|
|
(Coleoptera, Diptera, Hymenoptera and Lepidoptera)
by
Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds
|
|
|
MYRICA.
Bog-myrtle. [Myricaceae]
|
Two
species of Myrica are recorded in Britain, Bog-myrtle (M.
gale) and Bayberry (M. pensylvanica).
Ten British miners are recorded on Myrica.
A key to the European miners recorded on Myrica is provided in Bladmineerders van Europa.
|
Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Myrica
|
1a > Leaf-miner and case-bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tissues via a hole cut in the epidermis. From that point it eats away as much leaf tissue as it can reach without fully entering the mine. Mine does not contain frass (Coleophora species) |
2 |
1b > Leaf-miner, but not a case-bearer: The larva lives mainly inside the mine. Mine usually contains frass. In later instars the larva may live sandwiched between two more or less circular sections cut from the leaf. |
3 |
2a > Leaf-miner
and case-bearer: As with other Coleophorids, the larva forms
a case from the leaf, in which it overwinters. The case formed by
this species is long, slender and frequently woolly in appearance.
Bivalved
composite leaf case of 8-10 mm, rather strongly compressed and keeled,
with a mouth angle of 30-45°. |
|
|
On Betula, Myrica and Salix in Britain and Myrica and Salix elsewhere. Throughout the whole of Britain, except
the far north of Scotland. Also recorded in the Republic of Ireland.
Widespread in continental Europe.
|
Coleophora
lusciniaepennella (Treitschke, 1833) [Lepidoptera: Coleophoridae]. |
2b > Leaf-miner
and case-bearer: Larva mining leaves, the blotches brownish. The final case is 8-11
mm long, slender, and fixed at 45° to leaf surface, with anal
end laterally compressed. The case has a serrated keel due to formation
from the edge of a leaf.
Spatulate
leaf case. Strikingly slender, bivalved case, 8-11 mm long, with
a slight curve at the rear end, that is keeled and often toothed.
The end is laterally compressed. Mouth angle 45°. The full depth
mines often are conspicuously brown.
|
|
|
On Betula and Carpinus, but not yet on Myrica,
in Britain plus Alnus, Corylus and Myrica elsewhere. Widespread in Britain and continental Europe. Also
recorded in the Republic of Ireland.
|
Coleophora
milvipennis Zeller, 1839 [Lepidoptera: Coleophoridae]. |
2c > Leaf-miner
and case-bearer: The larva feeds by inserting its head into small mines it creates
on the leaves of birch, elm, alder, or hazel. Occasionally it is
found feeding on other trees, or on herbaceous plants onto which
it has accidentally Fallén. It forms two cases during its larval
life. The first case is initially curved, smooth, laterally compressed
with a bivalved anal opening, and about 2 mm long in September.
During October it feeds, and adds a few rough collars of larval
material around the oral opening. After hibernation, it feeds again
in April and early May, adding more protruding collars until they
equal or exceed the original smooth part of the case. At the same
time, it expands the case girth by the creation of a silk gusset
ventrally. The second case, 6 or 7 mm long, is formed in May, leaving
the vacated first case attached to its last feeding mine. The new
case is tubular with a trivalved crimp at the anal opening. The
dorsum is formed from the edge of the leaf from which the case was
cut. This results in a more or less serrated dorsal keel, depending
on the plant species and the individual piece of leaf used. Considerable
variation in the degree of serration can be found, even among specimens
off the same tree. The case colour varies with food plant, from
yellowish brown on birch, darkening through elm and hazel to dark
brown on alder.
The
strongly curved young case is is a composite leaf case, the adult
case is a tubular leaf case. The adult case is bivalved, about 7
mm in length; the mouth angle is around 30°. The case is straw
coloured and almost always has a toothed dorsal keel (remnant of
the margin of the leaf from which the case was cut). Neither larvae
or cases of C.
coracipennella, prunifoliae, serratella and spinella can be
separated; from serratella. |
|
|
On Alnus, Betula, Corylus, Ulmus and Sorbus, but
not yet on Myrica, in Britain plus Carpinus,
Mespilus, Ostrya, Hippophae, Ribes, Myrica, Forsythia, Amelanchier,
Chaenomeles, Cotoneaster, Crataegus, Cydonia, Eriobotrya, Malus,
Prunus, Sorbus,
Spiraea, Populus and Salix elsewhere. This is probably the commonest species of British
coleophorid, and is found throughout the British Isles. Widespread
in continental Europe.
|
Coleophora
serratella (Linnaeus 1761) [Lepidoptera: Coleophoridae]. |
3a > Leaf-miner: The
larva of this species creates a gallery mine. The mine is similar
to those of the alder-feeding Nepticulidae, but is generally shorter,
with the larval exit-hole on the upperside of the leaf rather than
the underside. After vacating the mine, the larva grazes on the
underside of the leaf in the manner of other Bucculatricidae.
