Laboratory Evaluation of Egg White and Milk External Biomarkers for Wasmannia auropunctata (Hymenoptera: Formicidae).

Acquisition and retention of two protein markers were tested on little fire ants, Wasmannia auropunctata Roger. Pure (100%) cow's milk and a dilution (10%) of chicken egg whites were applied to W. auropunctata directly by contact spray plus residue or indirectly via residual contact only with protein-marked plant debris. Protein-marked ants were held in plastic shoe-box-sized containers, collected at 0, 24, and 48 h after exposure to their respective marks, and then examined for the presence of the marks by a chicken egg albumin and milk casein-specific enzyme-linked immunosorbent assay. Cross-contamination rates were assessed by allowing ants marked with egg whites to interact with an equal number marked milk for 24 and 48 h, and then collected either individually or in bulk. Results indicated that the egg white biomarker was retained longer than milk and that more ants were successfully marked when the direct spray application method was employed. Cross-contamination rates were highest among bulk-collected ants and lowest among ants collected individually after 24 h. However, the rates of cross-contamination among individually collected ants increased and were similar to that of bulk-collected ants after 48 h. On the basis of our results, external protein marking may not be suitable if mass trapping is required or if the study extends beyond 24 h due to high cross-contamination rates among specimens collected in bulk and reduced marker detection rates.

Patterns of Occurrence of Sharks in Sydney Harbour, a Large Urbanised Estuary.

Information about spatial and temporal variability in the distribution and abundance of shark-populations are required for their conservation, management and to update measures designed to mitigate human-shark interactions. However, because some species of sharks are mobile, migratory and occur in relatively small numbers, estimating their patterns of distribution and abundance can be very difficult. In this study, we used a hierarchical sampling design to examine differences in the composition of species, size- and sex-structures of sharks sampled with bottom-set longlines in three different areas with increasing distance from the entrance of Sydney Harbour, a large urbanised estuary. During two years of sampling, we obtained data for four species of sharks (Port Jackson, Heterodontus portusjacksoni; wobbegong, Orectolobus maculatus; dusky whaler, Carcharhinus obscurus and bull shark, Carcharhinus leucas). Only a few O. maculatus and C. obscurus were caught, all in the area closest to the entrance of the Harbour. O. maculatus were caught in all seasons, except summer, while C. obscurus was only caught in summer. Heterodontus portusjacksoni were the most abundant species, caught in the entrance location mostly between July to November, when water temperature was below 21.5°C. This pattern was consistent across both years. C. leucas, the second most abundant species, were captured in all areas of Sydney Harbour but only in summer and autumn when water temperatures were above 23°C. This study quantified, for this first time, how different species utilise different areas of Sydney Harbour, at different times of the year. This information has implications for the management of human-shark interactions, by enabling creation of education programs to modify human behaviour in times of increased risk of potentially dangerous sharks.

Stream biomonitoring using macroinvertebrates around the globe: a comparison of large-scale programs.

Water quality agencies and scientists are increasingly adopting standardized sampling methodologies because of the challenges associated with interpreting data derived from dissimilar protocols. Here, we compare 13 protocols for monitoring streams from different regions and countries around the globe. Despite the spatially diverse range of countries assessed, many aspects of bioassessment structure and protocols were similar, thereby providing evidence of key characteristics that might be incorporated in a global sampling methodology. Similarities were found regarding sampler type, mesh size, sampling period, subsampling methods, and taxonomic resolution. Consistent field and laboratory methods are essential for merging data sets collected by multiple institutions to enable large-scale comparisons. We discuss the similarities and differences among protocols and present current trends and future recommendations for monitoring programs, especially for regions where large-scale protocols do not yet exist. We summarize the current state in one of these regions, Latin America, and comment on the possible development path for these techniques in this region. We conclude that several aspects of stream biomonitoring need additional performance evaluation (accuracy, precision, discriminatory power, relative costs), particularly when comparing targeted habitat (only the commonest habitat type) versus site-wide sampling (multiple habitat types), appropriate levels of sampling and processing effort, and standardized indicators to resolve dissimilarities among biomonitoring methods. Global issues such as climate change are creating an environment where there is an increasing need to have universally consistent data collection, processing and storage to enable large-scale trend analysis. Biomonitoring programs following standardized methods could aid international data sharing and interpretation.

