Browsing by Author "Villa, María"
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- Are wild flowers and insect honeydews potential food resources for adults of the olive moth, Prays oleae?Publication . Villa, María; Marrão, Rosalina; Mexia, António; Bento, Albino; Pereira, J.A.The use of non-crop resources by natural enemies and their potentialities to enhance their effectiveness as pest control agents is increasing as a method for conservation biological control. Nevertheless, the effect of consumption of non-crop resources by pests has been generally overlooked being this knowledge crucial to favor natural enemies but not pests. In the present work, insect honeydews and flowers suitability as food resources for the olive tree key-pest Prays oleae were analyzed under laboratory conditions. The selected honeydews were excreted by Saissetia oleae and Euphyllura olivina, two olive pests, and the selected plants were seven abundant species in the olive grove agroecosystem that bloom simultaneously with the flight period of the anthophagous generation of P. oleae. In this work, some of these resources were identified as potential food sources for P. oleae. Despite the general findings, which indicate that honeydews have less nutritional value for insects than nectar, P. oleae reached the best survival and reproduction performance with the insects’ honeydews. Several of the tested flowers were identified as potential food resources for P. oleae, being Malva sylvestris the one that originated the best performance. Moreover, our results suggest that P. oleae females are synovigenic and emerge with nutritional reserves for reproduction. We highly recommend accomplishing further research before establishing these resources in biological control methods in order to confirm their effect on pests in fields.
- Efecto del paisaje y del manejo del olivar sobre la polilla del olivo Prays oleae (Bernard)Publication . Villa, María; Santos, Sónia A.P.; Sousa, J. Paulo; Ferreira, Alberto; Silva, Pedro Martins; Patanita, M. Isabel; Ortega, M.; Pascual, Susana; Pereira, J.A.El manejo del paisaje y los cultivos puede constituir una herramienta importante para la implementación de estrategias de control biológico por conservación, como consecuencia de la contribución que el uso de diseños paisajísticos adecuados y la aplicación de determinados manejos pueden representar en el incremento de las necesidades y la acción de los enemigos naturales. En el presente trabajo fue realizado un estudio multi-escala sobre el efecto de la estructura del paisaje y el manejo del cultivo en la polilla del olivo, Prays oleae. Para ello, se analizó: (i) la respuesta de la plaga a la estructura del paisaje a diferentes escalas usando como variables explicativas diferentes índices de composición y configuración del paisaje previamente seleccionados; (ii) la respuesta de la plaga al manejo de olivar (integrado y orgánico). El análisis fue realizado mediante modelos aditivos generalizados mixtos. Los resultados indicaron que varios índices de composición del paisaje (índices de biodiversidad, presencia de matorrales y de otros cultivos) influenciaron negativamente la abundancia de la polilla del olivo siendo el efecto menor a escalas mayores. Sin embargo, el efecto de los índices de configuración no fue concluyente. La latitud y probablemente las diferencias climáticas se mostraron determinantes en la abundancia de la polilla del olivo. El manejo del cultivo sin embargo no afectó a la plaga. Por tanto, los diseños de la composición del paisaje a pequeña escala parecen ser cruciales para el control de la polilla del olivo. Cabe destacar que la configuración y el manejo a escalas mayores podrían ser importantes para otras plagas y enemigos naturales, debiendo tenerse en consideración en el diseño de estrategias para control biológico por conservación en olivar.
- Effect of different plant species and temperatures on the survival of Philaenus spumariusPublication . Villa, María; Lantero, Ester; Pereira, J.A.The spittlebug Philaenus spumarius (L.) has been identified as vector for the damaging bacterium X. fastidiosa in Europe. The knowledge about this insect biology and survival developing on native plants from Europe is crucial to establish ground cover management strategies in olive orchards to control the X. fastidiosa spread. In this study we aimed to evaluate the survival of adults developing on two native and common plants in Europe as well as the effect of different temperatures on the P. spumarius survival. The species selected for the survival analysis were Medicago arabica (L.) Huds. and Sanguisor baverrucosa (Link exG.Don) Ces. These plants are distributed all across Europe and presented foams near the campus, where they were collected. New born adults (<24h) were used for survival analysis. Six treatments (M. sativa 21⁰C, M. sativa 25⁰C, S. verrucosa 21⁰C, water 21⁰C, water 25⁰C and water 4⁰C) with 21 to 30 replicates were accomplished. Results indicated that survival of P. spumarius could improve when developing on different plants species. Variation in temperatures also affected the P. spumarius survival, being particularly remarkable the improvement of survival under 4⁰C when compared with the other water treatments.
