P. Fernández

Bio: P. Fernández is an academic researcher from International Trademark Association. The author has contributed to research in topics: Sterile insect technique & Optical switch. The author has an hindex of 5, co-authored 15 publications receiving 77 citations. Previous affiliations of P. Fernández include National Scientific and Technical Research Council.

Plant Chemicals and the Sexual Behavior of Male Tephritid Fruit Flies

Abstract: Plant compounds affect insects in many different ways. In addition to being a food source, plants also contain secondary metabolites that may have positive and negative impacts on insects. The influence of these compounds on sexual behavior, in particular, has been the focus of many recent studies. Here, we review the existing literature on the effects of plant compounds on the sexual behavior of tephritid fruit fly males. We put special focus on polyphagous species whose males congregate in leks, where females exert strong mate selection. We first summarize the main findings related to plant compounds that increase male signaling behavior and attraction of females and consequently increase mating frequency, a phenomenon that has been recorded mainly for species of Anastrepha and Ceratitis. In other tephritid species, males are attracted to phenylpropanoids produced by plants (such as methyl eugenol or raspberry ketone) that, upon encounter, are consumed and sequestered by males. These compounds, or metabolic derivatives, which normally have negligible nutritional value, are included in the pheromone and also confer advantages in a sexual context: enhanced female attraction and improved male mating success. These phenomena have been reported for several Bactrocera species as well as for Zeugodacus cucurbitae. Because many tephritid species are serious pests, the effect of plant compounds on male behavior has been explored for potential incorporation into control strategies such as the sterile insect technique (SIT). We conclude noting several factors, such as age and nutrition during larval and adult stage, that modulate the effect of plant compounds on male mating behavior as well as some prominent gaps that preclude a thorough understanding of the plant-mediated enhancement of male sexual performance and hence limit our ability to effectively utilize phytochemicals in pest control strategies.

Gut bacterial diversity and physiological traits of Anastrepha fraterculus Brazilian-1 morphotype males are affected by antibiotic treatment.

Abstract: The interaction between gut bacterial symbionts and Tephritidae became the focus of several studies that showed that bacteria contributed to the nutritional status and the reproductive potential of its fruit fly hosts. Anastrepha fraterculus is an economically important fruit pest in South America. This pest is currently controlled by insecticides, which prompt the development of environmentally friendly methods such as the sterile insect technique (SIT). For SIT to be effective, a deep understanding of the biology and sexual behavior of the target species is needed. Although many studies have contributed in this direction, little is known about the composition and role of A. fraterculus symbiotic bacteria. In this study we tested the hypothesis that gut bacteria contribute to nutritional status and reproductive success of A. fraterculus males. AB affected the bacterial community of the digestive tract of A. fraterculus, in particular bacteria belonging to the Enterobacteriaceae family, which was the dominant bacterial group in the control flies (i.e., non-treated with AB). AB negatively affected parameters directly related to the mating success of laboratory males and their nutritional status. AB also affected males’ survival under starvation conditions. The effect of AB on the behaviour and nutritional status of the males depended on two additional factors: the origin of the males and the presence of a proteinaceous source in the diet. Our results suggest that A. fraterculus males gut contain symbiotic organisms that are able to exert a positive contribution on A. fraterculus males’ fitness, although the physiological mechanisms still need further studies.

Nature-Inspired Routing and Wavelength Assignment Algorithms for Optical Circuit-Switched Polymorphic Networks

Abstract: Polymorphic optical networks simultaneously support several optical switching paradigms over a single physical network. In this way, they provide service differentiation at the optical layer by employing the most appropriate paradigm for each service. One type of such architecture is the optical circuit-switched polymorphic network (OCSPN), which combines optical circuit switching paradigms with different grades of dynamism. The performance of this network relies on the utilization of efficient routing and wavelength assignment (RWA) algorithms. In this article, we review the fundamentals of OCSPNs and present a set of efficient RWA algorithms based on ant colony optimization and genetic algorithms.

