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Yield losses caused by pests, including aphids, can be substantial in cereals. Breeding for resistance against aphids is therefore desirable for enhancing the economic and environmental sustainability of cereal production. The aim of our study was to reveal the degree of antibiosis against Metopolophium dirhodum (Walker) (Homoptera: Aphididae), in four cultivars of spring wheat, Triticum aestivum L. (‘Alicia’, ‘Odeta’, ‘Libertina’, ‘Astrid’), and two cultivars of emmer, Triticum turgidum ssp. dicoccum (Schrank ex Schübler) Thell. (‘Rudico’, ‘Tapiruz’) (both Poales: Poaceae) under controlled laboratory conditions. Using age-stage, two-sex life table, we quantified responses of M. dirhodum to each cultivar and to project population growth. The spring wheat and emmer cultivars varied in their suitability to M. dirhodum. The cultivar most susceptible to M. dirhodum was the emmer cultivar ‘Rudico’; the projected population size of M. dirhodum on this cultivar was one order of magnitude larger than those on other cultivars. The most resistant cultivar was the spring wheat cultivar ‘Libertina’. Since emmer is commonly used as a gene source for breeding T. aestivum, we advocate that care be taken to avoid the transmission of genes responsible for suitability to aphids from emmer to T. aestivum.

Temperate forest canopies support a high diversity of insects, but in comparison to the tropics, little is known about insect spatial distribution, particularly in terms of vertical stratification. 2 We used an aerial lift platform to sample a temperate floodplain forest canopy during two seasons. We aimed to describe patterns of aphid density and diversity in terms of vertical canopy stratification within a 0.2 ha forest plot. 3 Vertical gradient affected both the density and diversity of aphids. There was no general pattern in aphid distribution that applied to the eight tree species included in our survey. The aphid taxocoenosis was stratified differently on particular tree species and changed during the season. 4 Species composition was better explained by aboveground absolute position (in m), while aphid density was better explained by relative height in the tree (position in the crown). Considering that these factors were significant but that the same statistical models excluding any influence of relative or absolute position provided more robust explanations, we concluded that aphid spatial distribution in temperate forests is difficult to simplify. This likely depends on environmental factors, such as wind direction and strength, that affect aphid flight and landing.