Short
and narrow corridor, starting at an oval, iridescent egg shell that
is usually placed at the leaf underside, close to a thick vein.
The larval chamber is more than three times as long as wide and
is vacated through an upper surface exit slit. Frass in a narrow
central black line; when the mine is made in Bog-Myrtle the thick
frass line almost fills the corridor. Older larvae live free and
cause window-feeding. The larva pupates in a cocoon and is illustrated in British
leafminers. |
|
Bucculatrix cidarella cocoon
Image: Rob Edmunds (British leafminers) |
On Alnus glutinosa and Myrica gale in Britain plus Alnus incana and Alnus viridis elsewhere. Widespread
in Britain and continental Europe.
|
Bucculatrix
cidarella (Zeller 1839) [Lepidoptera: Bucculatricidae]. |
3b > Leaf-miner: Initially
a lower epidermal gallery which leads to a blotch at the leaf-edge.
Subsequently creates two or three cones by folding the edge or tip
of a leaf downwards.
The
mine begins with an unusually long lower-surface epidermal corridor
that often follows the midrib for some distance, but finally turns
towards the leaf margin, where a small blotch is made of up to 1
cm in diameter. The blotch initially is fully epidermal, but later
the larva starts consuming parenchyma, silk is deposited, and the
blotch begins to develop into a somewhat contracted tentiform mine.
In the end the mine is vacated and the larva continues living freely
under a leaf fold that has been fixed with silk, or in a leaf tip
that has been turned into a cone. Pupation in a shiny cocoon at
the underside of the leaf. |
|
On Betula, Populus and Salix, but not
yet on Myrica, in Britain and Populus, Salix and Myrica elsewhere. Widespread in Britain, Ireland
and continental Europe.
|
Caloptilia
stigmatella (Fabricius, 1781) [Lepidoptera: Nepticulidae]. |
3c > Leaf-miner: Oviposition in the midrib. From there a corridor the larva enters
the lamina which suddenly and strongly widens. The larva finally
pupates in a globular cocoon inside the mine. Because the mine is
formed when the leaf already is fully developed mined leaves have
a normal shape. |
|
On Alnus, Betula and Myrica in Britain and elsewhere.
A southern species in the Britain. Widespread in continental Europe.
|
Orchestes
iota Fabricius, 1787) [Coleoptera: Curculionidae]. |
3d > Leaf-miner: Generally small, upper-surface, pear-shaped mines, half of their
surface stuffed with frass. In the frass-free part an oval, flattened
larva. Often several mines in a leaf. Prior to oviposition the larvae
eat, a large number of tiny holes in the leaves. |
|
Rhamphus pulicarius larva, dorsal
Image: © Willem Ellis (Bladmineerders van Europa) |
On Betula, Myrica, Populus and Salix in Britain
and elsewhere. Widespread in Britain, Ireland and continental
Europe.
|
Rhamphus
pulicarius (Herbst, 1795) [Coleoptera: Curculionidae]. |
3e > Leaf-miner: A contorted gallery leading to small blotch.
Egg
at the underside of the leaf, mostly close to a vein or the leaf
margin. The mine, a corridor, is rather variable, mostly strongly
contorted, sometimes even forming a secondary blotch, but at times
only a little sinuous, running along a vein or following the leaf
margin. The frass line is broad, especially in the first half of
the mine. |
|
|
On Myrica and Salix in Britain and elsewhere. Widespread
in Britain, Ireland and continental Europe.
|
Stigmella
salicis (Stainton, 1854) [Lepidoptera: Nepticulidae]. |
3f > Leaf-miner: The young larva lives in a silken tube, open at both ends, on the underside of a leaf. Occasionally one makes an irregular brownish corridor or blotch. How often this happens perhaps differs regionally. Hering (1957a) describes the species as a full blown miner, but Bradley et al (1979a) make no mention of a mining habit, not even facultatively.
|
Mine of Spilonota ocellana
Image: © Willem Ellis |
Hosts in Britain unconfirmed. Elsewhere recorded on Hippophae and Myrica. Widespread in Britain, continental Europe and elsewhere.
|
Spilonota
ocellana (Denis & Schiffermmüller, 1775) [Lepidoptera: Tortricidae]. |
|