- Ground cover management affects parasitism of Prays oleae (Bernard)Publication . Villa, María; Santos, Sónia A.P.; Mexia, António; Bento, Albino; Pereira, J.A.Spontaneous ground covers comprise ecological infrastructures that may provide food, alternative hosts and shelter for parasitoids in olive groves, thus contributing to biological control of pests. This study investigated the effects of herbicide application, tillage, and conservation of spontaneous ground covers on parasitism of the anthophagous generation of the olive moth, Prays oleae (Bernard). The study was performed in northeast Portugal in 2011 and 2013 in 14 and 15 olive groves, respectively, with different management types. Generalized Estimating Equations (GEE) were used to analyze olive moth emergence, overall parasitism rate, relative abundance of parasitoid species, and total parasitismof olive moth larvae. Ageniaspis fuscicollis (Dalman) accounted for the majority of the parasitism, followed by Elasmus flabellatus (Fonscolombe). In both years, ground cover management type did not influence the emergence rate of P. oleae. However, overall parasitism rate, emergence of A. fuscicollis, and the number of A. fuscicollis emerging per olive moth larvae varied among years. In 2011, the latter response variables were significantly higher in groves with spontaneous ground cover than in those treated with herbicide, indicating a negative effect of herbicides on parasitoids. Although tilled groves obtained higher values for these variables in 2013, parasitism rates were generally very low. In sum, the management of ground covers seemed to influence the overall rate of P. oleae parasitism in some years, but longer-term experiments are needed to clarify this trend.
- Life-history parameters of Chrysoperla carnea s.l. fed on spontaneous plant species and insect honeydews: importance for conservation biological controlPublication . Villa, María; Santos, Sónia A.P.; Benhadi-Marín, Jacinto; Mexia, António; Bento, Albino; Pereira, J.A.Chrysoperla carnea s.l. (Stephens) (Neuroptera: Chrysopidae) larvae are generalist predators feeding on many crop pests while adults feed on nonprey food. The knowledge about the nutritional suitability of non-prey food for adults in agroecosystems is crucial to establish conservation biological control strategies and is poorly known in olive groves, where C. carnea s.l. larvae prey on different pests. In this study, the effect of honeydew secreted by two hemipteran olive tree secondary pests and 11 plant species on the life-history parameters (survival, reproduction and development time) of C. carnea s.l. were analyzed. Insect pest honeydew from the olive agroecosystem and several plant species, blooming throughout the year, were found to improve C. carnea s.l. adult survival. Pollen consumption seems to be essential for reproduction. These findings are important for designing and implementing new conservation biological control approaches.
- 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.
- Quercus pyrenaica Forests Under Contrasting Management Histories in Northern Portugal: Carbon Storage and Understory BiodiversityPublication . Pousa, Eduardo; Villa, María; Souza, Júlio Henrique Germano de; Castro, MarinaOld-growth forests are crucial for biodiversity conservation and climate change mitigation due to their high carbon storage, structural complexity, and resilience to environmental stressors. Yet, such ecosystems are rare in Europe, and their ecological functioning remains poorly understood. This study assesses the capacity of Quercus pyrenaica forests in the Montesinho-Nogueira Natura 2000 site (Bragança, Portugal) to develop maturity attributes under different forest management histories. We compare an area with low human intervention for over 80 years (10.2 ha) to two areas harvested for traditional small-scale firewood and timber extraction around 30 years ago (11.4 ha and 2.73 ha). Dendrometric measurements, carbon storage, floristic inventories of understory vegetation, and regeneration surveys were conducted across 42 sub-plots during June–July 2024. Results show that older forests store significantly more carbon and support greater biodiversity, evenness and regeneration, while younger forests present higher values of species richness, including several rare taxa. Our findings suggest that under favorable conditions, secondary forests can recover substantial biomass and carbon stocks within a few decades, while mature stands continue to accumulate carbon and maintain complex structures. Differences in floristic composition between sites may also reflect distinct silvopastoral practices between patches, such as itinerant grazing through forest patches, which historically characterized the Montesinho landscape. These results highlight the value of preserving a mosaic of successional stages, as both mature and intermediate-phase forests, together with compatible human activities, provide complementary biodiversity benefits and contribute to the multifunctionality of Mediterranean agroforestry systems.
