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- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Saissetia oleae (Olivier) (Hemiptera: Coccidae)Publication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Lacewings are common biocontrol agents against a wide range of agricultural pests.These predators are highly voracious against soft-bodied preys such as juveniles of scale insects. In this context, the present work aims to study the use of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) as biological control agent against Saissetia oleae (Olivier) (Hemiptera: Coccidae). For that, we studied the functional response of the larval instars of C. carnea to nymphs of S. oleae. Increasing densities (3, 5, 10, 15, 25 and 40) of S. oleae nymphs were offered to the three larval stages of C. carnea in a controlled laboratory environment. After 24 hours, the number of S. oleae consumed by C. carnea larva was recorded and the functional response calculated. The three larval stages of C. carnea displayed a type II functional response behavior. Prey consumption by C. carnea larvae increased with high S. oleae densities. Moreover, younger larvae showed a lower predation rate in comparison with the older ones. The search rate and handling time of the third instar larvae were lower than those of the younger larval instars, and the simulated max. attack rate of the third instar larvae was higher than those of the first and second instar larvae. Our results suggest that all larval stages of C. carnea could be important in S. oleae biological control in olive orchards, although the third larval stage of the predator was more efficient in reducing S. oleae densities than first and second C. carnea larval instars.
- A cochonilha negra, Saissetia oleae, como alimento para larvas e adultos de Chrysoperla carnea s.l.Publication . Villa, Maria; Mahzoum, Abdelkader; Benhadi-Marín, Jacinto; Pereira, J.A.As larvas de Chrysoperla carnea s.l. (Stephens) são amplamente utilizadas em programas de luta biológica devido à sua ação como predadores de insetos. Por sua vez, os adultos alimentam-se de meladas de hemípteros, pólen e néctar de flores. No olival são potenciais predadores de várias pragas. Assim, neste agroecosistema a existência de recursos alimentícios é essencial para manter as populações de C. carnea e melhorar a sua ação numa perspetiva de proteção biológica por conservação. A cochonilha negra, Saissetia oleae (Olivier), é uma praga secundaria da oliveira em grande parte da região mediterrânica. A existência desta praga pode proporcionar recursos alimentícios para as diferentes fases de desenvolvimento de C. carnea, nomeadamente, as ninfas como presas para alimentação das larvas do predador, e as meladas que o adulto excreta como fonte de energia para adultos. Assim, o objetivo deste trabalho foi avaliar o potencial de S. oleae como alimento para larvas e adultos de C. carnea. Para avaliar o efeito nas larvas, foram disponibilizadas diferentes densidades de ninfas de S. oleae a larvas de C. carnea, e avaliadas taxas de consumo; para os adultos, foram disponibilizadas meladas excretadas por S. oleae e avaliada a sobrevivência, em ambos os sexos, e fecundidade em fêmeas. Verificou-se que as larvas de C. carnea consomem eficientemente ninfas de S. oleae. Por sua vez nos adultos, o consumo de meladas melhora a sua sobrevivência em comparação ao controlo (água), mas não a reprodução, o que estará relacionado com a inexistência de proteína necessária para a formação de ovos. Assim, numa estratégia de proteção biológica por conservação, baixos níveis populacionais da praga podem contribuir para a manutenção e aumento de crisopídeos no olival
- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) Larvae on Saissetia oleae (Olivier) (Hemiptera: Coccidae): implications for biological controlPublication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a voracious predator of soft-bodied insects such as juveniles of scale insects and the black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) is an important pest of several crops, such as the olive tree. However, the predatory effciency of C. carnea on S. oleae has been unstudied yet. The present work aimed to study the functional response of larvae of C. carnea fed on S. oleae nymphs. In a controlled laboratory environment, increasing densities of S. oleae second and third nymph stages were offered to newly emerged specimens of the three larvae instars of C. carnea. After 24 h, the number of killed S. oleae was recorded and the functional response of C. carnea was assessed. The three larval stages of C. carnea displayed a type-II functional response, i.e., killed prey increased with higher S. oleae densities up to a maximum limited by the handling time. The attack rate did not significantly differ among the three instars while the maximum attack rate was significantly higher for the third instar. The handling time of the first larval instar of C. carnea was higher than that of the third instar. Our results demonstrated that S. oleae could act as a food resource for all larval stages of C. carnea. Furthermore, the third larval stage of the predator was the most effcient in reducing S. oleae densities. These results suggest that C. carnea larvae could contribute to S. oleae control in sustainable agriculture.
- Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Saissetia oleae (Olivier) (Hemiptera: Coccidae)Publication . Mahzoum, Abdelkader; Villa, Maria; Benhadi-Marín, Jacinto; Pereira, J.A.Lacewings are common biocontrol agents against a wide range of agricultural pests. These predators are highly voracious against soft-bodied preys such as juveniles of scale insects. In this context, the present work aims to study the use of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) as biological control agent against Saissetia oleae (Olivier) (Hemiptera: Coccidae). For that, we studied the functional response of the larval instars of C. carnea to nymphs of S. oleae. Increasing densities (3, 5, 10, 15, 25 and 40) of S. oleae nymphs were offered to the three larval stages of C. carnea in a controlled laboratory environment. After 24 hours, the number of S. oleae consumed by C. carnea larva was recorded and the functional response calculated. The three larval stages of C. carnea displayed a type II functional response behavior. Prey consumption by C. carnea larvae increased with high S. oleae densities. Moreover, younger larvae showed a lower predation rate in comparison with the older ones. The search rate and handling time of the third instar larvae were lower than those of the younger larval instars, and the simulated max. attack rate of the third instar larvae was higher than those of the first and second instar larvae. Our results suggest that all larval stages of C. carnea could be important in S. oleae biological control in olive orchards, although the third larval stage of the predator was more efficient in reducing S. oleae densities than first and second C. carnea larval instars.
- Prays oleae (Bernard), its potential predators and biocontrol depend on the structure of the surrounding landscapePublication . Pascual, Susana; Ortega, Marta; Villa, MariaArthropod populations from agricultural fields sometimes depend on the surrounding landscape structure, both composition and configuration, which affects multiple life-history traits of arthropods such as resources for survival, dispersion or death risk (e.g., predation or parasitism). Moreover, the effect of the landscape may vary with the distance to the crop, depending on factors such as the organism requirements and dispersion capabilities. This work addresses the effect of landscape (at five different scales from 250 to 1500 m) on the olive moth (Prays oleae Bernard, a key pest in olive orchards), some of its most relevant natural enemies, and biological control. The two-years study in 15 olive groves in southeastern Madrid, Spain shows that landscape complexity favours control of the olive moth, P. oleae. Simple landscapes favour P. oleae attack to the crop (measured as oviposition of the anthophagous generation) and that egg predation of the carpophagous generation is in some cases enhanced in complex landscapes. Lacewings (Neuroptera: Chrysopidae) are responsible for egg predation and populations increase in complex landscapes. On the other hand, the role of pirate bugs (Hemiptera: Anthocoridae) as a biological control agent of this part of the life cycle of P. oleae was not demonstrated. They respond primarily to Euphyllura olivina (Costa) (Hemiptera: Psyllidae) populations and are more abundant in simple landscapes. Most of the significant relationships of pest attack were detected at 750–1000 m radii buffers around the sampled olive groves suggesting that this is the main activity range for adults of P. oleae anthophagous generation. In sum, our results suggest complex configurations of the landscape enhance the biological control of P. oleae through favouring lacewings and egg predation of the carpophagous generation.
