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Genus Essigella

American pine needle aphids

On this page: Essigella Essigella californica

 

Genus Essigella [Eulachnini]

Essigella are small, long-bodied greenish to brown or black aphids that are all native to the Americas. They are the New World equivalent of Eulachnus, but are smaller and have rather short 5-segmented antennae. The claws have modified apices - either bifurcate or double.

The Essigella genus comprises about 14 species, most of which live on the needles of Pinus. They are cryptic when feeding, but move quickly when disturbed.

 

Essigella californica (Monterey pine needle aphid)

Apterae of Essigella californica are spindle-shaped and have very short 5-segmented antennae (cf. Eulachnus aphids which have longer 6-segmented antennae ). The thorax is grey-green and the abdomen pale lime green, with or without rather faint brown dorsal spots. The legs of Essigella californica are variably pigmented, often mainly pale but with the tibiae darker. Abdominal tergites II-IV each have a transverse row of 6 spinopleural hairs, and 2 marginal hairs on each side. Abdominal tergite VIII has 6-8 hairs. The second hind tarsal segment is less than 1.9 times as long as the first hind tarsal length. The images below are both of Essigella californica recently discovered in UK.

The alate (see second picture below) is green, again with rather short 5-segmented antennae.

The identity of this new species for Britain was confirmed by the UK Food and Environment Agency (Fera) molecular diagnostics team, who compared our sample with verified specimens of Essigella californica from a New Zealand population: the COI gene was sequenced for both samples and found identical.

Essigella californica has a sexual reproductive stage at high altitudes in North America, but are only parthenogenetic elsewhere. The Monterey pine needle aphid is native to North America, from British Columbia south to Mexico. In recent years it has been introduced into Europe (France and Spain) and we now have two confirmed sightings in Britain (in Kew, and our own observations in Kent). We found it on several Montezuma pines (one of its natural hosts in America) growing in the Bedgebury Pinetum. Essigella californica has also been found in Australia, New Zealand and Brazil, and is considered an invasive pest.

Our observations are the second record of Essigella californica in UK to date.
First observedby: S. ReidNov 2010at: Kew Gardens, London
Secondby: Influential PointsSep. 2012 & Aug. 2013at: Bedgebury Pinetum, Kent

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Acknowledgements

We would like to especially thank Sharon Reid (of Fera) for confirming the identity of this pine-feeding aphid new to Britain.

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).

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