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Aphidomorpha : Aphididae : Baltichaitophorinae
 

 

Subfamily Baltichaitophorinae (= Parachaitophorinae)

Biology and Morphology

On this page: Biology Morphology Parachaitophorus spiraeae

Biology

The Baltichaitophorinae has 2 species in 2 genera, of which one is extinct (Baltichaitophorus jutlandicus). The remaining genus currently has one oriental species, Parachaitophorus spiraeae (= Parachaitophorus yamashitai = Parachaitophorus sikhotealinicus). This species lives on Spiraea spp. forming compact ant-attended colonies on stems and the bases of young offshoots. Their life cycle is unknown, but Japanese populations disappeared in late May perhaps indicating migration to an unknown secondary host. If so, the alatae produced in spring and autumn may have been migrants. Oviparae and alate males have been found on Spiraea cantoniensis in October-November. Parachaitophorus spiraeae are found in Japan, Korea and east Siberia.

In 1984, Remaudiére and Stroyan synonymized the Baltichaitophorinae and Parachaitophorinae. Sugimoto (2011) synonymized Parachaitophorus spiraeae with Parachaitophorus yamashitai and Parachaitophorus sikhotealinicus - and describes the known morphs thereof. As would be expected of a host alternating species, there were several differences between spring- and autumn-alates, in other words spring migrants and autumn migrants. Despite host-alternation being unknown in that subfamily, Sugimoto (2011) proposed putting Parachaitophorus in the Drepanosiphinae on the basis of characters of their oviparae. Whether the same arguments apply to Baltichaitophorus jutlandicus is of course unknown.

 

Morphology

Since this subfamily contains just 2 species, one extinct and one liable to be relocated, we consider the morphology of both. The following description of Baltichaitophorus jutlandicus, adapted from Heie (1967), is based upon 2 specimens from a piece of Tertiary Baltic amber (~66-2.6 million years ago).

Baltichaitophorus jutlandicus

Only the apterous morph of Baltichaitophorus jutlandicus is known. Its general appearance is similar to some Lachnus species, whilst the eye, siphunculi and terminal process resemble those of some Greenideinae. However, the Greenideinae have long abdominal processes. In life the aptera was presumably brown, darker around the siphunculi, and covered with long, acute bristles on the head, dorsum and underside. The head and pronotum are separated by a distinct suture. The head has 2 pairs of very long spinal bristles, one behind the other, placed on low conical tubercles. The eyes are hemispherically protruding triommatidia. The frons is convex, with slightly developed lateral tubercles bearing the antennae. These are 6-segmented, about 0.7 mm long, very long-haired with bristles about 0.03 mm long. They have a well-defined terminal process, which is longer than the base of antennal segment VI. Two primary rhinaria are visible, but no secondary rhinaria. The rostrum appears to reach behind the hind coxae, its apical segment undivided. The siphunculi are apparently on abdominal segment VI, low and truncate, broad at base, 0.3-0.4 mm long, with a well-developed flange. The cauda is apparently very short, with a well rounded apex, but these may be immature specimens. The body length of Baltichaitophorus jutlandicus is 0.7-1 mm.

Baltichaitophorus jutlandicus (immature?) aptera. Image redrawn from Heie (1967).

Comparing Baltichaitophorus jutlandicus with Parachaitophorus spiraeae, Heie noted these two species were very similar: except apterous Parachaitophorus spiraeae has a relatively short terminal process, and 5 antennal segments and Baltichaitophorus jutlandicus had 6 antennal segments. Also Parachaitophorus spiraeae has very long bristles on low, conical tubercles, usually in rows of 10 per segment; whereas Baltichaitophorus jutlandicus had more than 10 scattered bristles per segment, not apparently on tubercles except for the head.

Parachaitophorus spiraeae

Parachaitophorus spiraeae adult viviparae may be apterous or alate. Apterae of the only extant species are brown with dark brown head, antennae, legs, siphunculi, cauda and dark brown spots at bases of dorsal hairs. The antennae are 5 or 6-segmented with the terminal process as long as or longer than the base of the last antennal segment V, but much shorter than in alatae. The apterae have reduced eyes (just triommatidia in nymphs, fundatrices and oviparae). The second segment of the rostrum is without the usual wishbone-shaped stiffening. The head and pronotum of apterae are not fused. There are very long dorsal hairs arising from dark tuberculate bases. The siphunculi are low, truncate, broad at the base, and have a large flange but small aperture. The anal plate is emarginate. The body length of Parachaitophorus spiraeae is 1.2-1.7 mm.

Parachaitophorus spiraeae aptera, mount. Image via HUSCAP, copyright Shun'ichiro Sugimoto.

In the alate the secondary rhinaria are roundish, placed on small tubercles. The pterostigma is rather long, and the radial sector departs the apical part of pterostigma or is absent. The hind wing is reduced, with only one oblique vein. The body is covered with numerous long hairs. Oviparae have subsiphuncular wax gland plates.

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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