Responses of ant communities to dry sulfur deposition from mining emissions in semi‐arid tropical Australia,with implications for the use of functional groups

Abstract The impact of dry deposition of SO₂ emissions on ant abundance, diversity and composition was investigated at Mount Isa in the semiarid tropics of northern Australia. Forty plots were sampled, stratified at two levels: sulfur deposition zones (high, medium, low, and two control zones) and habitat (Ridge and Plain). The two habitats supported distinctly different ant communities. Ants had clear responses to SO₂ emissions. Ant abundance was lowest in the high and medium sulfur zones in both habitats. Species richness in high SO² plots (up to 5 km from the source) was approximately half that of control plots in Ridge habitat, and was substantially less than controls in the Plain habitat. Ant community composition in the high sulfur zone was clearly separated from those of other zones in ordinations. Vector fitting showed soil SO₄ concentration as a primary correlative factor in this separation. Ant abundance and richness were both negatively correlated with soil SO₄ concentration, and positively correlated with plant species richness and distance away from the smelters. The abundance of 10 of the 21 most common species showed significant responses to emissions. Five species showed positive responses, and all belong to species‐groups known to be abundant at disturbed sites throughout northern Australia. Relative abundance and richness of Eyrean (arid adapted) taxa collectively responded positively to sulfur, and Torresian (tropical) and Widespread species responded negatively. Despite large changes in species composition and abundances, there was relatively little change in the abundance of functional groups that have been widely used in studies of Australian ant communities. Ants are sensitive to SO₂ emissions and appear to be good candidates as an indicator group in this context. However, an alternative functional group framework is required for the identification of recurrent responses of arid zone ant communities to disturbance.     

THE APPLICATION of ATP BIOLUMINESCENCE FOR the ASSESSMENT of MILK QUALITY and FACTORY HYGIENE

The speed of ATP bioluminescence assays makes them very useful for assessing product quality and efficiency of sanitation at food plants. the suitability of a new method for evaluating the quality of raw milk was compared with plate count. A good correlation was obtained between the ATP method and plate count for milks with counts above 1 × 10⁴ cfu/ml. the combination of ATP bioluminescence with preincubation procedures was investigated for predicting the shelf-life of pasteurized milk. the best correlations were obtained when milks were preincubated at 15C for 25 h or at 21C for 25 h in the presence of an inhibitor system to prevent Gram-positive bacterial growth.
Hygiene monitoring using bioluminescence gave a better indication of surface cleaniness than conventional swab counts. the reasons for the discrepancies in a small percentage of cases are discussed.     

An Apparent Carbohydrate-Amino Acid Interaction in Tetrahymena pyriformis

SYNOPSIS. Experiments were designed to examine the nature of the response of Tetrahymena pyriformis to inhibitory levels of L-serine when growing in defined media with carbohydrate as mono-, or polysaccharide. Growth curves indicated that, when a polysaccharide is being utilized, inhibition by serine affects at least 2 different loci. At one locus, inhibition causes a marked increase in the growth lag, at the other a significant decrease in the maximum rate of growth. Since the inhibition was completely reversible by glucose supplementation, it is evident that the initial inhibition, expressed as increased lag time, is specifically related to uptake or metabolism of the polysaccharide, i.e., it precedes glucose in the metabolic sequence. The inhibition expressed as decreased rate of maximum growth appears to be due to interference at some stage in the glycolytic pathway. The results suggest that in metabolizing a polysaccharide, T. pyriformis utilizes 2 mechanisms simultaneously. One involves phagocytic ingestion of molecular dextrin followed by phosphorylytic cleavage whereby the energy of the glycosidic bond is utilized to form glucose-1-phosphate. The 2nd mechanism depends upon elaboration of extracellular hydrolytic enzymes to cleave the polysaccharide to glucose, which enters the glycolytic pathway via glucose-6-phosphate in the usual manner.     

