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Identification & Distribution:

Maculolachnus submacula apterae (see first picture below) are yellowish-brown, reddish-brown or dark chestnut brown. The dorsum has many fine hairs placed on small scleroites. Their dark brown antennae are about half the body length and the antennal terminal process is less than 0.25 times the length of the base of the sixth antennal segment. The legs of Maculolachnus submacula are dark brown, except for the bases of the femora and middle parts of tibiae. The hairs on the tibia are about half the diameter of the tibia. The siphuncular cones are dark and also have many hairs. The body length of Maculolachnus submacula is 2.7-3.8 mm.

The alate Maculolachnus submacula (not pictured) is dark brown or bronze brown, and has a dark spot on its forewing between the pterostigma and base of media. Antennal segment III has 5-10 secondary rhinaria and segment IV has 1-3. Immatures (see second picture above) are a little paler than the adults.

Maculolachnus submacula feed on Rosa species (including roses). Much of the year they feed on stems near the ground, but in summer they move to the surface roots. They have also been found on the roots of dove's-foot cranes'-bill (Geranium molle), silverweed (Potentilla anserina) and salad burnet ( Sanguisorba minor). Colonies are tended by ants which often tent over the aphids with soil particles. They do not host alternate. Oviparae and apterous males are found in September-October. Maculolachnus submacula are distributed throughout Europe eastward to Ukraine, Kazakhstan and India.

 

Biology & Ecology:

Life cycle

Although Maculolachnus submacula seems to be common in much of Europe, finding it in Britain was something of a special event. We found it first on an old cultivated climbing rose late in 2014 at Alfriston in East Sussex where the aphids were feeding on the stems (see picture below).

Gottschalk (1989) gives an account of the biology of Maculolachnus submacula and describes the sexuales (males and oviparae). Oviparae have only slightly swollen hind tibiae bearing up to 80 small scent glands on the basal halves of their hind tibiae. Males are smaller and have secondary rhinaria on antennal segments III and IV. These sexuales develop in autumn and, after mating, the oviparae deposit large numbers of rather shiny black eggs on the stems of roses (see first picture below). The following year the eggs hatch in early spring (see second picture below).

We found Maculolachnus submacula in 2015 and 2016 on the same roses in Alfriston that we found them on in 2014. By October fairly dense populations had built up (see picture below).

In 2015 aphid activity continued on the plants at least up till late December, with the ants vigorously tending the aphids and the aphids laying huge numbers of eggs. This activity was doubtless enhanced by the exceptionally mild weather in Britain in December 2015.

Maculolachnus submacula is not only found on rose stems - in hot years it has been found to live on the surface roots of rose and various other members of the Rosaceae, usually under ant tenting. One such non-rose host is salad burnet which we found ant-tented in 2016. Excavation of the plants revealed vigorous colonies of Aphis sanguisorbae and also a single very active Maculolachnus submacula (see first picture below). The salad burnet was growing on chalk downland so not surprisingly the Maculolachnus colony was tended, not by Lasius niger, but by Lasius flavus (see second picture below).

In 2017 we also found a thriving colony of Maculolachnus submacula on the roots of another member of the Rosaceae, dove's-foot crane's-bill, growing in Alfriston, the same village where we had found the aphid on rose.

 

Population dynamics

There have been a few studies carried out on the ecology of the rose stem aphid. Jaskiewicz (2003) describes the species composition and number of aphids on rose bushes in urban conditions over three years. Maculolachnus submacula fed on the lignified shoots of roses from April till November. Their numbers varied over time with peak numbers in May or June. Maculolachnus submacula remained on the rose shoots longer than any of the other aphid species inhabiting these plants.

Kmiec (2007) sampled four varieties of rose on 28 occasions over 3 years and calculated a constancy index (the percentage of occasions when the species was present) for each of seven species of aphids. Maculolachnus submacula was mainly found on noble roses but its constancy varied greatly between sites.

