Out and Look for Cases!

Ingemar Frycklund
Kyrkkullen, Svia,
755 94 Uppsala

The pistol case in the photograph contains the larva of the Yellow-striped birch case-bearer Coleophora betulella. The case is deceptively similar to bird droppings stuck to the birch leaf. This species' larva is bound to birch, whose leaves it eats. The case in the picture I found on a 2 m tall birch on June 4, 1994 along the road near Mårtsbo. The case is 6 mm long. Already the year before, an adult moth of this species was found, which was then new for Gä. (Photo Nils Ryrholm).

In the butterfly genus Coleophora (case-bearers), there are 128 species in Sweden. Ingvar Svensson has in his excellent book, Fjärilskalendern (1993), given the following designation for the cases built by the larvae depending on their appearance and building material, see below. After the case description, the number of species that have a described case is indicated.

S — larval case (non-specific larval case) 10 species
bS leaf case 14 "
fS seed case 6 "
lS lapp case 6 "
piS pistol case 7 "
puS pupa case 5 "
rS tube case 54 "
sS ski case 15 "

In addition to this are cases that resemble a dry leaf, 2 species, and 11 species with undescribed cases.

In this article I will show representative pictures of the different case types. The different examples are chosen on the basis of the Coleophora species that should occur in Gä, but which have not yet been found in the region. Furthermore, I will provide a tabulated overview of which case types and how many species live on different host plants and how many species from each plant are still missing from Gä.

Examples of different types of cases

bS. Leaf cases

A. Bearberry case-bearer C. arctostaphyli. The butterfly has a two-year development cycle in Sweden. One can therefore find cases throughout the season. At the end of July when the butterfly has emerged, it can be swept from the host plant. (Svensson 1983).

B. Small heather case-bearer C. juncicolella. The species is recorded up to Vb, not Gä.

fS. Seed cases

A. Forest woodrush case-bearer C. antermariella. The butterfly lives on spring woodrush and is not recorded in Gä. Otherwise it is recorded in half of the regions between Sk - Nb.

B. Golden-lined sedge case-bearer C. taeniipennella. The butterfly which lives on sedge is recorded up to Nb, not Gä.

lS. Lapp cases

A. Stinking ground-pine case-bearer C. lineola. This species is on the red list. Previously it was only known from two localities in Skåne. In 1990, Ingvar Svensson found the species at Kilskär in NE Uppland. (Svensson 1992). Four years later it was found in Gä, see (Källander & Frycklund) in this Insectifera.

B. C. cornutella. A species that exists in Finland but has not yet been found in Sweden. In Finland it lives on bog myrtle and small birch shrubs on wetlands.

piS. Pistol cases

A. Dusty willow case-bearer C. albidella. The butterfly was recorded as new for Gä in 1993 by K.C.

B. Brown-striped oak case-bearer C. ibipennella. It is recorded up to Up.

puS. Pupa cases

A. Bilberry case-bearer C. vaccinella. The larva makes surface mines on the leaves. In Sweden, the bilberry case-bearer is recorded in most regions, not Gä.

B. Grey birch case-bearer C. orbitella. The cases can be found on both birch and alder. The butterfly is recorded in every other region up to Ly, not Gä.

rS. Tube cases

A. Goldenrod case-bearer C. obscenella (virgaurea). The case is very common on goldenrod in late autumn. One should also look for another species, White-antennae goldenrod case-bearer C. ramosella (albicornis), whose case lacks the sparse hairs.

The case is somewhat larger, 8-8.5 mm compared to obscenella's 6 mm. The butterfly is on the red list and recorded as close to the Gä border as at Älvkarleby but also north of Gä, closest to Hr, see below under threatened species. The larva should be reared for a certain determination.

B. Silver-striped case-bearer C. challogrammella. The case can be found on mouse-ear chickweed (Cerastium) and stitchwort (Stellaria). The butterfly is on the red list and is recorded up to Up.

sS. Ski cases

A. Light-edged alder case-bearer C. alnifoliae. Recorded up to Sm and Go as well as Gä. In Gä it was reported as a new regional find in 1983 by Ingvar Svensson.

B. Mint case-bearer C. albitarsella. The butterfly lives on wild marjoram and is recorded up to Up. Something to look for at Eggegrund.

Most of the species overwinter as larvae. If you want to rear the larvae, the best results are obtained if you collect the cases in early summer. Be careful to note the locality and host plant. Most species are bound to a specific plant which can serve as a guide for future species determination. When rearing small moth larvae, pet bottles can be used to advantage. Place the leaf or plant with the larva in, for example, a film canister with water. The upper part of the film canister should be covered so that the larva does not drown. Synthetic cotton wool, used for aquarium filters, is excellent for this purpose. Cut off the upper half of the pet bottle and place the canister with the host plant in the lower half. Cover the opening with fine mesh tulle or with a nylon stocking, fastened with a rubber band. A number of pet bottles with larvae can then be placed in a tray.

When you start looking, you will find that there are many cases. Many species are difficult to identify both with regard to cases and adult moths. A suitable species to start with is the Stinking ground-pine case-bearer C. lineola (see the description of this year's butterfly finds from Gästrikland). In this case, it is sufficient to photograph the case given that the host plant and case are so specific and protected. The species has reached threat category 2 (vulnerable) on the red list. It has further been given the designation Ss,Ö which stands for threat factors "Clear-cutting and whole-tree utilization and other exploitation (buildings, roads)." Because the species is on the red list, all finds should be reported. If you then want to proceed further, you can look for pistol cases which are easy to recognize. Of Sweden's seven species that build pistol cases, only the Yellow-striped birch case-bearer C. betulella is recorded in Gä, see picture above.

