Pheromone Values Research Articles

Parametric Study for an Ant Algorithm Applied to Water Distribution System Optimization

Much research has been carried out on the optimization of water distribution systems (WDSs). Within the last decade, the focus has shifted from the use of traditional optimization methods, such as linear and nonlinear programming, to the use of heuristics derived from nature (HDNs), namely, genetic algorithms, simulated annealing and more recently, ant colony optimization (ACO), an optimization algorithm based on the foraging behavior of ants. HDNs have been seen to perform better than more traditional optimization methods and amongst the HDNs applied to WDS optimization, a recent study found ACO to outperform other HDNs for two well-known case studies. One of the major problems that exists with the use of HDNs, particularly ACO, is that their searching behavior and, hence, performance, is governed by a set of user-selected parameters. Consequently, a large calibration phase is required for successful application to new problems. The aim of this paper is to provide a deeper understanding of ACO parameters and to develop parametric guidelines for the application of ACO to WDS optimization. For the adopted ACO algorithm, called AS/sub i-best/ (as it uses an iteration-best pheromone updating scheme), seven parameters are used: two decision policy control parameters /spl alpha/ and /spl beta/, initial pheromone value /spl tau//sub 0/, pheromone persistence factor /spl rho/, number of ants m, pheromone addition factor Q, and the penalty factor (PEN). Deterministic and semi-deterministic expressions for Q and PEN are developed. For the remaining parameters, a parametric study is performed, from which guidelines for appropriate parameter settings are developed. Based on the use of these heuristics, the performance of AS/sub i-best/ was assessed for two case studies from the literature (the New York Tunnels Problem, and the Hanoi Problem) and an additional larger case study (the Doubled New York Tunnels Problem). The results show that AS/sub i-best/ achieves the best performance presented in the literature, in terms of efficiency and solution quality, for the New York Tunnels Problem. Although AS/sub i-best/ does not perform as well as other algorithms from the literature for the Hanoi Problem (a notably difficult problem), it successfully finds the known least cost solution for the larger Doubled New York Tunnels Problem.

Evaluation of dog-appeasing pheromone as a potential treatment for dogs fearful of fireworks

Thirty dogs that showed signs of fear in response to fireworks participated in an open clinical trial to assess the potential value of dog-appeasing pheromone for the alleviation of their...

Monitoring Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae) with synthetic sex pheromone and small scale disruption trial with controlledrelease PVC resin formulation

A monitoring experiment and a small scale mating disruption trial were carried out to investigate the potential value of the synthetic sex pheromone of the oriental tobacco budworm, Helicoverpa assulta (Guenee) (Lepidoptera : Noctuidae). The pheromone trap was more effective in detecting the field population than the black-light trap. The treatment with controlled-release PVC resin dispensers loaded with synthetic sex pheromone, applied at a rate of 30 g/ha in a hot pepper field, resulted in significant reduction of trap catches, indicating effective disruption of pheromonal cpmmunication of H. assulta in the field. The disruptive effect of the PVC formulation lasted for one month in the field.

Value of pheromone traps for predicting infestations of red scale, Aonidiella aurantii(Maskell) (Hom., Diaspididae), limited by natural enemy activity and insecticides used to control citrus thrips, Scirtothrips aurantii Faure (Thys., Thripidae)

