Zeugophora flavicollis (Marsham, 1802)
In Europe this is a mostly western and northern species, it is locally common from Spain to southern parts of Fennoscandia and the UK, to the south it reaches northern Italy, Slovenia and Bulgaria, and to the east it extends through Russia into Siberia. In the UK it has suffered a drastic decline in recent decades; it was formerly widespread though local through England north to the Lake District but is now restricted to a few sites in Surrey, this decline is thought to be due to inappropriate woodland management and a general removal of the host plants. Adults occur from April until October although they may be absent during the summer before the new-generation appears, and typical habitats are broad-leaved woodland and wooded commons with plenty of host trees in various stages of development. In the UK the usual host is aspen (Populus tremula L.), more rarely black poplar (P. nigra L.) and hybrid black poplar (P. x canadensis Moench), but more widely they also occur on various willows, especially white willow (Salix alba L.) and goat willow (S. caprea L.). Adults spend some time feeding on host foliage before breeding proceeds through spring and early summer, females choose leaves on larger trees to oviposit; they chew small pits into the underside of leaves and insert small batches of eggs which they then cover with a defensive secretion. Larvae have been recorded from June until September, they feed communally within the leaf, producing large dark blotch mines which are visible on the upper surface with the oviposition site visible as a small translucent spot on the margin, they are legless, flattened and yellow and are easily seen through the mined leaf surface. Mature larvae cut small slits in the upper surface of the mine and fall to the ground where they burrow into the soil and pupate in a small earthen cell. New generation adults emerge from late summer and will feed on host foliage before entering the soil to overwinter, however in some continental areas the larvae are known to overwinter in the soil and pupate during the following spring.
2.5-3.5 mm. Distinctive due to the overall colour and the form of the pronotum. Head substantially black, elytra black, pronotum and legs yellow, antennae black with three or four basal segments yellow. Head transverse from above, with prominent convex and weakly emarginate eyes and rounded temples, moderately strongly punctured though more sparsely so medially, without impressed lines between the eyes, antennae filiform and only slightly thickened towards the apex. Pronotum rounded apically from large and pointed lateral teeth, basal half almost parallel-sided to slightly obtuse posterior angles and a straight basal margin, surface strongly punctured, more densely so towards the lateral and apical margins. Elytra with broadly-rounded shoulders and only weakly dilated before a continuous apical margin, surface without striae, strongly and evenly punctured throughout, Legs long and slender, entirely yellow but sometimes with darkened posterior femora, femora not toothed below, front tibiae with a single apical spur, middle and hind tibiae with two. Tarsi 5-segmented but appearing 4-segmented as the tiny fourth segment is partly hidden in the folds of the widely bilobed third segment. Claws smooth and bifid.