Holly is evergreen, so the mines can be found all year It is also rather sparsely distributed, so we will run this as our target from December to February to give the best chance of getting records.
| Species of the month, December-February: The Holly Leaf Gall Fly Phytomyza ilicis | ||||
| The Holly Leaf Gall Fly Phytomyza ilicis is a tiny insect which develops inside the leaf of Holly, pupating inside the leaf and emerging in midsummer. It produces a characteristic blotch on the leaf - actually classed as a gall, as the presence of the larva causes the leaf to produce abnormal growth in the affected area. More information on its biology is available in two papers here and here (.pdf files, 1.6MB and 440kB). It is much more widely distributed than the map suggests. If you see Holly in Highland, check the upper surface of the leaves for these unmistakeable marks, and report them via the 'Submitting records' page. This allows you to submit records on line. Most will be found in gardens, parks etc., but records from more remote areas (Holly often grows on crags and in mountain gullies and riverbanks) will be especially valuable. Holly is evergreen, so the mines can be found all year It is also rather sparsely distributed, so we will run this as our target from December to February to give the best chance of getting records. | ||||
| | Mature mines on a leaf. | Current map. From 3 locations in December (blue), we now have the map at left. The virtual absence of records in the NW and the N coast appears to reflect real absence of the fly. We still have no returns from Lochaber, positive or negative, so its status there remains unknown. Many thanks to all who contributed records. Because Holly is evergreen, the gall can be found all year, so please continue to report it, especially from areas where it is not currently mapped. | ||
| | The oviposition (egg-laying) scars on the mid rib on the underside of the leaf. | The National Biodiversity Network records are shown on the map. (see terms and conditions). Data providers (list and interactive map ) and the NBN Trust bear no responsibility for any further analysis or interpretation of the information in the map. | ||
| | Close-up showing an exit hole from the mine (but from a wasp parasitic on the fly, not the fly itself).Photos © Murdo Macdonald. | |||
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