Xanthogramma pedissequum sensu lato

    Description

    Quite a distinctive hoverfly, Xanthogramma pedissequum is best distinguished from the similar X. citrofasciatum by the dumpy appearance of the yellow triangles on tergite 2. However the very similar Xanthogramma stackelbergi was added to the British list in 2012 (see Similar Species below).

    Similar Species

    Xanthogramma stackelbergi was added to the British list in 2012, meaning that all old records of Xanthogramma pedissequum without accompanying voucher material or a good supporting photo can no longer be assigned to species level. Males of Xanthogramma stackelbergi have the spots on tergite 2 angled downwards on the inner edge with their lateral edges pinched posteriorly (neatly triangular in pedissequum). The spots on tergites 3 and 4 are more oblique than in pedissequum. The sides of the thorax have several yellow spots in addition to the yellow mesopleural stripe of typical pedissequum.

    Females have the black stripe on the frons very narrow and often petering out where it meets the lunule. The yellow spots on tergite 2 are squarer than in pedissequum and those on tergites 3 and 4 more oblique. The sides of the thorax below the level of the wingbases seem to always have five yellow spots, with two always located near the halteres (often missing in pedissequum). This is one of the best field characters, so always try to retain specimens with these extra yellow spots for critical checking.

    Further differences exist in the wings and underside of the abdomen. The dark costal patch of stackelbergi does not usually extend below vein R3+4 in contrast to typical pedissequum. Viewed from the underside, both sexes have the narrow membranous area between the sternites and tergites mainly yellow except for a dark patch coinciding with the posterior transverse stripe of sternite 2, and this creates a dark band that is less than half of the length of this sternite i.e. much less extensively darkened than pedissequum.

    Identification difficulty
    Habitat

    Grassland and open woodland rides preferring short turf and some bare ground such as pathways.

    When to see it

    May to September peaking in late June and early July.

    Life History

    Males are sometimes seen hovering just a few centimetres above the ground, particularly over bare ground like paths. The larvae feed on aphids within the nests of ants.

    UK Status

    The species is quite frequent in southern England south of a line from 'The Wash' to the south Wales coast.

    VC55 Status

    Fairly frequent in Leicestershire and Rutland.

    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

    UK Map