When males outlive females Archive Data

Lifespan (LS) data for D. magna clones (K), (T) and (B), for males (M) and females (F), recorded at temperature (16) and (20) degrees. The death of an individual was either observed (fin=1), or an individual lived to the end of the experiment (fin=0)

Data from: When males outlive females: sex-specific effects of temperature on lifespan in a cyclic parthenogen

Lifespans of males and females frequently differ as a consequence of different life history strategies adopted to maximize fitness. It is well visible in cyclic parthenogens, such as water fleas of the genus Daphnia, where males appear in the population usually only for periods when receptive females are available. Moreover, even within one sex, different life history strategies and mechanisms regulating lifespan may exist. Previous studies suggested that Daphnia males may regulate their lifespan by staying in colder waters than females. We hypothesize that such behavioural mechanism should be associated with stronger reaction to low temperature that is greater lifespan extension in males than in females. In this study, we monitored survivorship of Daphnia magna females and males of three clonal lines cultured at 16 or 20°C. The results did not provide a species-level corroboration of our hypothesis, instead, they revealed very strong intraspecific differences in the responses of male and female lifespan to temperature change. They further suggest the existence of parallel life history strategies, hypotheses whose tests would bring new insights into the ecology of males in cyclic parthenogens

A massive harmful algal bloom on the U.S. West Coast and the future of monitoring for early warning

In 2015, a massive bloom of the marine diatom Pseudo-nitzschia, stretching from central California to northern British Columbia, resulted in significant impacts to coastal resources and marine life. This bloom was first detected in early May 2015, when Washington closed its scheduled razor clam digs on coastal beaches. It is the largest bloom in at least the past 15 years, and concentrations of domoic acid in seawater, some forage fish, and crab samples were the highest ever reported for this region. By mid-May, domoic acid concentrations in Monterey Bay, California, were 10 to 30 times the level that would be considered high for a normal Pseudo-nitzschia bloom. Impacts to coastal communities and marine life include razor clam and Dungeness crab closures in multiple states, impacting commercial, recreational and subsistence harvesters, anchovy and sardine fishery health advisories in some areas of California, and sea lion strandings in California, Oregon, and Washington. Causes of the bloom’s severity and coastwide distribution include Pseudo-nitzschia’s resilience in the unusually warm, nutrient depleted Pacific Ocean water, combined with perfectly timed storms, followed by the transition to spring upwelling conditions. This bloom highlights the need for an early warning system that can provide forecasts of the increased risk for toxic events. The Environmental Sample Processor (ESP) offers near real-time (~3 h), quantitative, automated, in-situ detection capabilities by filtering water samples and analyzing them onboard. Specific HAB target organisms, including Pseudo-nitzschia, are detected using DNA and RNA-based methodologies, and HAB toxins are detected using antibody-based assays. In the summers of 2012, 2013 and 2015, six ESP deployments (totaling ~110 days) provided near real-time monitoring of HABs in the Salish Sea to support proactive fisheries management efforts. In 2016, an ESP will be deployed on the Northwest Enhanced Moored Observatory off the Washington coast to monitor and provide early warning of toxic Pseudo-nitzschia blooms for coastal managers. Data generated by the ESP will be rapidly distributed to end-users via online data visualization tools hosted by the Pacific Northwest regional ocean observing system of the Integrated Ocean Observing System