Retention and mobility of atmospheric particle-associated organic pollutant PCDD/Fs and PAHs in maize leaves

The fate of polychlorinated dibenzo- p -dioxins and dibenzofurans and polycyclic aromatic hydrocarbons deposited to maize leaves under ambient conditions was investigated, with focus on those compounds that are primarily associated with particles in the atmosphere. Leaf samples collected from mature maize plants over an 8-wk period were subjected to four extraction procedures: (1) rinsing with distilled water; (2) shaking in aqueous EDTA solution; (3) immersion in chloroform/methanol; (4) soxhlet extraction with toluene. Of the compounds deposited primarily in association with particles, > 20% of the total leaf contamination was present in the first two aqueous extracts, indicating that only a small portion of these substances was subject to ready erosion from the leaf surfaces. Some 50–60% of the chemical was present in the third extract, while 20–40% was found in the final extract. The chemical in the final extract was no longer associated with particles, since these had been removed with the first three extractions. This chemical must have desorbed from the particles with which it was originally deposited, and migrated through the epicuticular waxes. Model calculations indicated that 15–35% of the chemical in the third extract had also desorbed from the particles, and there was evidence that polychlorinated dibenzo- p -dioxins and dibenzofurans desorb more readily than polycyclic aromatic hydrocarbons. It is concluded that desorption of chemical from particles and subsequent transport through the cuticle is an important process determining plant accumulation of organic contaminants associated with atmospheric particles.     

Aspects of insect chemical ecology: exploitation of reception and detection as tools for deception of pests and beneficial insects

Empirical exploitation of insect reception and detection at the peripheral neurosensory level has been extremely valuable for identifying pheromones and other semiochemicals, mainly by electroantennogram or single cell preparations coupled with capillary gas chromatography. Differential sensitivity to semiochemicals at the single‐cell level has allowed the identification of some of the most active semiochemicals relating to host location and, more importantly, to the avoidance of nonhosts. However, in terms of molecular recognition, there is still a considerable gap in understanding the detection of particular molecules and their discrimination from closely‐related chemical structures. New approaches will be needed to understand the processes of molecular recognition more precisely. Nevertheless, from electrophysiological studies to the most advanced molecular techniques, it has been possible to identify semiochemicals for the deception of pests in their quest to find plant and animal hosts, as well as mates. Even the deception of insects antagonistic to pests, particularly parasitoids, can now be exploited for managing pests in more sustainable systems. Successes in exploiting insect semiochemicals in the interests of better agriculture and animal husbandry are exemplified, and potential new ways of learning more about reception and detection for deception are discussed. This takes the subject beyond the management of pest and beneficial insects to wider commercial and social opportunities.     

Revised status of Chloridea Duncan and (Westwood), 1841, for the Heliothis virescens species group (Lepidoptera: Noctuidae: Heliothinae) based on morphology and three genes

The Heliothinae comprise some of the world's most injurious agricultural pests. This study reanalyses a subsample of the Heliothis group to determine the monophyly of Chloridea (Heliothis virescens and H. subflexa). Two nuclear gene regions, elongation factor‐1α (EF‐1α; 1240 bp) and dopa decarboylase (DDC; 687 bp), and the barcoding region of mitochondrial cytochrome oxidase I (COI; 708 bp) were used in this analysis for a total of 2635 bp and a morphological dataset of 20 characters and 62 character states. Sixteen species representing five genera plus two outgroup species were used in the analysis. Analyses used were Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI). The revised status for the monophyletic genus Chloridea Duncan and (Westwood) was supported by a very strong bootstrap support (BP = 98–100). Larval host‐plant usage is discussed within the Heliothis clade. Polyphagy is most likely the ancestral condition with a host shift to monophagy and oligophagy. Based on known larval hosts, Heliocheilus is oligophagous on Poaceae. Traits of host plant use in Helicoverpa and Chloridea where both polyphagy and oligophagy occur in closely related species are discussed.     

