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Myzocallis punctata

Regular oak aphid

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

Identification & Distribution

All adult viviparae are alate. Adult alatae of Myzocallis punctata (see pictures below) are generally described as being yellow, as shown in the preserved alate in the fifth picture below. Providing we are correct in our identification of the live aphids in the first three pictures below, the lateral parts of the dorsum may also be suffused with pink. Dark dorsal body markings are often present but these markings are seasonally variable, and may be absent (see Richards, 1968 and Quednau, 1999). Their antennae are ringed with black, and the legs are mainly pale. The clypeus is not produced anteriorly (cf. Myzocallis tuberculata on oak, which has the clypeus produced anteriorly). The apical rostral segment (RIV+V) is 0.80-0.95 times as long as the second hind tarsal segment (HT II) (cf. Myzocallis asclepiadis on milkweed, which has RIV+V 1.03-1.17 times the length of HT II). The forewings are variably pigmented, sometimes almost hyaline in early spring populations except for dark spots at ends of veins, but later with a distinctive pattern of patchy infuscation. Abdominal tergites I & II may or may not bear small paired wart-like spinal processes not more than 0.5 × their basal widths (cf. Myzocallis tuberculata, which has low paired spinal processes on abdominal tergites I & II in spring populations, and much longer conical or finger-like processes in summer populations). The siphunculi are pale, with spiculose ornamentation (cf. Myzocallis discolor on oak, which has dark siphunculi on dark siphuncular sclerites). The anal plate is deeply indented and the cauda is knobbed. The body length of adult Myzocallis punctata viviparae is 1.8-2.5 mm.

Note: The seasonal variation in this species was not initially recognised, and the pale form (not pictured here) was described as a separate species (Myzocallis mimica Richards). That name was synonomized with Myzocallis punctata by Quednau (1999).

Images above copyright Jesse Rorabaugh under a public domain (CCO) licence.

Immatures of Myzocallis punctata (see first picture below) are yellow with a variably developed pattern of brownish pigmented areas around the bases of their spinal and marginal setae. The second picture below shows a preserved alate of Myzocallis punctata.

Images above copyright Salvador Vitanza under a Creative Commons Attribution License.

Myzocallis punctata is one of the most common oak aphids in North America, and can be found on many different oak (Quercus) species, especially of the white oak group. It does not host alternate. In north east USA sexuales occur in the autumn, and overwintering eggs are laid on the oak twigs. In California parthenogenetic viviparae are present all year. Myzocallis punctata is native to eastern North America, but has been introduced into western states.

 

Other aphids on the same host

Myzocallis punctata has been recorded on 13 species of oak (Quercus alba, Quercus bicolor, Quercus engelmannii, Quercus gambelii, Quercus garryana, Quercus imbricaria, Quercus macrocarpa, Quercus marilandica, Quercus montana, Quercus palustris, Quercus phillyraeoides, Quercus prinus, Quercus rubra).

Acknowledgements

We are grateful to Jesse Rorabaugh (glmory) for the pictures of Myzocallis punctata that he has made available to everyone under a 'public domain' (CC0) licence (for more of his excellent pictures see).

We have made provisional identifications from high resolution photos of living specimens. We have used the keys and species accounts of Richards (1968) and Quednau (1999) 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

  • Quednau, F.W. (1999). Atlas of the Drepanosiphine aphids of the World. Part I: Panaphidini - Myzocallidinae. Contrib. Am. ent. Inst 31, 1-281.

  • Richards, W.R. (1968). A synopsis of the world fauna of Myzocallis (Homoptera: Aphididae). Memoirs of the Entomological Society of Canada, Ottawa 100 Supplement S57, 3-76. Abstract