Antennal olfactory responses of black turpentine beetle,Dendroctonus terebrans (Olivier), to bark beetle pheromones and host terpenes

Electroantennograms (EAGs) were recorded from male and female black turpentine beetles,Dendroctonus terebrans (Olivier), exposed to bark beetle pheromones and host terpenes. The dose-response curves indicated similarities in the receptor mechanisms for both sexes for each compound. Antennal sensitivity was greatest toendo-brevicomin, which correlates with the importance of the compound in the behavior of the beetles. At above-threshold concentrations, EAGs were greatest toendo-brevicomin and frontalin, suggesting a large population of antennal receptors for these compounds. A large population of receptors would be expected for compounds that play such a significant role in this beetle's behavior. Beetles were also shown to have receptors that respond to theIps pheromones, ipsenol, and ipsdienol.Research done in part while in the Department of Entomology, Texas Agricultural Experiment Station (TAES), Texas A&M University, and supported in part through McIntire-Stennis project 1525, USDA-CR Grant 85-CRCR-1-1856, and NATO Collaborative Research Grant 86-0710. All programs of the Agricultural Experiment Station are available without regard to race, ethnic origin, sex, or age. Virginia Polytechnic Institute and State University does not discriminate against employees, students, or applicants on the basis of race, sex, handicap, age, veteran status, national origin, religion or political affiliation.     

Identification of a Widespread Monomolecular Odor Differentially Attractive to Several <Emphasis Type="Italic">Delia Radicum</Emphasis> Ground-dwelling Predators in the Field

Dimethyl disulfide (DMDS) was identified as a major volatile constituent of Brassica napus roots heavily infested by Delia radicum, the cabbage root fly. Attractiveness of this widespread compound was tested in the field in a naturally complex odorous environment. By using an original setup especially designed for ground dwelling beetles, different concentrations of the pure molecule as well as attractiveness of the natural blend emitted by the rotten part of infested roots were tested simultaneously. The use of general linear model (GLM) statistics permitted us to finely discriminate the responses among the different treatments. The main predators of D. radicum (i.e., two staphylinids Aleochara bilineata and Aleochara bipustulata and carabid beetles of the genus Bembidion) were significantly attracted by DMDS, but responded in different ways to the natural blend and to the different concentrations tested. The dose–response curves were similar for the two staphylinids. However, whereas A. bilineata was more attracted by the natural volatile blend than by its preferred DMDS concentration, A. bipustulata was attracted as much by the natural blend as by its preferred DMDS concentration. Carabid beetles exhibited a different response. They were not attracted by the natural blend, but responded to a wider range of DMDS concentrations that included low concentrations that did not attract the staphylinid beetles. These results are discussed according to the potential resources searched by each taxon studied and their specificity for the resources. The possible use of DMDS for enhancing biological control of D. radicum is mentioned.     

Comparative Study of Prey Predator Algorithm and Firefly Algorithm

Metaheuristic algorithms are found to be promising for difficult and high dimensional problems. Most of these algorithms are inspired by different natural phenomena. Currently, there are hundreds of these metaheuristic algorithms introduced and used. The introduction of new algorithm has been one of the issues researchers focused in the past fifteen years. However, there is a critic that some of the new algorithms are not in fact new in terms of their search behavior. Hence, a comparative study in between existing algorithms to highlight their differences and similarity needs to be studied. Apart from knowing the similarity and difference in search mechanisms of these algorithms it will also help to set criteria on when to use these algorithms. In this paper a comparative study of prey predator algorithm and firefly algorithm will be discussed. The discussion will also be supported by simulation results on selected twenty benchmark problems with different properties. A statistical analysis called Mann—Whitney U 2 test is used to compare the algorithms. The theoretical as well as simulation results support that prey predator algorithm is a more generalized search algorithm, whereas firefly algorithm falls as a special case of prey predator algorithm by fixing some of the parameters of prey predator algorithm to certain values.     

Rater (dis)agreement on risk assessment measures in sexually violent predator proceedings: Evidence of adversarial allegiance in forensic evaluation?

Actuarial risk assessment measures are often admitted in court, partly because strong psychometric properties such as interrater agreement suggest that they increase reliability and reduce subjectivity in forensic evaluation. But how strong is rater agreement when raters are retained by opposing sides in adversarial legal proceedings? The authors review sexual offender civil commitment cases in which opposing evaluators reported scores on the STATIC-99, the Minnesota Sex Offender Sex Offender Screening Tool—Revised (MnSOST–R), or the Psychopathy Checklist—Revised (PCL–R) for the same individual. Differences between scores from opposing evaluators were often greater than expected based on rater agreement values reported in the instrument manuals and research literature. Score differences were often in a direction that supported the party who retained each evaluator. Rater agreement was stronger for the STATIC-99, intraclass correlation coefficient ([ICC]A,1) = .64; than for the MnSOST–R, ICC(A,1) = .48; and the PCL–R, ICC(A,1) = .42. STATIC-99 scores appeared less influenced by adversarial allegiance. Overall, however, results raise concern that an evaluator's adversarial allegiance could influence some assessment instrument scores in forensic evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representations of odors in the rat orbitofrontal cortex change during and after learning.

