Temporal patterns in diversity and species composition of deep-sea benthic copepods in bathyal Sagami Bay,central Japan

Little is known about temporal changes in the diversity and species composition of deep-sea metazoan meiofauna and their relationships with changes in the food supply. Those changes were studied for benthic copepod assemblages based on 2-year time-series data at a bathyal site in Sagami Bay (1430 m depth), central Japan, where annual fluctuation in the abundance of benthic foraminiferans was previously observed. Species diversity of benthic copepods at the site was as high as, or slightly higher than, that observed at other deep-sea sites, but did not fluctuate temporally through the study period. Multivariate analyses did not reveal any clear seasonal or directional change occurring over the longer term in their species composition, although there was some consistent pattern. These results indicate a lack of, or only weak, seasonality in the diversity and species structure of the deep-sea benthic copepod assemblages, even though the fresh organic food supply fluctuates seasonally. They also suggest that there are differences between copepods and foraminiferans in the response to changes in environmental factors, and that spatial differences in the composition of copepod communities are greater than temporal ones at this deep-sea site.Communicated by T. Ikeda, Hakodate     

Photocatalytic removal of nitrogen oxides via titanium dioxide

We studied the removal of nitrogen oxides pollutants via TiO₂ Degussa P25 powder by photocatalysis. Parameters such as mass of catalyst, geometric irradiated surface, catalyst morphology, and thermal treatment were tested to explain the photocatalytic concentration decrease of nitrogen oxides. According to our working conditions, the conversion rates increased until an optimal value of the TiO₂ weight, 35% of NO concentration and around 20% of NOx, was decomposed by the photocatalysis. The NOx removal increased proportionally with the irradiated geometric surface. The structural transformation of anatase to rutile performed by thermal treatment involved the decrease of the photocatalytic activity.     

Phylogenetic relationships of deep-sea mussels of the genus<Emphasis Type="Italic"> Bathymodiolus</Emphasis> (Bivalvia: Mytilidae)

We examined phylogenetic relationships among three Bathymodiolus species in Japanese waters and Bathymodiolus spp. from the Manus Basin by two different approaches. Two-dimensional gel electrophoresis allowed us to compare 263–407 (average=318) proteins, giving comprehensive information on genetic distances among the species. The neighbor-joining tree presented two clusters: (1) B. japonicus and B. platifrons and (2) B. septemdierum and B. sp. Members of the first cluster contain methanotrophic endosymbiotic bacteria and members of the second cluster contain thioautotrophic endosymbionts. DNA sequencing of a fragment (415 bp) of mitochondrial cytochrome c oxidase subunit I (COI) provided a neighbor-joining tree with the same topology as that derived from protein analysis. Inspection of intraspecific variation in COI in B. japonicus and B. platifrons revealed no genetic differentiation between mussel populations of either species from cold-water seeps versus hydrothermal vents, suggesting high adaptability of these Bathymodiolus species to deep-sea chemosynthetic environments. Our results indicated genetic exchanges between mussels from distant localities, suggesting that a limited dispersal capability of the larvae is not the likely factor leading to speciation events in these Bathymodiolus species.Communicated by T. Ikeda, Hakodate     

Environmental Conflicts and the SLAPP

A citizen has the right to challenge a firm's actions regarding development plans or violations of environmental laws. Firms have responded with the SLAPP—Strategic Lawsuit Against Public Participation. Fearing the loss of the Constitutional Right to Petition, several U.S. states have or are considering explicitly restricting the SLAPP. For a class of environmental conflict models with one-sided asymmetric information, our results suggest that restricting the SLAPP does not increase the efficiency of the dispute.     

Group size and ectoparasitism affect daily survival probability in a colonial bird

Little is known in general about how group size or ectoparasitism affect survival in colonial animals. We estimated daily within-season survival probabilities for nesting adult and recently fledged juvenile cliff swallows (Petrochelidon pyrrhonota) at 239 colonies from 1983 to 2003 in southwestern Nebraska, USA. Some colonies had been fumigated to remove ectoparasites. We conducted mark-recapture at each colony site to estimate daily survival. There were no systematic differences between males and females in daily survival. Adults and juveniles occupying parasite-free colonies had, on average, 4.4% and 62.2% greater daily survival, respectively, than their counterparts in naturally infested colonies. Daily survival of all birds increased with colony size for both parasite-free colonies and those under natural conditions, although the effect was stronger for adults at fumigated sites and for juveniles. Average daily survival probability for adults tended to increase during warmer and drier summers. Although daily survival varied at some sites over the course of the nesting cycle, there were no strongly consistent within-year temporal effects on survival. Even small differences in daily survival probability can translate into large effects on mean lifespan. The deleterious effects of ectoparasites on daily survival within the season represent a previously unknown cost of ectoparasitism. The increase in within-season survival with colony size reflects the net effects of many costs and benefits associated with colony size. Ectoparasitism is probably the most important cost that tends to partly balance the positive effects of large colonies. The greater survival of cliff swallows in the larger colonies is a previously unknown advantage of colonial nesting.Communicated by P. Heeb     

Female courtship in the Banggai cardinalfish: honest signals of egg maturity and reproductive output?

