Blends of (R)-3-hydroxyhexan-2-one and alkan-2-ones identified as potential pheromones produced by three species of cerambycid beetles

We present data indicating that three species of cerambycid beetles (subfamily Cerambycinae) produce the common cerambycine pheromone component (R)-3-hydroxyhexan-2-one as well as an alkan-2-one component, a possible new motif for cerambycid pheromone components. GC/MS analyses of headspace volatiles produced by male beetles indicated that Cyrtophorus verrucosus (Olivier) produced (R)-3-hydroxyhexan-2-one but also nonan-2-one at ~18 % of the hydroxyketone component, whereas Orwellion gibbulum arizonense (Casey) and Parelaphidion aspersum (Haldeman) produced decan-2-one at ~40 and 7 % of the amount of the hydroxyketone, respectively. In field bioassays, adult C. verrucosus were attracted by (R)-3-hydroxyhexan-2-one alone, but attraction was significantly enhanced by nonan-2-one. This effect was lost if the quantity of nonan-2-one exceeded 100 % of the hydroxyketone, suggesting that beetles could discern ratios of the two chemicals and were most strongly attracted to those approximating the blend produced by males. We suggest that nonan-2-one plays a role in the species specificity of the pheromone signal of C. verrucosus, and that decan-2-one plays a similar role in the semiochemical communication of O. g. arizonense and P. aspersum.     

Experimental evidence that workers recognize reproductives through cuticular hydrocarbons in the ant Odontomachus brunneus

Eusociality is characterized by a reproductive division of labor, wherein workers respond to the presence of reproductive individuals by refraining from reproduction themselves and restricting the reproductive efforts of others. Our understanding of how eusociality is maintained therefore depends on characterizing the mechanism by which workers detect the presence of a reproductive. Variations in cuticular hydrocarbons correspond to changes in reproductive ability in ants, and experimental studies are beginning to reveal the function of hydrocarbons as signals. In this study, we compare the cuticular hydrocarbon profiles of dominant and reproductive workers and queens of the ant Odontomachus brunneus with profiles of non-reproductive workers. Using split/reunification tests we document the existence of worker policing in both queenless and queenright colonies; supernumerary reproductives were treated aggressively by nestmates. Finally, we induce aggression and replicate queen-like submissive nestmate responses by supplementing the hydrocarbon profile of workers with (Z)-9-nonacosene, a compound that was significantly more abundant on the cuticles of reproductives. In three bioassays, we compare this manipulation to various control manipulations of the hydrocarbon profile and demonstrate that workers gauge the reproductive activity of nestmates through changes in their cuticular hydrocarbon profiles.     

分担责任:作为南非及其它发展中国家实现工业可持续发展的一种手段的共律政策手段

发展中国家的环境政策制订者是否应当力求采用"自律"和"共律"政策手段?本文确认了若要在那些还没有坚强环境执法传统的国家中采用此类手段则需要满足的一批体制条件和程序性条件.利用南非作为一个案例研究,提出了建立谈判协议的充分体制条件可能已经存在或者可以适当地加以发展.     

分担责任:作为南非及其它发展中国家实现工业可持续发展的一种手段的共律政策手段

发展中国家的环境政策制订者是否应当力求采用"自律"和"共律"政策手段?本文确认了若要在那些还没有坚强环境执法传统的国家中采用此类手段则需要满足的一批体制条件和程序性条件.利用南非作为一个案例研究,提出了建立谈判协议的充分体制条件可能已经存在或者可以适当地加以发展.     

Controlled food-chain transfer of dieldrin residues from phytoplankters to clams

The marine phytoplankter Dunaliella peircei was exposed to a concentration of 10.00μg/l of the chlorinated hydrocarbon insecticide dieldrin in sea-water solution. After 24 h exposure, the dieldrin residue level in the alga was 12.10μg/g, corresponding to a magnification factor of 1210. Clams, Rangia cuneata, allowed to feed on dieldrin-contaminated phytoplankters for 48 h exhibited a magnification of dieldrin residues in tissues up to 54 times greater than the concentration resulting from the resuspension of contaminated algal cells in clean seawater. This study demonstrates the transfer of dieldrin residues in a two-level food chain, i.e., from a contaminated alga to a bivalved mollusc allowed to feed on this alga.     

