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Macrosiphum albifrons

Lupin aphid, Essig's lupin aphid

Identification & Distribution  Biology & Ecology  Damage & Control 

Identification & Distribution:

Macrosiphum albifrons apterae are large pale bluish grey-green aphids dusted with white wax. Their antennae and legs are pale or dusky with blackish apices. The siphunculi are brownish with dark tips. The siphunculi are 0.21-0.32 times the body length, and 1.6-2.2 times the length of the cauda. The cauda is pale, slender and rather pointed. The body length of adult Macrosiphum albifrons apterae is 3.2-5.1 mm.

 

The nymphs (see second picture above for the nymph of a future alate) have all dark siphunculi and are dusted with wax. The alates have a dusky head, brown thorax, a bluish green abdomen with small marginal spots, dusky siphunculi and are dusted with wax. The micrographs below are (first) of an aptera in alcohol and (second) of the apex of the siphunculi. Note the polygonal reticulation on the siphunculi - characteristic of the genus Macrosiphum.

 

The clarified slide mounts below are of adult viviparous female Macrosiphum albifrons : wingless, and winged.

 

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

The lupin aphid does not host alternate but spends its entire life cycle on Lupin (Lupinus sp). It lives mainly on the leaves, stems and flower spikes. It originates in North America where sexual forms with alate males develop in the autumn, and the aphid overwinters as eggs. In Europe Macrosiphum albifrons was first recorded in England in 1981 where it overwinters as viviparae. It is now widely distributed and considered an invasive pest species over much of Europe.

 

Biology & Ecology:

We have found the lupin aphid several times in Britain, sometimes in considerable numbers. An adult aptera is shown below giving birth.

Carter & Nichols (1989)  reported that, since its first appearance in 1981, Macrosiphum albifrons has recurred on lupin plants in Britain every year up to 1988, in spite of harsh winter weather. Experimental tests of exposure to freezing conditions are reported and indicate that, due to its low-temperature tolerance, this aphid probably survives and reproduces on lupins through most winters in the parthenogenetic viviparous stage.

Further evidence of the low-temperature tolerance of the lupin aphid comes from Frazer & Gill (1989) . They determined the fecundity, survivorship, and rate of development of the aphid Macrosiphum albifrons. These statistics were summarized into life tables and the intrinsic rate of increase computed. The life tables, using a time scale in days, were converted to a variable life table model using a physiological time scale based on an estimated thermal threshold of development of only 3.59°C.

Natural enemies

Wink & Witte (1991)  identified 31 quinolizidine alkaloids in Macrosiphum albifrons, up to 1.8 mg/g fresh weight. Experimental evidence confirmed that the aphid exploits the dietary alkaloids (which serve as chemical defense compounds in the plant) for their own defense. The recovery of alkaloids in aphids confirms that the alkaloids are transported via the phloem in Lupinus.

We have found syrphid adults laying eggs on lupins near aphid colonies (see picture below) , but we have not encountered any coccinellid or syrphid larvae in the colonies.

Cohen & Mackauer et al. (2010)  looked at parasitoids attacking Macrosiphum albifrons in Canada. There it is parasitized by four species of Aphidiidae: Aphidius lupini, Ephedrus californicus, and two unidentified species of Praon. The percentage of parasitism varied seasonally, and between collecting sites. Aphidius lupini was the most common and widespread parasite, killing an average of 5.2, 7.6, and 9.0% of second-, third- and fourth-instar aphids, respectively, over the season as a whole. A fungal pathogen, Entomophthora sp., caused ca. 60% mortality among third- and fourth-instar aphids during rainy periods in late spring and late summer. We have also found Entomophthora attacking lupin aphid colonies (see picture below) in Britain.

In USA Finlayson et al. (2010)  found that all coccinellids studied consumed fewer Macrosiphum albifrons compared with three other aphid species, likely because of deterrent compounds sequestered by this species from its host plant. Macrosiphum albifrons is native to the study area and is known to sequester toxic compounds from its host plant that have been shown to cause a "narcotizing effect" on Coccinella septempunctata (Gruppe & Roemer 1988 ). It is thus notable that Harmonia axyridis and Coccinella septempunctata, both introduced species without historical exposure to Macrosiphum albifrons, consumed the lowest numbers of this species. In contrast, Coccinella trifasciata, which is native to the area, consumed the most Macrosiphum albifrons adults. It would seem that Coccinella trifasciata may have evolved the ability to tolerate these compounds, whereas the recently introduced non-native species have yet to do so. By virtue of being able to exploit lupine aphids, Coccinella trifasciata may enjoy a refuge from prey competition with the non-native species. Aphidius lupini was considered as a potential agent for biological control of the lupin aphid in England.

 

Damage and control

Ferguson (1994)  monitored pests on plots of lupins in Hertfordshire and Bedfordshire in Britain between 1986 and 1990. The aphid Macrosiphum albifrons was present each year, and probably overwintered on autumn-sown Lupinus albus in 1989/1990. Its distribution was patchy, and injury was most severe in flowering plants. It was concluded that Macrosiphum albifrons was one of four most damaging pests for lupins.

Natural enemies have been found to attack the lupin aphid (see above), but they often only come in after the damage is done. Most horticulturists consider that insecticide application (deltamethrin, thiacloprid or acetamiprid) is the only option for lupin aphid control (see lupin aphid , but lupins should not be sprayed when in flower (often the first time the aphids are noted) to avoid killing pollinating insects.

 

Acknowledgements

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

  •  Carter, C.I. & Nichols, J.F.A. (1989). Winter survival of the lupin aphid Macrosiphum albifrons Essig. Journal of Applied Entomology 108 (1-5), 213-216. Abstract 

  •  Cohen, M.B & Mackauer, M. (1986). Lupine aphid, Macrosiphum albifrons (Homoptera: Aphididae): Distribution and hymenopterous parasites in British Columbia. Environmental Entomology 15(3), 719-722. Abstract 

  •  Ferguson, A.W. (1994). Pests and plant injury on lupins in the south of England. Crop Protection 13(3), 201-210. Abstract 

  •  Finlayson, C. et al. (2010). Differential consumption of four aphid species by four lady beetle species. Journal of Insect Science 10 Article 31. Full text 

  •  Frazer, B.D. & Gill, B. (1981). Age, fecundity, weight, and the intrinsic rate of increase of the lupine aphid Macrosiphum albifrons (Homoptera: Aphididae). The Canadian Entomologist 113(08), 739-745. Abstract 

  •  Gruppe, A. & Roemer, P. (1988). The Lupin Aphid (Macrosiphum albifrons Essig, 1911) (Hom., Aphididae) in West Germany: its occurrence, host plants and natural enemies. Journal of Applied Entomology 106 (1-5), 135-143. Abstract 

  •  Wink, M. & Witte, L. (1991). Storage of quinolizidine alkaloids in Macrosiphum albifrons and Aphis genistae (Homoptera: Aphididae). Entomol Gen 15(4): 237-254. Full text 

 

Identification requests

Alan Outen, 11 June 2014

Our neighbours lupins are devastated by Macrosiphum albifrons but ours, which I have been inspecting daily for three weeks, remain clean!

Image(s) copyright Alan Outen,  all rights reserved.

 

Bob, InfluentialPoints:

  • Sometimes I feel the Macrosiphum albifrons are much more impressive than the lupins. Wish I could convince gardeners of that!