Surface glycoproteins serve as mate- and gamete-recognition molecules in some marine animals such as rotifers and sea urchins. We investigated the role of contact chemoreception of surface ...glycoproteins in mate recognition, mate-guarding, and spermatophore transfer in the marine harpacticoid Tigriopus japonicus Mori. Adult males accurately distinguished immature females from a pool of mixed-sex juveniles, and their behavior towards both live and dead females is described.
There are relatively few reports of the influence of environmental factors on the development and reproduction of harpacticoid copepods. In this study, we establish the effect of temperature (15, 20 ...and 25°C) and food concentration (83–3250 μg of carbon per litre of the alga
Isochrysis galbana Parke) on the reproduction of the marine harpacticoid
Tisbe battagliai Volkmann-Rocco. Reproductive lifespan, total number of broods and total number of offspring produced were recorded from females reared individually in the laboratory. Reduction in algal concentration from 3250 to 1300 μg C l
−1 resulted in significant decreases in the number of broods and offspring produced at 15 and 20°C, but not at 25°C. Algal concentrations lower than 1300 μg C l
−1 elicited significant reductions in reproductive output throughout the temperature range. There was an inverse relationship between female lifespan and temperature; females reared at 15°C lived approximately twice as long as those reared at 25°C. Increases in temperature (15–25°C) and algal concentration (520–3250 μg C l
−1) resulted in a reduction in the time interval between hatching of successive broods. Larger brood sizes were observed with increased algal concentration, however, there was no clear trend of temperature on brood size. The implication of these results to the development of harpacticoid populations in the natural environment is discussed.
In the northern Baltic Sea juvenile flounder,
Platichthys flesus, occur in high abundances on shallow sandy bottoms in late summer and autumn. They feed mainly on meiofauna and the ontogenetic switch ...to macrofaunal sized food occurs at a larger size here than in other areas, exemplifying the high relative importance of meiofauna. Consequently, juvenile
P. flesus in the Baltic feed for a longer period on meiofauna, and could thus be expected to have a stronger predation effect on the meiofaunal assemblages. In this study the predation effects of juvenile
P. flesus on meiofaunal abundances and community structure were studied using microcosms that were sampled repeatedly over a 3-week period. Significant differences between treatment and control were found for the total number of taxa, for abundances of harpacticoids, copepod nauplii and ostracods. The nematode community was not affected, but one genus,
Axonolaimus, was negatively affected by predation. The predation affected meiofaunal community structure as the major taxon diversity was significantly reduced. The results suggest that the meiofauna on shallow sandy bottoms may be structured by juvenile
P. flesus, and the combined predation pressure of juvenile flounder and other epibenthic predators in the area might be considerable. Microcosms are effective in testing natural predation, especially on meiofaunal communities, but field experiments should be conducted to account for the physical characteristics of the area studied.
The genus Morariopsishas a disjunct distribution. It has been found in south-eastern Europe and in the Baikal region in Russia. In Europe two species are known, both from the Dinaric region. They ...have been found in three caves only, but always in puddles filled with percolating water. This indicates that they inhabit an unsaturated karstic environment. A third species, Morariopsis dumontin.sp has now been found, in the same type of habitat, on several dates, in a small cave in central Slovenia. Males were recorded for the first time in this genus. The new species is related to Morariospsis kieferiPetkovski, 1959 from Dalmatia. The main differences are in the ornamentation of the furca and of the abdominal segments. P5 and particularly endopodite of P4 in males suggest a close relation between Morariaand Morariopsis. PUBLICATION ABSTRACT
Meiofauna were collected from the pools of small (0 order) streams in the Ouachita National Forest, Arkansas to examine the impact of forest harvest methods. The study streams and their watersheds ...(2-6 ha) were located in 14-16 ha forest stands that were selected based on comparability of stands. Five treatment stands were paired with adjacent undisturbed reference stands (10 total). Treatment stands were subjected to one of five harvest methods, listed in order of decreasing severity of harvest disturbance to the stands: (1) clearcut; (2) pine seed-tree; (3) pine shelterwood; (4) pine-hardwood group selection; and (5) pine single-tree selection. Although the mean density of meiofauna collected in 22 l samples pumped from pools was low (1 No. l ^sup -1^), significant differences were identified. Densities of total meiofauna, harpacticoid copepods, nauplii, ostracods and `other' meiofauna varied significantly by site and treatment (forest harvest). The highest densities of these taxa occurred at the single-tree treatment sites. Greater densities of meiofauna corresponded to greater diversity. The mean number of taxa per site was 11 with a range of 5-24. Rotifers, copepods, nematodes, ostracods and `other' meiofauna taxa were collected. The pattern of diversity of meiofauna at treatment sites from the least intensive (single-tree) to most intensive (clearcut) suggests a curve related to disturbance intensity.PUBLICATION ABSTRACT
Spilt oil from ships, naval accidents and establishments on shore is probably the most dramatic marine pollution, and is one of catastrophic disasters that happened frequently in aquatic ...environments. For evaluating the toxic effects of oils on marine ecosystem when a significant amount of oils is spilt in the sea, it is necessary to examine experimentally the degree of toxic impact of oils on marine organisms. A lot of extensive studies have been performed to examine the toxic effects of crude, refined and fuel oils and petroleum products on marine organisms such as commercially important fishes, crabs and shellfishes (e.g. Capuzzo 1987; Koyama et al. 1998). However, there is yet little information on the toxic effects of oils on small marine organisms such as copepods, that are important prey items for various aquatic animals. In the present study, we present here the acute toxicity (LC sub(50): the concentration resulting 50% of the exposed organisms being died) of Banker A and C refined oils on the demersal harpacticoid copepod Tigriopus japonicus, which is widely distributed along the coast of Japan, attaining dense populations in tide pools.
Two new Cletocamptus species, C. axi and C. schmidti, collected from lagoons of the Islands of Santa Cruz and Floreana, Galapagos Archipelago, are described and illustrated. A careful morphological ...analysis established a close relationship, or even the identity, with the widely distributed species C. deitersi. The two forms differ slightly from each other in their body ornamentation and in the chaetotaxy of the exopodites of pereiopods 3 and 4. Nevertheless, they fit well in the often-documented variability of C. deitersi. Their co-occurrence at one study site, however, suggests the existence of two distinct species, without intermediates, in the Galapagos Islands. A map showing the distribution of both species known so far in the area of investigation is provided.
In the main channel of the Upper Paraná River, four sampling sites were established according to the profile of the bottom. Samples were carried out monthly from July 1993 to February 1995 with a ...modified Petersen grab. Four species were found at four sites: Potamocaris bifida, P. bidens, P. bidentata and P. tridentata. Canonical correspondence analysis indicated differences in the preferred microhabitats of the Potamocaris species, mainly in regard to sand particle size in the main river channel. Bedform stability was the most important factor affecting the abundance of this community.PUBLICATION ABSTRACT
The post-embryonic development of Psammopsyllus maricae Cottarelli, Saporito & Puccetti, 1983 has been described for the first time. Six morphologically distinct naupliar and five copepodid stages ...were discerned and studied using light microscopy. Some features were also examined by scanning electron microscopy.PUBLICATION ABSTRACT
