Wild bees (Hymenoptera: Apoidea) play an important role as pollinators of many crops and managed populations of Osmia spp. (Megachilidae), through the installation of trap-nests, proved to be efficient in several fruit orchards. In order to optimize the trap-nest protocols, it is necessary to understand which environmental factors play a major role in the reproductive success of these bees. Here, we studied how climate, land use and vegetation affect nest occupation rate (OR, i.e. total number of colonized tunnels/total number of tunnels in the trap-nest), brood productivity (BP, i.e. total number of brood cells built in a completed nest tunnel) and parasitism rate (PR, i.e. total number of parasitized brood cells/BP) in Osmia bees nearby almond orchards in South-East Spain, a largely understudied Mediterranean area. We found that the summer solar radiation positively influenced all three parameters, while spring solar radiation positively affected OR and BP, and negatively PR. Higher abundance of pastures and forests compared with crops increased OR, though not BP, and reduced PR. Vegetation evenness and diversity of dominant plant species also positively affected OR and BP, while they were unimportant for PR. OR was not affected by climate, but BP increased with maximum temperature in the warmest month and decreased with temperature annual range. PR also increased with high temperature, as well as with precipitation. Arid conditions limited OR and BP and boosted parasitism. Overall, it seems that Osmia bees nearby almond field in this area would benefit from trap-nest installation in well solar-radiated, hot and humid sites with a diverse vegetation. Since we have also found a negative association between PR and BP in nests with at least one parasitized cell, environmental conditions which improve productivity will also likely reduce parasitism in these bees.Implications for insect conservation Optimization of trap-nesting protocols for maintaining abundant Osmia populations is crucial to an effective use of these bees as managed pollinators. In our study we suggest that trap-nests locations should be chosen also taking into account a number of local climatic and habitat factors, given their importance in affecting key traits of reproductive success in these solitary bees.

Summary Pollinators of most of the plants cultivated in the Mediterranean regions of Europe are still unknown. We provide new data and we review previously available information on bees (Apoidea) associated with three economically important crops in Spain: melon (Cucumis melo L.), watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) and almond (Prunus dulcis (Mill.) D.A.Webb). We found that, overall, 98 bee species spanning four families visit flowers of the studied crop species, and 46 additional species were sampled within the crops with pan-traps. The bee assemblages visiting melon include 7–33 species, with moderate to high importance of small Lasioglossum (Halictidae) and of honey bee (Apis mellifera Linnaeus, 1758: Apidae), and in one case of small Ceratina: Apidae. Watermelon flowers are visited by 11–14 species of bees, with highest abundance of honey bees or of small Lasioglossum, depending on the locality. Bees collected on almond trees included 12–37 species, with the honey bee and medium-size to large Andrena (Andrenidae) and Osmia (Megachilidae) being predominant. The new samples expanded the geographical distributions of nearly one-fourth of the collected species. Diversity estimators slightly varied even within fields of the same crop, and a cluster analysis suggested both a certain overlap between melon and watermelon and a role of geographical distance on similarity among bee assemblages, though these patterns were much clearer using presence data rather than abundances. Below-ground-nesting and solitary species were more frequently collected than above-ground-nesting and eusocial species, but for melon and watermelon the highest abundances were recorded for eusocial species. Almost exclusively polylectic species visited the flowers of the three studied crops. The results of this study could help in planning conservation actions to maintain this important diversity of potential pollinators in Spanish areas covered by these crops.

In spite of its incidence on pistachio trees, the chemical ecology of Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae) has been neglected so far. In this work, we provide the first evidence of a biologically active male-specific compound that may be promoting field aggregation. Headspace collections through solid-phase microextraction from feral males and females reported the presence of 2-isobutyl-3-methoxypyrazine exclusively in males. Electroantennographic recordings revealed that males and females responded in a dose-dependent manner to increasing stimuli of 2-isobutyl-3-methoxypyrazine, with females overall displaying a higher response than males. In dual-choice tests, both males and females showed a significant preference for the compound in comparison to a pure air stimulus. In light of these results, the possible role of 2-isobutyl-3-methoxypyrazine as an aggregation cue in L. lusitanica is discussed.

Se presentan los resultados de diversos muestreos llevados a cabo sobre parcelas cultivadas de pistachero en diferentes localidades de Castilla – La Mancha, en las provincias de Ciudad Real, Cuenca y Toledo. Se han encontrado un total de 8 especies de Curculionidae, de 5 géneros (Brachyderes, Otiorhynchus, Polydrusus, Sitona y Lixus) correspondientes a 2 subfamilias: ENTIMINAE y LIXINAE. Brachyderes marginellus, B. pubescens, Polydrusus subglaber, Otiorhynchus cribricollis y Lixus acicularis se han observado alimentándose de hojas de P. vera y se citan por primera vez sobre esta planta huésped. Polydrusus subglaber y Otiorhynchus cribricollis devoran intensamente sus hojas, por lo que se propone seguir investigando estas dos especies como importantes defoliadores de pistacho en la región. Se aportan datos biológicos y corológicos para las especies encontradas.

In spite of its incidence on pistachio trees, the chemical ecology of Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae) has been neglected so far. In this work we provide the first evidence of a biologically active male-specific compound that may be promoting field aggregation. Headspace collections by solid-phase microextraction from feral males and females reported the presence of 2-isobutyl-3-methoxypyrazine exclusively on males. Electroantennographic recordings revealed that males and females responded in a dose-dependent manner to increasing stimuli of 2-isobutyl-3-methoxypyrazine, with females overall displaying a higher response than males. In dual-choice tests, both males and females showed a significant preference for the compound in comparison to a pure air stimulus. In the light of these results, the possible role of 2-isobutyl-3-methoxypyrazine as an aggregation cue in L. lusitanica is discussed.