresistant seizures. This present report highlights the in vivo and in vitro findings associated with the initial pharmacological validation of this testing approach using a number of mechanistically diverse, commercially available antiseizure drugs, as well as several probe compounds that are of potential mechanistic interest to the clinical management of epilepsy.