Heteroecious
Guides
Andricus chrysolepidicola
Irregular Spindle Gall Wasp, irregular-spindle gall wasp
Andricus chrysolepidicola is a cynipid gall wasp that induces distinctive stem galls on several oak species in western North America. The species exhibits a complex heteroecious life cycle with alternating generations: first-year unisexual wasps produce irregular spindle-shaped stem galls, while second-year bisexual wasps induce bud galls. The species is primarily documented from California but has been recorded elsewhere along the Pacific coast and eastward to Nevada.
Aphthargelia
Snowberry Aphids
Aphthargelia is a small genus of aphids in the family Aphididae, tribe Macrosiphini, containing two described species. The genus was long considered monotypic until the description of A. rumbleboredomia in 2013. Both species are associated with host plants in the mountains of northwestern North America.
Capitophorus hippophaes
Polygonum Aphid
Capitophorus hippophaes is a species of aphid in the family Aphididae, first described by Francis Walker in 1852 as Aphis hippophaes. It exhibits a heteroecious life cycle, alternating between primary hosts in the genera Hippophae and Elaeagnus (family Elaeagnaceae) and secondary hosts in the genera Persicaria and Polygonum (Polygonaceae). Native to Europe, it has established populations across multiple continents including North America, Oceania, and Asia. The species is commonly known as the polygonum aphid.
Carolinaia rhois
Sumac-Grass Aphid
Carolinaia rhois is an aphid species in the family Aphididae, commonly known as the Sumac-Grass Aphid. The species is associated with sumac (Rhus) as a primary host and grasses as secondary hosts, following the typical heteroecious life cycle of many aphids. Taxonomic records indicate some historical confusion regarding authorship, with both Monell (1879) and Tissot (1928) cited in different sources. The species has been documented through limited but verified observations, primarily in North America.
Ceruraphis viburnicola
Snowball Aphid
An aphid species found in spring and autumn on Viburnum hosts in North America. It induces curled leaf galls on primary hosts. The secondary hosts remained unrecorded as of 1960. The apterous viviparous female was first described in a 1960 Canadian Entomologist paper.
Eriosomatinae
Woolly Aphids, Gall-making Aphids
Eriosomatinae is a subfamily of aphids distinguished by filamentous waxy secretions that produce a cotton-like or woolly appearance. Members exhibit typically heteroecious holocyclic life cycles, alternating between primary and secondary host plants, with strong primary host plant specialization. Many species induce galls on primary hosts, particularly on Ulmaceae (elms, zelkovas), Salicaceae (poplars), and Anacardiaceae (sumacs). The subfamily contains three tribes: Eriosomatini, Fordini, and Pemphigini.
Heteroecus pacificus
beaked spindle gall wasp
Heteroecus pacificus, commonly known as the beaked spindle gall wasp, is a species of cynipid gall wasp native to western North America. It induces distinctive galls on canyon live oak (Quercus chrysolepis) and huckleberry oak (Quercus vaccinifolia). The species exhibits a complex life cycle with two annual generations: one sexual generation producing males and females, and one parthenogenetic generation consisting solely of females.
Metopolophium dirhodum
rose-grain aphid, rose-grass aphid
Metopolophium dirhodum is a globally distributed aphid species with a heteroecious life cycle alternating between rose (Rosa) as primary host and grasses, particularly cereal crops, as secondary hosts. It is a significant agricultural pest and vector of barley yellow dwarf virus (BYDV), causing yield reductions in wheat, barley, oats, and rye. The species exhibits wing dimorphism with both apterous and alate morphs, and shows genetic variability in host plant adaptation among populations.
Patchiella kolokasia
Patchiella kolokasia is a gall-forming aphid in the subfamily Pemphiginae. It forms distinctive leaf nests on Tilia species and exhibits host alternation, with Araceae serving as secondary hosts. The species was described from China in 1999 and has since been recorded from Japan and, more recently, South Korea. This represents the first documentation of the genus Patchiella on the Korean Peninsula.
Pemphigus betae
sugarbeet root aphid, sugar-beet root-louse
Pemphigus betae is a gall-forming aphid with a complex heteroecious life cycle involving host alternation between cottonwood trees (Populus angustifolia, P. balsamifera) and sugar beet roots. Stem mothers emerge in spring to form galls on poplar leaves, producing up to 300 progeny per gall. Winged migrants disperse to Chenopodiaceae roots for summer feeding, causing significant agricultural damage. The species exhibits clonal variation in host-alternation propensity, with some lineages remaining on roots year-round. Molecular studies reveal cryptic sympatric diversity, with morphologically indistinguishable galls formed by P. betae, P. populivenae, and a third undetermined species.
Pemphigus populicaulis
Poplar Leaf-base Gall
Pemphigus populicaulis is a gall-forming aphid species that induces distinct galls at the leaf bases of poplar trees. As a member of the genus Pemphigus, it exhibits the typical life cycle of root-gall aphids, alternating between primary hosts (Populus species) and secondary hosts (often roots of herbaceous plants). The species was described by Fitch in 1859 and is widely distributed across North America. It is frequently referenced in historical literature on gall aphids but has been subject to taxonomic confusion with related Pemphigus species.
Pemphigus populiramulorum
Poplar Twig Gall Aphid
Pemphigus populiramulorum is a gall-forming aphid in the family Aphididae, known from poplar (Populus) hosts. It induces distinctive twig galls on its primary host. The species has a complex life cycle involving host alternation, though specific secondary host details are not well documented in available sources. It has been confused with other root-feeding Pemphigus species in informal literature.
Tetraneura
elm-grass root aphids, woolly elm aphids
Tetraneura is a genus of gall-forming aphids in the family Aphididae, comprising more than 30 described species. These aphids are heteroecious, alternating between primary hosts in the genus Ulmus (elms), where they induce characteristic galls on leaves, and secondary hosts in the family Poaceae (grasses), where they feed on roots. The genus is notable for complex host manipulation, with species capable of altering host plant biochemistry to create nutritional sinks within galls. Several species, including the alien T. nigriabdominalis, are expanding their ranges in Europe and pose potential threats to cereal crops such as maize.
Tetraneura nigriabdominalis
Tetraneura nigriabdominalis is a holocyclic, heteroecious gall-forming aphid native to East Asia that has expanded its range globally and is now established in Europe and North America. The species alternates between primary hosts (elm trees, genus Ulmus) and secondary hosts (roots of grasses in the family Poaceae, including maize). On elms, fundatrices induce characteristic galls on leaves, with development rates and fecundity strongly influenced by spring temperatures. The species has been documented as a potential agricultural pest due to its association with cultivated maize.