The vertical distribution of small flying insects in the lowland rain forest of Zaire

To monitor the vertical distribution of flying insects in the semi-deciduous rain forest of Zaire, two types of trap were hung at four vertical levels. Large insects were excluded. The entire catch was analysed. There was a marked concentration of flying insects within and above the canopy, over a wide range of orders. The most abundant taxa showed the greatest tendency to occur at these upper levels. Within the size range collected, biomass in general reflected abundance, but was influenced by the relatively high proportion of small insects in and above the canopy. There was a strong similarity in the relative abundance of orders between trap types and sites, but total numbers varied greatly. This variation and the biases inherent in these trapping methods are discussed and we conclude that the bulk of the small flying insects of the rain forest are concentrated in the upper canopy.     

A Modified Method for Extraction and Identification of Abscisic Acid and Gibberellin-like Substances from the Olive (Olea europaea)

A procedure for extracting and identifying plant hormones, particularly abscisic acid (ABA) and the gibberellins (GA) was developed through modification of methods described in the literature. The procedure is particularly useful for studying more than one hormone simultaneously in a given sample, and when the supply of plant material is limited. The procedure was used to isolate ABA and GA-like substances from olive tissue (i.e., leaves, buds and inflorescences). Gibberellin-like substances were identified by their action on α-amylase release from embryoless barley half-seeds. Characterization of an acidic inhibitor extracted from olive inflorescences by thin-layer chromatography, fluorescence under ultraviolet light, gas chromatography, and physiological effects on wheat coleoptile sections indicate that this inhibitor, or at least a component of it, is very similar if not identical with at least one isomeric form of synthetic abscisic acid.     

Transmission of louping ill virus between infected and uninfected ticks co-feeding on mountain hares

Abstract. Most of the data on oral infection of ticks by louping ill virus have been obtained from experiments in which animals were infected by syringe inoculation with infectious material. Using infected ticks to mimic the natural situation, we have demonstrated that louping ill (LI) virus transmission can occur from infected to uninfected Ixodes acinus feeding in close proximity on mountain hares (Lepus timidus). Under these conditions the hares developed either low or undetectable viraemias. Highest prevalence of LI virus infection was observed in recipient nymphs which had fed to repletion between days 3 and 7 post-attachment of virus-infected adults; following engorgement, 56% of nymphs acquired virus. These results demonstrate the efficient transmission of LI virus between co-feeding ticks on naive mountain hares. However, when ticks were allowed to co-feed on virus-immune hares a significant reduction in the frequency of infection was observed. Neither red deer (Cervus elaphus) nor New Zealand White rabbits supported transmission of LI virus. The significance of virus transmission between cofeeding ticks on LI virus epidemiology is discussed.