Biology and host selection behaviour of the aphid hyperparasitoid Alloxysta victrix in association with the primary parasitoid Aphidius colemani and the host aphid Myzus persicae

The biology of the aphid hyperparasitoid Alloxysta victrix was investigated with respect to its interaction with the primary parasitoid Aphidius colemani and the host aphid Myzus persicae. Laboratory investigations of host selection behaviour indicated that naive A. victrix females could rapidly distinguish between unparasitized aphids and those parasitized by A. colemani, but showed little tendency to discriminate between aphids parasitized by the primary parasitoid three, five, seven, or ten days earlier (even though the latter were already mummified). Host suitability studies, in contrast, indicated that aphids parasitized by A. colemani became progressively less suitable as the primary parasitoid developed. When aphids were exposed to A. victrix more than seven days after being parasitized by A. colemani, survivorship of both primary and secondary parasitoid species decreased, with a significantly higher proportion of mummies producing no viable adult parasitoid of either species. The developmental period (egg to adult eclosion) of surviving hyperparasitoids was also longer in older host stages, and females developed significantly more slowly than males (14.2 days versus 13.6 days, respectively). The sex ratio of hyperparasitoid broods emerging from all host stages was consistently male-biased (31–46% female), but adult longevity was higher for females than for males (37.1 days versus 23.6 days).     

Long‐term Effects of Prenatal Stress and Glucocorticoid Exposure

There is a growing body of evidence suggesting that events during prenatal life can have long‐lasting effects on development and adult health. Stress during pregnancy is common and has been linked to increased incidence of a range of affective and behavioral outcomes in the offspring in later life and also some somatic outcomes. Glucocorticoids, and their actions on the fetus, which are regulated by placental 11β‐hydroxysteroid dehydrogenase type 2 (11β‐HSD2), are hypothesized to mediate these effects. Animal studies have demonstrated long‐term effects of stress and glucocorticoid administration on behavioral outcomes, as well as increased blood pressure, altered hypothalamic pituitary adrenal axis (HPA) function, and decreased glucose tolerance and brain size. In humans, licorice, which inhibits placental 11β‐HSD2 when consumed during pregnancy, has been shown to increase the risk of behavioral problems linked to altered HPA activity. Synthetic glucocorticoids administered during pregnancy to improve fetal lung maturity in threatened preterm birth have been shown to reduce birth weight and head circumference, but have not been linked to grosschanges in long‐term health todate. It is important to consider thelong‐term consequences of stress, and medication that mimics stress, during pregnancy. Birth Defects Research (PartC) 96:315–324, 2012. © 2013 Wiley Periodicals, Inc.     

A marine protected area network does not confer community structure resilience to a marine heatwave across coastal ecosystems

Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014–2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States. The network consists of 124 MPAs (48 no-take state marine reserves, and 76 partial-take or special regulation conservation areas) implemented at different times, with full implementation completed in 2012. We compared fish, benthic invertebrate, and macroalgal community structure inside and outside of 13 no-take MPAs across rocky intertidal, kelp forest, shallow reef, and deep reef nearshore habitats in California's Central Coast region from 2007 to 2020. We also explored whether MPA features, including age, size, depth, proportion rock, historic fishing pressure, habitat diversity and richness, connectivity, and fish biomass response ratios (proxy for ecological performance), conferred climate resilience for kelp forest and rocky intertidal habitats spanning 28 MPAs across the full network. Ecological communities dramatically shifted due to the marine heatwave across all four nearshore habitats, and MPAs did not facilitate habitat-wide resistance or recovery. Only in protected rocky intertidal habitats did community structure significantly resist marine heatwave impacts. Community shifts were associated with a pronounced decline in the relative proportion of cold water species and an increase in warm water species. MPA features did not explain resistance or recovery to the marine heatwave. Collectively, our findings suggest that MPAs have limited ability to mitigate the impacts of marine heatwaves on community structure. Given that mechanisms of resilience to climate perturbations are complex, there is a clear need to expand assessments of ecosystem-wide consequences resulting from acute climate-driven perturbations, and the potential role of regulatory protection in mitigating community structure changes.