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Hormaphidinae : Nipponaphidini : Thoracaphis linderae
 

 

Thoracaphis linderae

Wax-crusted scale aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult apterae of Thoracaphis linderae (see first picture below) are aleyrodiform, flattened and broadly oval, with a dorsum coloured green or reddish-brown, becoming sooty black with age. Published descriptions do not mention wax production, but 3 sets of marginal wax gland plates on each side of the cepalothorax are clearly visible in the first picture below; these produce the ring of wax visible in the second picture. In old specimens wax may completely cover the dorsum. The head is fused with the thorax to give the cephalothorax (= prosoma), which comprises the anterior 80% of body length (in the first picture below the aphids are viewed dorsally, and face upwards). Their eyes are 3-faceted and marginal. The 3-segmented antennae are submarginal, on the underside, shorter than the distance between themselves, reaching the level of the eyes, and nearly as long as hind tibia. The rostrum is short, the apical rostral segment a little longer than segment III, much longer than the tarsus, tapering, about 1.7 times as long as wide. There are many small papillae densely scattered over cephalothorax, and 6 long thick-based (prosomal) hairs on each side arising from the submarginal area of the underside.

Images above by permission, copyright Akihide Koguchi, all rights reserved.

The much-reduced abdomen is short, comprising only about 20% of the body length. It is separated from, but sunken into the cephalothorax, with the anterior part having 5 faint traces of segmentation and some small papillae. There are also 6 lateral abdominal submarginal hairs on each side, but only the anterior one is long and visible. The siphunculi are very small, visible as small pores on tergite V. The cauda is pale, short, constricted basally, almost straight at the hind margin, with some long hairs. The anal plate is pale, divided, with some very long hairs on each lobe. The subgenital plate is pale, much larger than anal plate, with about 25 long hairs along the hind margin. The body length of adult Thoracaphis linderae apterae is 1.8-2.0 mm.

Images above by permission, copyright Akihide Koguchi, all rights reserved.

Whilst Thoracaphis linderae alatae have been recorded (Shinji, 1926) we are unable to find a description of this morph. Immature Thoracaphis linderae (see the pictures above) have the anterior dorsum rather more strongly sclerotized than other parts. Numerous long wax tendrils arise from the margin of their cephalothorax and abdomen.

Image above by permission, copyright Akihide Koguchi, all rights reserved.

Note: Most, if not all, aphids in the old colony shown above appear to be dead - wax rings mark the locations of previous aphids.

Thoracaphis linderae feeds on the twigs and stems of Lindera species. Alatae have been collected in May. The life cycle is uncertain. Most Thoracaphis species are thought to have had winter hazel (Distylium) as their primary host in the past, but are now only known from parthenogenetic generations on the secondary host. Shinji (1926) reported Thoracaphis linderae overwintering as eggs on Lindera, but this was neither confirmed nor refuted by Takahashi (1958) in his redescription of the species. Thoracaphis linderae is only known to occur in Japan.

 

Other aphids on the same host

Primary host

The primary host of Thoracaphis linderae, like all Thoracaphis and most Nipponaphidini species, is unknown - assuming such exists. All Nipponaphidini species whose primary hosts are known use two just two species of winter hazels, Distylium racemosum & Distylium stellare (Yeh, 2009).

Of these, Distylium racemosum is the most likely being also native to Japan, whereas Distylium stellare has a more southerly distribution.

Secondary hosts

Thoracaphis linderae has been recorded from 4 species of spicebush (Lindera praecox, Lindera triloba, Lindera umbellata and, from this report, Lindera obtusiloba).

Acknowledgements

We are especially grateful to Akihide Koguchi for allowing us to reproduce the images of Thoracaphis linderae from his blog page, and to Dr Shigeyuki Aoki who confirmed the identification.

We have used the keys and species accounts from Takahashi (1965) along with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. 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).

Useful weblinks

References

  • Shinji, O. (1926). [Description of a new species of Thoracaphis.] Zool. Mag., Tokyo 38, 359-361.

  • Takahashi, R. (1958). Thoracaphis and some related new genera of Japan. Insecta Matsumurana 22 7-14.

  • Yeh, H.-T. (2009). Biosystematics and molecular phylogeny of the Hormaphidinae (Hemiptera: Aphididae) in Taiwan, Ph.D. thesis, National Taiwan University.