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The larva of Cassida rubiginosa carries a tight packet of cast skins and feces on a fork held over its back. The packet is a maneuverable shield used by the larva to protect itself against attack. It is highly effective in blocking the bite of ants. 相似文献
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Solitary injuries of the gall bladder and the bile ducts are very seldom and dangerous. The prognosis of such injuries depends of the delay until the diagnosis is made and of the method of the bile ducts reconstruction. Several methods have been described; we present a method of reconstruction of the bile ducts after cholecystectomy with a bilio-digestive anastomosis with following advantages: no tension on the anastomosis, possibility of several anastomoses on the same jejunal loop, exact adaptation of the mucosa and elimination of the reflux of intestinal contain in the bile ducts with a long and isoperistaltic Roux-loop. 相似文献
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Domestic poultry act as a reservoir for persistent H5N1 endemicity in Vietnam, and the circulation of poultry flocks across farms and to market is thought to drive the spatial movement and evolution of avian influenza viruses. Using a dataset of complete or nearly full genomic sequences from highly pathogenic H5N1 avian influenza viruses collected in domestic poultry in Vietnam from 2003 to 2007, we explore potential differences in genetic characteristics according to species of isolation and the spatiotemporal characteristics of the viruses. Clustering algorithms and ANOVA indicate that H5N1 viruses in Vietnam show differences in the amount of genetic change that chicken viruses experience as compared to duck viruses, with duck viruses showing higher rates of molecular evolution on all eight of influenza's gene segments. There also exist distinct patterns of genetic differentiation according to the year in which they were isolated. These findings suggest that genetic evolution of avian influenza viruses is continuous through time but could also be mediated by the species in which the viruses occur, information that has implications for prevention efforts. 相似文献
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Eisner T Silberglied RE Aneshansley D Carrel JE Howland HC 《Science (New York, N.Y.)》1969,166(3909):1172-1174
A television camtiera, like the eyes of some insects, is sensitive to ultraviolet light. When equipped with an appropriate ultraviolet-transmitting lens, such a camera can be used for the direct examtiination of ultraviolet reflectiont patterns (for example, on flowers, butterflies) that are invisible to us, but visible to inisects. 相似文献
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Bernadette Bounket Hélène Tabouret Pierre Gibert Gilles Bareille Christophe Pecheyran Georges Carrel Christine Argillier Fabien Morat 《水产资源保护:海洋与淡水生态系统》2021,31(10):2772-2787
- In the context of the River Rhône restoration programme, the objective of this study was to assess the dispersal and population connectivity of the European chub, Squalius cephalus (Linnaeus, 1758) in a section of the natural, free-flowing part of the lower River Rhône.
- The elemental water signatures for Sr:Ca and Ba:Ca were measured at seven stations within the river section, including its tributaries and backwaters, to determine whether they could be differentiated by microchemistry. From August to October the signatures differed among three sectors of the study reach: the Rhône; the Ardèche; and the backwaters.
- The elemental signatures of the otoliths of 178 young-of-the-year (YOY) chub from the stations were measured to assess spawning areas and identify early migratory life histories. Analyses of otolith microchemistry identified the natal origin of 95% of the fish. Sr:Ca signatures of otoliths showed early downstream migration for 30.4% of the YOY chub; however, 70% of the fish recruited relatively close to their spawning origin suggesting a potential inshore retention of fish.
- The results showed (i) a non-negligible contribution of the tributaries and backwaters in the recruitment of fish into the main channel; and (ii) the ability of chub to migrate over several kilometres during their first few months of life.
- This study shows that the combination of water and otolith microchemistry analyses of fish growth increases the understanding of fish life history. Moreover, the study revealed that half of the YOY fish from this river section came from the tributaries and the other half came from reproduction in the River Rhône (despite its high anthropization).
- These methods offer promising future applications of otolith microchemistry for river management in the context of ecological rehabilitation, especially to assess the effectiveness of measures applied in the restoration of floodplain connectivity for riverine fish population conservation.
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Defensive use by an insect of a plant resin 总被引：7，自引：0，他引：7
T Eisner J S Johnessee J Carrel L B Hendry J Meinwald 《Science (New York, N.Y.)》1974,184(140):996-999
Larvae of the sawfly Neodiprion sertifer (Hymenoptera: Diprionidae), when disturbed, discharge an oily oral effluent essentially identical chemically to the terpenoid resin of its host plant (Pinus sylvestris). The resin is sequestered by the larva upon feeding, and stored in two compressible diverticular pouches of the foregut. The fluid is effectively deterrent to predators. The defensive use by an insect of a plant resin provides an instance of secondary utilization by a herbivore of the protective chemical weaponry of its host. 相似文献
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The phalangid Vonones sayi has a pair of exocrine defensive glands that secrete quinones (2,3-dimethyl-1,4-benzoquinone and 2,3,5-trimethyl-1,4- benzoquinone). When distributed, the animal emits the secretion, dilutes it with aqueous regurgitated fluid, and effects dosaged delivery of the mixture by brushing it on the assailant with the tips of its forelegs. Predators such as ants are effectively repelled. 相似文献