Miofilia en el cultivo protegido de mango (Mangifera indica L.) y sandía (Citrullus lanatus Thunb.) por el sírfido Eristalinus aeneus (Scopoli, 1763) (Diptera: Syrphidae)

Abstract

Pollination in protected crops plays a fundamental role in crop productivity and, therefore, its profitability. Yield of protected crops can be reduced by the lack of or incorrect management of pollinating insects inside greenhouses. It should be noted that pollinating insects studied so far for this purpose show different behavior depending on the crop where they are found, even presenting considerable floral preferences that can trigger pollination deficits in those flowers not visited. This happens due to the important modification of environmental conditions in greenhouses or the scarcity of floral resources. During the last few years, the industrial development of insect pollinators has undergone an important impulse (Chapter I). After previous positive field experiences, this Doctoral Thesis proposes the use of eristaline syrphids, more specifically the species Eristalinus aeneus (Scopoli, 1873), as a pollinator of two crops of great importance: watermelon (Citrullus lanatus Thunb.) and mango (Mangifera indica L.), both under greenhouse conditions. First, floral rewards and attractions that these two crops presented and that could influence the behavior of E. aeneus were studied. It was observed that the biology, phenology and floral rewards offered by the crops favored the attraction of syrphids (Chapter II and V). The activity pattern of E. aeneus presented a good adaptation to a wide range of environmental conditions. In addition, its behavior was optimal, with a high number of visits to mango and watermelon flowers in search of pollen and nectar (Chapter III and VI). This Thesis also proved the effect of three release densities of this insect on the production of both crops. It was proved that a release density of 30-45 individuals/m2 offers optimum results on the production and quality of mango and watermelon fruits (Chapter IV and VII). Finally, the equal production of watermelon under protected cultivation through pollination with E. aeneus with respect to that obtained through the usual management of pollination with Apis mellifera (Linnaeus, 1758), confirms the good aptitude of this syrphid as an alternative pollinator of this emblematic crop in Almería (Chapter VIII).