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 impatientis
 

 

Aphis impatientis

Dogwood-balsam aphid

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

Identification & Distribution

Adult apterae of Aphis impatientis (see first picture below) have a black head, siphunculi and cauda, and a purplish brown or brownish abdomen dusted with white wax. Antennal segments I & VI are dusky, and the others pale. The antennae are six-segmented, and shorter than the body (cf. Uroleucon impatiensicolens, Macrosiphum impatientis and other Macrosiphum species on Impatiens, which all have antennae longer than the body). The antennae are without secondary rhinaria. The hairs on antennal segment III are short, usually less than middle diameter of that segment (cf. Aphis maculatae, Aphis fabae, Aphis neogillettei & Aphis salicariae, which all have those hairs longer than the middle diameter of the segment). The rostrum reaches to the mesocoxae. The apical rostral segment (RIV+V) is 0.7-1.0 times the second hind tarsal segment (HTII) (cf. Aphis nasturtii, which has RIV+V 0.9-1.2 times HTII). Marginal sclerites are pale, but pre-siphuncular and post-siphuncular sclerites are absent. Marginal tubercles are present on abdominal segments I and VII, but absent from II, III, and IV. The siphunculi are dark, curved outwards with flange, much broader at the base than at the apex, and 0.9-1.6 times the caudal length (cf. Aphis cornifoliae on dogwood, which has siphunculi hardly broader at base than apex, and 1.2-2.0 times longer than the cauda). The cauda is dark, thumb-shaped and blunt. The body length of adult Aphis impatientis apterae is 1.0-1.8 mm.

Note: Lagos-Kutz et al. (2018) showed convincingly that Aphis floridanae Tissot, 1933 is a junior synonym of Aphis impatientis.

First image above copyright James Bailey, second image copyright Ryan Sorrelis;
both under a Creative Commons License.

The alate vivipara of Aphis impatientis (see second picture above and below) has a black head and thorax, a brown, shiny abdomen with no wax, and dusky wings. The antennae are six-segmented, shorter than body, with all antennal segments dark. Antennal segment III bears 7-17 secondary rhinaria, segment IV has 1-10 (and V has 0), all arranged in a single row. The rostrum does not reach the metacoxae. Marginal tubercles are present on abdominal segments I and VII. Marginal and post-siphuncular sclerites are present and dark. The dorsal abdomen has transverse sclerites on tergites VII, and VIII. The siphunculi are dark, and weakly curved outwards with a flange. The cauda is dark and finger shaped.

Image above copyright Lagos-Kutz et al. (2018) under a Creative Commons License.

Aphis impatientis host alternates from dogwood (Cornus spp.) to jewelweeds (Impatiens spp.) Additional secondary hosts recorded by Lagos-Kutz et al. (2018) include fireweed (Erechtites hieracifolius) and Florida lettuce (Lactuca floridana). The aphids seem to concentrate their feeding sites along the main leaf veins (see top pictures). Sexual morphs have been obtained by transfer to grey dogwood (Cornus racemosa). The dogwood-balsam aphid is found in eastern USA and Canada.

 

Other aphids on the same host

Primary host

Aphis impatientis has been recorded on 1 Cornus species (Cornus racemosa).

Blackman & Eastop list 3 species of aphid as feeding on grey dogwood (Cornus racemosa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).

Secondary hosts

Aphis impatientis has been recorded on 3 Impatiens species (Impatiens balsamina, Impatiens capensis, Impatiens pallida).

Acknowledgements

We are grateful to James Bailey & Ryan Sorrelis for making their images of Aphis impatientis available for use under a creative commons licence.

We have used the species accounts given by Thomas 1878[1877] and Lagos-Kutz et al. (2018), together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections as the source for the (summarized) taxonomic information we have presented. Any errors in 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

  • Thomas, C. (1878) [1877]. A list of the species of the tribe Aphidini, family Aphidae, found in the United States, which have heretofore been named, with descriptions of some new species. Bulletin of the Illinois State Laboratory of Natural History 1(2), 1-16 (p. 12)

  • Lagos-Kutz, D. et al. (2018). Revision of the taxonomic status of Aphis floridanae Tissot (Hemiptera: Aphididae) using morphological and molecular insight. Insecta Mundi 0627, 1-10. Full text