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Aphid predator (Hemiptera : Miridae)

Harpocera thoracica

Oak catkin mirid bug

On this page: Identification & Distribution Biology & Ecology

Identification & Distribution

Adults of Harpocera thoracica are sexually dimorphic. Males (see first picture below) are more elongated, have longer tibiae and their second antennal segment is enlarged. The colour ranges from black, dark brown to orange to pale brown with the males usually darker than the females. The tips of the hemelytra are black, surrounded by white markings. The legs are brown or yellowish brown and the antennae are brown. Immatures are reddish and covered in dark hairs and with the two basal antennal segments thickened.


Biology & Ecology

Bugs of the family Miridae are inflorescence specialists on European trees, feeding on the staminate catkins of a variety of deciduous trees (Wheeler, 2001). On oak the catkin specialist is Harpocera thoracica. We have found large numbers of this bug on flowering holm oak trees (Quercus ilex) in May - along with large numbers of potential prey.

The aphid Myzocallis schreiberi (holm oak aphid) is usually abundant on holm oak at flowering time, along with small numbers of Thelaxes suberi. It seems very likely that Harpocera thoracica supplements its catkin diet with these aphids, although we have yet to photograph them doing so.


For the mirid bugs we have used Southwood & Leston (1959) and British Bugs to aid in identification and for the key characteristics.

For aphids 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. For aphids 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).

Useful weblinks


  •  Wheeler, A.G.W. (2001). Biology of the Plant Bugs (Hemiptera: Miridae) . Cornell University Press.