Heptyl butyrate, a putative pheromone involved in social communication of Vespula germanica wasps

Abstract: Greater knowledge on the social communication of invasive Vespula germanica wasps is needed to fully understand their foraging behavior. This is particularly valuable considering that poison baiting is currently the only effective way of reducing wasp density. Heptyl butyrate is an attractant for many wasp species, but attempts to determine effects on V. germanica have yielded mixed results. We studied the behavior elicited by heptyl butyrate on V. germanica wasps in field experiments with foraging wasps. We also analyzed headspace volatiles of live V. germanica workers, to determine if heptyl butyrate is emitted. Heptyl butyrate was present in the headspace of live workers. Amounts of heptyl butyrate averaged 1.4 ± 0.2 ng per sample per hour, where each sample included six workers. Wasps approaching filter papers treated with different concentrations of heptyl butyrate hovered over it, but only a small percentage landed on it. Pure heptyl butyrate elicited the greatest response although all the concentrations tested were attractive. When heptyl butyrate was applied to protein baits, a greater number landed on the treated baits than on untreated ones, demonstrating this compound enhances attractiveness of baits. Results from our study suggest that heptyl butyrate is a pheromonal compound involved in attracting conspecifics to food resources, but other cues are needed to trigger landing.

Plant‐based compounds with potential as push‐pull stimuli to manage behavior of leaf‐cutting ants

Abstract: Leaf-cutting ants are a serious pest of young forestry plantations. Currently, the main control method is the use of broad-spectrum insecticides, which have a negative effect on non-target organisms and the environment. In this work, plant-based compounds were evaluated in laboratory assays with Acromyrmex ambiguus Emery (Hymenoptera: Formicidae) for their potential use as repellent and attractant stimuli to be used in a push-pull strategy. Farnesol, a sesquiterpene present in many essential oils, was tested as a repellent at doses of 10, 50, and 100 mg. Its distance of action was studied by comparing the repellent effect of farnesol in a situation in which ants had to touch the farnesol in order to reach the food source in comparison to when ants could reach the food source without getting into direct contact with it. Different parts of the orange fruit (pulp and peel) were evaluated and compared as attractants, given that citrus-based baits are among the most popular attractants used. Results from laboratory bioassays indicated that farnesol is repellent at doses of 50 mg and acts upon contact or at a very short distance. Furthermore, orange pulp was more attractive than the peel, and volatile compounds were highly responsible for the attraction. When both stimuli were tested simultaneously in a laboratory experiment, repellency of farnesol was enhanced in the presence of orange pulp odor. When tested in a field push-pull experiment, the results also showed a good repellent effect of farnesol as well as an attractant effect of the orange pulp. These results encourage long-term studies with these substances in a field setting and suggest that repellents can be enhanced by the use of attractants to manage leaf-cutting ants behavior.

OPHMR: An Optimized Polymorphic Hybrid Multicast Routing Protocol for MANET

Abstract: We propose in this paper an optimized, polymorphic, hybrid multicast routing protocol for MANET. This new polymorphic protocol attempts to benefit from the high efficiency of proactive behavior (in terms of quicker response to transmission requests) and the limited network traffic overhead of the reactive behavior, while being power, mobility, and vicinity-density (in terms of number of neighbor nodes per specified area around a mobile node) aware. The proposed protocol is based on the principle of adaptability and multibehavioral modes of operations. It is able to change behavior in different situations in order to improve certain metrics like maximizing battery life, reducing communication delays, improving deliverability, etc. The protocol is augmented by an optimization scheme, adapted from the one proposed for the optimized link state routing protocol (OLSR) in which only selected neighbor nodes propagate control packets to reduce the amount of control overhead. Extensive simulations and comparison to peer protocols demonstrated the effectiveness of the proposed protocol in improving performance and in extending battery power longevity

Tephritid Fruit Fly Semiochemicals: Current Knowledge and Future Perspectives.

Abstract: The Dipteran family Tephritidae (true fruit flies) comprises more than 5000 species classified in 500 genera distributed worldwide. Tephritidae include devastating agricultural pests and highly invasive species whose spread is currently facilitated by globalization, international trade and human mobility. The ability to identify and exploit a wide range of host plants for oviposition, as well as effective and diversified reproductive strategies, are among the key features supporting tephritid biological success. Intraspecific communication involves the exchange of a complex set of sensory cues that are species- and sex-specific. Chemical signals, which are standing out in tephritid communication, comprise long-distance pheromones emitted by one or both sexes, cuticular hydrocarbons with limited volatility deposited on the surrounding substrate or on the insect body regulating medium- to short-distance communication, and host-marking compounds deposited on the fruit after oviposition. In this review, the current knowledge on tephritid chemical communication was analysed with a special emphasis on fruit fly pest species belonging to the Anastrepha, Bactrocera, Ceratitis, Rhagoletis and Zeugodacus genera. The multidisciplinary approaches adopted for characterising tephritid semiochemicals, and the real-world applications and challenges for Integrated Pest Management (IPM) and biological control strategies are critically discussed. Future perspectives for targeted research on fruit fly chemical communication are highlighted.