Habitat alteration and biotic invasions are the two leading causes of global environmental change and biodiversity loss. Recent innovative experiments have shown that habitat disturbance can have drastic effects that cascade to adjacent ecosystems by altering the flow of resource subsidies from donor systems. Likewise, exotic species invasions could alter subsidies and affect distant food webs, but very few studies have tested this experimentally. Here we report evidence from a large-scale field experiment in northern Japan that invasion of nonnative rainbow trout (Oncorhynchus mykiss) interrupted reciprocal flows of invertebrate prey that drove stream and adjacent riparian forest food webs. Rainbow trout usurped terrestrial prey that fell into the stream, causing native Dolly Varden charr (Salvelinus malma) to shift their foraging to insects that graze algae from the stream bottom. This indirectly increased algal biomass, but also decreased biomass of adult aquatic insects emerging from the stream to the forest. In turn, this led to a 65% reduction in the density of riparian-specialist spiders in the forest. Thus, species invasions can interrupt flows of resources between interconnected ecosystems and have effects that propagate across their boundaries, effects that may be difficult to anticipate without in-depth understanding of food web relationships.

Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.

Ivermectin mass drug administration (MDA) to humans is used to control onchocerciasis and lymphatic filariasis. Recent field studies have shown an added killing effect of ivermectin MDA against malaria vectors. We report that ivermectin MDA reduced the proportion of Plasmodium falciparum infectious Anopheles gambiae sensu stricto (s.s.) in treated villages in southeastern Senegal. Ivermectin MDA is a different delivery method and has a different mode of action from current malaria control agents. It could be a powerful and synergistic new tool to reduce malaria transmission in regions with epidemic or seasonal malaria transmission, and the prevalence and intensity of neglected tropical diseases.

BackgroundIn south-eastern Senegal, malaria and onchocerciasis are co-endemic. Onchocerciasis in this region has been controlled by once or twice yearly mass drug administration (MDA) with ivermectin (IVM) for over fifteen years. Since laboratory-raised Anopheles gambiae s.s. are susceptible to ivermectin at concentrations found in human blood post-ingestion of IVM, it is plausible that a similar effect could be quantified in the field, and that IVM might have benefits as a malaria control tool.MethodsIn 2008 and 2009, wild-caught blood fed An. gambiae s.l. mosquitoes were collected from huts of three pairs of Senegalese villages before and after IVM MDAs. Mosquitoes were held in an insectary to assess their survival rate, subsequently identified to species, and their blood meals were identified. Differences in mosquito survival were statistically analysed using a Glimmix model. Lastly, changes in the daily probability of mosquito survivorship surrounding IVM MDAs were calculated, and these data were inserted into a previously developed, mosquito age-structured model of malaria transmission.ResultsAnopheles gambiae s.s. (P < 0.0001) and Anopheles arabiensis (P = 0.0191) from the treated villages had significantly reduced survival compared to those from control villages. Furthermore, An gambiae s.s. caught 1-6 days after MDA in treated villages had significantly reduced survival compared to control village collections (P = 0.0003), as well as those caught pre-MDA (P < 0.0001) and >7 days post-MDA (P < 0.0001). The daily probability of mosquito survival dropped >10% for the six days following MDA. The mosquito age-structured model of malaria transmission demonstrated that a single IVM MDA would reduce malaria transmission (Ro) below baseline for at least eleven days, and that repeated IVM MDAs would result in a sustained reduction in malaria Ro.ConclusionsIvermectin MDA significantly reduced the survivorship of An. gambiae s.s. for six days past the date of the MDA, which is sufficient to temporarily reduce malaria transmission. Repeated IVM MDAs could be a novel and integrative malaria control tool in areas with seasonal transmission, and which would have simultaneous impacts on neglected tropical diseases in the same villages.

The Rht-B1b and Rht-D1b alleles, which occur at homoeologous loci on chromosomes 4B and 4D, respec-Reduced height alleles at the Rht-B1 and Rht-D1 loci have been tively, reduce sensitivity to gibberellic acid (GA), which widely incorporated into wheat (Triticum aestivum L.) cultivars with the intent of improving partitioning of assimilates to grain. Although is necessary for stem elongation (Flintham et al., 1997). generally effective at increasing yield in high yield environments, In favorable environments, the reduced demand for astheir effects under heat and drought stress have been variable. We similates by a shorter stem results in improved assimilate undertook this study to evaluate the effects of the Rht-B1b and Rhtpartitioning to the developing head, leading to higher D1b dwarfing alleles in a recombinant inbred line (RIL) spring wheat spikelet fertility and more but smaller grain per head. population under a range of soil moisture conditions. Rht-B1 and Semidwarf wheats have smaller leaves, but compensate Rht-D1 genotypes of 140 RILs derived from a cross between 'Kauz' with increased photosynthetic rates resulting in a bioand MTRWA116 were determined by polymerase chain reactions mass similar to that of tall lines (LeCain et al., 1989;(PCR). The population was evaluated for yield and agronomic traits Morgan et al., 1990;Flintham et al., 1997). in four Colorado environments under fully irrigated, partially irri-The relative yield advantage of dwarf and semidwarf gated, and rainfed conditions in 2001 and 2002. Lines with both dwarfing alleles were significantly (P Ͻ 0.01) shorter, lower yielding, and cultivars varies with spring or winter habit, genetic backlater heading in all environments compared with lines with one or no ground, and environmental conditions. The benefits of dwarfing allele. Lines with both tall alleles performed equal to or the dwarfing alleles are more pronounced in high yieldbetter (P Ͻ 0.05) than all other classes for grain yield, test weight, ing winter wheat environments (Flintham et al., 1997) and kernel weight in all environments. Among lines with a single and in high yielding spring wheat locations at latitudes dwarfing allele, those with Rht-B1b on average outyielded those with less than 40Њ (Fischer and Quail, 1990). However, under Rht-D1b in the fully irrigated environment (5432 versus 4993 kg heat and drought stress, there may be no benefit of the ha Ϫ1 , P Ͻ 0.05), but elsewhere their yields did not differ (P Ͼ 0.05).dwarfing alleles in spring wheat (Flintham et al., 1997; Desirable values for most traits occurred across a relatively wide range Nizam Uddin and Marshall, 1989; Richards, 1992a,b). of plant heights, with the best performing lines either shorter lines inRichards (1992a) concluded that grain yield does not the tall class or taller lines in the semidwarf classes. edu).Published in Crop Sci. 45:939-947 (2005).