A new Spanish species of Linaria Miller (Scrophulariaceae)

Linaria arabiniana sp. nov. is described from coastal sand dunes of a very reduced area in Alicante Province (south-eastern part of the Iberian Peninsula). It is a perennial herb characterized by its 3–4-verticillate leaves, glabrous stems, large violet or rarely yellow flowers, and bicoloured usually flat seeds. Morphological characteristics and taxonomic affinities of this taxon are discussed, as are data on its ecology, phytosociology, and eventual conservation features.     

Synomone-induced suppression of take-off in the phytoseiid mite Phytoseiulus persimilis Athias-Henriot

Plant-inhabiting predatory mites in the family Phytoseiidae are known to disperse passively on air currents. In this article ww analyse observations on the behaviour that initiates aerial dispersal, the so-called take-off behaviour. When starved for 24 hours at 25°C and 35% RH, about 80% of the females of Phytoseiulus persimilis Athias-Henriot became airborne during 10 minute exposure to wind velocities of 2 ms^-1 or higher. However, take-off was suppressed when females were exposed to volatile chemicals emanating from leaves that had been infested by two-spotted spider mites (Tetranychus urticae Koch) during one day preceding the experiments. This result is the first unambiguous proof that phytoseiid mites exert control over take-off. Interestingly, the females of the predator strain under study did not show the characteristic upright posture that was hypothesized to be important for take-off in two other species of phytoseiid mites (Amblyseius fallacis Garman and Metaseiulus occidentalis (Nesbitt)). These observations shed new light on the behaviour involved in controlling take-off. It is suggested that take-off control is exerted mainly via the grasp of the claws and the adhesive empodia in a way reminiscent of that described for aphids.