- Recursos polínicos explorados por Chrysoperla carnea (Stephens) no agroecossistema olivalPublication . Villa, María; Somavilla, Iana; Santos, Sónia A.P.; Pereira, J.A.Os estádios larvares de Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) são predadores generalistas de artrópodes e têm sido amplamente utilizados na regulação de diversas pragas, nomeadamente nas da oliveira. No entanto, os adultos são glicopalinofagos e necessitam da presença de recursos florísticos nas parcelas agrícolas ou nas suas áreas adjacentes. O conhecimento sobre os potenciais recursos alimentares explorados pêlos adultos de C. carnea no olival é limitado mas necessário para estabelecer medidas de proteção biológica por conservação. O objetivo do presente trabalho foi identificar os recursos florísticos consumidos pêlos adultos de C. carnea no agroecossistema olival. Para tal, foi analisado o conteúdo polínico do tubo digestivo de indivíduos capturados em olivais localizados na zona de Mirandela, de abril a dezembro de 2012 e 2013. Os adultos foram inteiramente submetidos a acetólises para eliminar os conteúdos celulares dos grãos de pólen e facilitar quer a observação da exina quer a sua identificação e contagem. Simultaneamente, foram identificadas as espécies vegetais, herbáceas e arbustivas, presentes no olival e nas parcelas adjacentes: foi registada a abundância de cada espécie e, posteriormente, foram agrupadas por tipos polínicos. Finalmente o conteúdo polínico no tubo digestivo foi comparado com a abundância das espécies vegetais observadas nas parcelas. Foram identificados mais de 50 tipos polínicos em 295 adultos. O tipo mais consumido foi o pertencente a Olea, seguido do tipo Brassicaceae, Fabaceae (arbustivas do tipo Cytisus/Genista), Plantago e diferentes tipos de Asteraceae. A família Cistaceae também apresentou uma abundância relevante. Os adultos de C. carnea presentes no olival utilizaram recursos presentes tanto nas parcelas de olival como nas parcelas adjacentes. Neste sentido, a gestão do olival numa perspectiva de promover a proteçao biológica por conservação deverá ter em conta não só o olival e a manutenção da sua cobertura vegetal mas também as parcelas adjacentes com vegetação arbustiva.
- Syrphids feed on multiple patches in heterogeneous agricultural landscapes during the autumn season, a period of food scarcityPublication . Villa, María; Santos, Sónia A.P.; Marrão, Rosalina; Pinheiro, Lara Alina; López-Sáez, José António; Mexia, António; Bento, Albino; Pereira, J.A.Many syrphid larvae are predators and have an important role as biological control agents of pests in agroecosystems. However, adults feed on non-prey resources such as pollen from flowers. Heterogeneous landscapes can provide syrphids with a great biodiversity of plants and ensure the existence of food resources. This is particularly important during periods of food scarcity, such as autumn, for syrphid species that spend those periods as adults. Nevertheless, the feeding habits of syrphid adults in resource-scarce agroecosystems are poorly known. In this study, the pollen consumption and preferences of Eupeodes corollae (Fabricius) and Episyrphus balteatus (De Geer) were analyzed in olive groves and surrounding herbaceous and woody patches in the autumns of 2012 and 2013 in northeastern Portugal. The guts were dissected, and the pollen types were identified and compared with the ground cover plants in the studied patches. Both species consumed and selected pollen types from herbaceous and woody vegetation that occurred in different patches, indicating that they flew between patches. These results highlight the importance of conserving heterogeneous agricultural landscapes to guarantee the existence of food resources for beneficial insects during periods of scarcity.