Macrosiphum euphorbiae (potato aphid).

Host-alternating populations of M. euphorbiae disperse through migratory flights in the spring and autumn. The spring migration takes aphids from the over-wintering host-plant (Rosa spp.) to a wide range of secondary host-plants, including potato, tomato, lettuce and other cultivated plants. Non-host alternating populations can survive year-round on secondary hosts, especially in greenhouse and other indoor environments. Aphids can be carried on foliage in trade. There is little evidence to suggest that the geographical range of this aphid is currently expanding.

Patterns of coordination of the development of Rhopalosiphum padi (L.) (Hemiptera, Sternorrhyncha, Aphididae) and its primary and secondary host plants

For example of the bird cherry-oat aphid, the analysis of the timing of development in the “plant-phytophage” system in heterocyclic aphids with alternation of the primary (winter, arboreal) host plant to the secondary (summer, herbaceous) ones was done. The similarity in the phenology of colonization by aphids of primary and secondary hosts was shown. The features of the stages of plant organogenesis and the formation of the number of aphids in connection with their harmfulness are noted. Modeling shifts in the synchronization of the work of this trophic system contributes to its destabilization.

Olfactory activity of ethyl (E,Z)-2,4-decadienoate on adult oriental fruit moths

We investigated whether or not pear ester (ethyl (E,Z)-2,4-decadienoate) attracted adult oriental fruit moths, Cydia molesta (Busck) (Lepidoptera: Tortricidae). The electroantennographic responses of C. molesta to pear ester were recorded and dose–response curves calculated. In laboratory bioassays, the attractiveness of different dosages was assessed in a dual-choice olfactometric arena. The responses of virgin males and females to pear ester in the presence and absence of pear (Pyrus communis L.), peach (Prunus persica (L.) Batsch.), and apple (Malus ×domestica Borkh.) (Rosaceae) shoots were evaluated. Electroantennographic recordings demonstrated that both male and female C. molesta were able to detect the pear ester. In our bioassay, however, pear ester readily attracted males but attracted very few females. The response of males was dose-dependent and they preferred pear ester over apple- and pear-shoot volatiles, whereas no apparent preference between pear ester and peach-shoot volatiles was observed. Therefore, this kairomonal compound could be more effective in attracting C. molesta when applied in orchards of secondary host plants, like apple or pear, than in peach orchards.

Variability and genetic basis for migratory behaviour in a spring population of the aphid, Aphis gossypii Glover in the Yangtze River Valley of China

The population dynamics, development of gonads, takeoff and flight behaviour of Aphis gossypii Glover were investigated in order to test whether there was variation of migratory ability in the spring population. Field surveys showed that not all the aphids overwintering on hibiscus migrated to the secondary host plants, and the host-alternating and host-specific life-cycle forms coexisted in Nanjing, China. Substantial variation in flight capacity of winged individuals, development of gonads and takeoff behaviour were found within the spring population. The frequency distribution of flight duration and the number of ovarioles per individual alatae exhibited two peaks, representing the migratory and sedentary genotypes, respectively. Significant response to directional selection on takeoff behaviour demonstrated the additive genetic component of this variation. Selection for ‘takeoff’ individuals caused a significant increase in takeoff angle from 39.8° in the first selection to 68.7° in the fifth; and, hence, screened out the migratory genotype (M), while selection for the sedentary individuals increased the rate of non-takeoffs significantly, and screened out the sedentary genotype (S). The reciprocal cross, M♀×S♂, produced hybrid offspring performing significantly steeper takeoff angles compared with those from the cross S♀×M♂, suggesting the presence of a maternal effect. On the other hand, takeoff rate was ranked as M♀×S♂=S♀×M♂>M>S, involving no sex-linkage and maternal effect. The coexistence of host-alternating and host-specific life-cycle forms of A. gossypii on the primary host has, as deduced from the present studies, a genetic basis.

Morphological discrimination of six species of the genus Anuraphis (Hemiptera: Aphididae), including description of a new species

The most relevant morphometric characteristics of six species of the genus Anuraphis Del Guercio were compared. Anuraphis shaposhnikovisp. nov. is described and its morphological differences from the closely related species Anuraphis subterranea are presented. The new species was collected in Sicily and in the central area of the Italian peninsula on Magydaris pastinacea (Lam.) Paol. (Apiaceae) and Opopanax chironium (L.) Koch (Apiaceae), which are its secondary host plants. A key to the viviparous morphs (apterae and alatae) of the seven western Palaearctic species living on secondary hosts is provided. Discriminant functions have been derived to separate both apterae and alatae of A. shaposhnikovi and A. subterranea.