Uroleucon erigeronense

Identification & Distribution

Adult apterae of Uroleucon erigeronense are uniformly pale green or yellowish green, usually with a darker spinal stripe (see first two pictures below, from USA and Serbia respectively). The antennae are dark except for antennal segments I & II, which are pale. The terminal process is 3.1-4.7 times the length of the base of antennal segment VI. The apical rostral segment (RIV+V) is 0.9-1.1 times as long as the second hind tarsal segment (HTII). The dorsum is membranous, and the body hairs are not placed on scleroites. The siphunculi are mainly dark but have a pale basal section and are 1.8-2.4 times the length of the cauda. The cauda is pale or dusky and has 6-10 hairs, the most distal of which are shorter than the more proximal hairs. The body length of adult Uroleucon erigeronense apterae is 2.3-2.8 mm.

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

The 'typical' hosts of Uroleucon erigeronense are fleabane daisies (Erigeron and Conyza, but not Pulicaria, fleabane) where it feeds on the upper parts of the stems. In its native North America Uroleucon erigeronense is also found on several other genera in the Asteraceae, as it is in Central and South America where it is invasive. It has also been introduced to Europe where it is restricted to fleabanes, from where it has spread to most of the western Palaearctic as well as Korea and Australia. In northern temperate climates Uroleucon erigeronense produces oviparae and alate males in September-October.

Biology & Ecology

Jensen et al. (2010) describe the morphology and biology of Uroleucon erigeronense and provide an updated list of hosts in the USA, along with the results of host plant transfer experiments.

Brumley & Watson (2016) provide the first records of Uroleucon erigeronense on Conyza from Australia, along with biological and morphological information.

Other aphids on the same host

• Uroleucon erigeronense has been recorded on 8 Erigeron species (Erigeron acris, Erigeron annuus, Erigeron eximius, Erigeron jamaicensis, Erigeron politus, Erigeron pulchellus, Erigeron strigosus, Erigeron subtrinervis).

  Blackman & Eastop list at least 30 species of aphid as feeding on fleabane daisies (Erigeron) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).

• Uroleucon erigeronense has been recorded from 4 Conyza species (Conyza aegyptiaca, Conyza bonariensis, Conyza canadensis, Conyza stricta).

  Blackman & Eastop list at least 23 aphid species of aphid as feeding on Conyza canadensis worldwide, and provide formal identification keys. (Show World list) Of those aphid species, Baker (2015) lists 13 as occurring in Britain. (Show British list)

Acknowledgements We are extremely grateful to Marko Šćiban (HabitProt) for his image of live Uroleucon erigeronense in Serbia. Our particular thanks to Roger Blackman for images of his clarified slide mounts. 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).

Useful weblinks

References Brumley, C. & Watson, L. (2016). First records of Uroleucon erigeronense (Hemiptera: Aphididae) on Conyza (Asteraceae) from Australia, with descriptions of morphological variation, biological notes and an update for commonly used keys: Uroleucon erigeronense from Australia. Austral Entomology 56(3), 339-344. Abstract Jensen, A.S. et al. (2010). Host range and biology of Uroleucon (Lambersius) erigeronense (Thomas 1878), and its synonomy with Uroleucon (Lambersius) escalantii (Knowlton) 1928 (Hemiptera: Aphidiidae). Proc. Entomol. Soc. Wash. 112(2), 239-245. Full text