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Chaitophorinae : Atheroides serrulatus
 

 

Atheroides serrulatus

Orange grass aphid

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

Identification & Distribution

Adult apterae of Atheroides serrulatus (see first two pictures below) are yellow to yellowish-brown with elongate and slender bodies and visible rugose sculpture. The dorsal carapace is always solidly sclerotic from abdominal tergites II-VII. The antennae just reach the anterior margin of the prothorax, with the antennal 'flagellum' (=segments III-V/VI) more than 0.25 mm long (cf. Atheroides brevicornis, which has the antennal flagellum less than 0.25 mm long). The terminal process is 1.1-1.3 times the length of the base of the last antennal segment (V). The apical rostral segment (RIV+V) is blunt and about 0.75 times the length of the second hind tarsal segment (HTII). The dorsal body hairs and those on antennal segment III (when present) are less than 0.03 mm long, and less than one-third as long as basal part of last antennal segment. Abdominal tergite VIII bears 11-17 pointed, thorn-like hairs, and has a somewhat rounded, overhanging hind margin which normally conceals the cauda (see clarified mount below). The Atheroides serrulatus cauda has 4 hairs. The body length of adult Atheroides serrulatus apterae is 1.7-2.4 mm.

First and third images above by permission, copyright Jessica Joachim, all rights reserved.
Second image above copyright Poul Ulrik, all rights reserved.

Immature Atheroides serrulatus (third picture above) tend to be flattened dorso-ventrally, as are their adults.

The siphunculi of Atheroides serrulatus are borne on the fifth abdominal segment, and reduced to 'siphuncular pores' which are notoriously difficult to see. The first image below is a clarified mount of an aptera; the second is a scanning electron micrograph of an aptera, viewed dorsally (arrows indicate siphuncular pores). The third image is a scanning electron micrograph showing a siphuncular pore (actually a minute siphunculus) in semi-profile.

Three images above copyright Wieczorek et al. (2017) under a creative commons attribution license.

Atheroides serrulatus alatae (see image below) have the head and pterothorax blackish sclerotic, and the dorsal abdominal carapace of apterae replaced by separate segmental dark bands and marginal sclerites on the tergites. Secondary rhinaria are few, with up to 7 in a single row on antennal segment III, and rarely 1 on IV. Siphuncular pores are located on the inner front angle of marginal sclerite of abdominal tergite V.

Micrograph of clarified mount by permission Karina Wieczorek, all rights reserved.

Atheroides serrulatus is found, often singly, on the leaves of many different grasses (Poaceae) and possibly on species of sedge (Cyperaceae). Most specimens are obtained by the use of sweep nets, so the identity of the host plant species is often indeterminate. There is no host alternation. Sexual forms (apterous males and oviparae) develop in autumn. Atheroides serrulatus is widespread and often common in Europe as well as parts of Asia and Canada.

 

Other aphids on the same host

Acknowledgements

Our special thanks to Poul Ulrik, and Jessica Joachim, for permission to use several of the pictures shown above.

We particularly thank Karina Wieczorek (University of Silesia, Poland) for the image of an alate Atheroides serrulatus.

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 Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). 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).

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References

  • Wieczorek, K., Lachowska-Cierlik, D., Kajtoch, Å. and Kanturski, M. (2017). The relationships within the Chaitophorinae and Drepanosiphinae (Hemiptera, Aphididae) inferred from molecular-based phylogeny and comprehensive morphological data. PLoS ONE 12(3): e0173608. Full text