Ant attendance

All the colonies of Maculolachnus that we have found have been attended by ants, usually Lasius niger or Lasius flavus.

The ants do not just glean the honeydew that the aphids have deposited - they actively tend the aphids to encourage the production of honeydew.

The aphids we have found on rose have usually not been tented over with soil particles - unlike those found by Simon Leather Don't Forget the Roundabouts. We suspect the tenting over with soil is mainly done in summer, partly to protect the aphids from predators and partly to maintain a high humidity.

In January 2015 we received an identification query for aphids on rose (see picture below) from Thomas Legrand in Oxelaere, in the north of France. These too were Maculolachnus submacula and were also attended by ants.

Guest image copyright Thomas Legrand, all rights reserved

Natural enemies

Lubiarz & Cichoka (2014) carried out a fascinating study on aphid egg predation by Coccinellidae. One of the aphid species considered was Maculolachnus submacula which laid eggs in three locations on grandiflora rose plants. Ladybirds destroyed 31% of those eggs in autumn 2011 and 14% in spring 2012. In autumn 2012, they destroyed 42% of the eggs. In spring 2013, 14-20% of eggs were destroyed. In 2013 the process was observed: Ladybird beetles foraged for several hours per day, either eating out holes in egg patches or placing themselves in the middle of an egg-ring encircling a shoot, and eating their way round the shoot. The ladybirds bit into the tops of eggs and ate out the egg interior. The destroyed eggs often fell off the plants, leaving visible gaps in egg deposits.

Guest image copyright Thomas Legrand, all rights reserved.

The picture above shows a large batch of eggs laid by Maculolachnus submacula apparently attacked by a fungal entomopathogen on rose in northern France.

Few parasitoid species have been recorded as attacking Maculolachnus submacula. Starý (1979) records Pauesia maculolachni in Central Asia. We have found mummified Maculolachnus on one occasion (see picture below), but unfortunately no parasitoids subsequently emerged.

The white scale insects on the rose stem are most likely Aulacaspis rosae.

 

Other aphids on same host:

Maculolachnus submacula has been recorded from 19 Rosa species.

Blackman & Eastop list 61 species of aphid as feeding on Rosa spp. (both cultivated and wild) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 24 as occurring in Britain (Show British list).

Blackman & Eastop (1984) list 32 species of aphid as feeding on cultivated 'roses' worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).

 

Damage and control

Jaskiewicz (2003) commented on the damage caused by Maculolachnus. They fed on young twigs in spring and caused twisting, bending, growth-inhibition, and even dying-out of the shoot-ends.

Acknowledgements

Our particular thanks to Thomas Legrand for his images of Maculolachnus submacula.

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

  • Blackman, R.L. & Eastop, V.F. (1984). Aphids on the world's crops: an identification guide. J. Wiley & Sons, Chichester, UK.

  • Gottschalk, H.J. (1989). Zur Verbreitung von Maculolachnus submacla (Walker, 1848) in den Nordbezirken de DDR und die Beshreibung der Sexuales (Homoptera: Aphidinea: Lachnidae). Entomologische Nachritten undBerichie 33, 161-163.

  • Jaskiewicz, B. (2003). The species composition and number of aphids on the shrubs Pinus mugo Turra and Rosa sp. in urban conditions. Electronic Journal of Polish Agricultural Universities, Horticulture 6(2). Full text

  • Kmiec, K. (2007). Constancy of occurrence of aphid community (Hemiptera, Aphididae) on roses in the urban conditions of Lublin. Annales Universitatis Marie Curie-Sklodowska Lublin - Polonia. 17(1), 53-59. Full text

  • Lubiarz, M. & Cichoka, E. (2014). The process of aphid egg-laying and the little known role of the Coccinellidae in aphid egg destruction in Poland - preliminary results. Journal of Plant Protection Research 54(3), 242-249. Full text

  • Starý, P. (1979). Aphid Parasites (Hymenoptera, Aphidiidae) of the Central Asian Area, Springer-Science +Business Media, B.V.