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Japanese elm aphidOn this page: Identification & Distribution Biology & Ecology Introduction to Britain Life cycle Natural enemies Other aphids on the same host
Identification & Distribution
All adult Tinocallis takachihoensis viviparae are winged. These alates (see first picture below) are pale yellow-green with a shiny black head and thorax (cf. Tinocallis platani, which has head and prothorax yellow with brown longitudinal stripes). The pattern of black markings on the wings is diagnostic. The antennae are about 0.88 times as long as the body, and segment III bears 19-24 (mostly 22) secondary rhinaria. The terminal process is 0.92-1.2 times as long as base of antennal segment VI. The head bears no dorsal processes (cf. Tinocallis ulmiparvifoliae, which has three pairs of dorsal processes on the head). The pronotum and mesonotum each bear a pair of dorsal processes. The pair on the pronotum are small and pale, whilst the pair on the mesonotum are large and dark. There are also two pairs of paired dorsal processes on the abdominal dorsum. There are no brown markings on the abdominal dorsum (cf. Tinocallis platani, which has extensive dark dorsal makings on the abdomen). There is a black patch where the hind femur meets the hind tibia. The body length of Tinocallis takachihoensis alates is 1.8-2.0 mm.
Immature Tinocallis takachihoensis are pale yellow green with numerous tubercles topped with capitate hairs. They form large colonies with the alates on the undersides of the leaves (see second picture above). The micrographs below show (first) an alate in posterior-lateral view and (second) a dorsal close-up of the head and thorax showing the two pairs of dorsal processes.
The Japanese elm aphid feeds on elm (Ulmus species) and some other genera in Japan, China and eastern Siberia. Tinocallis takachihoensis has also been introduced to Europe (France, Germany, England, Netherlands, Sicily, Andorra) and the USA. It now appears be established in most of these countries.
Biology & Ecology:
Introduction to Britain
In Britain Tinocallis takachihoensis has been regularly found on imported Bonsai plants (Ulmus and Zelkova spp.) (Roques & Auger-Rozenberg, 2006). It was first recorded in England in 'the wild' by Döring (2007, 2008) who collected it on whych elm (Ulmus glabra) in Berkshire. Tinocallis takachihoensis has also been recorded in 2012 from Lincoln, UK by Mick Talbot.
We first confirmed the presence of Tinocallis takachihoensis in East Sussex in July 2010 on elm trees at Friston Forest, although immatures we found there in 2007 were also probably of this species.
When we first found Tinocallis takachihoensis in Britain, in 2010, it was unclear how the species was overwintering. Was it producing sexuales and overwintering as eggs? Or was it continuing to reproduce parthenogenetically regardless of the colder weather? Then in October 2018 we found immature and mature oviparae on elm at Alfriston in East Sussex, England, thus confirming that at least some of the population overwinters in the egg stage. The pictures below show (first) an immature ovipara and (second) a mature ovipara. It is yellow with orange hues and has strongly swollen tibiae.
Some of the oviparae were instead bright orange from the mesonotum to around tergites VI-VII (see picture below).
Patti & Barbagallo (1998) report alate males and oviparae in Sicily from mid-October. Piron (2013) suggested that with climate change in Western Europe the climate may be similar enough to Japan to enable Tinocallis takachihoensis to survive milder winters parthenogenetically, even with occasional severe frosts.
There are few observations on the natural enemies of Tinocallis species. Lumbierres et al. (2005) have recorded the coccinellid Oenopia conglobata (see picture below) as a predator of Tinocallis takachihoensis in Lieida, in the Iberian Peninsula.
Other aphids on same host:
Tinocallis takachihoensis has been recorded from 4 Ulmus species (Ulmus canescens, Ulmus glabra, Ulmus ×hollandica, Ulmus japonica).
Blackman & Eastop list about 75 species of aphids as feeding on elms worldwide, and provides formal identification keys for aphids on Ulmus.