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Aphidomorpha : Aphididae : Aphidinae genera
 

 

Subfamily Aphidinae

Biology and Morphology

On this page: Biology Morphology Tribes Aphidini & Macrosiphini The (former) Pterocommatinae

Biology

The Aphidinae is the largest subfamily in the Aphididae with at least 2483 species in 256 genera in 2 tribes: the Macrosiphini (with 3/4 of the species) and the Aphidini. Most Aphidinae live on angiosperms, but a small number of secondarily adapted species attack conifers and ferns. Some or all species in many genera undergo a regular seasonal host alternation (heteroecy) between a woody perennial primary host, on which the diapausing eggs overwinter, and one or more herbaceous secondary hosts, to which some or all of the populations migrate by means of alate viviparae during the spring and early summer.

Aphis fabae : Aphidini, adult aptera & nymphs.

Alate sexuparae and male migrants return in autumn to the primary host. Remaining on one host all year (monoecy) may be either primitive or secondarily derived from heteroecy, either by transfer of overwintering to the secondary host, or by loss of the emigratory phase. Both monoecy and heteroecy may be combined with varying degrees of polyphagy. Most aphid pests on crops and ornamental plants are Aphidinae, and some of these are among the most polyphagous.

Macrosiphum euphorbiae aptera, green form.

Because the migrant morphs of Aphididae probe and feed repeatedly during their largely random dispersal in search of hosts they tend to be important as vectors of plant viruses, even to hosts on which they do not stay to reproduce. Unlike in some other subfamilies, the migrants of Aphidinae revert to a non-migratory reproductive life after their settlement on an acceptable host; the wing musculature is histolysed, the power of further flight is lost, and a succession of embryos is matured and deposited over a considerable period. Males may be alate or apterous, depending upon species, and both sexual morphs have fully developed mouth-parts. Oviparous females lay a variable number of winter eggs, never only one (unlike the Eriosomatinae). Members of the Aphidinae occur in nearly every region of the world, but particularly in the holarctic and oriental regions.

 

Morphology

Adult Aphidinae viviparae may be apterous or alate. The body shape and colour are very variable. The head and pronotum are not fused. The antennae are long and usually 6-segmented, rarely 5-segmented and only 4-segmented in fundatrices of some species. The terminal process is of variable length, but it is rarely very short; in the majority of species it is more than twice as long as the base of antennal segment VI, and is always at least half its length. Secondary rhinaria are frequently present in both apterae and alatae. The compound eyes are always multi-facetted, and usually with the triommatidium forming a distinct protuberance at the posterior margin. The rostrum is normally of four apparent segments, with segments IV and V fused into a single compact apical segment (cf. members of the Lachninae, where segments IV and V are separate).

Aphis nerii : Aphidini, adult aptera.

The dorsum is without extensive areas of wax pores and hairs on the dorsum are usually rather sparse. Marginal tubercles and occasionally spinal tubercles are often present on the prothorax and on some or all the abdominal segments I-VIII. The first tarsal segment has 2-6 hairs. Their siphunculi are very variable in shape and size but are usually longer than their width at base, and are rarely absent. They are most commonly elongate cylindrical or tapering - but may be pore- or rim-like, truncate conical, club-shaped and flangeless, variably swollen or vasiform - they are only exceptionally stump-shaped. They are usually situated on abdominal tergite 5. The anal plate is never bilobed or emarginate. The cauda is usually tongue-shaped, sometimes short and broad, but never knobbed (cf. Calaphidinae and Drepanosiphinae, where the cauda is always knobbed - or cf. Hormaphidinae, Lizerinae, Macropodaphidinae, Neophyllaphidinae, Thelaxinae, where it may be rounded or knobbed).

Macrosiphum rosae alate giving birth.

