Alder
(A. glutinosa) is the only native species of Alnus
in Britain, although Italian Alder (A. cordata), Grey Alder
(A. incana), Seaside Alder (A. maritima), Oriental
Alder (A. orientalis), Red Alder (A. rubra) and Green
Alder (A. viridis) have been introduced.
Only
one Diptera miner, the agromyzid Agromyza
alnivora, is recorded on Alnus in Britain and elsewhere.
Thirty-eight
non-Diptera miners are recorded on Alnus in Britain (see
below).
Elsewhere
two additional British non-Diptera miners are recorded on Alnus
(see below).
Alder Alnus glutinosa
Dickerson
provides keys to the mines of Lepidoptera: Nepticulidae, Heliozelidae,
Bucculatricidae and Gracillariidae recorded on Alnus glutinosa
in Britain (British
leafminers).
Leaf-miner
and case-bearer:
The larva creates a succession of cases, in this instance
fashioned from parts of a leaf. The final case is 11-13
mm long, slender, and fixed at 45° to the leaf surface,
with anal end laterally compressed and bivalved (British
leafminers).
A
slender, brown, spathulate leaf case, in the end about 13
mm long; mouth angle about 15°. Young case slender,
not hooked (Bladmineerders
van Europa).
Leaf-miner
and case-bearer:
Larva mines leaves. The case is enlarged several times by
mining a leaf-edge and inserting the existing case into
the mine which is joined with silk. The final case is 7-8
mm long (British
leafminers).
Larva
in a composite leaf case, composed of large leaf fragments.
Characteristically, the leaf fragments are attached in a
failry untidy way. In spring the case has two colours, because
the old material (dull yellowish, grey or pink) dates from
before the hibernation, while new, reddish brown material
dates from after the winter. The case finally is about 7-8
mm long; the mouth angle is 40-45°. (Bladmineerders
van Europa).
Leaf-miner
and case-bearer:
Composite leaf case. The material used to enlarge the case
consists of large pieces of full depth mine, that are attached
with such precision that they may seem seemless. In the
course of summer an autumn two (sometimes three, according
to Hering, 1927b) pieces are added. No more material is
added after hibernation, causing the case in spring to be
rather uniformly coloured (contrary to C. binderella,
that does add an extension in spring, and is made of fresh
leaf material) (Bladmineerders
van Europa).
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 fallen. 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 (UKMoths).
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,
serratela and spinella
can be separated; from serratella (Bladmineerders
van Europa).
Leaf-miner
and case-bearer:
The larva feeds on a wide range of trees, shrubs and herbs,
favouring Rosaceae, but not exclusively. The fully developed
cased larva may be found active in October and again, after
winter diapause, in April. Cases, about 6 mm, of diapausing
larvae may be found through winter, fixed to a tree or fence
post. The dorsal surface of the case is usually covered
in leaf fragments, but they can sometimes be worn off almost
smooth. The ventral surface is swollen at the middle and
has a keel, which usually bends upwards at the posterior.
The cases of C.
ahenella (on Rhamnus, Frangula, Viburnum
and Cornus) and C.
potentillae (case less swollen, keel not bent up,
resting position less prone) are very similar (UKMoths).
Brownish
lobe case that lies almost flat on the leaf, either on the
upper or on the lower side. Case widest about the middle.
Ventrally there is a distinct keel. Mouth angle 0°.
Full depth mines rather large. The flaps of cuticular tissue
that serve to enlarge the case are cut out of the upper
epidermis. (contrary to C.
ahenella and C.
potentillae, that use tissue from the lower epidermis).
The removal of these tissue flaps creates holes that are
much larger than those that serve as the entrance to the
mine (Bladmineerders
van Europa).
Leaf-mine:
Oviposition in the underside of the midrib or a thick lateral
vein; the oviposition site develops into a large scar. The
larva makes a corridor that runs towards the leaf margin.
