InfluentialPoints.com
Biology, images, analysis, design...
Aphids Find them How to ID AphidBlog
"It has long been an axiom of mine that the little things are infinitely the most important" (Sherlock Holmes)

Search this site

Aphidinae : Aphidini : Aphis horii
 

 

Aphis horii

Japanese elder aphid

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

Identification & Distribution

Adult apterae of Aphis horii (see largest individuals in first picture below) are dark green, with the head, antennae, siphunculi, cauda, anal plate and legs almost black. The abdomen has dark sclerotic cross bands on tergites VII and VIII. The antennae are rather short, and bear long and very fine hairs, the longest on segment III being 1.7-2.1 times the basal diameter of that segment (cf. the closely related Aphis sambuci, which has shorter hairs on segment III, the longest only 0.5-1.7 times the basal diameter). There are no secondary rhinaria on antennal segment III. The rostrum reaches beyond the middle coxae. The prothorax has a large marginal tubercle, and the abdomen has quite large domed marginal tubercles on tergites I-V & VII. The siphunculi are very long and slender, distinctly curved, moderately dilated towards the base, much longer than the 3rd antennal joint, and 2.2-4.0 times longer than the cauda. The cauda is short, dark and blunt, and is provided with many long fine hairs. The body length of adult Aphis horii apterae is 2.1-2.7 mm.

First image above Nan Yang, second image copyright zdk0812,
both under a creative common licence.

The alate Aphis horii is dark green like the aptera, but the thorax is black, and the abdomen has some short cross bands in the middle of the dorsum, and some small lilac patches on the sides. The wings are hyaline with brown veins and pterostigma. The antennae are short, and provided with many moderately long hairs. Secondary rhinaria are round, rather large, scattered over the whole length, numbering about 35 on segment III, 15-17 on segment IV, and 7 on V. The rostrum reaches a little beyond the middle coxae. The siphunculi are long and slender, about 3 times the caudal length.

Image above Nan Yang under a creative common licence.

The primary host of Aphis horii is elder (Sambucus spp.), mainly Japanese elder (Sambucus sieboldiana = Sambucus racemosa spp. sieboldiana). It has also been recorded on Korean sweetheart tree (Euscaphis japonica). Aphids live in large colonies on clustered on the stems and leaf petioles. It is possible that it host alternates to a (currently unknown) secondary host, and Blackman in Aphids on Worlds Plants notes that specimens possibly of this species have been collected in Korea on the roots of Rumex coreanus (for which is it is the only aphid sp. recorded). Aphis horii is restricted to Japan.

 

Other aphids on the same host

Primary hosts

Aphis horii has been recorded from 2 species of elders (Sambucus coreana, Sambucus racemosa ssp. sieboldiana).

Blackman & Eastop list 3 species of aphid as feeding on Japanese red elder (Sambucus racemosa ssp sieboldiana) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 2 as occurring in Britain (Show British list).

Aphis horii has been recorded from 1 Euscaphis species (Euscaphis japonica).

Blackman & Eastop list 4 species of aphid as feeding on Korean sweetheart tree (Euscaphis japonica) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

Acknowledgements

We are grateful to Nan Yang & zdk0812 for making their images of Aphis horii available for use under a creative commons licence.

We have used the species accounts of Takahashi (1923) (1966) (the latter as Aphis sambuci ssp. horii), together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors (see references below) 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

  • Takahashi, R. (1923). Aphids of Formosa. Part 2. Report of the Department of Agriculture Government Research Institute Formosa 4: p 61. Full text

  • Takahashi, R. (1966). Descriptions of some new and little known aphid species in Japan, with key to species. Transactions of the American Entomological Society 92, 519-556 (p. 546) Full text