Showing papers on "Uroleucon published in 1986"
TL;DR: The morphology of host‐specific Old World Uroleucon (Homoptera: Aphididae) species is related to features of their host plant species by canonical correlation analysis and the positive relationship between rostrum length and host trichome density is supported.
Abstract: The morphology of host-specific Old World Uroleucon (Homoptera: Aphididae) species is related to features of their host plant species (Asteraceae and Campanulaceae) by canonical correlation analysis. Aphid species on pubescent host species have longer rostra and shorter hind tarsi, adaptations for feeding and walking on hirsute surfaces. Also, aphid species on taller hosts are larger. The positive relationship between rostrum length and host trichome density is further supported by simple regression analyses on two species complexes. Regression parameters differ between groups, suggesting different responses to different trichome types. This morphological adaptation involves characters used extensively by taxonomists and could result in convergence obscuring phylogenetic relationships of herbivore taxa and, particularly, the relation of herbivore phylogeny to host phylogeny.
54 citations
TL;DR: In experiments using potted host plants, the specialist was better able than the generalist to escape predation by walking to nearby hosts, and this strategy of persistence depends on specificity to a long-lived, clumped, bushy host such as S. nemoralis.
Abstract: Benefits of host specificity for Uroleucon nigrotibium (Homoptera: Aphididae) include not only improved physiological efficiency but also enhanced success of dispersal and defense tactics. I tested the physiological efficiency hypothesis, which predicts a higher reproductive rate for this specialist than for the generalist U. gravicorne when each is reared on their shared host, Solidago nemoralis. Between-species comparisons of developmental times and fecundities of individuals reared on naturally occurring and potted screenhouse host plants supported this prediction for the spring but not in summer, when most reproduction occurs. Greater physiological efficiency of the specialist is also supported by its greater size, which may aid in dispersing and in escaping enemies by walking. Field colonies of the specialist were found to produce few winged forms and to disperse frequently via apterae walking between hosts; consequently, U. nigrotibium infestations are larger and longer lived and are attacked more by enemies than those of its generalist congener. In experiments using potted host plants, the specialist was better able than the generalist to escape predation by walking to nearby hosts. This strategy of persistence depends on specificity to a long-lived, clumped, bushy host such as S. nemoralis.
36 citations
TL;DR: A key is given for 29 species in the subgenus Lambersius Olive in America north of Mexico and descriptions for the following 7 new species: Uroleucon (Lambersius) carberriensis n.
Abstract: A key is given for 29 species in the subgenus Lambersius Olive in America north of Mexico. An annotated list is provided for 22 species, and descriptions for the following 7 new species: Uroleucon (Lambersius) carberriensis n. sp., U. (L.) clydesmithi n. sp., U. (L.) coloradensis n. sp., U. (L.) manitobensis n. sp., U. (L.) nevadensis n. sp., U. (L.) penderum n. sp., and U. (L.) suzannae n. sp. Uroleucon (Lambersius) tissoti (Boudreaux) is declared to be a synonym of U. (L.) luteolum (Williams) and U. (L.) baccharidis (Clarke) as a nomen dubium.
10 citations