Assessing the risk of Eccritotarsus eichhorniae to pickerelweed,Pontederia cordata in North America

The mirid Eccritotarsus eichhorniae is a newly described species with potential as a biological control agent for water hyacinth, Eichhornia crassipes, in North America. A series of quarantine-based studies quantified E. eichhorniae usage of Pontederia cordata with no-choice, adult choice, nymph choice, multi-generation, and impact tests. Although greater numbers of E. eichhorniae adults developed on E. crassipes in two separate no-choice trials, some E. eichhorniae were able to complete development on P. cordata in both trials. Adults showed a clear oviposition preference for E. crassipes and F₁ progeny reduced the mean relative growth rate of E. crassipes but not P. cordata. Naïve nymphs were more likely to leave P. cordata for E. crassipes but not all nymphs left P. cordata when given a choice. Both multi-generation trials showed a rapid increase in the density of adults and nymphs on E. crassipes over four to five generations while population densities on P. cordata did not change, indicating that this insect can maintain populations on this plant. The modest damage inflicted by a sibling species on E. crassipes, coupled with the ability of E. eichhorniae to persist on P. cordata, may pose an interpretation challenge to U.S. regulatory agencies concerned with non-target impacts by biological control agents. Another option for the continuing efforts to increase the biological control of E. crassipes is to prioritise the evaluation of other potential agents like Taosa longula Remes Lenicov (Homoptera: Dictopharidae) or Thrypticus truncatus Bickel and Hernández (Diptera: Dolichopodidae) over E. eichhorniae.     

Differential response to larval crowding of a long‐ and a short‐lived medfly biotype

Response of endophytic fruit fly species (Tephritidae) to larval crowding is a form of scramble competition that may affect important life history traits of adults, such as survival and reproduction. Recent empirical evidence demonstrates large differences in adult life history traits, especially longevity, among Mediterranean fruit fly (Ceratitis capitata; "medfly") biotypes obtained from different regions of the world. However, whether the evolution of long lifespan is associated with response to stress induced by larval crowding has not been fully elucidated. We investigated, under constant laboratory conditions, the response of a short‐ and a long‐lived medfly biotypes to stress induced by larval crowding. Survival and development of larvae and pupae and the size of resulting pupae were recorded. The lifespan and age‐specific egg production patterns of the obtained adults were recorded. Our findings reveal that increased larval density reduced immature survival (larvae and pupae) in the short‐lived biotype but had rather neutral effects on the longed‐lived one. Only larvae of the long‐lived biotype were capable of prolonging their developmental duration under the highest crowding regime to successfully pupate and emerge as adults. Response of emerging adults to larvae crowding conditions was similar in the two medfly biotypes. Those individuals emerging from high larval density regimes had reduced longevity and fecundity. Long‐lived biotype individuals, however, appeared to suffer a higher cost in longevity compared with the short‐lived one. The importance of our findings to understand the evolution of long lifespan is discussed.     

Cognitive Coping Style and the Effectiveness of Distraction or Sensation-Focused Instructions in Chronic Pain Patients

AimThis study set out to investigate whether cognitive coping strategies that match participants’ preferred coping style effectively reduce pain intensity and situational anxiety in a population of people with chronic pain.MethodChronic pain patients (N = 43) completed questionnaires on coping style, pain intensity, self-efficacy, and situational/trait anxiety. Participants were classified as Monitors (n = 16) or Blunters (n = 19) based on their Miller Behavioural Style Scale score. Participants were then provided with an audiotaped intervention in which they were instructed to focus on pain sensations or to engage in a distraction task and then to rate the pain intensity and their anxiety during and after the attentional focus and distraction conditions. The two interventions were each completed by all participants, having been presented in counterbalanced order.ResultsFindings revealed that Monitors’ level of anxiety decreased following a congruent (i.e., sensation-focused) intervention. No effects were obtained in terms of perceived pain. For blunters, however, their perceived levels of anxiety and pain did not attenuate following a congruent, distraction-focused intervention.ConclusionAmong persons experiencing chronic pain, tailoring coping strategies to match an individual’s preferred coping style–in particular, those with a high level of monitoring–may enhance the benefit of psychological approaches to management of anxiety.     

