Directional cues in tactile stimuli involved in agonistic encounters in cockroaches

ABSTRACT. The ability of male cockroaches, Nauphoeta cinerea and Periplaneta americana , to respond directionally to tactile agonistic acts was tested using stimulation by artificially manipulated appendages. Responses by Nauphoeta included turning towards the stimulus at preferred angles of c. 40°, 90° and 180°, apparently relying on internally-stored directional sensory information. This turning responsiveness depended in part on the social status of the receiving individual, since subordinate individuals often retreated or failed to respond. Periplaneta males reacted to tactile stimuli by quick movements away from the stimulus or by kicking towards it. The leg used in kicking was that nearest to the part of the body which was stimulated.     

A new transferrin allele in Australian goats

Subdivision of TF B into two variants, B1 (faster) and B2 (slower) in Australian goat breeds was accomplished by high voltage, thin layer polyacrylamide gel electrophoresis at pH 7.9. The genes controlling the caprine transferrins were shown to be autosomal codominant alleles, TFA, TFB1, TFB2 and TFC and in the various breeds of goats, the alleles were in Hardy-Weinberg equilibrium. TFA was the most common allele in the Australian and Texan Angora, Cashmere and Dairy breeds with gene frequencies ranging from 0.652 to 0.977. TFB1 and TFB2 occurred in all four breeds while TFC was only observed in very low frequencies in Australian Angora and Cashmere breeds.     

Canine plasma alkaline phosphatase polymorphism and its relationship with the canine Tr blood group system

A canine blood group antigen, QN, which was detected by a naturally occurring alloantibody in the antiglobulin test, was shown to be antigenically related to the human A and cattle J antigens by absorption experiments. Family studies supported a dominant mode of inheritance with the gene controlling the production of QN being dominant to the gene responsible for its absence. Frequencies of the QN and Tr antigens and serological data strongly suggested that the two antigens are identical. Two canine plasma alkaline phosphatase variants, F and S, were detected by starch gel electrophoresis, pH 8.65. Assuming genetic control of two codominant alleles, ALPF and ALPS, the distributions of types in families differed significantly from expectation. A relationship between the ALP and Tr(QN) systems was demonstrated with Tr-positive animals having a significant deficiency of S alkaline phosphatase types.     

Relationships among microclimate,edaphic conditions,vegetation distribution and soil nitrogen dynamics on the Bogong High Plains,Australia

We examined microclimatic conditions and soil nitrogen (N) dynamics of different alpine plant community types on the Bogong High Plains in Victoria, Australia. Three community types are predominant in the High Plains region, namely grassland, heathland and woodland and together they form so‐called inverted treelines, with grassland in valley floors below the treeline. Outdoor temperature loggers were deployed in the three vegetation types to establish differences among microclimatic conditions. We incubated soils to determine rates of N production and collected additional soil samples for analysis of soil properties and soluble N. Temperature data showed that only grassland communities experienced sub‐zero temperatures in winter. Temperature and soil moisture influenced indices of N mineralization and N nitrification in this alpine ecosystem. Rates of N mineralization were significantly faster than nitrification that only produced consequential amounts of nitrate in summer. This information, together with considerably lower pools of nitrate than ammonium and organic N in the soil, implies that ammonium is the dominant form of soluble N in the ecosystem whereas nitrate most likely only has minor importance for plant nutrition. The results of this study provide insight into ecological processes of this alpine ecosystem and demonstrate the vulnerability of the system to altered climatic and edaphic conditions in the course of climate change.     

A Handpiece for the Simultaneous Measurement of Photosynthetic Rate and Leaf Diffusive Conductance: II. CALIBRATION

The estimation of the photosynthetic rate and diffusive conductanceof a leaf depends on the accurate measurement of a number ofphysical properties of the leaf, the air around it, and thelight falling on it. This paper describes the calibration ofthe various sensors in a handpiece designed to measure simultaneouslyphotosynthetic rate and diffusive conductance of cereal leavesin the field. The expected errors of measurement are analysed,and the resulting uncertainties in photosynthetic rate and leafdiffusive conductance are derived.     

Impact of the predatory mite Anystis baccarum (Prostigmata: Anystidae) on apple rust mite Aculus schlechtendali (Prostigmata: Eriophyidae) populations in Northern Ireland Bramley orchards

Anystis baccarum is a common predatory mite in Northern Ireland Bramley orchards. To determine its effect on Aculus schlechtendali populations, sticky traps and sprays of demeton‐S‐methyl were used to exclude A. baccarum from branches. Out of four trials, exclusion of A. baccarum by sticky traps alone resulted in significantly greater numbers of A. schlechtendali in one trial. In the other trials where A. schlechtendali numbers were lower, there was either no effect, or possible evidence of fewer A. schlechtendali. The combination of demeton‐S‐methyl treatments and sticky traps to exclude A. baccarum resulted in significantly more A. schlechtendali in two trials out of three in 1998. It seems likely that this resulted from the dual effects of stimulation of A. schlechtendali reproduction by the acaricide and the absence of predation by A. baccarum, because acaricide treatment alone in 1999 resulted in significant reductions in A. schlechtendali numbers at the end of the season. This effect could have resulted from A. baccarum re‐invading the treatment branches after the effects of the acaricide had worn off. It is recommended that growers are encouraged to conserve A. baccarum within their orchards.