The ultimate part of the mine is a corridor in the leaf
tip, with frass in a narrow black central line (Bladmineerders
van Europa).
Mine
of Anoplus roboris on Alnus
Image: Rob Edmunds (British
leafminers)
Leaf-mine:
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 (Bladmineerders
van Europa).
Leaf-mine:
Oviposition in the underside of the midrib or a thick lateral
vein; later a large scar is visible there. Initially the
larva tunnels in the midrib or vein, that inflates and disfigures
somewhat as a result. Then the larva starts a corridor in
the leaf blade, quite narrow at first, but strongly widening
as the larva approaches the leaf margin or leaf tip. The
mine is reddish brown in colour. The mature larva makes
itself a dark brown globular cocoon in the mine and pupates
there. Because the mine is made at a time that the leaf
still is unfolding, the leaf becomes permanently rumpled.
In the course of the summer the mine erodes away, but the
combination of the oviposition scar, the swolllen mibrib
and the frayed leave missing a large part of its distal
half remains unmistakable (Bladmineerders
van Europa, as testaceus).
Leaf
mine:
A large brownish blotch, without an initial corridor. Usually
the mine starts near a vein axil, and expands towards the
leaf margin. The mine mostly remains enclosed by two thick
lateral veins; only near the leaf margin (and especially
in thin shadow leaves) the mine may trespass over the side
veins. Often several mines in a leaf. The mine is upper
surface, but quite deep, specially when the larva is young
not all tissue is eaten away, and the mine keeps a greenish
tinge there. Contrary to Heterarthrus vagans, at
least as common on the same host, the larva vacates the
mine prior to pupation (Bladmineerders
van Europa).
Leaf
mine:
A large, practically full depth brownish blotch, without
an initial corridor. The mine begins somewhere on the leaf
and expands in all directions, without having much consideration
with even major veins. In this respect the mine differs
from that of Fenusa dohrnii
on the same host plant. Moreover, as a rule there is just
one mine per leaf. The full grown larva makes a disc-shaped
cocoon within its mine, with a diameter of about 7-9 mm.
Unlike F. dohrnii the larva is rather vividly pigmented
and can easily be observed without dissecting the mine.
Like most sawflies the larva lies belly-up in its mine (Bladmineerders
van Europa).
Leaf
mine:
Large, transparent, in fresh condition pale green blotch
that begins at the leaf margin, without an accumulation
of frass. Mine and larva are undistinguishable from those
of S. vicina,
but vicina larvae live from mid May till mid June,
while the larvae of betuleti are found only in August
- October (Bladmineerders
van Europa).
Leaf-mine:
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 (UKMoths).
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
(Bladmineerders
van Europa).
Leaf-mine:
The
larvae feed at first in a mine, and later in a folded or
rolled leaf (UKMoths).
The
mine begins with a usually rather short gallery, that opens
into (and often is overrun by) a silvery epidermal upper-surface
blotch with light brown frass. When the mine gets older
it contracts and becomes an elongate blister or even a tube.
Soon the larva leaves the mine and continues feeding within
a downwards rolled leaf margin, that is fastened with silk
(Bladmineerders
van Europa).
Leaf-mine:
Initially in short gallery becoming a brownish blotch near
the leaf margin. Later in two or three Parornix-like
folds at the edge of the leaf (British
leafminers).
Small
(up to 10 mm long), lower-surface blotch near the leaf margin,
with a brownish lower epidermis. The mine in fact is a tentiform
mine, but so little silk is produced that the blotch hardly
contracts at all. The mine is preceded by a quite short
corridor, that is overrun by the later blotch. The older
larva leaves its mine and starts feeding under a flap of
the leaf margin that is folded down and fixed with silk
on the blade underside. Two or three such folds are made,
not necessarily on the same leaf. The fact that no leaf
rolls are made, but parts of the leaf are folded down rather
makes one think of the work of a Parornix (Bladmineerders
van Europa).
