Patch leaving decision rules in parasitoids: do they use sequential decisional sampling?

Within the framework of optimal foraging theory, models assume that parasitoid insects are able to evaluate the quality of the patch in which they are currently searching for hosts and the travel time between patches. They can adjust their residence time in consequence. Simple and more realistic decision mechanisms that induce behavior compatible with the predictions of these models have been proposed for a number of species. Most of these decision mechanisms only take into account the presence of unparasitized hosts. Here, we studied the consequences for leaving patches containing different proportions of unparasitized and parasitized hosts. We support the hypothesis that parasitoids sample their environment and we propose a binomial sequential model, based on the type of host encountered (unparasitized or parasitized) instead of on the time spent in a patch, to explain the giving-up behavior of a parasitoid in a patch. A motivational incremental/decremental stochastic process is proposed to explain a possible mechanism of the apparent sampling scheme followed by the insect. The empirical data support the hypothesis of a sequential, decisional, binomial sampling scheme performed with a limited memory. This memory is, in fact, more an effect of habituation than the "true memory" of the parasitoid. The theoretical model was applied to real data obtained with an encyrtid parasitoid. These data were also compared to realizations of the incremental/decremental process.     

Effects of Motorized Tourboats on the Behavior of Nonbreeding American Flamingos in Yucatan, Mexico

We assessed the effect of motorized tourboats on the behavior of nonbreeding American flamingos (  Phoenicopterus ruber ruber) in the Celestún Estuary, a Special Biosphere Reserve in Yucatán, Mexico, from November 1994 through February 1995. We measured these effects by comparing activity budgets between flocks of flamingos disturbed and undisturbed by tourboats. Disturbance reduced feeding time from 40% before disturbance to 24% after, a 40% loss. Boat disturbance increased alert behavior by 400%. Tourboats averaged 13 per day and caused a disturbance 75% of the time or 3.3 hours per day. Potential loss of feeding time for individuals was estimated at 13% but is likely much higher on days with excessive numbers of tourboats. Flamingos returned to normal feeding rates (40%) within 20 minutes after disturbance. Most tourists (52%) were from Mexico, followed by Germany (14%), and 88% of Mexican visitors were willing to pay an entrance fee to the Celestún Reserve. Conservation efforts should focus on education of tourboat operators to reduce disturbance to flamingos, education of tourists through a visitor's center and brochures produced in Spanish and English, and expanded involvement of local people.     

Interactions of secondary amines with bentonite clay and humic materials in dilute aqueous systems

The speciation of dimethylamine, diethylamine, dibutylamine, and diethanolamine on bentonite clay saturated with 1) Na and Ca cations, 2) dodecyltrimethylammonium cation, and 3) tannic acid, and on humic acid and peat, has been studied. Adsorption isotherms were determined and the effect of ionic strength and pH on the adsorption were studied. The results show that the amines react with the particulates by ion exchange mechanisms. Hydrogen bonding seems to also contribute to the binding of dibutylamine.     

Rapid assessment of insect pollination services to inform decision-making

Pollinator declines have prompted efforts to assess how land-use change affects insect pollinators and pollination services in agricultural landscapes. Yet many tools to measure insect pollination services require substantial landscape-scale data and technical expertise. In expert workshops, 3 straightforward methods (desk-based method, field survey, and empirical manipulation with exclusion experiments) for rapid insect pollination assessment at site scale were developed to provide an adaptable framework that is accessible to nonspecialist with limited resources. These methods were designed for TESSA (Toolkit for Ecosystem Service Site-Based Assessment) and allow comparative assessment of pollination services at a site of conservation interest and in its most plausible alternative state (e.g., converted to agricultural land). We applied the methods at a nature reserve in the United Kingdom to estimate the value of insect pollination services provided by the reserve. The economic value of pollination services provided by the reserve ranged from US$6163 to US$11,546/year. The conversion of the reserve to arable land would provide no insect pollination services and a net annual benefit from insect-pollinated crop production of approximately $1542/year (US$24∙ha^–1∙year^–1). The methods had wide applicability and were readily adapted to different insect-pollinated crops: rape (Brassica napus) and beans (Vicia faba) crops. All methods were rapidly employed under a low budget. The relatively less robust methods that required fewer resources yielded higher estimates of annual insect pollination benefit.     

Surface functionalization of natural hydroxyapatite by polymerization of β-cyclodextrin: application as electrode material for the electrochemical detection of Pb(II)

Environmental Science and Pollution Research - A composite material prepared by polymerization of β-cyclodextrin (β-CD) on the surface of natural hydroxyapatite using citric acid as cross...