The following species build a pistol case. Host plant Recorded in most
regions between
Lingonberry pistol case-bearer C. vitisella lingonberry Sk - To
Dusty hazel case-bearer C. bernouillella hawthorn Sk - Vb
Dusty willow case-bearer C. albidella willow Sk - To
White oak case-bearer C. kuehnella oak Sk - Sm
Brown-striped oak case-bearer C. ibipennella oak Sk - Nb
Yellow-striped birch case-bearer C. betulella birch Sk - Nb
Yellow-striped service tree case-bearer C. currucipennella service tree, hazel Sk - Vb

Since only the Yellow-striped birch case-bearer is recorded in Gä, there are great opportunities to find new regional finds. When you have mastered these species, you can start looking for cases on the following plants, see table below. Only plants found in Gä are included as well as plants that harbour Coleophora larvae that have not yet been reported in Gä. Therefore, for example, Stinking ground-pine is not in this table.

Plant Number of species
type of case

Yarrow A. millefolium 1 rS

Alder Alnus 1 sS, 1 rS, 2 puS

Catspaw Antennaria
Kidneyvetch Anthyllis

Bearberry Arctostaphylos uva-ursi
Artemisia

Mugwort A. absinthium
Field mugwort A. campestris

Grayish mugwort A. vulgaris

Sea aster Aster tripolium
Sweet vetch Astragalus glycyphyllos
Atriplex

Birch Betula

Heather Calluna
Centaurea

Brown knapweed C. jacea

Mouse-ear chickweed Cerastium
Chenopodium

Hazel Corylus

Hawthorn Crataegus
Houndstongue Cynoglossum
Dianthus

Blueweed Echium

Fleabane Erigeron
Boneset Eupatorium
Black bindweed Fallopia convolvulus
Filipendula

Meadowsweet F. ulmaria
Rock rose Helianthemum
Knawel Herniaria
Inula

Narrowleaf inula I. britannica
Sedge Juncus

Jointed rush J. articulatus
Salt rush J. gerardii
Larch Larix
Labrador tea Ledum
Birdsfoot trefoil Lotus

Woodrush Luzula

Spring woodrush L. pilosa
Sticky catchfly Lychnis viscaria
Apple Malus

Forget-me-not Myosotis
Wild marjoram Origanum
Cinquefoil Potentilla

Plum Prunus

1 rS

18

1 bS, 1 iS

1 bS, 1 iS

1 rS

4 iS

1 sS, 1 lS, 1 like dry leaf, 1 rS, 1 puS, 1 piS

1 bS, 1 sS

1 bS, 1 rS

1 sS

1 iS

5 1 rS, 2 like dry leaf

1 iS, 1 puS, 1 piS

1 rS, 1 piS

1 lS

1 iS

1 rS

1 rS

1 sS

1 lS

1 rS

1 rS

1 sS like dry leaf

1 puS

1 rS, 2 like dry leaf

1 fS, 1 rS

1 iS

1 fS

1 iS

1 rS

1 sS

1 bS, 1 piS

2 iS, 1 piS

1 iS

1 bS, 1 rS

1 sS

Lungwort Pulmonaria 1 sS 1
Pyrola 1 puS 1
Oak Quercus 2 iS, 2 piS 4
Rosa 1 rS 1
Cloudberry Rubus chamaemorus 1 iS 1
Water dock Rumex hydrolapathum 1 iS 1
Willow Salix 1 iS 1
Soapwort Saponaria 1 rS 1
Saw-wort Serratula 1 rS 1
Silene 1 fS 1
Nottingham catchfly S. nutans 2 iS 2
Goldenrod Solidago 3 rS 2
Rowan Sorbus 2 iS 1
Stitchwort Stellaria 1 rS 1
Thyme Thymus 1 bS 1
Clover Trifolium 3 iS 1
Elm Ulmus 2 sS 2
Bog bilberry Vaccinium uliginosum 1 iS like dry leaf, 1 iS like dry leaf, 1 puS, 1 iS 1 puS
Lingonberry V. vitis-idea 1 iS toothed back, 1 piS, 1 bS 1 piS, 2 bS

Threatened species: In addition to the Stinking ground-pine case-bearer, one should pay particular attention to the following species that are listed on the red list.

Black-and-white case-bearer C. albella Sticky catchfly
Silver-striped case-bearer C. chalcogrammella Mouse-ear chickweed, Stitchwort
Kilstripe yarrow case-bearer C. partitella Yarrow, ? Artemisia
Knawel case-bearer C. scabrida Knawel
White-antennae goldenrod case-bearer C. ramosella Goldenrod
Boneset case-bearer C. follicularis Narrowleaf inula, Boneset
Carnation case-bearer C. dianthi Nottingham catchfly

The White-antennae goldenrod case-bearer is recorded as close to the Gästrikland border as at a clear-cut near Norway close to Älvkarleby.

More detailed descriptions of the appearance and placement of the cases, as well as the larvae, pupae and flight times of the butterflies can be found in Ingvar Svensson's book, Fjärilskalendern. The book covers all butterfly species found in Scandinavia. The price is 110 kr or 210 kr depending on the edition and can be ordered from Hans Hellberg, Lofotengatan 16, 164 33 Kista, pg. 4199669-5. The book is a must if you want to learn more about butterfly biology. The depicted cases are taken from Polish and German sources, see the literature references below. Both booklets depict most of the Scandinavian species. The booklets can be ordered from Appolo Books, Kirkeby Sand 19, DK-5771 Stenstrup, Denmark. If the booklets are out of stock, the pictures are available from the society. To make it easier to orient yourself regarding the names and distribution of butterflies, you should have the List of Swedish butterfly names and the Butterfly catalogue. They cost 40 kr and 100 kr respectively for members.