Mines
of Caloptilia falconipennella on Alnus
Image: Ian Thirlwell (British
leafminers)
Leaf-mine:
The mine is underside, about 25 mm long, often from midrib
to margin of leaf. The lower epidermis appears smooth. There
may be several mines in a leaf (British
leafminers).
Large,
lower-surface tentiform mine, often occupying the entire
space between two side veins, from the midrib almost to
the leaf margin, Lower epidermis without clear folds.The
larva is grey (all other phyllonorycters on Alder are white).
Pupa in a light brown cocoon that is fastened to the roof
of the mine. The cocoon is entirely free of frass: all frass
is accumulated in the inner corner of the mine (Bladmineerders
van Europa).
Mines
of Phyllonorycter froelichiella
Image: Rob Edmunds (British
leafminers)
Leaf-mine:
The mine is underside, small, seldom reaching midrib. The
lower epidermis with several small creases, sometimes several
larvae mine the same leaf (British
leafminers).
Lower-surface
tentiform mine between two side veins, often at quite some
distance from the midrib. Lower surface with many folds,
all very weak. Often several mines in one leaf. Pupa in
a white cocoon in an angle of the mine, attached to the
roof. The cocoon is free from frass; all frass is heaped
in an angle of the mine, opposite to the cocoon (Bladmineerders
van Europa).
Mine
of Phyllonorycter kleemannella on Acer glutinosa
Images: Willem Ellis (Bladmineerders
van Europa).
Leaf-mine:
The mine is underside, small, at or near midrib. The
lower epidermis with one strong crease (British
leafminers).
Lower-surface
tentiform mine, not longer than 20 mm, usually in the axil
of a thick lateral vein, with one strong length fold. Pupa
in a tough off-white cocoon that is fastened to the floor
and the roof of the mine. Almost all frass is incorporated
in the sides of the cocoon (visible with a loupe in transparancy
as two dark lines). In autumn not infrequently five or more
mines in one leaf (Bladmineerders
van Europa).
Leaf-mine:
The mine is upper side, oval, over midrib or side-vein
- the upper epidermis flimsy with one strong crease (British
leafminers).
Unlike
other species that form an upperside mine, the surface is
not papery, but quite glossy and heavily creased. The mine
begins green and then turns orange or brown when more mature
(UKMoths).
Upper-surface,
fairly small, almost flat tentiform mine with a characteristic
yellow green colour. The mine has a single, moderately strong,
fold. Generally the mine is positioned over a lateral vein.
Frass in a clump in a corner of the mine (Bladmineerders
van Europa).
Mine
of Phyllonorycter stettinensis on Alnus
glutinosa
Image: Willem Ellis (Bladmineerders
van Europa)
Leaf-mine:
The mine is underside, between veins, narrow and close
to midrib (British
leafminers).
Often
there are several to one leaf, and have a distinct brown
tinge (UKMoths).
Elongated,
lower-surface, in the end tubular contracted tentiform mine,
usualy starting at a small distance from the midrib. The
lower epidermis with many weak wrinkles but no clear folds.
Often several mines in a leaf. All frass is accumulated
in an angle of the mine. Pupa in a white cocoon that is
free from frass (Bladmineerders
van Europa).
Mines
of Phyllonorycter strigulatella on Alnus
incana
Image: Willem Ellis (Bladmineerders
van Europa)
Leaf-mine:
The mine formed in the leaf-veins and midrib leads to
an oval blotch (British
leafminers). When fully fed, the larva cuts out an oval
case, in which it descends to the ground and pupates (UKMoths).
