Two New Species of Plistophora (Microsporidea) from North American Fish with a Synopsis of Microsporidea of Freshwater and Euryhaline Fishes

SYNOPSIS. Two new species of Microsporidea, Plistophora salmonae from steelhead and rainbow trout (Salmo gairdntri) and Plistophora crpedianar from gizzard shad ( Dorosoma cepedianum) are described. Schizonts to spores of P. cepedianae were found at one time within the same cyst, while only sporonts and spores of P. salmonae were found within the cyst.
An illustrated synopsis of the known Microsporidea of freshwater and euryhaline fishes is given.     

Plants,fungi and bettongs: A fire-dependent co-evolutionary relationship

Digging activity by Bettongia gaimardi increased in small areas burnt by a low intensity fire at a site in northern Tasmania. A gap of several days occurred after the fire before digging began. Sporocarps of only one genus of mycorrhizal fungi (Mesophellia) were eaten by bettongs after the fire, in contrast to high numbers of species eaten in surrounding unburnt areas. It is hypothesized that the fire selectively stimulated the production of sporocarps by Mesophellia (a genus associated with eucalypts) rather than by simply making them more accessible or detectable. Stimulation of production of sporocarps by fire may ensure high infection rates and facilitate the uptake by eucalypts of nutrients released by the fire. These observations have important management implications.     

Hunting and Gathering in Tropical Rain Forest: Is It Possible?

Hunters and gatherers living in tropical forests represent an important part of the total range of variation among contemporary hunting and gathering societies. Studies of tropical forest hunting and gathering peoples have contributed to our perceptions of the foraging way of life. Yet no peoples have ever been directly observed living independently of agriculture in tropical rain forest. This article tests the hypothesis that humans do not exist nor have ever existed independently of agriculture in tropical rain forest. We find no convincing ethnographic evidence and, with the possible exception of Malaysia, no archeological evidence for pure foragers in undisturbed tropical rain forests. Negative evidence cannot be conclusive, but it suggests that we need to carefully reexamine common assumptions concerning the recent history of tropical forest dwellers, the adaptability of preagricultural humans, the geographic and environmental range of hominids, and the form and consequences of selection pressures acting on humans in warm, humid environments. The overriding purpose of this article is to stimulate further ecological and archeological research in the neglected tropical forest areas of the world.     

Behavior-Genetic Mechanisms of Population Regulation in Microtine Rodents

We examine three behavior-genetic mechanisms of vole populationregulation. Each predictsan increase in aggressive behavioramong individuals as density increases. The polymorphic behaviorhypothesis predicts heritable changes in aggressive behavioramong individuals; the sociobiological hypothesis predicts heightenedaggression among nonrelatives; and the outbreeding hypothesispredicts an increase in heterozygosity-caused aggressiveness.In order to test these hypotheses, it is necessary to know relatedness,aggressive behavior levels, and genotypes of individuals, aswell as demographic and reproductive parameters. Aggressivelevels can be obtained during paired encounters; genotypes canbe ascertained by electrophoresis; and relatedness can be determinedusing radionuclides or radiotelemetry, and electrophoresis.In this paper we discuss the hypotheses, data-gathering protocols,and the ways in which the data can be used to test the hypotheses     

Habitat Use by Female Mallards in the Lower Mississippi Alluvial Valley

ABSTRACT Mallard (Anas platyrhynchos) populations in the lower Mississippi Alluvial Valley (LMAV), USA, historically averaged 1.6 million and represented the largest concentrations of wintering mallards in North America. Effective management of this wintering population requires current information on use of habitats. Accordingly, we employed radiotelemetry techniques to assess proportional use of habitats by female mallards during winters 2004–2005 and 2005–2006. We divided winters into 4 time periods defined by hunting seasons (FIRST, SPLIT, SECOND, and POST) and recorded diurnal and nocturnal locations. We examined variations in proportional use of habitats and use of areas closed to hunting due to effects of age (immature or ad), winter (2004–2005 or 2005–2006), time period (SECOND or POST), individual female, and all potential interactions of these effects, using locations recorded during the latter 2 time periods. We found that diurnal and nocturnal proportional use of habitats varied inconsistently among time periods and winters. Mean proportional use of forested wetlands ranged from 0.475 to 0.816 and from 0.428 to 0.764 during diurnal and nocturnal sampling periods, respectively. Diurnal proportional use of areas closed to hunting varied inconsistently among time periods and winters. Mean proportional use of areas closed to hunting ranged from 0.183 to 0.423 during diurnal sampling periods. Nocturnal use of areas closed to hunting varied inconsistently among female ages and time periods and among female ages and winters. Mean proportional use of areas closed to hunting ranged from 0.211 to 0.445 during nocturnal sampling periods. Our research suggests that forested wetlands in the LMAV provide important wintering habitats for female mallards; continued restoration and establishment of these habitats should benefit female mallards.