RESUMEN
Field experiments were carried out to study responses of male moths of the carpenterworm, Chilecomadia valdiviana (Lepidoptera: Cossidae), a pest of tree and fruit crops in Chile, to five compounds previously identified from the pheromone glands of females. Previously, attraction of males to the major component, (7Z,10Z)-7,10-hexadecadienal, was clearly demonstrated while the role of the minor components was uncertain due to the use of an experimental design that left large portions of the design space unexplored. We used mixture designs to study the potential contributions to trap catch of the four minor pheromone components produced by C. valdiviana. After systematically exploring the design space described by the five pheromone components, we concluded that the major pheromone component alone is responsible for attraction of male moths in this species. The need for appropriate experimental designs to address the problem of assessing responses to mixtures of semiochemicals in chemical ecology is described. We present an analysis of mixture designs and response surface modeling and an explanation of why this approach is superior to commonly used, but statistically inappropriate, designs.
Asunto(s)
Mariposas Nocturnas/fisiología , Atractivos Sexuales/farmacología , Animales , Conducta Animal/efectos de los fármacos , Femenino , Masculino , Modelos Teóricos , Mariposas Nocturnas/efectos de los fármacos , Atractivos Sexuales/química , EstereoisomerismoRESUMEN
While adult parasitic Hymenoptera in general feed on floral and extrafloral nectars, hemipteran-honeydews and fluids from punctured hosts, Diachasmimorpha longicaudata (Ashmead), an Old World opiine braconid introduced to tropical/subtropical America for the biological control of Anastrepha spp. (Tephritidae), can survive on fruit juices as they seep from injured fruit. An ability to exploit fruit juice would allow such a parasitoid to efficiently forage for hosts and food sources simultaneously. Two New World opiines, Doryctobracon areolatus (Szepligeti) and Utetes anastrephae (Viereck), are also prominent Anastrepha parasitoids and are roughly sympatric. All three species were provided with: (1) pulp and juice diets derived from a highly domesticated Old World fruit (orange, Citrus sinensis L.) that is only recently sympatric with the Mexican flies and parasitoids and so offered little opportunity for the evolution of feeding-adaptations and (2) a less-domesticated New World fruit (guava, Psidium guajava L.), sympatric over evolutionary time with D. areolatus and U. anastrephae. Both sexes of D. longicaudata died when provided guava pulp or juice at a rate similar to a water-only control. D. areolatus and U. anastrephae, presumably adapted to the nutrient/chemical constituents of guava, also died at a similar rate. Survival of all three species on orange pulp and juice was greater than on water, and often equaled that obtained on a honey and water solution. In confirmatory experiments in Mexico, D. areolatus and U. anastrephae, as well as other tephritid parasitoids Doryctobracon crawfordi (Viereck) and Opius hirtus (Fisher), all died at a significantly higher rates when provided guava in comparison to a honey and water diet. Such a result is likely due to guavas being repellent, innutritious or toxic. D. longicaudata clearly consumed guava juice tagged with a colored dye. Dilutions of orange and guava juice resulted in shorter lifespans than dilutions of orange juice and water demonstrating that there while diluted orange juice provided nutrition the addition of guava created toxicity. Given the differences in fruit-food quality, adult opiine food sources would not be obtainable at all oviposition sites and in the case of guava, more additional sites and foraging for food than previously postulated may be required.
Asunto(s)
Dieta , Frutas , Longevidad , Tephritidae/parasitología , Avispas/fisiología , Animales , Citrus sinensis , Femenino , Miel , Masculino , Manosa/toxicidad , México , PsidiumRESUMEN
The leaf feeding beetle Gratiana boliviana Spaeth has been released since 2003 in the southeastern United States for biological control of tropical soda apple, Solanum viarum Dunal. In Florida, G. boliviana can be found on tropical soda apple growing in open pastures as well as in shady wooded areas. The objectives of this study were to determine the effect of light intensity on the performance of tropical soda apple and G. boliviana under greenhouse conditions, and to determine the abundance and mortality of G. boliviana in open and shaded habitats. Leaves growing in the shade were less tough, had higher water and nitrogen content, lower soluble sugars, and less dense and smaller glandular trichomes compared with leaves growing in the open. Plants grew slightly taller and wider under shaded conditions but total biomass was significantly reduced compared with plants grown in the open. In the greenhouse, G. boliviana had higher immature survival, greater folivory, larger adult size, and higher fecundity when reared on shaded plants compared with open plants. Sampling of field populations revealed that the overall abundance of G. boliviana was lower but leaf feeding damage was higher in shaded habitats compared with the open habitats. The percentage of eggs surviving to adult was greater in shaded compared with open habitats. The abundance of predators was higher in the open pasture and was positively correlated with the abundance of G. boliviana. These results indicate that not only plant quality but also habitat structure are important to the performance of weed biological control agents.
Asunto(s)
Agentes de Control Biológico , Escarabajos/fisiología , Control Biológico de Vectores/métodos , Solanum/crecimiento & desarrollo , Animales , Escarabajos/crecimiento & desarrollo , Ambiente , Conducta Alimentaria , Femenino , Florida , Cadena Alimentaria , Larva/crecimiento & desarrollo , Larva/fisiología , Luz , Masculino , Densidad de Población , Dinámica Poblacional , Solanum/fisiologíaRESUMEN
The reproductive biology of Fidiobia dominica Evans (Hymenoptera: Platygastridae) was studied in the laboratory (25.6 +/- 1 degrees C) using host eggs of Diaprepes abbreviatus L. (Coleoptera: Curculionidae). F. dominica readily parasitized D. abbreviatus eggs on both host plant and wax paper substrates. The number of egg masses parasitized and the number of offspring produced were higher when females were offered more than one host egg mass but did not differ when either two or three egg masses were offered. Female parasitoids that were provided with host eggs and a honey food source lived significantly longer than those that were not provided a food source; however, they did not parasitize more D. abbreviatus eggs. Oviposition occurred in host eggs from 0 to 7 d old, and host mortality was relatively consistent for eggs 0-5 d old and lower for eggs 6-7 d old. Successful parasitoid emergence seldom occurred after host eggs were 4 d old, and by 7 d, no adults successfully emerged. Developmental time from egg to adult was 19.3 +/- 0.2 d for males, significantly more rapid than the females (20.4 +/- 0.1 d). The mean longevity of adult females was 8.0 +/- 0.4 d, with a mean oviposition period of 2.7 +/- 0.3 d; males survived 8.1 +/- 0.4 d. The demographic parameters including intrinsic rate of increase (r(m)), generation time (T), and net reproduction (R(o)) were 0.142/d, 22 d, and 22.4 female eggs/d, respectively.