The
mine begins in one of the more heavy veins of a leaf. Boring
in the vein the larva descends towards the midrib. Often
in this process the larva moves from one thick vein to another
by way of a hair-thin transverse corridor. Once in the midrib
the larva descends, not rarely even for one or two cm into
the petiole (one can see that by cleaving a petiole). Finally
the larva returns into the leaf by way of the midrib, and
makes a short, full depth, quickly widening corridor with
a clear central line of frass. In the end an oval excision
of made of about 2 x 5 mm, in which the larva drops to the
ground (Bladmineerders
van Europa).
Leaf-mine:
The larva starts making a corridor of a few mm, followed,
and mostly overrun, by a circular blotch of 4-5 mm diameter
(Bladmineerders
van Europa).
Generally
several larvae feed in a single leaf, creating a distinctive
pattern of feeding windows. The larvae then cut out circular
cases and drop to the leaf-litter to continue feeding, leaving
behind a leaf containing many circular or oval cut-outs
(UKMoths).
Leaf-mine:
A
narrow gallery with frass in thin central line. The moths
must be bred through to distinguish S.alnetella and
S.glutinosae
(British
leafminers).
Ovipostion
at the leaf lower surface. Then a full depth slender, corridor,
often following a vein or the leaf margin for some distance.
Frass in a continuous central line that nowhere is wider
than one third of the corridor width. Frass never coiled.
Usually only one mine in a leaf. Pupation outside the mine
(Bladmineerders
van Europa).
Leaf-mine:
A gallery with frass partly dispersed, but sometimes
in a thin line (as S.
alnetella). The moths must be bred through to distinguish
between this and S.alnetella (British
leafminers).
Oviposition
at the leaf underside. Then a full depth, fairly slender
corridor, often several in a leaf. Frass line very variable,
sometimes coiled, mostly more than on third of the width
of the corridor. Pupation outside the mine (Bladmineerders
van Europa).
Leaf-miner
and case-bearer: The early case is tiny and the larva
makes a series of tiny holes on the leaf. After overwintering
it makes a shiny pistol shaped case in spring and window
feeds (British
leafminers).
The
young larva, before hibernation, makes tiny mines, sometimes
tens in one leaf. After hibernation window feeding is done.
In this latter stage the larva lives in a shining black
pistol case of about 7 mm, that, with a mouth angle of 70°-80°,
stands almost perpendicular on the leaf (Bladmineerders
van Europa).
Feeding
damage caused by Coleophora anatipennella
Image: Ian Thirlwell (British
leafminers)
Leaf-miner
and case-bearer:
Lobe case. The full grown case is about 7 mm long. The mouth
angle is 0°, causing the case to lie flat on the leaf.
The case is gradually enlarged by the addition of rings
that are cut out of the epidermis. The rings become gradually
larger, and stick irregularly out of the contour of the
case. The rings are cut out of the lower epidermis of the
mine. This implies that mines may have both normal, small
openings, and large ones. Compare for instance C.
violacea, that cuts rings out of the upper epidermis
(Bladmineerders
van Europa).
Mine
and case of Coleophora ahenella on Rhamnus
frangula
Image: Willem Ellis (Bladmineerders
van Europa).
Leaf-miner
and case-bearer:
Lobe case. Many small leaf fragments are attached to the
tubular case; its end is strongly curved downwards. The
larvae are attached to the leaf underside, where they make
a large number of relatively small full depth mines (Bladmineerders
van Europa).
Mines
of Coleophora fuscocuprella on Corylus avellana
Image: Willem Ellis (Bladmineerders
van Europa)
Leaf-miner
and case-bearer:
This species produces a distinctive larval case in its later
stages with a noticeably serrated upper edge, and affixed
almost parallel to the leaf surface. The larvae overwinter
when small and recommence feeding in late spring (UKMoths).
Oviposition
generally in a vein axil. From there a short, relatively
wide corridor is made that quickly widens into an elliptical
blotch. Much of the frass is ejected through the hole that
the larva has made to bore itself into the leaf (in C.
badiipennella, on the same host plant, the frass
remains within the mine. This blotch is excised to make
the juvenile case. The full grown larva lives in a brown
spatulate leaf case of 9-11.5 mm; its rear end is bivalved.
