Macrosiphoniella artemisiae

Identification & Distribution

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

The mugwort aphid lives on the upper parts of mugwort (Artemisia vulgaris) especially amongst the flowers. Sexual forms occur in the autumn (apterous oviparae and winged males). The species overwinters as eggs. Macrosiphoniella artemisiae is found in Europe, north Asia, North Africa and North America.

Biology & Ecology

Colour

Most of the literature describes adult apterae of Macrosiphoniella artemisiae as being greyish green and wax dusted (Heie, 1980-1995, Blackman, 2010) or "green covered with white wax so the colour appears pale green with a darker longitudinal stripe" (Jensen et al., 2020). We have found that colour in UK populations is rather more variable than that, with various pink forms present especially later in the year.

We first encountered pink forms in 2015 and then again in four of the following five years. Some are uniformly pink, but many are variegated pink and green over the dorsum (see picture below).

Pink forms tend to occur in groups, so one colony will be pink and or pink/green variegated and the other green. The group shown below included pink immature oviparae (with swollen greyish tibiae).

Other colour forms of Macrosiphoniella artemisiae have been reported including a 'mutant yellow form' in Kent (Blackman, 2010).

Ant attendance

Like all aphids, the mugwort aphid exudes honeydew as an excretory product - a droplet can be seen below.

The honeydew produced by Macrosiphoniella aphids tends to have little or no melezitose - a sugar specially attractive to ants (Fischer & Shingleton (2001)) - so Macrosiphoniella artemisiae is not tended by ants.

Defensive behaviour

There is no information in the literature on whether Macrosiphoniella artemisiae has any specific defensive behaviour against parasitoids, although 'kicking' is the most likely.

However, Ghish & Inbar (2006) have described defensive behaviour in response to vibration such as may be caused by a mammalian herbivore which may consume both vegetation and aphids - namely the aphids may drop from their host plant to the ground. Experimentally, vibration of the apical bud induced dropping in 36% of the colony members. Dropping rates were highest in mature aphids (63%). Relocation was remarkably efficient with nearly all mature aphids that were dropped 13 cm from the plant, finding their way back in about 40 seconds. Location was apparently based on visual cues. The authors concluded that Macrosiphoniella artemisiae is capable of visually discriminating between host and non-host targets and apparently does not react to volatiles emitted from the plant.

Natural enemies

The mugwort aphid is often attacked by parasitoids. We are not certain of the identity of parasitoid that mummified the aphid below, but it is most likely to be Aphidius absinthii.

Aslan et al. (2004) found the parasitoid Aphidius absinthii parasitizing Macrosiphoniella artemisiae in Turkey. Kavallieratos et al. (2004) recorded Aphidius absinthii, Binodoxys centaureae and Lysaphidus arvensis parasitizing Macrosiphoniella artemisiae in Serbia.

Other aphids on same host:

Macrosiphoniella artemisiae has been recorded from 17 Artemisia species.

Blackman & Eastop list 73 species of aphid (including 28 Macrosiphoniella species) as feeding on mugwort (Artemisia vulgaris) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 27 as occurring in Britain (Show British list).

Macrosiphoniella artemisiae is commonly found on the flower heads in mixed species populations with other species of aphids - as illustrated with a nymph of Macrosiphoniella oblonga below.

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 Aslan, M. et al. (2004). A survey of aphid parasitoids in Kahramanmaras, Turkey (Hymenoptera: Braconidae, Aphidiinae; and Hymenoptera: Aphelinidae). Phytoparasitica 32(3), 255-263. Blackman, R.L. & Eastop, V. (2006). Aphids on the World's Herbaceous Plants and Shrubs. Vols 1 & 2. J. Wiley & Sons, Chichester, UK. Full text Fischer, M.K. & Shingleton, A.W. (2001). Host plant and ants influence the honeydew sugar composition of aphids. Functional Ecology 15, 544-550. Abstract Full text Ghish, M. & Inbar, M. (2006). Host location by apterous aphids after escape dropping from the plant. Journal of Insect Behavior 19(1) , 143-153. Full text Kavallieratos et al. (2004). A survey of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) of Southeastern Europe and their aphid-plant associations. Appl. Entomol. Zool. 39(3), 527-563. Full text

 

Identification requests Alan Outen, 6 June 2014 Yesterday the Beds Invertebrate Group were at Stratton Moat, Biggleswade (a medieval ancient monument). This was heavily overgrown with nettles and goosegrass in particular but with a lot of Red Campion and old apple and plum trees. Sadly very few aphids and the apples were completely devoid of these and psyllids. A good list of species generally was assembled nonetheless. Prior to the meeting however on the road verge right beside where I had parked my car, I found another aphid species that I think is new for Beds. Macrosiphoniella artemisiae on Artemisia vulgaris. I surely have this one right so just a single record image attached here. Image(s) copyright Alan Outen, all rights reserved. Bob, InfluentialPoints: Macrosiphoniella artemisiae - yes! A very photogenic aphid which can form enormous colonies. Many thanks Bob. Glad I at least got those right.