AbstractIn South Africa, red scale (Aonidiella aurantii [Maskell]) males and several of its Aphytis Howard parasitoid species, were monitored using sticky yellow card traps, each with a rubber septum impregnated with synthetic female red scale sex pheromone. Traps were exposed in 72 different orange (Citrus sinensis [L.] Osbeck) orchards in 3 different areas and were changed weekly during two seven‐week periods in winter and early summer. Correlations between the maximum weekly numbers of trapped red scale recorded during each period were significant at P = 0.10 only in the coldest area where A. melinus DeBach was not recovered and where winter oil treatments were applied. Summer trap catches of Aphytis spp. were depressed by all spray programmes for citrus thrips (Scirtothrips aurantii Faure) including tartar emetic plus sugar. Trap counts of Aphytis were significantly (P < 0.05) lower after a single triazophos (0.024 % AI) treatment than after a single fenpropathrin (0.006 % AI) treatment. No correlation between the maximum number of trapped red scale in summer and fruit infestation at harvest was significant at P = 0.10, presumably due to variable impact from Aphytis spp. Prediction of expected red scale fruit infestation at harvest and the development of a treatment threshold based on numbers of trapped red scale were therefore not possible.ZusammenfassungZur Bedeutung von Pberomonfallen zur Befallsvorhersage bei der Roten Schildlaus, Aonidiella aurantii (Mask.) (Horn., Diaspididae) unter Einwirkung natürlicher Feinde und Insektizidanwendungen zur Bekämpfung des Citrus‐Thrips, Scirtothrips aurantii Faure (Thys., Thripidae)In Südafrika wurden die Männchen der Schildlaus Aonidiella aurantii sowie einige ihrer Aphytis How.‐Parasitoiden mittels gelber Klebkarton‐Fallen überwacht, deren jede mit dem synthetischen Sexualpheromon des Schildlausweibchens versehen war. Die Fallen wurden in 72 Orange‐Plantagen (Citrus sinensis) in 3 verschiedenen Arealen ausgebracht und wöchentlich während zwei Siebenwochen‐Perioden im Winter und frühen Sommer kontrolliert. Korrelationen zwischen den maximalen wöchentlichen Fangzahlen von Schildläusen während der 2 Perioden waren nur signifikant (P = 0,10) im kältesten Areal, wo Aphelinus melinus DeBach nicht vorkam und wo es im Winter Anwendungen mit Ol gab. Die Sommer‐Fallenfänge von Aphytis spp. wurden durch alle Sprühprogramme gegen den Citrus‐Thrips, Scirtothrips aurantii vermindert. Die Fangzahlen von Aphytis waren signifikant (P < 0.05) geringer nach einer einzelnen Triazophos‐Behandlung als nach einer einzelnen Fenpropathrin‐Anwendung. Es bestand keine signifikante Korrelation mit P = 0,10 zwischen der maximalen Zahl gefangener Schildläuse im Sommer und dem Fruchtbefall zur Erntezeit, vermutlich wegen des variablen Auftretens der Aphytis‐Parasitoiden. Eine Vorhersage des Fruchtbefalls zur Ernte und die Erstellung einer Behandlungsgrenze auf der Basis gefangener Schildläuse waren daher nicht möglich.

On the territorial behaviour of field colonies of the leaf-cutting ant Atta laevigata (Hymenoptera: Myrmicinae)

The adaptative value of the territorial pheromone in leaf-cutting ants was investigated by studying the territorial behaviour of Atta laevigata in the field through a 2-yr-long observation period of four neighbouring adult nests in a pine tree plantation in Estado Monagas, Venezuela. Workers were found to secrete a colony-specific pheromone around their nest and along trunk trails. The extent to which ants marked the trail depended on the quality of the available food. This pheromone stimulated the aggressiveness of the resident workers and induced transport behaviour toward intruders. Its sole perception induced alarm in intruders, which, when encountering a resident worker, adopted a characteristic submissive posture. The same alarm behaviour was also observed among conspecifics, though without the same level of aggressiveness, when workers from one mound were introduced to territories of another mound of the same nest. Territory recognition depended simultaneously on visual and chemical cues, allowing the workers to orientate towards the nest mound they exited. Results suggest a double function for the territorial pheromone: to repel intruders from other colonies and to orientate workers on their way back to the nest.

Relationship Between Time of Boll Weevil (Coleoptera: Curculionidae) Emergence from Winter Habitat and Response to Grandlure-baited Pheromone Traps

A 4-year study indicated a strong correlation between time of emergence of boll weevils, Anthonomus grandis Boheman, from overwintering cages and response of native overwintered weevils to grandlure-baited pheromone traps. These results indicated that the response of overwintered weevils to pheromone traps is an accurate reflection of the emergence profile of boll weevils from overwintering habitat. The positive correlation between overwintered weevil response to pheromone traps and very recent overwintered weevil emergence greatly enhances the previously established value of pheromone traps as sampling tools for use in overwintered boll weevil management.

Intraspecific competition between different aged larvae of Agromyza frontella (Rondani) (Diptera: Agromyzidae): advantages of an oviposition-deterring pheromone

In laboratory studies evaluating the effects of intraspecific competition between Agromyza frontella larvae of different ages, individuals starting 24 or 48 h before other larvae within the same leaflet largely escaped the negative effects of competition. However, larvae starting development later experienced a higher incidence of mortality and reduced pupal weight. Thus an oviposition-deterring pheromone laid down by ovipositing A. frontella females would only have to remain effective for 24 h to confer a competitive advantage to the first individual developing within the leaflet. In two separate field tests this proved to be the case, with active pheromone remaining for > 24 h under both hot and rainy conditions. There has been some doubt concerning the adaptive value of certain oviposition-deterring pheromones under field conditions because of their water-soluble nature. The results of these experiments would suggest that the required active life of an oviposition-deterring pheromone may be considerably shorter than previously thought, and thus their persistence, even for short periods, may be adequate to reduce intraspecific competition in natural populations.