Mouth angle 0°-20°; just behind the mouth the case
shows a conspicuous bend (Bladmineerders
van Europa).
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 (British
leafminers).
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
(Bladmineerders
van Europa).
Leaf-miner
and case-bearer:
Tubular leaf case. The case is almost barrel-shaped, with
a large leaf fragment that, while withering, folds itself
untidily arround the tube (Bladmineerders
van Europa).
Leaf-mine:
Long, full depth mine, starting at an oviposition scar,
mostly in the distal part of the midrib; the scar may be
swollen and gall-like. Frass line variable in width, sometimes
quite broad. Usually the corridor loosely follows the leaf
margin, and the part of the leaf that is cut off from the
centre dies off. The larvae live in spring, when the leaf
is unfolding; later in summer affected leaves are recognisable
because the tip of the leaf and parts of the marginal teeth
are missing, by remnants of the corridor and by a general
disfiguring of the leaf. The larva leaves the mine before
pupation (Bladmineerders
van Europa).
Leaf-mine:
A
very clear blotch, without preceding corridor, usaally harbouring
several crimson marbled larvae. The mine mostly begins near
the base of the midrib. Most frass is ejected from the mine,
but some of the grains are trapped in a loose spinning below
the leaf, that has been made by the larvae during excursions.
The larvae can leave their mine and restart elsewhere (Bladmineerders
van Europa).
Leaf-mine:
The mine begins as a contorted gallery, when the young larva
can be seen to have dark plates on each segment. These plates
are later lost and the gallery becomes a blotch with scattered
frass (UKMoths).
Mine
begins at a globular, black, lower-surface egg shell. From
there starts a short tortuous corridor, that widens into
a blotch, often between to lateral veins. Frass dispersed.
Pupation outside the mine (Bladmineerders
van Europa).
Leaf
mine: A
rather large, clear, partly full depth blotch that begins
in the axil of a thick lateral vein. Often the ovipostion
leaves a greyish-green scar. Generally several mines in
a leaf. The mine expands within the confines of the midrib
and two lateral veins; only close to the leaf margin, where
the lateral veins are thin, the mine may trespass over a
vein (Bladmineerders
van Europa).
Leaf-mine:
A circular or oval brownish blotch with a central spiral
of dense blackish frass (British
leafminers), sometimes several mines in one leaf (UKMoths).
Oviposition
is at the leaf underside, well away from the leaf margin;
the egg has a fine reticulate surface. The mine is a rather
large, perfectly circular blotch without a trace of a preceeding
corridor. Around the dark centre the frass, glued to the
upper epidermis is arranged in distinct arcs (Bladmineerders
van Europa).
Leaf-mine:
The
larva feeds on hazel or hornbeam, creating blotches with
intertwining threads of frass, typical of the genus (UKMoths).
Large
white blotch, starting at the leaf margin. Frass in long
threads. Often several larvae in a mine. Pupation outside
the mine (Bladmineerders
van Europa).
Mine
of Eriocrania chrysolepidella
Image: Rob Edmunds (British
leafminers)
Leaf-mine:
Full depth corridor, beginning at the base of the midrib
and very roughly following the leaf margin; all the while
the corridor widens, until almost the entire leaf has been
mined out. Frass, as coarse grains or thread fragments,
in the centre of the mine. The larva pupates in the mine,
in a globular cocoon made of secretion (Bladmineerders
van Europa).
Leaf-mine:
Oviposition in the base of the midrib, without giving rise
to an oviposition scar. The larva initially bores inside
the midrib. Later it leaves the midrib, forming a broad
corridor in the blade, that widens into a blotch. Finally
the legless larva pupates in a globular cocoon inside the
mine. Because the mine develops at a time that the leaf
is fully developed, mined leaves are not disfigured (Bladmineerders
van Europa).