Predicted taxonomic patterns in pheromone production by longhorned beetles

Males of five species of three tribes in the longhorned beetle subfamily Cerambycinae produce volatile pheromones that share a structural motif (hydroxyl or carbonyl groups at carbons two and three in straight-chains of six, eight, or ten carbons). Pheromone gland pores are present on the prothoraces of males, but are absent in females, suggesting that male-specific gland pores could provide a convenient morphological indication that a species uses volatile pheromones. In this article, we assess the taxonomic distribution of gland pores within the Cerambycinae by examining males and females of 65 species in 24 tribes using scanning electron microscopy. Gland pores were present in males and absent in females of 49 species, but absent in both sexes of the remaining 16 species. Pores were confined to indentations in the cuticle. Among the species that had male-specific gland pores were four species already known to produce volatile compounds consistent with the structural motif. These findings support the initial assumption that gland pores are associated with the production of pheromones by males. There were apparently no taxonomic patterns in the presence of gland pores. These findings suggest that volatile pheromones play an important role in reproduction for many species of the Cerambycinae, and that the trait is evolutionarily labile.     

Conserved male-specific cuticular hydrocarbon patterns in the trap-jaw ant Odontomachus brunneus

Cuticular hydrocarbons have been identified as the source of sex-recognition signals for many insects, but for social insects, specifically ants, cuticular hydrocarbon profiles of males are often ignored. This study reports male-specific cuticular hydrocarbon patterns for the trap-jaw ant Odontomachus brunneus. Analysis of samples from four Florida populations demonstrated that male-specific overabundance of four hydrocarbons is conserved across populations despite population-level divergence of the remainder of the profile. In addition, hydrocarbon patterns unique to adult males were not present on the cuticle of final instar male larvae, indicating that male-specific profiles arise late in development. The pattern of an abundant subset of conserved cuticular hydrocarbons characteristic of males across divergent populations was compared to earlier findings of the conservation of fertility signals of females across these same populations.     

南非引进MMT:伴随预防措施和预防原则实施所带来的不确定性

Sasol,南非的一家跨国石化公司.当这家公司介绍燃料添加剂MMT来代替汽油中的铅后,便开始着手实施一套预防措施.该措施包括选择替代方法的评估,与外部利益相关者进行对话,同时着手开展研究和监控.尽管像Sasol这样的多家公司都签署了全球协议,承诺实施预防方法.但本文结论是预防措施的全面落实(即便预防措施还没有预防原则所要求的那么严格)还未被合作团体所完全接受.     

Bioenergetic responses of Chesapeake Bay white perch (<Emphasis Type="Italic">Morone americana</Emphasis>) to nursery conditions of temperature,dissolved oxygen,and salinity

Changes in the physical and chemical structure of estuaries control the aerobic scope for activity of coastal fishes and thereby influence the quality and extent of nursery habitats. We evaluated the effects of temperature, dissolved oxygen, and salinity on the ecophysiology of a species that completes its life cycle in estuaries: white perch (Morone americana), which were reared at treatment levels that emulated nursery conditions in the Chesapeake Bay. Salinity influenced only consumption rate and energy density, which were diminished at the highest salinity level (16). In hypoxic environments (≤40% saturation), routine metabolic rates increased as much as fourfold while growth rate decreased threefold and consumption rate decreased twofold. Experimental growth rates were within the range of growth rates observed in the field. Results indicate that hypoxia substantially reduces potential nursery production for a dominant estuarine species, through its influence on diminished aerobic capacity for growth and activity.