Male choice

Summary Male preference for large females as mates was demonstrated in the wood-boring weevil, Brentus anchorago (Coleoptera: Brentidae) by observation and by mate choice experiments in which the complicating factor of male rivalry was eliminated. Adult weight varied at least 23-fold in a large breeding aggregation in Panama. Drilling females guarded by males were larger than unguarded drilling females, and the number of males attending a drilling female increased with length of the female. Thus despite a sex ratio of about 1:1, males were unevenly distributed among the females. A male attending a female had on average about 1 rival male in his vicinity (Lloyd's Index of Mean Crowding). Male preference for large females in the absence of rival males was directly tested in choice arenas on the surface of the host tree. When a large and a small female were simultaneously presented, large and small males alike mated first with the large female. Male choice of large females is probably adaptive in Brentus anchorago because larger females lay larger eggs, which produce larger offspring in a competitive larval environment. Male choice in this species is associated with high male mating investment and time commitment per female, and not with high male parental investment.     

Achieving public participation in coastal zone environmental impact assessment

The case is made in this paper for early and integrative public participation in planning decisions concerning proposals major development in the zone. This is perhaps easy to subscribe to in theory but much more difficult in practice. Currently the extent and timing of public involvement in such decisions varies widely. A key benefit is the legitimacy that public participation provides to the planning process and, perhaps as a result, a variety of public involvement methodologies have emerged. Important considerations include which sections of the public to involve and at what stage in the decision-making process to involve them. The multidisciplinary nature of coastla zone issues will tend to engage a wide variety of stakeholder groups who in turn will influence the topics for discussion. A major port expansion proposal in the UK is used to illustrate a range of ways in which the public can be involved. The case study also highlights that public participation is an uncertain science, and to be successful can require skilled personnel and significant resources. The papper concludes that more guidance for developers, some standardisation of public involvement, training for facilitatiors and a more responsible stance from some environmental pressure groups would be advantageous. The complexity of coastal decision-making, tensions between science and policy, and the inter-dependency of coastal activities mutually reinforce the view that inclusive participation is an important issue for all coastal communities.     

Purification of triolein for use in semipermeable membrane devices (SPMDs)

Analyses of triolein-containing semipermeable membrane devices (SPMDs) have sometimes been impeded by interferences caused by impurities endemic to triolein that codialyze with the analytes. Oleic acid and methyl oleate have been the most troublesome of these impurities because of their relatively high concentrations in triolein and because significant residues of both can persist even after size exclusion chromatographic (SEC) fractionation. These residues have also been blamed for false-positive signals during bioindicator testing of SPMD dialysates. To prevent these problems, a simple, cost-effective procedure was developed for purifying triolein destined for use in SPMDs: the bulk triolein is repeatedly (6x) partitioned against methanol. Tests of the procedure show that 14C-oleic acid is completely removed from the triolein. After SEC fractionation, dialysates of standard-size SPMDs made with the purified triolein contain less than 5 microg of methyl oleate as compared to sometimes more than 500 microg for dialysates (also after SEC) of SPMDs made with unpurified triolein. Gas chromatographic analyses with flame ionization and electron capture detection show that the purification treatment also greatly reduces the number and size of peaks caused by unidentified contaminants in the triolein. Microtox basic assay of dialysates of SPMDs shows that those made with the purified triolein have lower acute toxicities than dialysates of SPMDs made with unpurified triolein. Yeast estrogen screen (YES) testing of SPMDs fabricated with unpurified and purified triolein demonstrates that the purification process removes all background estrogenic activity.     

Ammonia removal from facultative pond effluents in a constructed wetland and an aerated rock filter: performance comparison in winter and summer.

The effluent from a facultative pond loaded at 80 kg BOD ha(-1) day(-1) was treated in a subsurface horizontal-flow aerated rock filter (RF) and a subsurface horizontal-flow constructed wetland (CW) planted with Typha latifolia. Over a 12-month monitoring period BOD and TSS removals were higher, and effluent ammonia concentrations lower, in the RF than in the CW (> 75% vs. 25-75%, and 3.6 mg N L(-1) vs. 6 mg N L(-1), respectively). However, the ammonia concentration was lower in the CW effluent than in the aerated RF effluent during mid-July to mid-September (1.1 mg N L(-1) vs. 2.2 mg N L(-1)), but in winter it was higher than the influent concentration. Overall the performance of the aerated RF was better and more consistent than that of the CW.     

