The Geomorphological Landscape of Trás-os-Montes and Alto Douro

Abstract

The main geomorphological features of the eastern part of the Trás-os-Montes and Alto Douro region are presented, namely the Iberian Meseta, the residual ridges, the Serra de Montesinho, the tectonic landforms and the Douro River incision. The Iberian Meseta is represented by extensive plateaus shaped in pre-Mesozoic rocks of the Iberian Massif. Above the Meseta plateaus, Appalachiantype reliefs are built in metamorphic rocks, testifying an older planation surface. Below the plateaus, the incised river network and the canyon-type Douro River Valley in the Portugal-Spain border region reveal a recent Atlantic capture of the northern interior of Iberia. Nonetheless, it is the Vilariça NNE-SSW trending strike-slip fault system that is the main source for the push-up elevations and strike-slip tectonic basins bordered by pop-up type mountains that define the tectonic landscape of the region.

An autoparasitoid wasp, inferior at resource exploitation, outcompetes primary parasitoids by using competitor females to produce males

“…This pestiferous insect is oviparous and parthenogenetic. It has one annual generation, although in the studied region a second partial generation is possible in olive trees (Pereira, ; Tena et al ., ). Eggs are laid at the end of spring and in autumn when the second generation occurs.…”

“…The first instar, also known as the crawler, is mobile and is not attacked by parasitoids. The second and third instars are the predominant instars from September to May and they tend to settle on leaves (Pereira, ; Tena et al ., ). There, they are attacked by a complex of parasitoids dominated by the genus Metaphycus and Coccophagus .…”

“…Adults of coccid are attacked by the parasitoid Metaphycus lounsburyi (Howard) (Hymenoptera: Encyrtidae). Saissetia oleae oviposition occurs predominantly from the end of May to July, the eggs of which are attacked by the egg predator Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae) (Pereira, ; Tena et al ., ).…”

“…The three species of Metaphycus [ M. helvolus , M. flavus (Howard) and M. lounsburyi ] were included in the research. The two former species are the main parasitoids of S. oleae nymphs in the Mediterranean region (Pereira, ; Tena et al ., ), whereas M. lounsburyi is often considered specific to adult scales, even though it has also been recovered from immature instars (Pereira, ; Tena et al ., ; Tena & Garcia‐Marí, 2009). The three species are facultatively gregarious endoparasitoids (generally a single egg is laid inside the host but not always), arrhenotokous (unfertilised eggs produce males and fertilised eggs produce females), and synovigenic (females emerge with at most a small fraction of their lifetime complement of mature eggs).…”

“…Here, we report data on insects sampled at 40 olive orchards where several primary parasitoids of the Metaphycus genus and one autoparasitoid, C. lycimnia , coexist simultaneously and regulate the black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) (Pereira, ). These data were used to analyse the mechanisms that regulate the interspecific competition between primary parasitoids and an autoparasitoid, as well as whether this competition affects the density of their shared coccid host.…”