- Plantas espontâneas em floração como recurso alimentar para adultos de Chrysoperla carnea s.l. no agroecossistema olivalPublication . Villa, Maria; Somavilla, Iana; Santos, Sónia A.P.; López-Sáez, José António; Pereira, J.A.As larvas de Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) são consumidores generalistas de pragas nos agroecossistemas, nomeadamente no olival. Os adultos alimentam-se de meladas de hemípteros, pólen e néctar de plantas desempenhando a flora adventícia do olival um papel relevante em proteção biológica de conservação. Considerando que o pólen pode ser um recurso florístico essencial para a reprodução e fecundidade no predador e que o conhecimento acerca da dieta polínica de C. carnea é escasso, o presente trabalho teve por objetivo estudar a potencial seleção de tipos polínicos consumidos por C. carnea s.l. no agroecossistema olival. De abril a dezembro de 2012 e 2013, em olivais com coberto vegetal na região de Mirandela foram capturados adultos de C. carnea s.l. na copa da oliveira. Em laboratório, procedeu-se à remoção do conteúdo estomacal dos insetos para identificação, ao microscópio ótico, dos diferentes tipos polínicos. Paralelamente realizaram-se inventários das plantas em floração nos olivais e parcelas adjacentes de vegetação herbácea e arbustiva para comparação dos tipos polínicos consumidos e presentes no agroecossistema. Os resultados indicaram que os indivíduos de C. carnea s.l. consumiram pólen de diferentes plantas anemófilas e entomófilas pertencentes aos extratos arbóreo e arbustivo (Fabaceae, Pinaceae, Cistaceae ou Ericaceae) e ao extrato herbáceo (Asteraceae, Apicaceae, Brassicaceae, Poaceae, tipo Rumex o tipo Plantago). Por outro lado, verificou-se ainda que os adultos de C. carnea se alimentaram não só do pólen das flores mas também do outro pólen que provavelmente se encontra depositado sobre a superfície da vegetação, o que poderá representar um reservatório alimentar para períodos de escassez. Os resultados obtidos evidenciam a importância da flora espontânea nos agroecossistemas e podem contribuir para a gestão destas espécies no olival com vista ao fomento da comunidade de inimigos naturais de pragas da cultura.
- Biodiversity and pollen feeding habits of syrphids in olive groves and surrounding landscape in Northeastern Portugal during springPublication . Villa, Maria; Santos, Sónia A.P.; Marrão, Rosalina; Pinheiro, Lara Alina; López-Sáez, José António; Aguiar, Carlos; Pereira, J.A.Many syrphid larvae are predators of aphids and early stages of moths and psyllids, being potential control agents of some olive pests. However, adults need pollen and nectar for energy and reproduction. An increase of plant resources biodiversity in heterogeneous landscape could benefit these natural enemies. Thus, our goal of was to study the syrphid biodiversity and their pollen sources in olive agroecosystems from the northeast of Portugal during spring, that coincides with the availability of pests. For that, syrphids were captured in three not-tilled olive groves and two surrounding field areas (an herbaceous vegetation patch and a scrubland) next to each olive grove. Simultaneously, flowering plant inventories were carried out. Syrphids and the pollen contained in the guts of the most abundant species were identified. Thereafter pollen in guts was compared with pollen in the environment to evaluate a potential pollen selection. The most abundant species were Sphaerophoria scripta and Melanostoma mellinum. During the spring syrphids did not consume all the occurring plant species but did not actively selected pollen types. Results indicated that Asteraceae, Plantaginaceae, Caryophyllaceae, Echium type, Rumex type and Jasione type are important food sources for M. mellinum and S. scripta. These results will allow managing ground cover vegetation more efficiently in order to conserve syrphids in the olive agroecosystem.