Influence of Behavior on Bird Mortality in Wind Energy Developments

ABSTRACT As wind power generation is rapidly expanding worldwide, there is a need to understand whether and how preconstruction surveys can be used to predict impacts and to place turbines to minimize impacts to birds. Wind turbines in the 165-km² Altamont Pass Wind Resource Area (APWRA), California, USA, cause thousands of bird fatalities annually, including hundreds of raptors. To test whether avian fatality rates related to rates of utilization and specific behaviors within the APWRA, from March 1998 to April 2000 we performed 1,959 30-minute behavior observation sessions (360° visual scans using binoculars) among 28 nonoverlapping plots varying from 23 ha to 165 ha in area and including 10–67 turbines per plot, totaling 1,165 turbines. Activity levels were highly seasonal and species specific. Only 1% of perch time was on towers of operating turbines, but 22% was on towers of turbines broken, missing, or not operating. Of those species that most often flew through the rotor zone, fatality rates were high for some (e.g., 0.357 deaths/megawatt of rated capacity [MW]/yr for red-tailed hawk [Buteo jamaicensis] and 0.522 deaths/MW/yr for American kestrel [Falco sparverius]) and low for others (e.g., 0.060 deaths/MW/yr for common raven [Corvus corax] and 0.012 deaths/MW/yr for turkey vulture [Cathartes aura]), indicating specific behaviors or visual acuity differentiated these species by susceptibility to collision. Fatality rates did not correlate with utilization rates measured among wind turbine rows or plots for any species except burrowing owl (Athene cunicularia) and mallard (Anas platyrhynchos). However, mean monthly fatality rates of red-tailed hawks increased with mean monthly utilization rates (r² = 0.67) and especially with mean monthly flights through turbine rows (r² = 0.92). Fatality rates increased linearly with rates of utilization (r² = 0.99) and flights near rotor zones (r² = 1.00) for large raptor species and with rates of perching (r² = 0.13) and close flights (r² = 0.77) for small non-raptor species. Fatalities could be minimized or reduced by shutting down turbines during ≥1 season or in very strong winds or by leaving sufficiently large areas within a wind farm free of wind turbines to enable safer foraging and travel by birds.     

DNA microsatellites in Acanthochromis polyacanthus

To determine genetic substructuring in populations of the spiny damselfish Acanthochromis polyacanthus among different reefs of the Great Barrier Reef, Australia, we characterized six polymorphic microsatellite loci.     

Energy Budgets for Eared Grebes on the Great Salt Lake and Implications for Harvest of Brine Shrimp

ABSTRACT About 1.5-million eared grebes (Podiceps nigricollis), representing half of the North American population, stage on Utah's Great Salt Lake, USA (GSL) during autumn migration to forage on brine shrimp (Artemia franciscana). Indirectly competing with birds for brine shrimp are commercial harvesters who annually collect >1 million kg (dry wt) of shrimp cysts (i.e., hardened eggs), an amount that during some years equals up to half of all brine shrimp cysts produced annually on the GSL. No information was available regarding what impact this commercial harvest was having on eared grebes. We determined daily energy requirements of eared grebes so that regulations governing brine shrimp cyst harvest would better reflect foraging needs of grebes. We measured basal metabolic rate (BMR) of eared grebes from June 2000 to October 2000. Mean BMR of 106 adult and subadult eared grebes was 0.023 kJ/g/hour (SD = 0.004), and mean BMR of 37 juveniles was 0.024 kJ/g/hour (SD = 0.003). Resting and preening metabolic rates were 1.2 times higher than BMR, whereas diving-bout metabolic rate was 1.7 times higher than BMR. Daily energy needs of an average-sized grebe (550 g) during November were 391 kJ. Meeting this energy need requires daily consumption of 24,400 adult brine shrimp. In addition, grebes must consume 2,100–5,200 adult shrimp daily to obtain enough energy reserves to continue their migration to California, USA, and Mexico. Hence, grebes need to consume 26,500–29,600 adult brine shrimp daily while staging on GSL. To achieve this high harvest rate, grebes need adult brine shrimp densities at >380 shrimp/m³during autumn. Commercial harvest of brine shrimp cysts from GSL should be curtailed when cyst densities fall below 20,000 cysts/m³to ensure enough adult brine shrimp for grebes during the subsequent year.     

Cross‐species amplification at microsatellite loci in Australian quolls including the description of five new markers from the Chuditch (Dasyurus geoffroii)

The quolls are the largest native predators remaining on mainland Australia. We describe the cross‐species testing of all available microsatellite loci for representative across the entire distribution of quolls, with the additional characterization of five new microsatellite loci from the Chuditch. All primers produced clear and polymorphic amplification patterns containing between nine and 17 alleles and with high levels of diagnostic variability. These highly polymorphic primers make them useful additional tools in planning conservation strategies across related conspecifics, many of which are under threat.