The role of avian ‘seed predators’ as seed dispersers

Seed dispersal is a central process in plant ecology with consequences for species composition and habitat structure. Some bird species are known to disperse the seeds they ingest, whereas others, termed ‘seed predators’, digest them and apparently play no part in dispersal, but it is not clear if these are discrete strategies or simply the ends of a continuum. We assessed dispersal effectiveness by combining analysis of faecal samples and bird density. The droppings of seed dispersers contained more entire seeds than those of typical seed predators, but over a quarter of the droppings of seed predators contained whole seeds. This effect was further magnified when bird density was taken into account, and was driven largely by one frequent interaction: the Chaffinch Fringilla coelebs, a typical seed predator and the most abundant bird species in the area and dispersed seeds of Leycesteria formosa, a non‐native plant with berry‐like fruits. These results suggest the existence of a continuum between seed predators and seed dispersers.     

A LABORATORY TEST FOR EVALUATING CHEMICAL STERILIZERS FOR DAIRY FARMS

SUMMARY: A technique for testing chemical sterilizers for dairy farms, using moulded rubber teat cup liners, is described. Results are based on colony counts of rinses taken after disinfection. The test can be used for comparing a new disinfectant with a standard sodium hypochlorite.     

Characterization of microsatellite loci in the endemic mound spring snail Fonscochlea accepta and cross species amplification in four other hydrobiid snails

We identified and characterized nine microsatellite primer pairs from Fonscochlea accepta, a species of hydrobiid snail endemic to artesian mound springs associated with the Great Artesian Basin in arid South Australia. The loci were highly polymorphic, with five to 30 alleles per locus. Gene diversity, estimated as expected heterozygosity ranged from 0.364 to 0.851, and was generally matched by levels of observed heterozygosity (0.373–0.829). Cross‐species amplification trials with four other hydrobiid species associated with these southern mound springs showed that these primers will be useful for genetic analyses of these other endemic snails.     

Are there correlates of male Australian Magpie Gymnorhina tibicen reproductive success in a population with high rates of extra‐group paternity?

The reproductive success of a male bird is often correlated with measurable traits that predict his intrinsic quality. Females are thought to base their selection of mates on the latter's 'quality' in order to gain their 'good genes'. Male Australian Magpies Gymnorhina tibicen of the white-backed race tyrannica were trapped in two breeding seasons. Measurements were taken of morphometric and other characteristics in order to discover whether particular traits of males were associated with: (1) percentage of offspring sired in the territory, (2) number of fledglings produced in the territory per season and (3) whether females select males for their 'good genes'. There were no consistently significant correlations between any of the measured variables and male Magpie reproductive success within territories. In particular, none of the traits measured had any consistent correlation with the percentage of offspring sired in a territorial group. This was an unexpected result given that the species is strongly territorial but also engages regularly in extra-group copulations. These findings appear contrary to the predictions of the 'good genes' hypothesis. The general lack of correlation between the variables and level of genetic paternity may in fact be due to females engaging in extra-group mating primarily to avoid breeding with a close relative rather than to choose a high-quality male. In this case, males would not have to be 'high quality', but merely genetically different from the female's social mate.     

MODELING CONSUMER INTENTION TO PURCHASE FRESH PRODUCE

The effect of some fresh‐cut carrot label attributes on consumer purchase intention was evaluated using conjoint analysis. The following three attributes were chosen and manipulated: price (high and low), packaging type (polyethylene bags and expanded polystyrene trays) and production process (organic with certification stamp, organic without certification stamp and no information). A complete factorial design was used, and 12 hypothetical packages of fresh‐cut carrot were developed and evaluated by 96 consumers based on their purchase intention. The consumers were divided into four groups with different opinions. Low price and organic with certification label were the favorite choices of the groups. Only one group preferred expanded polystyrene trays. No interactions were exhibited among the attributes in all groups.     