Cells in the orbitofrontal cortex (OF) respond to odors and their associated rewards. To determine how these responses are acquired and maintained, the authors recorded single OF units in rats performing an odor discrimination task. Approximately 64% of all cells differentiated between rewarded and nonrewarded odors. These odor valence responses changed during learning in 26% of all cells, and these changes were positively correlated with improving performance, supporting the idea that the information provided by these cells is used in learning the task. However, changes in odor valence responses were also observed after learning, and included not only increases in odor discrimination, but also decreases or mixed increases and decreases. Thus, only some of the changes in firing reflected acquisition of the task. The results suggest that learning triggers a continuing reorganization of OF neural ensembles representing odors and their rewards. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory predator recognition in predator-na?ve gray mouse lemurs (Microcebus murinus).

Olfactory cues of predators, such as feces, are known to elicit antipredator responses in animals (e.g., avoidance, activity). To date, however, there is little information on olfactory predator recognition in primates. We tested whether the odor of feces of different predator categories (historical Malagasy predators and introduced predators) and of Malagasy nonpredators (control) induces antipredator behavior in captive born, predator-na?ve gray mouse lemurs. In an olfactory predator experiment a mouse lemur was exposed to a particular odor, fixed at a preferred location, where the animal was trained to get a reward. The behavior of the mouse lemur toward the respective stimulus category was videotaped and quantified. Results showed that mouse lemurs avoided the place of odor presentation when the odor belonged to a predator. They reacted with a significantly enhanced activity when exposed to odors of carnivores compared to those of nonpredatory controls. These findings are in favor of a genetic predisposition of olfactory predator recognition that might be based on the perception of metabolites from meat digestion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prey predator hyperheuristic

Prey predator algorithm is a population based metaheuristic algorithm inspired by the interaction between a predator and its prey. In the algorithm, a solution with a better performance is called best prey and focuses totally on exploitation whereas the solution with least performance is called predator and focuses totally on exploration. The remaining solutions are called ordinary prey and either exploit promising regions by following better performing solutions or explore the solution space by randomly running away from the predator. Recently, it has been shown that by increasing the number of best prey or predator, it is possible to adjust the degree of exploitation and exploration. Even though, this tuning has the advantage of easily controlling these search behaviors, it is not an easy task. As any other metaheuristic algorithm, the performance of prey predator algorithm depends on the proper degree of exploration and exploitation of the decision space. In this paper, the concept of hyperheuristic is employed to balance the degree of exploration and exploitation of the algorithm. So that it learns and decides the best search behavior for the problem at hand in iterations. The ratio of the number of the best prey and the predators are used as low level heuristics. From the simulation results the balancing of the degree of exploration and exploitation by using hyperheuristic mechanism indeed improves the performance of the algorithm. Comparison with other algorithms shows the effectiveness of the proposed approach.     

Chemicals of predatory mosquitofish (Gambusia affinis) influence selection of oviposition site by Culex mosquitoes

Ovipositing insects may avoid aquatic sites where there is high predation risk to their offspring, but the proximate mechanisms that mediate avoidance behavior are poorly resolved. We conducted an experiment to determine whether mosquitoes would reduce oviposition rates in pools containing chemicals of the mosquitofish (Gambusia affinis), a voracious predator that is widely employed to control mosquitoes. Experimental treatments consisted of outdoor pools that contained known concentrations of fish chemicals (low, medium, or high) or no fish chemicals (control). The pools were arranged in a randomized block design, and the number of mosquito larvae in each pool served as the response variable to estimate relative oviposition rate. Members of the Culex pipiens complex were the main colonizers of the pools. The mean number of larvae per pool differed among treatments (P = 0.026) and was about three times greater in control pools compared with those receiving medium and high concentrations of fish chemicals. Pairwise comparisons indicate that only medium and high treatments differed significantly from controls, suggesting that a threshold concentration exists below which mosquitoes cannot reliably detect predators. Our data suggest that the effectiveness of Gambusia affinis in controlling mosquitoes may be compromised if adult mosquitoes respond to fish stocking by shifting to nearby breeding sites that lack fish. We discuss issues concerning the use of Gambusia in biological control programs within the context of these new findings.     

Coevolutionary adaptations of rootworm beetles (Coleoptera: Chrysomelidae) to cucurbitacins

The cucurbitacins are oxygenated tetracyclic triterpenoids produced as secondary plant compounds by nearly all genera of Cucurbitaceae. The very bitter and toxic cucurbitacins are effective semiochemicals acting ecologically as allomones to protect the Cucurbitaceae from attack by a variety of invertebrate and vertebrate herbivores. For the Luperini (Coleoptera: Chrysomelidae: Galerucinae) the cucurbitacins have become kairomones for host selection, affecting the behavior of this large group of 1500 species of Aulacophorina (Old World) and Diabroticina (New World) by arrest and compulsive feeding. When feeding on bitter cucurbits these beetles sequester large amounts of cucurbitacins in their blood and tissues, and these act as allomones to deter predation. Specific detoxification and excretory mechanisms of the Diabroticina enable these beetles to avoid the toxic effects of the cucurbitacins.     

Following of conspecific and avoidance of predator chemical cues by pine snakes (Pituophis melanoleucus)

The ability of hatchling pine snakes (Pituophis melanoleucus) to follow or avoid the chemical trails of conspecifics and a king snake (Lampropeltis getulus) on paper substrates was investigated inY-maze experiments. Hatchlings entered the arm with the adult conspecific trail and avoided the arm containing the king snake trail at a frequency much greater than that due to chance. The data support the hypotheses that pine snakes follow the chemical trails of adult conspecifics and avoid the chemical trails of a predator.