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Sustainability of agroecosystems depends on the ecosystem services, provided by beneficial organisms, such as the syrphids (Diptera: Syrphidae) acting as other‐insect predators and pollinators in different crops. In the case of olive groves, syrphids are predators of important pests and are endangered by the continuous intensification of agriculture, including landscape simplification. In this work, the effect of landscape structure on the abundance and species richness of syrphids in the olive agroecosystem of central Spain is assessed. Adult syrphids were sampled in 2015 and 2016 in the centre of circular areas of 15 olive grove landscapes (from 250 to 1500 m radius) representing a gradient of landscape complexity, in the province of Madrid, central Spain. The syrphid assemblage was made up of 57 species, although Eupeodes corollae, Eristalis tenax, Eristalis similis and Chrysotoxum intermedium made up 76% of the captures. Syrphid abundance and species richness were favoured in complex landscapes, with low olive grove area (CAO). Other landscape indices showed also this trend although their effect was not as strong and consistent as that of CAO. The area of scrublands (CAS) favoured syrphids in spring, but was unfavourable in autumn. The effect of Shannon's Evenness Index (SHEI) and mean shape index (MSI) was less consistent. The effect of CAO increased with increasing buffers radii, while the effect of CAS, SHEI and MSI was detected in general at smaller radii, indicating these indices affect different processes. Redundancy analysis (RDA) detected some differences between species regarding their abundance in spring autumn, and their relationship with landscape indices. This work provides new evidence that maintenance of complex landscapes is essential for maintaining functional biodiversity in the olive agroecosystem., Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Sustainability of agroecosystems depends on the ecosystem services, provided by beneficial organisms, such as the syrphids (Diptera: Syrphidae) acting as other-insect predators and pollinators in different crops. In the case of olive groves, syrphids are predators of important pests and are endangered by the continuous intensification of agriculture, including landscape simplification. In this work, the effect of landscape structure on the abundance and species richness of syrphids in the olive agroecosystem of central Spain is assessed. Adult syrphids were sampled in 2015 and 2016 in the centre of circular areas of 15 olive grove landscapes (from 250 to 1500 m radius) representing a gradient of landscape complexity, in the province of Madrid, central Spain. The syrphid assemblage was made up of 57 species, although Eupeodes corollae, Eristalis tenax, Eristalis similis and Chrysotoxum intermedium made up 76% of the captures. Syrphid abundance and species richness were favoured in complex landscapes, with low olive grove area (CAO). Other landscape indices showed also this trend although their effect was not as strong and consistent as that of CAO. The area of scrublands (CAS) favoured syrphids in spring, but was unfavourable in autumn. The effect of Shannon's Evenness Index (SHEI) and mean shape index (MSI) was less consistent. The effect of CAO increased with increasing buffers radii, while the effect of CAS, SHEI and MSI was detected in general at smaller radii, indicating these indices affect different processes. Redundancy analysis (RDA) detected some differences between species regarding their abundance in spring versus autumn, and their relationship with landscape indices. This work provides new evidence that maintenance of complex landscapes is essential for maintaining functional biodiversity in the olive agroecosystem.

The olive fruit fly (olf) Bactrocera oleae is the most damaging olive pest. The intensive use of organophosphates (OPs) to control it, led to an increase in resistance in field populations. This study assesses the presence and distribution of three mutations at the ace gene related to target site insensitivity to OPs in Spain. Samples from other Mediterranean countries were included as external references. Resistance-conferring alleles (from exons IV and VII of the ace gene) reached almost an 80% frequency in olf Spanish populations. In total, 62% of them were homozygous (RR/RR), this being more common in eastern mainland Spain. High frequencies of RR/RR individuals were also found in North Mediterranean samples. Conversely, in Tunisia, only sensitive alleles were detected. Finally, the exon X mutation ∆Q3 had an extremely low frequency in all samples. The high frequency of genotype RR/RR in Spain indicates high fitness in an agroecosystem treated with pesticides, in contrast to ∆Q3. At exon IV all flies carried the same haplotype for the allele conferring resistance. The sequence analysis at this exon suggests a unique origin and fast expansion of the resistant allele. These results provide evidence that OPs appropriate use is needed and prompt the search for alternative methods for olf pest control.

The European Union (EU) is facing the recent arrival of the bacterium Xylella fastidiosa. Its fast spread has caused great alarm because of the economic impact it implies for the agroeconomy of European countries. Among its insect vectors, Philaenus spumarius has been demonstrated to transmit the bacterium from infected to uninfected trees in the EU, where different measures have been established to control it. One of the proposals to manage this vector is the augmentation of natural enemy populations. However, the identification of candidate predator species is essential if such a management system is to be introduced. The present paper describes a set of species-specific primers designed to detect the presence of P. spumarius DNA in soil arthropod fauna generalist predators’ gut which can reveal candidate species for the pest’s biological control. Such primers have been proven to be a useful and reliable taxonomic tool for P. spumarius identification at any life stage, i.e., nymphs. This rapid and accurate identification is essential for control strategies designed to avoid the spread of the pest and consequently the considerable economic losses it causes in crops.

Bactrocera oleae, the olive fruit fly, is a major pest of olive (Olea europaea L.) trees worldwide. Its presence can cause important losses, with consequences for the economies of countries that produce and export table olives and olive oil. Efforts to control olive fruit fly populations have, however, been insufficient. Now more than ever, environmentally friendly alternatives need to be considered in potential control programs. Generalist predators could provide a way of managing this pest naturally. However, the identification of candidate predator species is essential if such a management system is to be introduced. The present paper describes a set of species-specific primers for detecting the presence of B. oleae DNA in the gut of predatory arthropods. All primers were tested for checking cross-reactive amplification of other fruit fly DNA and evaluated in heterospecific mixes of nucleic acids. All were found to be very sensitive for B. oleae. Subsequent feeding trials were conducted using one of the most abundant species of ground dwelling carabids in olive groves in south-eastern Madrid, Spain. These trials allowed determining that 253F-334R and 334F-253R primer pairs had the highest detection efficiency with an ID50 of around 78 h. These primers therefore provide a very useful tool for screening the gut contents of potential predators of B. oleae, and can thus reveal candidate species for the pest's biological control.