Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Aphis ? picridis
Yellow oxtongue aphidIdentification & Distribution Biology & Ecology Damage & Control
Identification & Distribution:Adult apterae of Aphis picridis are bright yellow with black siphunculi. The antennal terminal process is more than 2.1 times as long as the base of that segment, and there are no rhinaria on the third or fourth antennal segments. The antennal tubercles are weakly developed and there are marginal tubercles on abdominal tergites 1 and 7. The cauda is tongue shaped. The body length of adult Aphis picridis apterae is 1.1-1.8 mm.
The rostrum is unusually long, 0.35-0.38 times the body length, and reaches back beyond the hind coxae. This can be seen clearly in the second of the preserved specimens below. The alatae of Aphis picridis (second picture above) are pale green.
Aphis picridis has not been previously recorded from Britain, so specimens have been sent to the Natural History Museum in London for confirmation. Until we receive that confirmation, our identification should be regarded as provisional.
Aphis picridis is found on the rosette leaves and root collar of oxtongues (Picris spp.) and brighteyes (Reichardia spp.) It does not host alternate. It produces sexual forms in the autumn and overwinters as eggs. It has been recorded from Germany, Poland , Italy, Corsica, Spain & Portugal and now possibly England (see below).
Biology & Ecology:
We found this particular aphid in a somewhat unprepossessing habitat - namely a Bedfordshire roadside-verge nature reserve, beside a lay-by, in early September.
The grass had been recently cut (earlier than it should have been, given its nature reserve status), but despite that a large colony of the aphid survived on a small oxtongue plant (see picture below).
Prieto et al. (2004) recently added Spain and Portugal to the known distribution of this species. Hopefully we will soon be able to confirm Aphis picridis as a new species to Britain - possibly the first in a roadside verge nature reserve. It seems that the xeric roadside conditions enable otherwise rare species to flourish as is probably true for the new ant species Myrmica schenckioides in the Netherlands (Boer & Noordijk, 2005 ).