Rates of progress up odour plumes by tsetse flies: a mark-release video study of the timing of odour source location by Glossina pallidipes

Abstract. The arrival of individually marked Glossina pallidipes Austen at a host odour source after their video-timed release from 30–75 m downwind was measured in the field in Zimbabwe. In the absence of odour, the proportion recaptured was <2% (= - random expectation); when synthetic ox odour was released, the probability of recapture at the source increased with proximity of release, from 6% at 75 m to 21% at 30 m (about twice this number arrived within ∼2 m of the source). There were two distinct distributions of recaptures: a 'fast' cohort which found the source within 40 s, and a 'slow' cohort which took from one to >20 min, with ∼50% of the flies in each cohort. The fastest flies probably reached the source in a single, mainly straight flight from take-off, at an overall average (straight line) displacement speed of 2.8-4.5 ms^-1 (i.e. close to the preferred flight speed of ∼5 m s^-1). The flies apparently maintained their ground speed largely independent of the wind speed they headed into. The 'slow' cohort had a constant probability of arrival at the source, presumably after losing and re-contacting the plume, and after having stopped at least once on the way. There were no marked correlations with wind parameters, although the probability of recapture increased slightly with the directness of the wind from the source, and the probability of 'slow' flight increased slightly with wind speed. It is inferred that a repeated sequence of anemotactic 'aim-then-shoot' orientation at take-off plus optomotor-steered in-flight correction of direction is used as a form of biassed random walk to bring the flies close to the odour source, rather than the use of moth-type anemotactic zigzagging.     

Comparing Ground Telemetry and Global Positioning System Methods to Determine Cougar Kill Rates

ABSTRACT We assessed whether use of 2 methods, intensive very high frequency (VHF) radiotelemetry and Global Positioning System (GPS) cluster sampling, yielded similar estimates of cougar (Puma concolor) kill rates in Yellowstone National Park, 1998–2005. We additionally determined biases (underestimation or overestimation of rates) resulting from each method. We used modeling to evaluate what characteristics of clusters best predicted a kill versus no kill and further evaluated which predictor(s) minimized effort and the number of missed kills. We conducted 16 VHF ground predation sequences resulting in 37 kill intervals (KIs) and 21 GPS sequences resulting in 84 KIs on 6 solitary adult females, 4 maternal females, and 5 adult males. Kill rates (days/kill and biomass [kg] killed/day) did not differ between VHF and GPS predation sampling methods for maternal females, solitary adult females, and adult males. Sixteen of 142 (11.3%) kills detected via GPS clusters were missed through VHF ground-based sampling, and the kill rate was underestimated by an average of 5.2 (95% CI = 3.8–6.6) days/kill over all cougar social classes. Five of 142 (3.5%) kills identified by GPS cluster sampling were incorrectly identified as the focal individual's kill from scavenging, and the kill rate was overestimated within the adult male social class by an average of 5.8 (95% CI = 3.0–8.5) days/ungulate kill. The number of nights (locations between 2000 hours and 0500 hours) a cougar spent at a cluster was the most efficient variable at predicting predation, minimizing the missed kills, and minimizing number of extra clusters that needed to be searched. In Yellowstone National Park, where competing carnivores displaced cougars from their kills, it was necessary to search extra sites where a kill may not have been present to ensure we did not miss small, ungulate prey kills or kills with displacement. Using predictions from models to assign unvisited clusters as no kill, small prey kill, or large prey kill can bias downward the number of kills a cougar made and bias upward kills made by competitors that displace cougars or scavenge cougar kills. Our findings emphasize that field visitation is crucial in determining displacement and scavenging events that can result in biases when using GPS cluster methods in multicarnivore systems.     

Some problems of evaluating fungicides for use on coffee in Kenya

As part of a programme testing fungicides for control of coffee berry disease (CBD) promising materials were also tested in the field against leaf rust of coffee. In all, fourteen fungicides were tested, five of which have been recommended for control of CBD. Only Perenox (representative of 50% copper fungicides) and Du-Ter (not highly effective against CBD and no longer recommended) gave good control of rust; Difolatan gave some control but Benlate and Daconil were virtually ineffective.
Where only CBD is present there is generally a good relationship between disease control and yield, but in these experiments where leaf rust was also present, this relationship was seriously disturbed. The implications of this for testing fungicides for use on coffee in Kenya are discussed.