Invasion of the gall mite Aceria genistae (Acari: Eriophyidae), a natural enemy of the invasive weed Cytisus scoparius,into California,U.S.A. and predictions for climate suitability in other regions using ecological niche modelling

Scotch broom (Cytisus scoparius (L.) Link) is a European shrub that has naturalised in several countries worldwide and is recognised as an invasive weed in much of western North America. The mite Aceria genistae (Nalepa) is a coevolved, gall-inducing herbivore associated with Scotch broom in its native range and has been intentionally introduced as a classical weed biological control agent of C. scoparius in Australia and New Zealand. An adventive, never intentionally introduced, population of A. genistae was discovered in Washington and Oregon, U.S.A. in 2005. Surveys for A. genistae in California resulted in the discovery of the gall mite in 11 counties, with a widely scattered distribution. Molecular and morphological assessments confirm the mites collected from galls in California are A. genistae. Whether natural or anthropogenic, the estimated rate of long range dispersal for A. genistae from Washington or Oregon to California ranges from 39 to 62?km/yr. Niche model predictions indicate that A. genistae will continue to expand its distribution throughout much of the Scotch broom-invaded lands of California but areas supporting the weed in the Eastern U.S.A. appear less suitable. Modelling evidence also indicates that portions of Chile and Argentina are suitable for colonisation by A. genistae, also suggesting that expansion of the mite is possible in areas of Tasmania, southeastern Australia, and New Zealand where the mite was released. The environmental safety of A. genistae in relation to non-target plants and the influence of herbivory on Scotch broom fitness are discussed.     

LoCoH: nonparameteric kernel methods for constructing home ranges and utilization distributions

Parametric kernel methods currently dominate the literature regarding the construction of animal home ranges (HRs) and utilization distributions (UDs). These methods frequently fail to capture the kinds of hard boundaries common to many natural systems. Recently a local convex hull (LoCoH) nonparametric kernel method, which generalizes the minimum convex polygon (MCP) method, was shown to be more appropriate than parametric kernel methods for constructing HRs and UDs, because of its ability to identify hard boundaries (e.g., rivers, cliff edges) and convergence to the true distribution as sample size increases. Here we extend the LoCoH in two ways: "fixed sphere-of-influence," or r-LoCoH (kernels constructed from all points within a fixed radius r of each reference point), and an "adaptive sphere-of-influence," or a-LoCoH (kernels constructed from all points within a radius a such that the distances of all points within the radius to the reference point sum to a value less than or equal to a), and compare them to the original "fixed-number-of-points," or k-LoCoH (all kernels constructed from k-1 nearest neighbors of root points). We also compare these nonparametric LoCoH to parametric kernel methods using manufactured data and data collected from GPS collars on African buffalo in the Kruger National Park, South Africa. Our results demonstrate that LoCoH methods are superior to parametric kernel methods in estimating areas used by animals, excluding unused areas (holes) and, generally, in constructing UDs and HRs arising from the movement of animals influenced by hard boundaries and irregular structures (e.g., rocky outcrops). We also demonstrate that a-LoCoH is generally superior to k- and r-LoCoH (with software for all three methods available at http://locoh.cnr.berkeley.edu).     

Influenza in migratory birds and evidence of limited intercontinental virus exchange

Migratory waterfowl of the world are the natural reservoirs of influenza viruses of all known subtypes. However, it is unknown whether these waterfowl perpetuate highly pathogenic (HP) H5 and H7 avian influenza viruses. Here we report influenza virus surveillance from 2001 to 2006 in wild ducks in Alberta, Canada, and in shorebirds and gulls at Delaware Bay (New Jersey), United States, and examine the frequency of exchange of influenza viruses between the Eurasian and American virus clades, or superfamilies. Influenza viruses belonging to each of the subtypes H1 through H13 and N1 through N9 were detected in these waterfowl, but H14 and H15 were not found. Viruses of the HP Asian H5N1 subtypes were not detected, and serologic studies in adult mallard ducks provided no evidence of their circulation. The recently described H16 subtype of influenza viruses was detected in American shorebirds and gulls but not in ducks. We also found an unusual cluster of H7N3 influenza viruses in shorebirds and gulls that was able to replicate well in chickens and kill chicken embryos. Genetic analysis of 6,767 avian influenza gene segments and 248 complete avian influenza viruses supported the notion that the exchange of entire influenza viruses between the Eurasian and American clades does not occur frequently. Overall, the available evidence does not support the perpetuation of HP H5N1 influenza in migratory birds and suggests that the introduction of HP Asian H5N1 to the Americas by migratory birds is likely to be a rare event.     