- Predatory potential of two functional groups of spiders on Philaenus spumariusPublication . Banhadi-Marín, J.; Villa, María; Baptista, Paula; Pereira, J.A.There is an urgent need of increasing the knowledge about natural enemies of Philaenus spumarius and finding strategies to limit the spread of X. fastidiosa. Generalist predators, such as spiders, can arise as potential natural control agents. Determining the functional response is crucial for understanding the potentiality of a predator as biological control agent. In this work, the functional response of two widespread palearctic spider species belonging to two different functional groups was assessed. The ambusher spider Synema globosum and the orb-weaver Araniella cucurbitina were used as model species and P. spumarius as prey under laboratory conditions. In parallel, Ceratitis capitata was also used as prey in order to compare the spiders´ predatory potential between a non-flying insect (P. spumarius) and a flying one (C. capitata). A. cucurbitina and S. globosum showed a type II and type I functional response respectively when fed with P. spumarius and a type II response when fed with C. capitata. Both the handling time and attack rate were significantly different between spider species when fed with P. spumarius (p<0.01) and between prey types for each spider functional group (p<0.01). The results suggest that S. globosum was more efficient capturing spittlebugs one by one than A. cucurbitina. On the contrary, A. cucurbitina was more efficient killing flies in webs than S. globosum.
- Predatory potential of Forficulidae (Dermaptera) on the olive fly Bactrocera oleaePublication . Neto, Marco Aurélio; Benhadi-Marín, Jacinto; Gonçalves, Maria de Fátima; Villa, Maria; Pereira, J.A.Earwigs (Dermaptera: Forficulidae) are omnivorous insects, feeding on a variety of plants and animal material and are described as natural control agents of pests in several agroecosystems. Earwigs are abundant in olive orchards and their adult stage overlaps in time and space with the pupae stage of the main olive pest, the olive fly Bactrocera oleae (Rossi). However, the role of earwigs as natural control agents of B. oleae is almost unknown. The present work aimed to study the functional response of female and male earwigs on olive fly pupae in order to analyse their potential ability to limit this pest. Increasing densities of pupae were offered to starved earwigs in a controlled laboratory environment. After 24 h, the number of attacked pupae was recorded. The type of functional response, handling time, and attack rate of the earwigs was assessed. Our results disentangle the potentiality of earwigs as predators of B. oleae during the pupae stage and provide relevant information for further studies and applications.
- A guild-based protocol to target potential natural enemies of philaenus spumarius (Hemiptera: Aphrophoridae), a vector of xylella fastidiosa (xanthomonadaceae): A case study with spiders in the olive grovePublication . Benhadi-Marín, Jacinto; Villa, Maria; Pereira, Luís Fernando; Rodrigues, Isabel; Morente, Marina; Baptista, Paula; Pereira, J.A.The olive grove is a key landscape across the Mediterranean basin. This agroecosystem is threatened by Xylella fastidiosa, the causal agent of the olive tree quick decline syndrome, Philaenus spumarius being the main vector. A way to limit pest populations relies on the use of biological control agents such as arthropods. Among them, spiders are generalist predators with di erent hunting strategies that feed mostly on insects and can contribute to limit pests. In this work, field and laboratory data were used to provide a protocol aiming to facilitate the selection of species of spiders among di erent guilds that could represent potential natural enemies of P. spumarius. Sampling of spiders was conducted in olive groves in northeastern Portugal. Two species, namely the orb-weaver Araniella cucurbitina and the ambusher Synema globosum, were selected according to the dominant guilds of spiders inhabiting the olive crop. We tested the di erences of potential predatory e ciency using classical functional response tests with P. spumarius as prey. A type-II functional response was found for A. cucurbitina, whereas a type-I response was found for S. globosum. This di erence uncovers a di erent potential e ciency among the two species as natural enemies of P. spumarius with relevant implications at high prey density in the field. A conceptual workflow to follow the fieldwork and selection of species for further work (i.e., laboratory assays) is provided and discussed. Standardized methods regarding the assessment of the suitability and e ciency of potential natural enemies are essential for the integration of results at di erent geographical extents and crops. Selecting functional counterparts such as di erent species of predators occurring at di erent locations that use the same prey (e.g., a pest) in the same way (e.g., hunting strategy) would facilitate developing biological control schemes.