Rekrutmen Box Mussel, Septifer Bilocularis L. Efek Substratum Dan Kepadatan Dewasa

An intertidal population of Septifer bilocularis L. was studied in Tongkeina, North Sulawesi, Indonesia. Open and closed cages were applied in field experiments to study the effects of four types of substrata on settling of S. bilocularis: live shells of adults, dead shells, coral rubble, and sand. Each substratum was tested with four levels of adult mussel density: 0, 10, 50, 100 individuals per compartment. The number of recruits as a function of cage, substratum, and adult density was analysed using Two-way ANOVA. The experiment showed that new recruits were affected by the substratum but not by the density of adults. The surface of adult box mussels was the most attractive substratum for recruits

Changes in endogenous hormones and seed-coat phenolics during seed storage of two Suaeda salsa populations

Changes in endogenous hormones and seed-coat phenolics during the storage of the dimorphic seeds of two Suaeda salsa populations were investigated. The results showed that, regardless of salinity, storage did not reduce the germination of brown or black seeds from an inland population, but it significantly decreased the germination of dimorphic seeds from an intertidal population. Abscisic acid (ABA) concentration was significantly higher in old seeds than in fresh seeds (freshly harvested dry seeds), whereas the opposite trend was evident for gibberellic acid (GA, including GA1 and GA3) concentration and GA : ABA ratio in both populations, and especially in the intertidal population. Concentration of seed-coat phenolics extracted from brown seeds was much higher than in black seeds in both populations, regardless of extracting time and storage. Storage increased the concentration of phenolics extracted from brown seeds in the inland population, whereas the opposite trend was evident in the intertidal population. Storage did not significantly change seed-coat phenolics extracted from black seeds relative to brown seeds in either population. The results indicated that changes in seed vigour during storage in dimorphic seeds of the two S. salsa populations are related to changes in endogenous hormones and seed-coat phenolics.

A survey of larval digeneans in the commonest intertidal snails from Northern Patagonian coast, Argentina

Over a two-years period, a survey was carried out in order to increase the knowledge of digeneans parasitising the commonest intertidal gastropods on the Patagonian coast, Southwestern Atlantic Ocean. A total of 4,725 gastropods were examined. Six species of digenean parasitising four snail species were found; four of them were registered for first time: Maritrema sp. 1 (Microphallidae) in Crepidula dilatata (Calyptraeidae), Parorchis sp. (Philophtalmidae) and sporocyst of Renicolidae in Trophon geversianus (Muricidae), and Diphterostomum sp. (Zoogonidae) in Buccinanops globulosus (Nassariidae). Two other species were found in Siphonaria lessoni (Siphonariidae): Maritrema sp. 2 and Hemiuridae. One snail species, Tegula patagonica (Trochidae) was not parasitised. These gastropods act as first intermediate host, and C. dilatata, S. lessoni and B. globulosus also frequently host metacercariae within the sporocyst. Overall prevalences varied from 0.16% of Diphterostomum in the intertidal population of B. globulosus to 33.45% of Maritrema sp. 1 in C. dilatata.