Scale-dependent effects of landscape context on urban bee diversity

Journal of Insect Conservation - As urbanization continues throughout much of the world, there is great interest in better understanding the value of urban and residential environments to...     

River otter and mink occupancy dynamics in riparian systems

Semi-aquatic mammals are dependent upon streams and riparian areas, which are a product of the landscapes they drain. Both local stream morphology and surrounding land use are likely to have important influences on current occupancy of semi-aquatic mammals and potentially affect future geographic distributions. We identified aspects of the riparian system and stream structure at multiple scales that relate to the presence of river otter (Lontra canadensis) and mink (Neovison vison) to better understand how changing landscapes affect occupancy dynamics of these semi-aquatic mammals and to facilitate future monitoring and management. We estimated multi-season occupancy using 103 sites sampled over 6 seasonal sampling periods in southern Illinois, USA (44,526 km²) during 2012–2014. We hypothesized river otter and mink occupancy were related to multiple aspects of landscape and local habitat attributes including land cover, water availability, human disturbance, and stream characteristics. Occupancy of river otter was predicted by large stream size, less developed area near the stream site, and proximity to areas with reintroduced or remnant populations of river otter. Mink were more likely to occupy sites with small streams and decreased water availability near the site. However, top models for both species had low weights and high uncertainty for multiple variables. Habitat-based models may not be the best predictors of occupancy for these carnivores because they are more likely to respond to prey diversity or availability, but landscape changes that decrease natural water availability and increase human disturbance to the stream at the local scale are likely to negatively affect river otter. © 2019 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Relations between pigments and proteins in the photosynthetic membranes of Rhodopseudomonas spheroides

We have isolated from Rhodopseudomonas spheroides a pigment-protein complex of apparent weight 9 kdaltons that bears more than 60% of the light harvesting bacteriochlorophyll. The isolation procedure involved exposure to 1% lauryl dimethyl amine oxide (LDAO). The purified 9-kdalton fraction showed the light harvesting bacteriochlorophyll components B800 and B850, plus carotenoids. The ratio of bacteriochlorophyll to protein was 17%. This protein is probably the same as the “band 15” protein of Fraker and Kaplan. It may exist in vivo as characteristic aggregates of higher molecular weight. LDAO added to Rps. spheroides chromatophores converted the bacteriochlorophyll component B870 to a form absorbing at 770 nm but had little effect on the “B800 + B850” system, causing only a reversible shift of the 850-nm band to 845 nm. Anti-reaction center serum, added to subcellular fractions from Rps. spheroides with 1% LDAO, precipitated reaction center chromoprotein unaccompanied by light harvesting bacteriocholorophyll. Other antisera precipitated light harvesting components and left the reaction center chromophores in solution. A major protein of apparent weight 45 kdaltons was found in relatively nonpigmented fractions from Rps. spheroides, associated with cell wall fragments. The 45-kdalton protein showed considerable interstrain variability, whereas the 9-kdalton and reaction center proteins appeared constant.     

Motivational control of caching behaviour in the scrub jay, Aphelocoma coerulescens

We investigated the motivational control of caching behaviour in scrub jays using a two-stage procedure to examine the effects of prefeeding and/or precaching (stage 1) on subsequent caching behaviour (stage 2). Experiment 1 demonstrated that both prefeeding and precaching reduced the subsequent caching of both edible (peanuts) and inedible (stones) items. The reduction in caching was greatest when the items available for storing were the same in the two stages. This item specificity was confirmed in experiment 2 using two food types, peanuts and dog food kibbles. The final experiment demonstrated that the effect of prefeeding on subsequent caching can also be food specific, in that birds that received food in a powdered form that they could eat, but not cache in stage 1, showed a reduction in subsequent caching in stage 2 only when the food type was the same in the two stages. These results suggest that caching behaviour is controlled by both the feeding system and an independent caching system, and that this control is mediated by the incentive value of the specific items rather than by a general motivational state. Copyright 1999 The Association for the Study of Animal Behaviour.