Browsing by Author "Dinis, Ana Maria"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Feeding preferences and functional responses of Calathus granatensis and Pterostichus globosus (Coleoptera: Carabidae) on pupae of Bactrocera oleae (Diptera: Tephritidae)Publication . Dinis, Ana Maria; Pereira, J.A.; Benhadi-Marín, Jacinto; Santos, Sónia A.P.Carabid beetles are important predators in agricultural landscapes feeding on a range of prey items. However, their role as predators of the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), one of the most serious pests of olives, is unknown. In this context, the feeding preferences and the functional responses of two carabid beetle species, Calathus granatensis (Vuillefroy) and Pterostichus globosus (Fabricius), were studied under laboratory conditions. Feeding preference assays involved exposing carabid beetles to different ratios of B. oleae pupae and an alternative prey, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Both species fed on B. oleae pupae however, C. granatensis always showed a significant preference for that prey whereas P. globosus switched to C. capitata pupae when the offered ratio was below 0.5. The total prey biomass consumed was significantly higher for P. globosus than for C. granatensis. Functional response curves were estimated based on different densities of B. oleae pupae and both carabid beetle species exhibited a type II functional response using Rogers' random-predator equation. P. globosus showed shorter handling time (1.223 ± 0.118 h) on B. oleae pupae than C. granatensis (3.230 ± 0.627 h). Our results suggest that both species can be important in reducing the densities of B. oleae in olive groves, although P. globosus was more efficient than C. granatensis.
- A PCR-based diagnostic assay for detecting DNA of the olive fruit fly, Bactrocera oleae, in the gut of soil-living arthropodsPublication . Rejili, M.; Fernandes, Telmo J.R.; Dinis, Ana Maria; Pereira, J.A.; Baptista, Paula; Santos, Sónia A.P.; Lino-Neto, TeresaBactrocera oleae (Rossi) (Diptera: Tephritidae) is considered the most devastating pest of the olive tree worldwide. In an effort to develop management and biological control strategies against this pest, new molecular tools are urgently needed. In this study, we present the design of B. oleae-specific primers based on mitochondrial DNA sequences of cytochrome oxidase subunit I (COI) gene. Two pairs of B. oleae-specific primers were successfully designed and named as SBo1-F/SBo1-R and SBo2-F/SBo1-R, being able to amplify 108 and 214 bp COI fragments, respectively. The specificity of designed primers was tested by amplifying DNA from phylogenetically related (i.e. Diptera order) and other non-pest insects living in olive groves from the Mediterranean region. When using these primers on a PCR-based diagnostic assay, B. oleae DNA was detected in the gut content of a soil-living insect, Pterostichus globosus (Fabricius) (Coleoptera: Carabidae). The detection of B. oleae DNA in the guts of arthropods was further optimized by adding bovine serum albumin enhancer to the PCR reaction, in order to get a fast, reproducible and sensitive tool for detecting B. oleae remains in the guts of soil-living arthropods. This molecular tool could be useful for understanding pest-predator relationships and establishing future biological control strategies for this pest.
- Role of edaphic arthropods on the biological control of the olive fruit fly (Bactrocera oleae)Publication . Dinis, Ana Maria; Santos, Sónia A.P.; Pereira, J.A.The olive fruit fly, Bactrocera oleae (Rossi) is a major pest of the olive tree. A great part of its life cycle is spent inside the olive fruit, which hinders the action of natural enemies. However, pupation usually occurs on the ground, which makes this stage more vulnerable to predation by edaphic arthropods. In this context, with the present work, it was studied the role of the edaphic arthropods on the biological control of olive fruit fly. Under laboratory conditions, Calathus granatensis Vuillefroy and Pterostichus globosus Quensel, two species of carabids abundant in groves of Trás-os-Montes were evaluated as potential predators of olive fruit fly. The food preferences of both carabids were studied as olive fruit fly pupae were offered together with pupae of the Mediterranean fruit fly (Ceratitis capitata Wiedemann) in different proportions. It was also evaluated the functional responses of both carabids on different densities of olive fruit fly pupae. Under field conditions predation by edaphic arthropods on olive fruit fly pupae was evaluated using exposed-exclusion boxes to predators along with pitfall traps for capture of the arthropods active near the boxes. The assay was conducted in two olive groves of the region of Mirandela (northeast of Portugal) between January and May. Biological control provided by edaphic arthropods was measured by calculating biological control services indexes that were further correlated with the abundance of arthropods and functional groups captured in the pitfall traps. The results of the laboratory experiments indicate that both species of carabids studied preyed olive fruit fly pupae, however, C. granatensis proved to have more preference for olive fruit fly pupae over the alternative prey independently of the offered ratio whereas P. globosus demonstrated no preference for olive fruit fly having consuming the two types of pupae. This species of carabid proved to be more polyphagous and revealed a "switching" behavior. The functional response curves demonstrated that both carabids exhibited a type II functional response in which the number of pupae consumed increased as the density of offered pupae increased until it reached a plateau where the consumption remained constant regardless of the offered density. In the field experiment, it was demonstrated that family Formicidae, the order Araneae and family Forficulidae dominated the arthropod community, wherein family Formicidae dominated during the period between the end of winter and beginning of spring and Forficulidae during the winter period. Concerning functional groups, omnivorous arthropods dominated the community, followed by granivorous and predators. The maximum value of biological control services index was achieved in the period between late winter and early spring, when the abundance of predators and omnivorous arthropods reached its maximum. Relationships between the presence of these two functional groups and the biological service index values were found, especially the presence of omnivorous, in which the family Forficulidae stood out during the winter period and family Formicidae during the spring period. The results demonstrate that important biological control services can be provided by edaphic arthropods against olive fruit fly pupae in olive groves. These services are the result of great complementarity among arthropods groups in the different periods of the year. On one hand, during the fall, groups of arthropods such as carabids can be important predators of olive fruit fly pupae and during the period of winter and beginning of spring, omnivorous arthropods such as insects from families Forficulidae and Formicidae may have higher importance. Therefore, it becomes necessary to conserve these groups of arthropods in olive groves in order to maintain or even increase the biological control services against the olive fruit fly.
- Suppression of Bactrocera oleae (Diptera: Tephritidae) pupae by soil arthropods in the olive grovePublication . Dinis, Ana Maria; Pereira, J.A.; Pimenta, M.C.; Oliveira, João P.; Benhadi-Marín, Jacinto; Santos, Sónia A.P.Soil arthropods can provide ecosystem services, such as biological control of crop pests that spend part of their life cycle in the soil. This is the case of Bactrocera oleae (Rossi) (Diptera: Tephritidae), one of the most important pests of olives. The impact of edaphic arthropods on the abundance of B. oleae pupae was evaluated and their contribution for biological control of the pest was quantified. Exclusion and exposed boxes with B. oleae pupae were installed in olive groves in parallel with pitfall traps used for sampling arthropods and the percentage of pupae suppression was evaluated from January to May 2014. Forficulidae dominated the community during the winter period while Formicidae dominated in spring. Pupae suppression reached the maximum value in the beginning of spring and these results indicate that soil arthropods have strong impact in the decline of B. oleae pupae in olive groves.