Methods for the collection, fixation. preservation and examination of the cestodes parasitic in British freshwater fishes are described. An illustrated key to the species is provided, with the exception of the members of the genus Proreoccphalus. for which the information is tabulated.
The first terrestrial arthropods recorded from the Jamaican fossil record are millipedes (Diplopoda), representing at least three species, from a late Pleistocene or Holocene cave deposit. Taxa identified include Rhinom'cus sp. or spp., a& Chondrotropis sp. and Caraibodesmus verrucosus (Pocock). The associated fauna includes diverse vertebrates and gastropods, with rare isopods, nonmarine crab claws and ostracodes. Preservation of millipedes has been enabled by calcite coating, lining and impregnating the chitinous exoskeleton, which had a high original calcium content and acted as a nucleus for precipitation. Delicate structures such as limbs, antennae, gonopods and eyes may all be preserved. This preservation has been facilitated by the bottle-shaped cave with an opening at its apex, the surrounding limestone, the clastic infill, and the seasonality of precipitation with very high rainfalls during tropical storms and hurricanes. Millipedes most probably drowned in the cave during storms and formed a nucleus for the precipitation of calcite from solution. This suite of conditions is most likely to occur in the tropics.
Following the examination of 53 Lutzomyia spp., seven Phlebotomus spp. and five Sergentomyia spp. (Diptera: Psychodidae) new observations are recorded on the presence of pheromone disseminating structures on the tergites of male phlebotomine sandflies. Descriptions are given of 11 of the species which include structures such as simple cuticular pores in craters, pores with emergent spines, and mammiform papules with or without spiny processes. Pheromone papule distribution on the tergites of Lutzomyia pessoai (Coutinho & Barretto) is plotted and gas chromatography and GC-mass spectroscopy have been used to demonstrate the presence of a diterpene compound similar to a sexual attractant pheromone observed in some L. longipalpis (Lutz & Neiva) populations.
New polyacrylamides have been developed to improve the storage capability and the efficiency by which plants use water in agriculture and horticulture. These products are particularly useful where water is scarce or expensive and where drought is a significant hazard in crop production. However, there is considerable variation in the water absorption and release capabilities of different products that is explained by manufacturing conditions. Scanning electron microscopy shows that high performance products have a cellular structure in the expanded condition, with plant-available moisture stored both in enclosed vacuoles and within the polymer framework. The bridges that comprise the structure of the gel control water release under drying conditions and optimise recovery of the stored water by plants.
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