ABSTRACT Durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia triticina. To assess the durability of partial resistance, selection experiments were used to explore quantitative variation in parasitic fitness of P. triticina. Fungal populations 881-WT and 882-WT were select...

1. For the heart rate in Pterotrachea coronata, intermediate temperatures disclose a thermal increment of 11,200 +/-. This value is identical with the one reported by Crozier and Stier for the lamelli-branch, Anodonta. In the pteropod, Tiedemannia neapolitana the same temperatures typically reveal in the heart rate a micro value of 16,200 +/- This agrees quantitatively with 16,300 found by Croz...

Crop pathogens are notorious for their rapid adaptation to their host. We still know little about the evolution of their life cycles and whether there might be trade-offs between fitness components, limiting the evolutionary potential of these pathogens. In this study, we explored a trade-off between spore production capacity and latent period in Puccinia triticina, a fungal pathogen causing le...

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Co-evolution has been invoked as an explanation for Lake Tanganyika’s unusual endemic fauna. The crabs Platytelphusa armata and Potamonautes platynotus are molluscivores, found in the same habitats as the gastropods Lavigeria coronata, L. grandis, and L. nassa (West & Cohen 1994). As these are the largest gastropods in the Lavigeria species flock, and often the most exposed, we are determining ...