The influence of seed apparency,nutrient content and chemical defenses on dietary preference in Dipodomys ordii

Summary Physical, nutritional and defensive qualities of seeds differ in the extent to which they influence granivore preference. In a study aimed to quantifying those differences, Ord's kangaroo rats (Dipodomys ordii) were found to prefer the seeds of just three of twenty-nine species: Cryptantha crassisepala, Oryzopsis hymenoides and Salsola kali. Oryzopsis hymenoides was most preferred during the early plant growth season (April–July); preference for S. kali peaked during late (August–November) and dormant (December–March) seasons; and greatest preference for C. crassisepala occurred during dormant and early seasons. Regression of forage ratios, averaged across seasons, against seed length, mass, abundance, patchiness, percent nitrogen, energy content, and chemical defenses showed seed length to be the most important predictor of seed preference. Seed length combined with nitrogen (protein) content and levels of two defensive compounds, saponins and non-protein amino acids, to account for 68% of the variation in seed preference. The importance of seed length rather than biomass indicated that there are limits to the ability of D. ordii to detect small seeds and that small size facilitated escape of dispersed seeds. Seasonality in preference suggested, however, that seed escape was encountered by predispersal harvesting of newly maturing seeds still on plants. Maximization of protein intake contradicted previously published observations, but presumably reflected low nitrogen availability. In addition to small size, the presence of saponins or non-protein amino acids in seeds was sufficient to negate the positive influence of higher protein content.     

Epidemiological studies on horses infected with nematodes of the family Trichonematidae (Witenberg, 1925)

Observations are reported on seasonal changes in the age structure of populations of nematodes of the family Trichonematidae recovered at regular intervals from the lumens of the large intestines of horses slaughtered in S.W. England. The results show that changes in the size of parasitic populations of Trichonema nassatum follow seasonal variations in the rate of infection, more individuals maturing during summer/autumn than during winter/spring because of proportional differences in the numbers of infective larvae ingested from the pasture. In contrast, larvae of T. longibursatum, T. catinatum and T. goldi ingested by grazing horses during summer accumulate in the gut wall rather than promptly returning to the lumen and developing to maturity. Their development is apparently inhibited until the following spring when 4th-stage larvae emerge en masse and quickly reach the adult stage. The relationship between fluctuations in the size of the adult populations of the 4 species studied and the characteristic seasonal variations in horse faecal egg counts is discussed.     

The relation of sex,age, smoking status,birth rank and parental ages to pseudocholinesterase activity and phenotypes in a sample of Australian Caucasian adults

Summary The frequencies of the pseudocholinesterase alleles E₁ ^u, E₁ ^a and E₁ ^f have been determined in a random sample of Australian residents. The frequency of E₁ ^a is the highest yet reported in a large caucasian sample. The considerable variation in E₁ ^f frequencies in previously reported samples is discussed in terms of possible sources of error in fluoride number determinations.Enzyme activity was found to increase with age in adulthood and was higher in males than in females. It was also positively correlated with dibucaine number in type U subjects. These observations are in conflict with those reported in previous investigations.This work was supported by grants from the National Health and Medical Research Council of Australia and the Australian Tobacco Research Foundation.     

The type locality of <Emphasis Type="Italic">Pan troglodytes vellerosus</Emphasis> (Gray, 1862), and implications for the nomenclature of West African chimpanzees

We show that, in 1862, Richard Burton collected the type specimen of Pan troglodytes vellerosus not on Mount Cameroon, as has been generally assumed, but in Gabon. Therefore, P. t. vellerosus is not the correct name for the chimpanzee population of western Cameroon and southern Nigeria, if that population is taxonomically distinct. As First Reviser, we choose the name Pan troglodytes ellioti for this population of chimpanzees, based on Anthropopithecus ellioti named by Matschie [Matschie P (1914) Neue Affen aus Mittelafrika. Sitzungsber Ges Naturforsch Freunde Berlin 1914:323–342] from a specimen in the Humboldt Museum, Berlin, collected in Bascho (=Basho), Cameroon, and given to the museum in 1905.     

The Evolution and Genetics of Virus Host Shifts

Emerging viral diseases are often the product of a host shift, where a pathogen jumps from its original host into a novel species. Phylogenetic studies show that host shifts are a frequent event in the evolution of most pathogens, but why pathogens successfully jump between some host species but not others is only just becoming clear. The susceptibility of potential new hosts can vary enormously, with close relatives of the natural host typically being the most susceptible. Often, pathogens must adapt to successfully infect a novel host, for example by evolving to use different cell surface receptors, to escape the immune response, or to ensure they are transmitted by the new host. In viruses there are often limited molecular solutions to achieve this, and the same sequence changes are often seen each time a virus infects a particular host. These changes may come at a cost to other aspects of the pathogen''s fitness, and this may sometimes prevent host shifts from occurring. Here we examine how these evolutionary factors affect patterns of host shifts and disease emergence.     

Disseminated cutaneous and vascular invasion byFusarium moniliforme in a fatal case of acute lymphocytic leukemia

A 35 year old female patient with acute lymphocytic leukemia developed fusariosis in which dissemination appeared to be limited to cutaneous and vascular invasion. The first evidence of fungemia occurred nearly seven months after initial hospitalization. The fungus was identified asFusarium sp. and was considered a contaminant. Two weeks later blood cultures were again positive forFusarium sp. and the patient was placed on amphotericin B and 5-fluorocytosine therapy. The following day developing lesions were noted on her forearms and face; lesions ultimately spread to her trunk, abdomen, and lower extremities. Skin lesion biopsy sections revealed abundant septate and branching hyphae throughout the dermis and within capillaries. Twenty-six days after the initial isolation the patient died. Post-mortem blood cultures gave rise to the same fungus, which was identified asFusarium monoliforme. Postmortem cultures and stains of spleen, liver, lung, and brain specimens were all negative for fungi. The primary source and portal of entry of the organism remained undetermined.     

Morphological assessment of the Octopus vulgaris species complex evaluated in light of molecular‐based phylogenetic inferences

Cryptic species are common in the ocean, particularly among marine invertebrates such as octopuses. Delineating cryptic species is particularly problematic in octopus taxonomy where the plasticity recorded among taxonomic characters often results in low resolution at the species level. This study investigated the morphological relationships among seven phylogenetic clades (identified using cytochrome c oxidase subunit I) of the broadly distributed Octopus vulgaris species complex and close relatives. Morphological analyses in this study were successful in delimiting O. sinensis, Brazilian O. vulgaris and O. vulgaris sensu stricto, which was congruent with the molecular findings of this study. Analyses based on male morphology were successful in distinguishing 14 of 15 total pairwise comparisons and proved to be a more reliable indicator of species‐level relationships in comparison with female morphology. The majority of characters with the greatest discriminatory power were male sexual traits. Significant morphological differences were also recorded among sampling localities of conspecifics, with phenotype showing correlation with local environmental data. The findings of this study support the hypothesis that multiple O. vulgaris‐like species are currently being incorrectly treated under a single species name, O. vulgaris. Octopuses being exported globally under the name O. vulgaris are of extremely high fisheries market value and profile. Our findings have potentially significant implications for the naming and conservation of commercially harvested members of this species complex throughout their ranges.