Relative attractiveness of baits to Paratrechina longicornis (Hymenoptera: Formicidae).

Exotic ant incursions are becoming more frequent around the globe, and management with toxic baits is a suitable strategy for most species. Crazy ants, (Latreille) (Hymenoptera: Formicidae), however, are notoriously difficult to attract to commercial baits, which are generally tailored to the preferences of fire ants. We tested P. longicornis preferences for various food types and commercial ant baits. Baits trialed were commercially available products Amdro, Maxforce, Xstinguish (nontoxic monitoring version), Presto, and tuna (in spring water), sugar water (25%), boric acid (1% in 25% sugar water), and deionized water. Tuna and Xstinguish, along with sugar water and sugar water + boric acid, were the most attractive baits to P. longicornis foragers. The granular baits (Maxforce, Amdro, and Presto) were not as attractive to P. longicornis foragers. A decrease in temperature from summer (30 degrees C) to autumn (23 degrees C) trials did not seem to affect the food preferences of P. longicornis. Although P. longicornis recruitment was substantially lower during trials where there was concurrent high native ant abundance and diversity, P. longicornis still recruited to preferred baits in numbers higher than any other species. Given that tuna is impractical for management programs, the effectiveness of boric acid, sweet liquid baits in eliminating P. longicornis colonies should be compared with that of the toxic version of Xstinguish. If both are effective at eliminating colonies, we recommend sweet liquid baits containing boric acid be used for small-scale incursions (one or two nests), but a more practicable solid bait, such as Xstinguish, be used for larger scale incursions (numerous nests).

The use of the oyster Saccostrea glomerata as a biomonitor of trace metal contamination: intra-sample, local scale and temporal variability and its implications for biomonitoring.

Cu, Cd, Zn, Pb and Se concentrations were measured in the bivalve mollusc Saccostrea glomerata(Iredale and Roughly) from two uncontaminated locations, Clyde River Estuary, Batemans Bay and Moona Moona Creek, Jervis Bay, to determine natural variability of metals associated with mass, gender, age, tissue type and site within location. Trace metals were also measured in the Clyde River Estuary over an 11 year period and in five other NSW estuaries (Hastings River, Hunter River, Georges River, Tillgerry Creek and Lake Pambula) over a 13-month period to determine temporal variability and if diploid and triploid oysters accumulate trace metals differently. There were few significant relationships between trace metal concentrations and mass and no significant differences in trace metal concentrations between female and male oysters. Younger oysters (1.3 years) had significantly higher copper concentrations and higher trace metal variability than mature oysters (3 years). Different tissues have different trace metal concentrations with muscle tissues having lower concentrations. Considerable inherent variability occurs in oyster cohorts. Analysing specific tissues did not reduce variability of trace metal concentrations. Comparison of trace metal concentrations at two sites within the Clyde Estuary showed a significant difference in zinc concentrations. Cu, Cd, Zn and Se concentrations were generally higher and less variable in triploids than diploids. Pb had a variable pattern of accumulation with no consistent elevation in diploids or triploids. Inter annual variability of trace metal concentrations was considerable and trace metal concentrations also fluctuated throughout an annual cycle with no clear seasonal trends. Measurement of trace metals at known contaminated locations showed that Saccostrea glomerata accumulates metals in response to contamination. Saccostrea glomerata meet most of the requirements to be a biomonitor of trace metal contamination as they are abundant, sessile/sedentary, easy to identify, provide sufficient tissue for analysis, and accumulate trace metals in response to contamination. However, as trace metal concentrations can vary with mass, age, estuary position, ploidy type and temporally, care must be taken to collect individual organisms of similar mass, age and ploidy type to minimise variability, and from similar consistent positions and times to allow for seasonal changes in environmental conditions. Trace metal concentration variability is higher in young animals, thus to reduce variability, older mature animals could be selected. However, with immature oysters there are no complications because of the effects of spawning i.e. sudden loss of trace metals or body mass.