Sandfly distribution and abundance in a tropical rain forest

1. The distribution patterns of sandflies (Diptera: Psychodidae) upon tree buttresses were studied in tropical rain forest at Finca la Selva in the Caribbean lowlands of Costa Rica. 2. Four species of sandfly, Lutzomyia shannoni Dyar, L. trapidoi F. & H., L. ylephiletor F. & H. and L. vespertilionis F. & H. comprising 97% of those caught, used tree buttresses as diurnal resting sites. Their distribution on the buttresses was aggregated. 3. During the dry season tree species had no significant effect upon the distribution of the sandflies. However, during the wet season the distributions of two of the species, L. trapidoi and L. ylephiletor, were significantly affected by the species of tree; it is suggested that some species of tree may provide greater protection from rainfall than others. 4. L. vespertilionis was restricted to a single buttress on each positive tree. Distribution of this species is evidently determined by the distribution of its host animal, the bat (Emballonuridae). Female flies feed upon the bat's blood and male flies may be attracted to the bat as it provides a source of female sandflies. It is suggested, therefore, that tree buttresses serve as sandfly swarming sites. 5. Within a large buttress the sandflies are not randomly distributed but are aggregated in particular areas. Within these aggregations, the sandflies are vertically zoned upon the buttress with a shift in species composition with height. Two hypothesis were suggested to account for this distribution pattern: a response to an environmental gradient or an interaction between the four species of fly.     

Isolation and characterization of polymorphic microsatellite loci in the Australian smelt,Retropinna semoni

Five polymorphic microsatellite loci were isolated from the Australian smelt, Retropinna semoni, in order to study levels of connectivity among populations at various spatial scales. Screening of one natural population (n = 30) from central Victoria, southeastern Australia, yielded nine to 14 alleles per locus with observed levels of heterozygosity ranging from 0.40 to 0.80. All loci were in Hardy–Weinberg equilibrium after Bonferroni correction for multiple tests. These loci should provide a useful tool in further understanding the population genetics of this species.     

A comparison of the floristics and leaf chemistry of the tree flora in two Malaysian rain forests and the influence of leaf chemistry on populations of colobine monkeys in the Old World

A comparative floristic survey of lowland tropical rain forest at Kuala Lompat, Krau Game Reserve, West Malaysia and at Sepilok Virgin Jungle Reserve, Sabah, East Malaysia, revealed significant differences in the composition of canopy species, notably in the relative paucity of Dipterocarpaceae and abundance of Leguminosae at Kuala Lompat. A further comparison with data from other sites in Malesia indicated that Kuala Lompat was rather atypical, representing an extreme example of the relatively legume rich and dipterocarp poor forests of West Malaysia. Conversely, the predominance of dipterocarps and lack of legumes at Sepilok was similar to other sites in Borneo. Young and mature leaves were collected from a representative sample of the canopy flora of the two study sites; the levels of nitrogen, fibre, total phenolics and condensed tannins, and degree of digestibility by cellulase and pepsin, were measured. Levels of fibre, nitrogen and phenolics differed significantly between the two floras; foliage from Kuala Lompat being, on the whole, richer in nitrogen but lower in phenolics and fibre. As a consequence of the lower levels of fibre, and less certainly of phenolics, the Kuala Lompat foliage was comparatively more digestible. Possible reasons for the differences in foliar biochemistry between the two sites are discussed. Differences in rainfall and in soil quality are regarded as potential evolutionary causes. A further comparison of the chemical profiles with data for other forests in India and Africa indicate that Sepilok is a site in which trees invest heavily in quantitative defences such as fibre and phenolics whereas trees at Kuala Lompat place a lower emphasis on the production of these. Finally, attention is drawn to the use of foliar chemical profiles in predicting the carrying capacity for colobine monkeys at each of the five Old World forests where data are available. It was found that the ratio of nitrogen to fibre correlated well with the biomass of colobines at the five sites.