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LA RIVIERE JW 《Antonie van Leeuwenhoek》1955,21(1):1-8
Summary Cultures of 8 micro-organisms, grown in synthetic media free from surface active nutrients, were found to show a marked decrease
in surface tension on prolonged incubation. The depression started after about two days cultivation and attained values ranging
from 14–34 dyne/cm after 7 days. The possible origin of the substances responsible for this effect is briefly discussed. 相似文献
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Evidence for the transfer of a soil‐borne contaminant from plants to ants via an aphid mediator 下载免费PDF全文
1. Uptake of environmental contaminants by lower trophic groups can have negative effects on higher trophic groups. This study tested the ability of selenium, an environmental contaminant found in high concentrations throughout the tissues of certain accumulating plants, to be transferred to ants via aphid tissue and honeydew. 2. Plants of the selenium accumulator, Raphanus sativus (wild radish), were watered with three different selenium treatments (0, 0.25 or 0.5 µg Se ml?1). Aphids, Myzus persicae, and Argentine ant colonies, Linepithema humile, were added to each caged plant and allowed to interact freely. Ant colonies were supplemented with one of three different food options to encourage the consumption of aphids, aphid honeydew, or aphids and honeydew. 3. The accumulation of selenium by each trophic group and a trophic transfer factor (TTF) was calculated. The TTF for plants to aphids was > 1, indicating biomagnification, whereas the TTF for aphids to worker ants was < 1, indicating only biotransfer. Accumulated levels by worker ants did not statistically differ as a result of diet. 4. The amounts of selenium acquired by ants as a factor of diet and caste were compared. Plants, aphids and worker ants accumulated selenium in a dose‐dependent manner. Ant queens did not contain detectable amounts of selenium. Honeydew contained comparable amounts of selenium to plant selenium levels. 5. Access to toxic compounds via honeydew and insect protein may have negative effects on the range expansion of invasive species, such as the Argentine ant. 相似文献
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Comparative scanning electron microscopy of third-instar Hypoderma spp. (Diptera: Oestridae) 总被引:1,自引:0,他引:1
DOUGLAS D. COLWELL MARTÍNEZ-MORENO MARTÍNEZ-MORENO HERNÁNDEZ-RODRÍGUEZ DE LA FUENTE-LÓPEZ ALUNDA & HALL 《Medical and veterinary entomology》1998,12(2):181-186
Scanning electron microscope study of third-instar larvae of four species of Hypoderma revealed differences among species in the pattern of spination, spine morphology and morphology of the spiracular plates. These observations identify characters that enable the differentiation of Hypoderma actaeon and H. diana, parasitizing red deer ( Cervus elaphus ) in Europe, and provide additional characters for differentiating H. bovis and H. lineatum parasitizing cattle. 相似文献
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V.DE LA FUENTE E. ORTÜÑEZ 《Botanical journal of the Linnean Society. Linnean Society of London》1994,114(1):23-30
A new species of Festuca (Festuca rivas-martinezii de la Fuente & Ortúñez) is described from the Sierra de Ayllón, Sierra de Guadarrama, Sierra de Gredos and associated chains (northcentral Spain: provinces of Avila, Guadalajara, Madrid and Segovia. Some morphological, anatomical and cytological characters of the taxon are presented. 相似文献
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BETHAN V. PURSE BENJAMIN J. J. MCCORMICK PHILIP S. MELLOR MATTHEW BAYLIS JOHN P. T. BOORMAN DAVID BORRAS IBRAHIM BURGU RUBEN CAPELA SANTO CARACAPPA FRANCISCO COLLANTES CLAUDIO DE LIBERATO JUAN A. DELGADO ERIC DENISON GEORGI GEORGIEV MEDHI EL HARAK STEPHAN DE LA ROCQUE YOUSSEF LHOR JAVIER LUCIENTES OLGA MANGANA MIGUEL ANGEL MIRANDA NEDELCHO NEDELCHEV KYRIAKI NOMIKOU AYKUT OZKUL MICHAEL PATAKAKIS ISABEL PENA PAOLA SCARAMOZZINO ALESSANDRA TORINA DAVID J. ROGERS 《Journal of Applied Ecology》2007,44(6):1231-1242