Dispersal and extraterritorial movements of swift foxes ( Vulpes velox ) in northwestern Texas

Dispersal plays an important role in the population dynamics of many carnivores, yet little information exists about the dispersal and movement patterns of swift foxes ( Vulpes velox ). We radio-collared and monitored 68 swift foxes for dispersal at 2 study sites in northwestern Texas from January 2002 to April 2004. Dispersal distance for juveniles (13.1 ± 0.3 km, s ), adults (10 ± 4.7 km) and transients (25.4 ± 9.1 km) did not differ by age class ( F = 1.49, df = 2, P = 0.24) or sex ( F = 0.23, df = 1, P = 0.63) but differed by study site ( F = 4.72, df = 1, P = 0.04). Mean dispersal distance from private ranches (PR) was greater than from National Grasslands (NG). Peak dispersal occurred during October– November (13 individuals) and January–February (7 individuals). Dispersal direction was influenced by land-use practices (i.e., toward rangelands and away from anthropogenic features). Direction of dispersal among foxes that occupied the NG was uniform ( n = 16, P = 0.08), whereas foxes from PR dispersed in a northwesterly direction ( n = 18, P ≤ 0.001) away from a town and croplands. Three resident adult foxes made extraterritorial movements. Distances of these movements ranged from 0.2 km to 11.4 km. Distance of extraterritorial movements did not differ by sex ( F = 0.05, P = 0.83), nor by duration of movement ( F = 1.11, P = 0.32). Knowledge of movement distances and patterns is important for conservation and protection of swift foxes and their habitats.     

Evolutionary divergence in closely related populations of Mimulus guttatus (Scrophulariaceae)

The evolutionary divergence of five closely related populations of the yellow monkey flower. Mimulus guttatus was compared with the length of time the populations could have occupied the site and with the ability of the populations to intercross. Populations from the younger sites were found to be morphologically intermediate to populations from the older sites. Ability to intercross was not correlated with morphological divergence at this stage of evolution.       

Persistence of subalpine forest--meadow ecotones in the Gunnison Basin, Colorado

Forests of the southern Rocky Mountains are punctuated by persistent meadows called parks that are dominated by grasses and forbs. In an attempt to elucidate the maintenance of subalpine parks in the Gunnison Basin, Colorado, soil texture and tree morphology differences along 60-m transects spanning the forest-park ecotone were studied in 6 representative parks. Seedling survivorship, percent seed germination, and soil moisture available to plants were also studied along one of the transects in Willow Park. Soil analyses revealed 40% more silt and significantly less sand and clay in all 6 parks ( P P = 0.011), with 54% more water in forest than in park soils. Measures of growth rate obtained from tree height, dbh, and age were significantly higher nearer the ecotone ( P P = 0.002). These results suggest that stress of mature Engelmann spruce ( Picea engelmannii ) and lodgepole pine ( Pinus contorta ) is an unlikely explanation of park maintenance. P. engelmanii percent seed germination and seedling survivorship were significantly higher in the forest than in the park ( P < 0.001). This may be largely due to the more severe seedling microclimate observed in the park. Results indicate that limited seedling establishment is primarily responsible for maintenance of subalpine parks in the Gunnison Basin.     

Pigment granules in choroidal melanophores of the albino goldfish.

Pigment granules in choroidal melanophores of the albino goldfish contained fine particulate materials which were in various degrees aggregated in clumps. Tyrosinase was considered to be present in an inhibited state in these pigment granules.     

Effect of Tween 80 on lipids of Mycobacterium phlei ATCC 354

Addition of Tween 80 to the growth medium brings about qualitative and quantitative changes in the lipids of Mycobacterium phlei ATCC 354. The results suggest that Tween 80 itself may be a variant in the system.     

The genetic and evolutionary basis of colour variation in vertebrates

Variation in pigmentation is one of the most conspicuous phenotypic traits in vertebrates. Although mammals show less variation in body pigmentation than other vertebrate groups, the genetics of colour determination and variation is best understood for them. More than 150 genes have been identified that influence pigmentation, and in many cases, the cause for variation in pigmentation has been identified down to the underlying nucleotide changes. These studies show that while some genes are often responsible for deviating pigmentation, similar or almost identical phenotypes even in the same species may be due to mutations in different genes. In this review we will first discuss the current knowledge about the genes and their functions underlying the biochemical pathways that determine pigmentation and then give examples where the mutations responsible for colour variation have been determined. Finally, we will discuss potential evolutionary causes for and consequences of differences in pigmentation between individuals.     

Sylvaticin: a new cytotoxic and insecticidal acetogenin from Rollinia sylvatica (Annonaceae)

Sylvaticin (I), a new tetrahydroxy annonaceous acetogenin with nonadjacent tetrahydrofuran rings, has been isolated from the dried fruits of Rollinia sylvatica St. Hil. (Annonaceae). This compound is extremely cytotoxic to human tumor cells and shows promising insect control properties.     

Xanthumin and 8-epi-xanthatin as insect development inhibitors from Xanthium canadense Mill.

Two insect development inhibitors against Drosophila melanogaster have been isolated from the leaves of X. canadense and identified as xanthumin and 8-epi-xanthatin.