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Biology and MorphologyOn this page: Biology Morphology Genera Tribe Chaitophorini Tribe Siphini
The Chaitophorinae subfamily has 163 species in 11 genera in 2 rather different tribes: the Chaitophorini and the Siphini. Most Chaitophorini feed on woody angiosperms in the willow (Salicaceae), maple (Aceraceae) or horse chestnut (Hippocastanaceae) families. The hosts of the Siphini are mainly grasses (Poaceae), but some feed on sedges (Cyperaceae) or rushes (Juncaceae). Heteroecy (host alternation) and galling reactions by the host are not known. In the Chaitophorinae the predominant morph is the apterous viviparous female. Alatae are produced in variable numbers, and may sometimes predominate in certain generations, but are rare in Siphini and some species of Chaitophorini. Species of Periphyllus may aestivate on the host as specially modified first instar larvae ('dimorphs'). Species in the Chaitophorini are often attended by ants. Species in both tribes have a Holarctic distribution.
Chaitophorus ramicola colony attended by Lasius.
Adult Chaitophorinae viviparae may be apterous or alate. The body shape ranges from nearly linear to stoutly ovoid or pyriform, and their body length ranges from about 0.5 mm in some males to about 4.5mm in some fundatrices. Colour in life ranges from whitish through various shades of yellow, green and brownish to black. The dorsum is never wax-covered. The adult viviparae have antennae shorter than the body with 4, 5 or 6 segments (cf. Aphidinae, which often have the antennae longer than the body). There are usually no secondary rhinaria on the antennae of apterae. Compound eyes in the adults are multifaceted, with a distinct triommatidion. The rostrum is usually rather short, with the apical segment varying from extremely short and broad to fairly elongate. The basal part of segment II of the rostrum does not have a sclerotized wishbone-shaped arch. The dorsal cuticle is often sclerotic, with or without dark pigmentation, and sometimes also rugose, nodulose or spinulose. The body usually has numerous long hairs, which may be pointed, blunt, spatulate or furcate (cf. Aphidinae, which usually have rather sparse hairs on the dorsum).
Chaitophorus populeti aptera and nymph.
The siphunculi are usually truncate conical, subcylindrical or stump-shaped, sometimes with a pronounced apical flare (cf. Aphidinae, in which the siphunculi are usually longer than their width at base and only exceptionally stump shaped). In Siphini the siphunculi are reduced to slightly elevated rim-like structures or mere pores. The cauda varies from broadly crescent-shaped through semicircular or bluntly subtriangular to distinctly elongate with a more or loss marked constriction delimiting an apical knob. The subanal plate is sometimes very slightly emarginate in middle of posterior margin, but never deeply cleft or bilobed.
Chaitophorinae alatae at rest hold their wings vertical. They have secondary rhinaria present on antennal segment III or III-IV, more rarely with 1- 2 also on segment V. The primary rhinaria of alatae are sometimes surrounded by short setae. Accessory rhinaria on the ultimate antennal segment are near to the primary rhinarium, and sometimes more distinctly fringed. The wings are normal, to rather long and narrow. The forewing has the media either once- or twice-branched. Wing venation is sometimes brown-shadowed.
Male Chaitophorinae are alate or apterous, and always have secondary rhinaria on at least antennal segments III-IV. Oviparous females do not have lateroventral subsiphuncular wax gland fields. First instars have 4- or rarely 5-segmented antennae and multifaceted compound eyes, and siphunculi are present.
The Chaitophorinae subfamily has 163 species in 11 genera in 2 rather different tribes: the Chaitophorini and the Siphini.
Genus Chaitophorus [Chaitophorini]
Very hairy, small to medium-sized aphids which may be wingless or winged. The dorsal cuticle of the wingless adults is largely sclerotized. The siphunculi are short and stump-shaped, and the cauda is usually knobbed. Winged forms often have dark segmental cross-bands and marginal sclerites.
There are about 90 species with individual species feeding on either poplar or willow species in the Salicaceae. They have a sexual stage in the life cycle, but do not host alternate and may be ant attended.
Genus Periphyllus [Chaitophorini]
Medium-sized to large elongate oval or pear-shaped aphids which may be winged or wingless. The dorsum is mainly membranous (unsclerotized) but there are many small hair-bearing plates. The siphunculi are stump-shaped with a pronounced flange. The cauda at the tip of the abdomen is either rounded or tongue-shaped with a slight constriction. Antennal hairs are usually long and conspicuous.
There are about 42 species of Periphyllus aphids mostly living on maples and sycamore (Acer spp) in the Aceraceae. They have a sexual stage in the life cycle, but do not host alternate. Some species are usually ant-attended. They show seasonal polymorphism to cope with physiological changes in the host with several species having an aestivating nymphal stage which is often flattened and hairy.
Genus Atheroides [Siphini]
Apterous viviparae have an elongate slender, nearly linear, body or rarely oval. The head + thorax + abdominal segment I is almost as long as abdominal segments II-VIII. The antenna are short, 5 segmented or in one case, 4 segmented. The frons is convex. Abdominal tergites II-VII are sclerotized and usually fused. Tergite VIII is semicircular, usually covering the cauda. The siphunculi are pore-shaped, and the cauda and anal plate are broadly rounded. Alatae are rare.
Seven species are recognised worldwide. Six are palaearctic, one is either invasive in America or naturally holarctic and one is in the nearctic. They feed on grasses (Poaceae) and some sedges (Cyperaceae).
Image copyright Tim Hodge, all rights reserved.
Genus Caricosipha [Siphini]
Caricosipha are flattened pear-shaped aphids, broadest about the level of tergite 4. The dorsum and most of the venter are blackish sclerotic, with abdominal tergites 1-7 fused into a solid carapace. The head capsule is fused with the pronotum; the mesonotum, metanotum and abdominal tergite 8 are free. The antennae are mainly pale and the antennal tubercles are very low. Antennal hairs are nearly all long. The compound eyes are very prominent and are sited on lateral extensions of the head. The rostrum does not reach the middle coxae, and its apical segment is blunt, slightly longer than its basal width and with convex sides. The siphunculi are pale, smooth,truncate conical or stump-shaped, with a marked flange. The cauda is slightly knobbed with 5-8 hairs. Alates have the dorsal carapace broken into segmental dark bars and marginal sclerites. There are secondary rhinaria only on antennal segment 3.
There is only one species in the genus Caricosipha paniculatae which feeds on greater tussock sedge (Carex paniculata) and the true fox sedge (Carex vulpina).
Image copyright Stéphane Claerebout, all rights reserved.
Genus Laingia [Siphini]
Laingia are narrow-bodied aphids. They only differ from the related grass-feeding Atheroides in two respects:
The sole species within the Laingia genus mainly feeds on Ammophila arenaria (marram grass).
Genus Sipha [Siphini]
Sipha are medium-sized oval aphids that have conspicuous spiny hairs. They have 5-segmented antennae and a sclerotic upper surface. The short siphunculi are stump-shaped. The four species of the nominate subgenus Sipha have a knobbed cauda, and the eight species of subgenus Rungsia have a broadly rounded cauda.
Sipha feed on grasses. Some Sipha species are largely restricted to particular genera or even species of grass, whilst others are polyphagous. Several species are restricted to wetland or coastal habitats.
Image copyright Adam Polednicek, all rights reserved.