Dysaphis gallica

Identification & Distribution:

The aptera of Dysaphis gallica has been described variously as 'leaden coloured' and 'dark mottled blackish green, usually with a reddish tinge at bases of siphunculi'. The reddish tinge is more apparent in fourth instar nymphs (see below). The head has quite prominent antennal tubercles and a scabous median frontal tubercle. Their siphunculi are dusky, dark towards the apices, and are 2.4-3.3 times the length of the short, helmet-shaped cauda. The body length is 1.2-1.6 mm.

Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.

Dysaphis gallica has mostly been found on their secondary hosts - various members of the Scrophulariaceae, especially Cymbalara muralis (ivy-leaved toadflax), but also Antirrhinum majus (common snapdragon), and Veronica anagallis-aquatica (speedwell). In Britain they reproduce parthenogenetically through the winter, but in northern Germany they host alternate to a primary host, possibly Cotoneaster tomentosus or apple (Malus). Dysaphis gallica has been recorded on its secondary hosts in England, France, Switzerland, Italy, Sicily and Israel.

Biology & Ecology:

The main host plant of Dysaphis gallica is the ivy-leaved toadflax (Cymbalaria muralis), a plant with weak trailing stems, 5-lobed leaves and small mauve flowers with a white and yellow lip (see pictures below). It is native to Mediterranean Europe, but is widely naturalised elsewhere, and in Britain grows commonly on old walls.

We have found Dysaphis gallica active and reproducing from early March through to June and again in autumn and early winter.

Not a lot is known about Dysaphis gallica. The primary host has been tentatively identified as apple (Malus) following its discovery on apple in pseudogalls by Naumann-Etienne & Remaudière (1995) in Pakistan. Various transfer experiments have been attempted in Europe, but aphids reared on secondary hosts failed to feed on a range of likely primary hosts. Our observations of reproducing viviparae in March suggest it may not host alternate in UK, but remains all year on its secondary host Cymbalaria muralis (ivy-leaved toadflax).

The aphid is cryptically coloured, resembling the leaves and flower buds of its food plant.

We found no predators or parasitoids associated with the aphid populations, but one appeared to be infected with an orange Entomopthora fungus (see picture above).

Other aphids on same host:

• Blackman & Eastop list 10 species of aphid as feeding on common snapdragon (Antirrhinum majus) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists all 10 as occurring in Britain (Show British list).

• Blackman & Eastop list 6 species of aphid as feeding on ivy-leaved toadflax (Cymbalara muralis) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists all 6 as occurring in Britain (Show British list).

• Blackman & Eastop list 11 species of aphid as feeding on speedwell (Veronica anagallis-aquatica) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 10 as occurring in Britain (Show British list).

Acknowledgements Our particular thanks to Roger Blackman for images of his clarified slide mounts. Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made 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).

Useful weblinks

References Naumann-Etienne, K. & Remaudière, G. (1995). A commented preliminary checklist of the aphids (Homoptera: Aphididae) of Pakistan and their host plants. Parasitica 51, 1-61. Abstract