Alatae have secondary rhinaria present on antennal segment III and often also on IV and V. The secondary rhinaria are usually rounded and never slit-like, annular or strongly transverse (cf. Neophyllaphidinae and Eriosomatinae, which usually have annular or transverse-oval secondary rhinaria) The wings in alate morphs are held in a vertical or steeply roof-life posture over the back when folded in repose, never flat (cf. Phloeomyzinae, Hormaphidinae, Calaphidinae, Aploneura in the Fordini, and Monellia in the Panaphidini, some or all of which hold their wings flat when at rest). The forewing venation is of normal type, usually with a well-developed radial sector. The median vein is most often twice forked (i.e. with three branches reaching wing margin) but sometimes without a second fork of the anterior branch. Cubitus 1 and 2 are always present. The veins are sometimes partly or entirely margined with black, but most commonly only Cubitus 2 is so margined. The hindwings are normally well-developed, with two branch veins arising from the radius.

 

Tribes Aphidini & Macrosiphini

The Aphidini contains perhaps a tenth of Aphidinae species but nearly a third of its genera, whereas the Macrosiphini contains 9/10 of its species in more than 2/3 of its genera. There appear to be no consistent differences in the biology of aphids in the Aphidini compared to those in the Macrosiphini, except perhaps ant attendance is rather more common with members of the Aphidini. Hence we focus on which morphological characters can be used to distinguish them.

The most important characteristics are the number and position of marginal tubercles and the spacing of the spiracular pores.

  • In the Aphidini marginal tubercles are present on abdominal segments I & VII in most genera; other abdominal segments may or may not bear such tubercles. Those on segments I & VII, when present, may lie either dorsal or ventral to the spiracles. In the Macrosiphini marginal tubercles are frequently present on abdominal segments II-V, but rarely on I & VII.
  • In the Aphidini the pores of the stigmata are bean-shaped. The distance between the centres of the spiracular pores of abdominal segments III & III is typically less than 2.1 times the distance between the centres of those on segments I & II. In the Macrosiphini the distance between the centre of the pores of abdominal segments II & III is typically more than 2.1 times the distance between the centres of those on segments I & II.

Additional useful characteristics include:

  • The Aphidini never have spinal tubercles on the head or body segments, nor are there large capitate hairs on raised bases. Some genera in the Macrosiphini do have spinal tubercles, and/or large capitate hairs.
  • In the Aphidini the antennae are never longer than the body. In the Macrosiphini the antennae may be longer or shorter than the body.
  • The siphunculi of Aphidini never have annular imbrications producing a constriction immediately before the apical flange, nor do they have marked preapical reticulation consisting of closed cells. Some genera of Macrosiphini have a marked preapical constriction and/or preapical reticulation consisting of closed cells.
  • The first tarsal segments of Aphidini never have more than 3 hairs. Some species of Macrosiphini have 4 or 5 hairs on the first tarsal segments.

Tribe Aphidini is divided into 2 subtribes, Aphidina & Rhopalosiphina, which have 21 and 11 genera respectively. Tribe Macrosiphini has 244 genera.

Browse list of Aphidinae genera

 

The (former) Pterocommatinae

The Macrosiphini tribe of the Aphidinae currently includes the former subfamily Pterocommatinae - which comprised about 285 species in 2 genera (Pterocomma, Plocamaphis). Börner (1944) initially defined Pterocommatinae as being aphids with a short cauda, not narrowed basally. This taxonomy was revised by various authors until, on the bases of DNA evidence, Von Dohlen et al. (2006) suggested classing Pterocomma & Plocamaphis as Macrosiphini - a view supported by Heie and Wegierek (2009). More recent DNA sequencing, such as by Ortiz-Rivas & Martínez-Torres (2010) and Kim et al. (2011), calls this into question.

There is no host alternation, with species feeding on the branches or trunks of sallows and osiers (Salix spp). Pterocomma species (but not Plocamaphis) are often ant attended. Since their feeding sites are very exposed, many species adopt cryptic colouration for the immatures and often also the adults. Other species adopt aposematic colouration, with black and white patterning and/or contrastingly brightly coloured siphunculi to warn off potential predators (see picture below).

Pterocomma salicis apterae and nymph.

Antennae are shorter than the body. The first tarsal joints usually have 5 hairs. The cauda in adults is rounded to broadly tongue-shaped and its length is usually less and never more than 1.1 times its basal width. Compared to Pterocomma species, Plocamaphis are less hairy, have flangeless siphunculi, and most species secrete flocculent wax.

Browse list of Aphidinae 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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