A predator has nonconsumptive effects on different life-history stages of a prey

Through a field experiment, we show that a predator has negative nonconsumptive effects (NCEs) on different life-history stages of the same prey species. Shortly before the recruitment season of the barnacle Semibalanus balanoides (spring), we established experimental cages in rocky intertidal habitats in Nova Scotia, Canada. The cages were used to manipulate the presence and absence of dogwhelks, Nucella lapillus, the main predators of barnacles. At the centre of each cage, we installed a tile where barnacle pelagic larvae could settle and the resulting recruits grow. Mesh prevented caged dogwhelks from accessing the tiles, but allowed waterborne dogwhelk cues to reach the tiles. During the recruitment season, barnacle larvae settled preferentially on tiles from cages without dogwhelks. In the fall, at the end of the dogwhelk activity period and once the barnacle recruits had grown to adult size, barnacle body mass was lower in the presence of dogwhelks. This limitation may have resulted from a lower barnacle feeding activity with nearby dogwhelks, as found in a previous study. The observed larval and adult responses in barnacles are consistent with attempts to decrease predation risk. In the fall, dogwhelk cues also limited barnacle reproductive output, a possible consequence of the limited growth of barnacles. Overall, the results of this study suggest that a predator might influence trait evolution in a prey mediated by NCEs on different life-history stages

The Effect of Water Temperature on Drilling and Ingestion Rates of the Dogwhelk \u3cem\u3eNucella lapillus\u3c/em\u3e Feeding on \u3cem\u3eMytilus edulis\u3c/em\u3e Mussels in the Laboratory

In highly seasonal intertidal habitats, changes in temperature through the year may drive substantial shifts in feeding and growth rates of organisms. For the dogwhelk Nucella lapillus, attacking and consuming Mytilus edulis mussels can take hours or days, depending on temperature. Handling time of dogwhelks feeding on mussels is therefore greatly affected by ocean temperature. I recorded attack time in the laboratory, partitioned into drilling and consumption time, for juvenile dogwhelks across a range of seawater temperatures representative of field seawater temperatures during the main growing seasons of summer and autumn. The combined length of a drilling attack and subsequent ingestion time tripled across the 10 °C decline in water temperatures from July through November, driven primarily by an increase in ingestion time. The observed reduction in handling time, coupled with projected sea surface warming in New England by the end of the twenty-first century, could extend the length of the growing season for Nucella and subsequently have cascading effects on the prey community

Mitochondrial channels: ion fluxes and more.

The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information