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Identification & Distribution

Adult apterae of Catamergus fulvae are green, with a light dusting of white wax. Their antennae of adults are longer than the body and bear secondary rhinaria on antennal segment III (please note all the apterae in the two pictures below are immatures, which have heavier wax deposits and somewhat shorter antennae). Their antennal tubercles are well developed and divergent. The dorsal abdomen is entirely membranous without any sclerotization, and there are no marginal tubercles on abdominal tergites I and VII. Their siphunculi are rather thin, and about as long as the cauda. The siphunculi have a pale basal half, a dark distal half, and 1-4 rather indistinct rows of polygonal cells near the apex. The body length of adult apterae is 2.3-2.8 mm. Immature apterae (see pictures below) are similar in appearance to adult apterae, but have shorter antennae and cauda.

Note: Catamergus fulvae has been previously described under the synonyms Macrosiphum fulvae, Siphonophora fulvae, and Nectarophora fulvae (Williams, 1910; Oestlund, 1887).

Both images above by permission, copyright Claude Pilon, all rights reserved.

The alate Catamergus fulvae (see picture below) has the head and thorax dark green to brown, and the abdomen pale green. Their antennae are longer than the body and more-or-less dusky. The siphunculi are dusky to black, and are about as long as the cauda.

Image above by permission, copyright Claude Pilon, all rights reserved.

The waxy impatiens aphid is found on the lower parts of Impatiens species. It feeds only on Impatiens and does not host alternate. Oviparae and alate males are produced in September, and the species overwinters as eggs. Catamergus fulvae is found in north-eastern and midwestern USA, and eastern Canada.

 

Biology & Ecology

Natural enemies

Despite the waxy coating of the aphids, some of the members of the colony photographed above had been parasitized.

Image above by permission, copyright Claude Pilon, all rights reserved.

No primary parasitoids emerged, but a hyperparasitoid (see picture above) did emerge from one of the mummies. This is not a natural enemy of the aphid, but rather of the primary parasitoid that originally mummified the aphid. It is a member of the Charipinae (Hymenoptera: Figitidae), possibly an Alloxysta species.

 

Other aphids on the same host

Catamergus fulvae occurs on 2 species of Impatiens (Impatiens capensis, Impatiens pallida).

Acknowledgements

We are especially grateful to Claude Pilon for pictures of Catamergus fulvae (for more of her excellent pictures see).

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Oestlund (1887) and Williams (1910) along with Blackman & Eastop (1994) and Blackman & Eastop (2006). 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

  • Oestlund, O.W. (1887). Synopsis of the Aphididae of Minnesota. Bulletin No. 4. Full text

  • Williams, T.A. (1910). The Aphididae of Nebraska. University of Nebraska. Full text