Interspecific Variation in Life History Relates to Antipredator Decisions by Marine Mesopredators on Temperate Reefs

As upper-level predatory fishes become overfished, mesopredators rise to become the new ‘top’ predators of over-exploited marine communities. To gain insight into ensuing mechanisms that might alter indirect species interactions, we examined how behavioural responses to an upper-level predatory fish might differ between mesopredator species with different life histories. In rocky reefs of the northeast Pacific Ocean, adult lingcod (Ophiodon elongatus) are upper-level predators that use a sit-and-wait hunting mode. Reef mesopredators that are prey to adult lingcod include kelp greenling (Hexagrammos decagrammus), younger lingcod, copper rockfish (Sebastes caurinus) and quillback rockfish (S. maliger). Across these mesopredators species, longevity and age at maturity increases and, consequently, the annual proportion of lifetime reproductive output decreases in the order just listed. Therefore, we hypothesized that the level of risk taken to acquire resources would vary interspecifically in that same order. During field experiments we manipulated predation risk with a model adult lingcod and used fixed video cameras to quantify interactions between mesopredators and tethered prey (Pandalus shrimps). We predicted that the probabilities of inspecting and attacking tethered prey would rank from highest to lowest and the timing of these behaviours would rank from earliest to latest as follows: kelp greenling, lingcod, copper rockfish, and quillback rockfish. We also predicted that responses to the model lingcod, such as avoidance of interactions with tethered prey, would rank from weakest to strongest in the same order. Results were consistent with our predictions suggesting that, despite occupying similar trophic levels, longer-lived mesopredators with late maturity have stronger antipredator responses and therefore experience lower foraging rates in the presence of predators than mesopredators with faster life histories. The corollary is that the fishery removal of top predators, which relaxes predation risk, could potentially lead to stronger increases in foraging rates for mesopredators with slower life histories

A Case of Subjective Cognitive Complaints in Older Adults: Anxiety, Stress and Aging in an Elderly Client

Amongst healthy cognitively normal elderly, subjective memory complaint is positively associated with sub-syndromal anxiety and depression. Late-life anxiety and cognition are related, such that anxiety is more prevalent in cognitively impaired elderly, elevated anxiety is related to poorer cognitive performance, and severity of anxiety symptoms predict future cognitive decline. While depressive symptoms alone are not related to cognitive deficits in the elderly, coexisting anxiety and depressive symptoms are associated with a poorer memory and slower processing speed. Objective assessment with a detailed history taking (including the individual’s baseline status) is essential to distinguish between neurocognitive disorder and normal cognition, delirium, major depressive disorder, specific learning disorder, and other neurodevelopmental disorders

Stability of Genetic and Environmental Contributions to Anxiety Symptoms in Older Adulthood

Anxiety symptoms are common in later life and are associated with diverse adverse health outcomes. Little is known about how genetic and environmental influences on anxiety symptoms might vary across older adulthood. The purpose of this study was to explore change and stability of contributions to anxiety symptoms across older adulthood. We examined data from the Swedish Adoption/Twin Study of Aging (SATSA). Between the years 1984 and 2010, 2,021 participants (including 753 complete twin pairs) completed up to seven assessments containing two measures of anxiety symptoms. Longitudinal genetic simplex models were fit to examine the stability and change in genetic and environmental influences. Amplification of genetic factors at ages 75–80 suggests tentative new genetic contributions to anxiety symptoms. These findings suggest that the heritability of anxiety symptoms may increase later in life. Physiological factors associated with aging are discussed as potential factors explaining this increase