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Aphis gossypii Glover is cosmopolitan pest aphid, known to be represented by host-associated lineages. Although it is widespread in the Pacific Basin, there has been no assessment of this species in this region. We examined patterns of morphological variation within and among populations collected across hosts and islands using multivariate morphometric analyses. Genetic variation was determined using microsatellite flanking region sequences and mitochondrial cytochrome oxidase subunit 1. This study confirmed the existence of genetically distinct host-associated lineages. We found that host plant affects morphological expression and therefore morphological criteria cannot be used to identify lineages. Comments are provided on the origin and maintenance of these host lineages and implications for management of this important pest aphid species. [ABSTRACT FROM AUTHOR]

Aphis intybi Koch is recorded for the first time in North and South America. Measurements for the identification of this species in comparison with Aphis craccivora Koch are given. Aphis cytisorum Hartig is recorded for the third time in Argentina. Data on morphological variation, geographical distribution, and host plants of these species in Argentina are provided. Their morphological identification is supported by comparison of DNA sequences of the mitochondrial cytochrome oxidase subunit 1 (DNA barcode) and subunit 2. [ABSTRACT FROM AUTHOR]

The Adelgidae form a small clade of insects within the Aphidoidea (Hemiptera) that includes some of the most destructive introduced pest species threatening North American forest ecosystems. Despite their importance, little is known about their evolutionary history and their taxonomy remains unresolved. Adelgids are cyclically parthenogenetic and exhibit multigeneration complex life cycles. They can be holocyclic, with a sexual generation and host alternation, or anholocyclic, entirely asexual and without host alternation. We discuss adelgid behavior and ecology, emphasizing plant-insect interactions, and we explore ways that the biogeographic history of their host plants may have affected adelgid phylogeny and evolution of adelgid life cycles. Finally, we highlight several areas in which additional research into speciation, population genetics, multitrophic interactions, and life-history evolution would improve our understanding of adelgid biology and evolution. [ABSTRACT FROM AUTHOR]

Aphid species from 11 of the major islands of Micronesia ranging from Majuro, Republic of the Marshall Islands, in the east to Koror and Babeldaup, Republic of Palau, in the west, are documented based on 1,691 collections. Other islands sampled included Yap, Kosrae, and Chuuk in the Federated States of Micronesia; Saipan, Tinian, and Rota in the Commonwealth of the Northern Mariana Islands; and the Territory of Guam. Host-plant associations were documented at each collection site. Thirty-five aphid species were collected from 139 plant species in 43 different plant families. None of the aphids collected is indigenous to Micronesia. A key to the identification of the aphid species is provided. [ABSTRACT FROM AUTHOR]