Syrphids are holometabolic insects that provide several ecosystem services. In
Mediterranean perennial crops, these insects play a fundamental role in the biological
control of pests, in the pollination of agricultural crops and adjacent vegetation , and in
the decomposition of organic matter, while the inter-rows provide shelter for other natural
enemies, thus favouring predation and parasitism of crop pests. However, the ecosystem
services provided by these insects or other arthropods have been compromised due to the
simplification of the landscape, reduction of seminatural habitats, and increase in
urbanization and agriculture. Therefore, understanding how the surrounding landscape of
the crops and ground cover vegetation composition affects the syrphids is essential to
implementing strategies to promote the presence of the Syrphids in the Mediterranean
perennial crops and busting its ecosystem services. For that, this work was divided into
two parts. In the first (Chapter 3), the Syrphidae community in Portuguese vineyards was
described, and the response of the most abundant species, Sphaerophoria scripta
Linnaeus, 1758, and Melanostoma mellinum Linnaeus, 1758, to the landscape
composition and configuration within a gradient of distances (500, 1000, and 2000 m)
from the sampled vineyards was studied. And in the second (Chapter 4), the flowering
plants present in olive groves' vegetation cover were described, and these plant families'
effect on the abundance of S. scripta was studied. Our results in vineyards showed that
the presence of seminatural habitats and other crops in the surrounding landscape
increased the abundance of S. scripta and M. mellinum, at the largest distance. In contrast,
the artificial territory, olive orchards, and vineyards reduced M. mellinum at some of the
buffers. In olive groves, 90 plant species belonging to 20 families were identified in the
ground cover vegetation of olive groves. Asteraceae was the dominant flowering family,
followed by Poaceae. The flowering plants of the families Campanulaceae, Asteraceae,
Orobanchaceae, and Plantaginaceae in the ground cover vegetation promoted the
abundance of S. scripta in the olive grove. On the other hand, flowering plants of the
families Poaceae and Polygonaceae negatively affect the abundance of this syrphid.
Increasing seminatural habitats in the surrounding landscape and the percentage of plant
families more attractive in the adjacent vegetation and/or inter-rows in the Mediterranean
perennial crops may favour syrphid abundance.
