Showing papers on "Uroleucon published in 2007"

Ant–Aphid Interactions: Are Ants Friends, Enemies, or Both?

Abstract: Interactions between ants and aphids range from mutualistic to antagonistic. Understanding the ecological basis for such interactions requires understanding the costs and benefits to the aphids of ant-tending. Such an analysis is not simple, because ants can simultaneously have positive and negative effects upon aphids. The aphids Pleotrichophorus utensis Pack & Knowlton and Uroleucon escalantii Knowlton (both Hemiptera: Aphididae) are occasionally tended by Formica obscuripes Forel (Hymenoptera: Formicidae) at field sites in central Colorado. To compare the relative effects of protection and predation by ants on aphid abundance, we experimentally crossed the presence of the ants and other predators on host plants on which one or both aphids occur. Within a week of the start of the experiment, ants had a strong negative impact on aphid numbers that lasted the course of the experiment. Nonant predators initially had a weak negative effect on aphids, but by the end of the experiment, the negative effect of nonant predators was similar in magnitude to the effect of the ants. The negative effect of ants and other enemies on aphids was nonadditive; simultaneous predation by ants and other enemies was not as strong as expected from estimates of predation rates by only ants or only other enemies. This study suggests that ants simultaneously protect and prey upon aphids. We suggest selection to appease ants and to gain protection from ants can both be important forces generating ant-aphid mutualisms.

The genus Uroleucon (Hemiptera: Aphididae: Macrosiphini) in Argentina, with descriptions of five new species.

Abstract: Uroleucon is one of the largest genera of Macrosiphini, with 216 known species; it is one of the few genera of Aphidinae to have a diversification in South America, with 15 native species and 1 subspecies Moreover, 7 introduced species have been recorded in South America Five new species from Argentina are described herein: Uroleucon malarguense Ortego and Nieto Nafria, sp nov, U mendocinum Mier Durante and Ortego, sp nov, U patagonicum Nieto Nafria and Seco Fernandez, sp nov, U payuniense Ortego and Nieto Nafria, sp nov, and U riojanum Nieto Nafria and Mier Durante, sp nov One Palearctic species, U jaceae (Linnaeus), has been recorded for the first time in South America, and thus 28 species and 1 subspecies are now known from South America Uroleucon essigi Carvalho and U chilense (Essig) are recorded for the first time from Argentina, and 20 of these 29 taxa are known for this country New morphological and bionomic data from some previously known species are given Alate viviparous females of U gochnatiae Delfino and oviparae and males of U bereticum (Blanchard) and U macolai (Blanchard) are described A taxonomic discussion about native South American species of Uroleucon is given, and we include them at present in the subgenus Lambersius A key is provided for the identification of apterous and alate viviparous females

First records of some aphid species from Western Siberia (Homoptera: Aphididoidea).

Abstract: For the first timc, Protaphis dudichi (Bumer, 1940), Protnphis picridicola Holman, 1966 and Uroleucon (Lnmbersius) erigeronense (Thomas, 1878) arc recorded from Russia and Stomaphis quercus (Linnaeus, 1758), Anoecia (Paranoecia) pskovika Mordvilko, 1916, Euceraphis betulae (ICoch, 1855), Aphis etcphorbine Kaltenbach, 1843, Aphis molluginis (Bbmer, 1950), Aphidurapicta Hillc Ris Lambers, 1956, Myzus (Galiobium) langei (Rdrner, 1933) and Sitobion (Metobion) graminearum (Mordvilko, 191 9), from Western Siberia.