Results from 2011: summary

During 2011 we had two missions running: the alien moth survey and the pest controller mission. People could take part in both missions via our website, and they could take part in the alien moth survey via the LeafWatch app for iPhones and Android smartphones.

Mission: alien moth survey

Website results for the alien moth survey, 2011

We had 710 records from 250 people via the website (but many more took part via the smartphone app). From the snapshot of the results at the end of the season we can see that the leaf-mining moth is widespread over most of England, although it appears less abundant in the south-west of England. In Wales the records are less widespread, but we cannot tell if that is because they are fewer leaf-miners or fewer people sending in records. Again, there are few records in the north of England, but this does fit with other people's findings that it has not spread right into the north of England.

We had received positive records from as far north as Newcastle, Carlisle and Dundee, but only the record from Newcastle has been confirmed with a photograph. So, up until the end of 2011, the horse-chestnut leaf-miner still had not been confirmed in Scotland.

Mission: pest controllers

Website results for the pest controller mission, 2011

We had 383 results from 120 people via the website. This is a more involved study than the alien moth survey and has to be started in a one week period at the beginning of July. However, from the comments we received, those people taking part really enjoyed it.

Like last year, there was, overall, a very small number of pest controllers that emerged.

One person noted that there was a big difference in the numbers of pest controllers reared from trees that were very close together, which is an intriguing finding.

Although the graph shows a huge proportion of pest controllers in the square covering Cornwall, it is worth noting that these graphs do not show the 'sample size'. We received just two records from Cornwall, and both had quite high numbers of pest controllers. We received a record from Bath with a similarly high number of pest controllers, but lots of other records with very few pest controllers, which evens out the results. Of course, it may also be something specific about Cornwall - but in science it is wise not to base conclusions on small sample sizes.

Mission: pest controllers

Conker Tree Science

Can tiny parasitic wasps help to save our conker trees?

Believe it or not there are dozens of different kinds of tiny wasps (only distantly related to the stinging wasps that we are so familiar with) that attack the horse-chestnut leaf-miner. These wasps are so small that they lay their eggs inside the leaf-miner as it is eating the horse-chestnut leaf from the inside out! The developing wasp larvae eat the leaf-miner from the inside out and then burst out of the caterpillar, in the process killing it and so acting as a natural pest controller.

Can these potential pest controllers actually help by parasitising enough of the leaf-miners to control it's numbers? Given that we have so many of the leaf-miners in this country it would seem that they cannot, but we are interested in finding out more about them.