The helminths infesting the common lizard, Zootoca vivipara (Jacquin, 1787), were studied with special attention to the relations between the number of nematodes, Oswaldocruzia filiformis (Goezc,1782), and the size, sex and age class of the host. The possible seasonality of the parasite intensity and the relationship with the feeding habits of the host were also tested. Helminth infracommunities of Z. vivipara were depauperate with lizards harbouring only two species, the tremalode Plagiorchis molini (Lent et Freitas, 1940) and the nematode O, filiformis. A positive correlation between host size and the number of O. filiformis was found for female Z. vivipara. However, no correlation was detected between intensity and sex or age class. The feeding habits of Z. vivipara, the isolation of the population studied and the low level of interaction with other reptilian or amphibian species are suggested as the causes of the depauperate helminth infracommunities found in this laccrtid lizard.
We investigated the effects of genetic differences and host plant density on population development of the rose-grain aphid Sitobion avenae (F.) (Sternorrhyncha: Aphididae) in winter wheat stands. Aphid numbers on ears were recorded on 11 cultivars (6 years) and on plots where crop density was varied by thinning (12 years). Crop density significantly affected whole plant, tiller and ear mass, number of tillers, and leaf area and chlorophyll content. The duration and rate of aphid population growth, and the maximum numbers of aphids were ascertained by weekly counts. Maximum abundances increased with the length of time available for the growth of aphid populations while the rate of population growth was less important. Variation of maximum numbers of S. avenae on different cultivars was not significant, probably due to the small variation in the period available for the development of aphid populations. By contrast, there was a significant Variation of aphid performance associated with host plant density. Aphid populations on solitary plants persisted longer and became more abundant than in dense stands. The prolonged survival of aphid populations was probably caused by an extended period of tillering and lower average age of tillers of solitary plants. There was large annual variation in aphid abundance. It is likely that modifications of host plant development caused by differences in winter weather may contribute to this variation., Alois Honěk, Zdenka Martinková, and Lit
V osobní vzpomínce [1] na Bohuslava Hostinského, profesora Masarykovy univerzity a významného teoretického fyzika a matematika, naznačil její autor Čestmír Šimáně, mj. s odkazem na Nelsonovu práci [5], možnost, že prof. Hostinský, aniž sám byl příznivcem kvantové fyziky, mohl na základě svých vlastních výzkumů v oblasti mechanických kmitů intuitivně směovat k některým jejím výsledkům. Můžeme zjistit, zda tomu tak opravdu bylo nebo zda je to alespoň pravděpodobné? Tento příspěvek, přednesený též na semináři pořádaném letos k poctě Bohuslava Hostinského na Masarykově univerzitě v Brně [2], se pokouší najít možné souvislosti a odpovědi., Jana Musilová., and Obsahuje bibliografii