Despite the vast literature on male courtship behaviour, little is known about the function and information content of female courtship behaviour. Female courtship behaviour may be important in many species, particularly where both sexes invest heavily in the offspring, and if such behaviours contain honest information regarding a females potential reproductive investment, they may be particularly important in male mate choice. Using observations of two female courtship behaviours (the rush and the twitch) from experimental pairings in the Banggai cardinalfish (Pterapogon kauderni), I addressed the question of whether these courtship behaviours contained information on female reproductive output (clutch weight) and egg maturity (proximity to spawning), traits commonly associated with male mate choice. I especially focused on the importance of these courtship behaviours in relation to other female characters, such as size and condition, using multiple regression. I found that one of these behaviours, the rush, was strongly associated with fecundity, whereas size, condition and the twitch were not. Further, I found that the twitch behaviour was associated with how close to actual spawning a female was. The results suggest that female courtship behaviour may convey highly important information in a mate choice context. I discuss the adaptive value of honest information in female courtship behaviour in light of these results.Communicated by K. Lindström     

Time course of pyrrolizidine alkaloid sequestration in <Emphasis Type="Italic">Longitarsus</Emphasis> flea beetles (Coleoptera,Chrysomelidae)

Summary. Several species of Longitarsus take up, metabolize and store pyrrolizidine alkaloids (PAs) from their host plants. In feeding experiments using radioactively labeled PAs of different types we examined the time course of the sequestration process in L. jacobaeae and L. aeruginosus. We found that adapted species efficiently store PAs for at least two weeks without major losses. During that time, there is virtually no change in the ratio of tertiary alkaloids to stored non-toxic N-oxides, regardless of chemical form fed to the beetles. This implies a transient N-oxidation process where the alkaloids are only temporarily accessible to the enzyme. A dissection experiment with L. aeruginosus six days after uptake of labeled PAs showed that the tertiary alkaloids are not found in the hemolymph but are stored in the elytra and other body compartments. This conforms with earlier experiments that localized the enzymes site of action in the hemolymph. Furthermore we show that different total alkaloid doses in the diet of L. jacobaeae and the potentially less adapted L. succineus do not affect the ratio of recovered N-oxides to tertiary molecules. Thus, the efficiency of the N-oxidizing enzyme is not dependent on the concentration of alkaloids offered.     

Reproductive strategies of two deep-sea gastropod species from the Porcupine Seabight (Northeast Atlantic)

Two species of small gastropods (<6 mm in length), Amphissa acutecostata (Philippi, 1844) and Gymnobela subaraneosa (Dautzenberg and Fischer, 1896), widely distributed in the northeast Atlantic, were found in large numbers in the Porcupine Seabight (Northeast Atlantic). Except for some aspects of taxonomy and distribution, as well as some data on larval development, the biology of these species is unknown. This study describes basic aspects of the life-history strategies of both species. Histological studies showed that oocyte and sperm development in both species was similar to the gametogenetic patterns observed in other deep-sea gastropods. In females, oogonia proliferated in the germinal epithelium and developed into previtellogenic oocytes (30–40 m), which grew into vitellogenic primary oocytes. Vitellogenic oocytes were covered by a thin layer of follicle cells involved in the vitellogenic processes. The maximum size for mature oocytes was 99.06 m for A. acutecostata and 114.82 m for G. subaraneosa. In A. acutecostata most of the volume of the ovary was occupied by previtellogenic and early vitellogenic oocytes, whereas in G. subaraneosa most of the volume was filled by large vitellogenic oocytes. Both species showed quasi-continuous production of oocytes. The oocyte size-frequency diagrams suggested a continuous release of a small number of oocytes throughout the year for A. acutecostata, and asynchronous periodic spawning events for G. subaraneosa. Gonad development and gametogenesis could be strongly affected by presence of parasites in one of the populations of G. subaraneosa.Communicated by J.P. Thorpe, Port Erin     

广州市东部地区土地资源承载力研究

应用土地遥感解译图，对广州市东部地区的土地利用现状进行分析；并根据广州总体发展战略规划，进行了东部地区土地资源承载力研究。结果表明，如果2020年广州市东部地区耕地保有面积达到基本农田保护区面积。则城市发展所需的土地资源可以满足规划要求。城市发展建设应先占用那些质量较差的农用地。