Ground Roost Resource Selection for Merriam's Wild Turkeys

ABSTRACT Concealment cover is important for ground-roosting wild turkey (Meleagris gallopavo) poults immediately following hatch during the vulnerable, preflight stage. We compared concealment cover resources selected at ground roosts to those of nest sites and available resources for Merriam's turkeys (Meleagris gallopavo merriami) in the Black Hills of South Dakota, USA. Females with preflight poults selected ground roosts that were similar in structure to nest sites. Ground roosts and nests were greater in visual obstruction (unit odds ratios ≥1.19) than random sites. However, ground roosts were closer to meadow-forest edges than either nests or random sites (unit odds ratios ≤0.98). Structure at ground roosts may provide visual protection from predators, and management for shrub vegetation or woody debris along meadow-pine forest ecotones will provide cover for Merriam's turkey broods.     

Complex NAPL Site Characterization Using Fluorescence Part 1: Selection of Excitation Wavelength Based on NAPL Composition

Fluorescence has been demonstrated to be a viable method for detecting non-aqueous phase liquid (NAPL) contaminants comprised of polycyclic aromatic hydrocarbons (PAHs). Commercially available cone penetrometer (CPT)induced fluorescence based sensor platforms can be used to detect NAPLs such as petroleum oils and lubricants in-situ. In addition, these approaches can be used to detect dense non-aqueous phase liquid (DNAPL) source zones by detecting commingled oils, fuels, and naturally oc curring organic materials entrained by or in solution with DNAPLs and carried to depths below the water table. The currently available CPT-based fluorescence systems are typically restricted to a single wavelength excitation source, each demonstrating specific advantages and disadvantages with respect to detection capabilities for partic ular fluorophores. Several neat NAPLs and mixtures were analyzedfor specificfluores-cence characteristics to determine the optimal excitation source for site characterization efforts. Commercially available cone penetrometer based fluorescence detection systems were ranked according to the potential for likelihood of detection. Our work demon strates that an optimal range of excitation wavelength can be determined for specific fluorophores within NAPL mixtures, and that available systems can be ranked based on the specific contaminant and site characteristics. We have identified optimal excitation sourcesfor a number of common NAPL mixtures, including petroleum-basedfuels and a lubricant mixed with a chlorinated solvent.     

A NEW METRIORHYNCHID CROCODILIAN (MESOEUCROCODYLIA: THALATTOSUCHIA) FROM THE KIMMERIDGIAN (UPPER JURASSIC) OF WILTSHIRE,UK

Abstract: Recent revision of the marine metriorhynchid crocodilians indicates that a partial skull previously assigned to the species Metriorhynchus superciliosus and newly discovered postcranial elements from the Kimmeridge Clay of Westbury, Wiltshire belong to a new species of metriorhynchid. This material is herein described and referred to a new species of the genus Dakosaurus, characterised by four apomorphies: the size and shape of the enlarged supratemporal fossae; relatively large teeth, and half the number in relatives; the robust and unornamented cranium; and the angle that the prefrontal makes with the long axis of the skull. In a new phylogenetic analysis, Dakosaurus carpenteri sp. nov. is the basal member of a clade containing also D. maximus and D. andiniensis: it is not so short‐snouted and its teeth are not so few and large as in the other two species, but the new form illustrates the ecological transition among metriorhynchids from a piscivorous diet to high‐order carnivory.     

Effects of reproductive timing and colony size on the survival, offspring colony size and drone production in the honey bee (Apis mellifera)

ABSTRACT. 1. The effects of colony size and time of reproduction on the survival and size of offspring colonies and on drone production were examined for honey bees, Apis mellifera L. Drone and worker production and survival of parental and offspring colonies were monitored following swarming. Also, the temporal patterns of drone emergence and availability of unmated queens were examined.
2. Colony size at swarming was positively correlated with the number of workers invested in offspring colonies and the number of queens produced. However, colony size at swarming was not correlated with the number of offspring colonies produced.
3. Swarm size was positively correlated with drone and worker production after swarms were hived. Worker production of hived swarms was positively correlated with colony survival. Offspring queens which inherited a parental nest survived longer than queens in either primary swarms or afterswarms, presumably due to the advantage of inheriting a nest.
4. Drone emergence peaked just prior to swarming, the time when unmated queens were available. High drone production by colonies initiated by swarms probably reflected an attempt to reproduce prior to winter. The probabilities of a second swarming cycle within the same year and of surviving the winter were low for colonies initiated from swarms.     

Cycles in insect populations: delayed density dependence or exogenous driving variables?

Summary Delayed density dependence, and the cycles in insect populations that it can generate, are often investigated using time-series analysis. Recently, several authors have raised concerns about the validity of using time-series analysis to detect density dependence. One particular concern is the suggestion that exogenous driving variables, such as cyclic weather patterns, can lead to the spurious detection of density dependence in natural populations.
Using non-biological data (the electricity bills of one of the authors), we show how easy it is to be misled by the results of time-series analysis. We then present 16 years' data on the gall-forming sawfly, Euura lasiolepis (Hymenoptera: Tenthredinidae), and show that cycles in weather, specifically winter precipitation, lead to the spurious detection of density dependence in time-series analysis. We conclude that time-series analysis cannot stand alone as a method for inferring the action of density dependence, and urge further investigation of the effects of apparent cycles in abiotic forces on insect populations.     

Inferring evolutionary processes from phylogenies

Evolutionary processes shape the regular trends of evolution and are responsible for the diversity and distribution of contemporary species. They include correlated evolutionary change and trajectories of trait evolution, convergent and parallel evolution, differential rates of evolution, speciation and extinction, the order and direction of change in characters, and the nature of the evolutionary process itself—does change accumulate gradually, episodically, or in punctuational bursts. Phylogenies, in combination with information on species, contain the imprint of these historical evolutionary processes. By applying comparative methods based upon statistical models of evolution to well resolved phylogenies, it is possible to infer the historical evolutionary processes that must have existed in the past, given the patterns of diversity seen in the present. I describe a set of maximum likelihood statistical methods for inferring such processes. The methods estimate parameters of statistical models for inferring correlated evolutionary change in continuously varying characters, for detecting correlated evolution in discrete characters, for estimating rates of evolution, and for investigating the nature of the evolutionary process itself. They also anticipate the wealth of information becoming available to biological scientists from genetic studies that pin down relationships among organisms with unprecedented accuracy.     

Rapid isolation of anopheline mosquito eye-colour mutants, based on larval colour change

Abstract. A method is presented for the rapid isolation of eye-colour mutants in anopheline mosquitoes based on their inability to undergo a background-stimulated morphological colour change. For application of this method, larval mosquitoes, whose grandfathers had been mutagenized, were reared in black containers and examined with the naked eye en masse during the third or fourth instar. The vast majority of larvae became dark-coloured; however, rare exceptional pale larvae were observed and examined individually microscopically. Approximately half of the pale types examined were eye-colour mutants. By this method, seven sex-linked mutations in the mosquito Anopheles gambiae s.s. were easily isolated. Additional existing anopheline eye-colour mutants in An. gambiae and An. stephensi were tested and were found to be unable to undergo colour change. Several applications of this simple technique are suggested.