Dissipation of oxytetracycline, chlortetracycline, tetracycline and doxycycline using HPLC-UV and LC/MS/MS under aquatic semi-field microcosm conditions

A mixture of four tetracyclines; oxytetracycline (OTC), chlortetracycline (CTC), tetracycline (TC), and doxycycline (DC) was applied in fifteen 12000l outdoor microcosms at four treatment levels plus controls each with three replicates (n = 3). The dissipation times of parent compounds were monitored and half-lives (DT50) of 1-4 days, depending on treatment level were recorded. This is in accordance with half-lives from previous findings in bench-top experiments. Parent compound DT50, were determined using HPLC-UV. Furthermore, the samples were analyzed for ten different tetracycline products using LC/MS/MS. Two products were found for chlortetracycline; 4-epi-anh-chlortetracyline and the iso-chlortetracycline. Iso-forms were only found for CTC and only at the highest treatment (300 microg l(-1)). The half-lives, trajectories, and relative amounts of the products were analogous for all four tetracyclines. DT50 for products were less than 1.2 days. Formation of 4-epi-anh-tetracyclines, occurred at neutral to weak alkaline conditions.     

The contribution from shipping emissions to air quality and acid deposition in Europe

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO2, NOx, VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m(-2) yr(-1) over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met.     

Temporal variation in community interfaces: kelp-bed boundary dynamics adjacent to persistent urchin barrens

We examined, over 2 years, factors affecting the temporal stability of the lower limit of kelp beds (Alaria esculenta) at five subtidal sites in the Mingan Islands, northern Gulf of St. Lawrence. The position of the lower limit of the beds varied markedly among sites and over time and was largely controlled by the green sea urchin, Strongylocentrotus droebachiensis, which formed dense (up to 500 individuals m^–2) feeding fronts at the lower edge of the beds. These aggregations advanced over the kelp most rapidly during the summer (at rates as high as 2.5 m month^–1), and there appeared to be a threshold urchin biomass of ~5 kg m^–2 below which the fronts could not substantially reduce the limit of the beds. The fronts consisted mainly of large individuals, whereas smaller urchins predominated in the barrens zone below the kelp beds. At one site, we recorded large seasonal shifts in overall urchin densities, with large increases and decreases during the summer and winter, respectively. An urchin exclusion experiment indicated that algal recruitment in the barrens was two orders of magnitude greater in the absence than in the presence of urchins. The kelp Agarum cribrosum greatly restricted urchin movements, and the greater temporal stability of the kelp bed at one site appeared related to the gradual replacement of Alaria esculenta in the lower kelp bed by a large stand of Agarum cribrosum. We propose that perturbations by abiotic factors (e.g., ice scouring and water motion) trigger important but localized changes in urchin densities that, in turn, largely determine the limits of kelp bed distribution in this region of the Atlantic where urchin barrens are a persistent community state.Communicated by R.J. Thompson, St. Johns     

Chaotic genetic patchiness in an intertidal limpet,Siphonaria sp.

Variation of 4 polymorphic enzymes was studied for 2 yr (1978 and 1979) in an undescribed species of Siphonaria, a pulmonate limpet, from a rocky shore at Rottnest Island, Western Australia. Depending on the locus, significant genetic differences were found among sites along 50 m of shore, between high and low portions of the shore within sites, between adults and recruits, and between recruits in the 2 yr. This genetic heterogeneity does not follow a simple, consistent pattern, but forms a shifting, ephemeral genetic patchiness best described as chaotic. This patchiness may result from temporal variation of numbers and genotypes of recruits, which leads to the proposal that planktonic dispersal, although causing uniformity on a large scale, can give rise to fine-scale genetic patchiness.     

A field study of the toxicity of two oils and a dispersant to the mangrove Avicennia marina

The relative toxicities of Arabian Light crude oil, Tirrawarra crude oil, Dispersant BP-AB, and mixtures of oils and dispersant were assessed on 30 mangroves, Avicennia marina (Forsk.) Vierh. var. resinifera (Forst.) Bakh., in a coastal fringe on the eastern shore of Gulf St. Vincent, South Australia. Five treatments were applied: 100% Arabian Light crude oil, 100% Tirrawarra crude oil, Arabian Light crude oil plus dispersant (1:1), Tirrawarra crude oil plus dispersant (1:1) and 100% dispersant. Five mangroves were used for each of the treatments and five as controls. Defoliation, leaf damage, pneumatophore damage, flowering and fruiting were monitored for three years (September 1982–September 1985). Initially, the toxicity of both oils was increased by the addition of dispersant; Tirrawarra crude oil plus dispersant caused significant defoliation. 100% Tirrawarra crude oil was more toxic than 100% Arabian Light crude oil; the former caused significant leaf damage from Week 4 to Week 12 after treatment. After Week 49 production of new leaves was significantly greater in the Arabian Light crude oil plus dispersant treatment than with the Arabian Light crude oil. No such difference was found between the Tirrawarra treatments. Twelve to 26 weeks after treatment, partial pneumatophore damage was observed in all treatments. No atypical flower or fruit production was observed.