Self-association of human apolipoproteins A-I and A-II and interactions of apolipoprotein A-I with bile salts: quasi-elastic light scattering studies

We employed quasi-elastic light scattering (QLS) to systematically study the aqueous self-association of human apolipoproteins A-I and A-II (apo A-I and apo A-II) and the interactions of apo A-I with common taurine-conjugated bile salts. Self-association of apo A-I was promoted by increases in apolipoprotein concentration (0.09-2.2 mg/mL) and ionic strength (0.15-2.0 M NaCl), inhibited by increases in temperature (5-50 degrees C) and guanidine hydrochloride concentration (0-2.0 M), and unaffected by hydrostatic pressures up to 500 atm. The mean hydrodynamic radius (Rh) of apo A-I micelles ranged from 38 A to a maximum asymptotic value of 68 A. We examined several possible models of apo A-I self-association; the model that best fitted the Rh values assumed that apo A-I monomers first interacted at low concentrations to form dimers, which then further associated to form ring-shaped limiting octamers. Comparison of the temperature-dependent and ionic strength dependent free energy changes for the formation of octamers from apo A-I dimers suggested that hydrophobic forces strongly favored self-association and that electrostatic repulsive forces were only weakly counteractive. Apo A-II self-association was also promoted by increases in apolipoprotein concentration (0.2-1.8 mg/mL) and inhibited by increases in guanidine hydrochloride concentration (0-1.0 M) but was unaffected by variations in temperature (10-37 degrees C): the largest Rh values observed were consistent with limiting tetramers. As demonstrated by equilibrium dialysis, bile salts in concentrations below their critical micellar concentrations (cmc) bound to apo A-I micelles but had no effect upon apo A-I self-association, as inferred from constant Rh values. When bile salt concentrations exceeded their aqueous cmc values, a dissociation of apo A-I micelles resulted with the formation of mixed bile salt/apo A-I micelles. These studies support the concepts that apo A-I and apo A-II form small dimeric micelles at low concentrations that grow sharply to reach limiting sizes over a narrow concentration range. The influences of bile salt concentration and species upon these micelles have relevance to the plasma transport of bile salts in high-density lipoproteins and to the physical-chemical state of apo A-I and apo A-II molecules in native biles.     

Characterizing the role benthos plays in large coastal seas and estuaries: A modular approach

Ecologists studying coastal and estuarine benthic communities have long taken a macroecological view, by relating benthic community patterns to environmental factors across several spatial scales. Although many general ecological patterns have been established, often a significant amount of the spatial and temporal variation in soft-sediment communities within and among systems remains unexplained. Here we propose a framework that may aid in unraveling the complex influence of environmental factors associated with the different components of coastal systems (i.e. the terrestrial and benthic landscapes, and the hydrological seascape) on benthic communities, and use this information to assess the role played by benthos in coastal ecosystems. A primary component of the approach is the recognition of system modules (e.g. marshes, dendritic systems, tidal rivers, enclosed basins, open bays, lagoons). The modules may differentially interact with key forcing functions (e.g. temperature, salinity, currents) that influence system processes and in turn benthic responses and functions. Modules may also constrain benthic characteristics and related processes within certain ecological boundaries and help explain their overall spatio-temporal variation. We present an example of how benthic community characteristics are related to the modular structure of 14 coastal seas and estuaries, and show that benthic functional group composition is significantly related to the modular structure of these systems. We also propose a framework for exploring the role of benthic communities in coastal systems using this modular approach and offer predictions of how benthic communities may vary depending on the modular composition and characteristics of a coastal system.