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Aphidomorpha : Aphididae : Eriosomatinae genera
 

 

Subfamily Eriosomatinae

Biology and Morphology

On this page: Biology Morphology

Biology

The Eriosomatinae has 301 species in 48 genera and 3 tribes (Eriosomatini, Fordini, Pemphigini). They typically host alternate between trees and the roots of herbaceous plants. Most of the Eriosomatini use elms (Ulmaceae) as primary hosts, whilst the Fordini use pistachio (Pistacia) or sumac (Rhus). Most in the Pemphigini use poplar (Populus), but the genus Prociphilus has adopted a range of primary hosts in different plant families. Eriosomatinae spring generations induce characteristic galls or pseudogalls on the primary host.

Pemphigus spyrothecae galls.

On reaching maturity, large numbers of alate spring migrants leave the galls to colonise the secondary host.

Pemphigus bursarius alate.

Eriosomatinae alatae that make the autumn migration back to the primary host are sexuparae, producing both males and oviparous sexual females (in this respect they resemble Anoeciinae, but differ from Aphidinae, whose sexes migrate independently back to the primary host). The sexual morphs are apterous and dwarfish, and are deposited on the bark of the host tree where they reach maturity very quickly and without feeding. After mating the dwarf ovipara lays a single egg, which is almost as large as she is. One deviation from this typical life cycle is that some species do not migrate to a secondary host, but give rise after one or two generations to sexuparae in the gall, which then fly directly to the bark of the host tree to produce the sexual morphs. Many species are facultative anholocyclic, with part of the population continuing parthenogenetic reproduction on the secondary host roots through the winter if mild. Fordini that have Pistacia as their primary host only undergo the holocycle where Pistacia occurs naturally, so exist in northern Europe only as parthenogenetic females on their secondary host. Distribution differs for the various tribes. Eriosomatini and Pemphigini are holarctic, the Fordini are mostly Mediterranean & east Asian with a few American species. Aloephagus myersi is native to tropical Africa, but is invasive in Europe & North America, and Aploneura lentisci is cosmopolitan.

 

Morphology

Adult Eriosomatinae viviparae may be apterous or alate. Despite being biologically diverse, all the Eriosomatinae have certain morphological features in common. Apterae and nymphs generally have only triommatidia but no compound eyes, with the border between the head and pronotum normally distinct (cf. Aphidinae, which always have multi-facetted compound eyes, usually with a triommatidium). The antennae are short, normally 6 segmented, with a very short terminal process. The antennae of apterae very rarely have secondary rhinaria. The fourth and fifth rostral segments (RIV & RV) are fused into a single apical segment. Siphunculi are present only as pores or are absent, and they have a broad, rounded cauda which is not constricted. The anal plate is entire. Wax glands are often well developed, usually in groups of several roundish, faceted plates producing fibrous or filamentous wax.

Alatae have the antennae 5- or 6-segmented, usually with transversely oval, annular or circular rhinaria which are not confined to antennal segment III (see picture below).

Pemphigus bursarius antenna.

The media of the forewing is never twice-branched, but has only one fork or is unbranched. The hind wing has one or two oblique veins. The sexuales are dwarfish and apterous, and do not have a rostrum.

Browse list of genera

Acknowledgements

We particularly thank Colin Favret and Roger Blackman, who have provided invaluable assistance. Most of the subfamily diagnoses have been taken from Heie & Wegierek (2009b), Quednau (1999, 2003, 2010) and Blackman & Eastop (2021), with additional material from Russell (1982),Stroyan (1977), Stroyan (1984) and many others listed in the references for these pages.

Note: Any images on pages that are not individually credited are copyright InfluentialPoints under a Creative Commons Attribution License.

Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

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