Biological control is the use of natural enemies, such as predators, of crop pests. For instance, Chrysoperla carnea (Stephens) is a major predator of olive grove pests. To favor the abundance of C. carnea, flowering plants should provide them with carbohydrates. However, there is a lack of knowledge on the biology of flowering plants that grow in olive groves. Therefore, we studied in the laboratory 11 native Mediterranean plants commonly found in traditional olive orchards as food sources for C. carnea adults. Male and female longevity and female lifetime fecundity were measured on a daily base. Plant nectar and pollen were quantified by highperformance anion-exchange chromatography analysis (HPAEC-PAD). Our results show that the longevity of C. carnea females was higher, of 17 days, when fed with Conopodium majus flowers, and of 14 days when fed with Lonicera hispanica flowers. Female fecundity was higher for C. carnea individuals fed with C. majus, giving 71 eggs, and with Foeniculum vulgare, giving 66 eggs, than for C. carnea individuals fed with L. hispanica (19 eggs) and Asparagus acutifolius (4 eggs). These findings are explained by the higher concentration of trehalose in plant nectar and pollen. To our knowledge, this is the first study evaluating the sugar profile and content of Mediterranean flower plants as food resource of C. carnea adults indicating that trehalose content in pollen and nectar has a key role in C. carnea fecundity and longevity.

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Considering the present ecological crisis, land use-biodiversity relationships have become a major topic in landscape planning, ecosystem management and ecological restoration. In this scope, consistent patterns of outstanding biodiversity have been identified in agroforestry systems within diverse biogeographic regions and types of management. Empirical work has revealed that agroforestry higher structural complexity, when compared with current simplified agricultural systems, might be partially responsible for the observed patterns. The recently developed Habitat Amount Hypothesis predicts diversity for a local habitat patch, from the amount of the same habitat within the local landscape. We have expanded the previous hypothesis to the landscape level, computing the influence of the dominant land uses on the diversity of coexisting guilds. As a case study, we have considered archetypal landscapes dominated (or co-dominated) by crops or trees, which were compared using normalized diversities. The results obtained show that agroforestry systems substantially increase functional diversity and overall biodiversity within landscapes. We highlight that the normalized values should be parametrized to real conditions where the type of crop, tree and agroecological management will make a difference. Most importantly, our findings provide additional evidence that agroforestry has a critical role in enhancing biodiversity in agricultural landscapes and, in this way, should be regarded as a priority measure in European Agri-environmental funding schemes.

The longevity and reproduction of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) when fed on ten naturally occurring sugars and on an artificial diet composed by honey and pollen (1:1) were evaluated. The effect of these diets differed between sexes. However insects of both sexes lived longer when fed on fructose than on sucrose, melezitose or raffinose. None of the females oviposited when offered raffinose, galactose or mannose. Moreover, lifetime fecundity of females fed on trehalose was not different from the artificial diet. The intrinsic rate of natural increase did not differ between trehalose, maltose, melibiose, fructose, glucose and artificial diet, being significantly lower for individuals fed on melezitose and sucrose. The importance of these results for the selection of natural sugar sources that enhance C. carnea effectiveness as a biological control agent against crop pests is discussed.