Myrmica

Collingwood, C. A., 1979, The Formicidae (Hymenoptera) of Fennoscandia and Denmark., Fauna Entomologica Scandinavica 8, pp. 1-174 : 40-48

Genus Myrmica Latreille, 1804

Myrmica Latreille, 1804:175.

Type-species: Formica rubra Linne , 1758.

This holarctic genus includes about 70 species of which 10 occur in North Europe. Head oval, clypeus rounded, frontal lobes prominent; alitrunk with pronotum rounded antero-laterally, a well defined mesopropodeal furrow and, in most species, strongly developed propodeal spines. Pedicel with two large nodes - the petiole with a stout antero-ventral tooth and the postpetiole which, rubbed against the fine transverse striae on the first gaster segment, gives an audible stridulation. All tibial spurs are distinctly pectinate except in a very few semi-parasitic species. Gaster in female castes armed with a strong sting. Fore-wing in male and queen have the cubital cell characteristically partially divided by a transverse vein. Palp formula 6, 4; antennae 12 segmented in female caste, 13 in male.

Myrmica ants are robust, deliberate moving, nesting in stumps, under stones or in banks. Colonies are relatively small with individuals numbering from a few hundred to about 5000 according to species. Foraging is on the ground surface.

Keys to species of Myrmica

Workers

1 Antennal scape long and slender, gently curved near the base. Frontal triangle entirely smooth and shining ......................................................................... 2

Antennal scape sharply curved near the base or distinctly angled, with or without a toothlike or lamellar extension at the head ..................................... 3

2 (1) Petiole in profile with large truncate dorsal area, posteriorly with a distinct step down to its junction with the postpetiole. Infra-spinal area transversely striate; petiole nodes rugose; propodeal spines as long as the distance between their tips (Fig. 26) ......................................................... 6. ruginodis Nylander

Petiole in profile with dorsal surface a small rounded dome sloping posteriorly, without a distinct step to its junction with the postpetiole. Infra-spinal area smooth; petiole nodes shining, without rugose sculpture. Propodeal spines shorter than the distance between their tips (Fig. 25)............... 5. rubra (Linne)

3 (1) Antennal scape abruptly curved near the base but never angled nor with la- mellar outgrowth......................................................................................... 4

Antennal scape angled sharply near the base, with or without lamellar exten sion at bend ...................................................................................................... 6

4 (3) Body sculpture including nodes, clypeus and frontal triangle with coarse longi- tudinal rugae; petiole massively domed; propodeal spines rather blunt, incurved and subparallel from above (Fig. 27)................. 12. sulcinodis Nylander

Body sculpture finely striate or rugulose; frontal triangle striate or sculptured apically, only with lower part smooth and shining ................................. 5

5 (4) Head longer than broad with wide frons; petiole smooth, in profile simply angled without a distinct truncated dorsum; postpetiole cubical (Fig. 29) 7. rugulosa Nylander Head not longer than broad, frons narrower with diverging lobes. Petiolus striated, with a distinct truncated dorsal area; postpetiole higher than long. profile (Fig. 28) ............................................................... 3. gallieni Bondroit

6 (3) Antennal scape with a distinct transverse upright flange at bend seen as a tooth- like projection in profile............................................................................... 7

Antennal scape simply angled or with a more or less large lateral lamella and a distinct ridge running forward from the bend.................................................8

7 (6) Frons about 1/4 head width, with small narrow widely diverging lobes to accommodate the large lamelliform flange. Postpetiole in profile low, only slightly higher than long; petiole with rounded antero-dorsal angle, mesopropo- deal furrow shallow (Figs. 31,40)....................................... 10. schencki Emery

Frons about 1/3 head width, with more prominent blunter frontal lobes; lamelliform flange variable, often very large appearing as a distinct vertical tooth in profile. Postpetiole distinctly higher than long in profile, petiole with anterior and dorsal faces meeting at a sharp angle, mesopropodeal furrow deep (Figs. 32,41)......................................................... 4. lobicornis Nylander

8 (6) Petiole in profile with dorsal area curving backward to the junction with the postpetiole without a distinct step. Postpetiole about as long as wide from above, slightly higher than long in profile (ratio 10:8) (Figs. 30, 36) 11. specioides Bondroit

Petiole in profile high with a flattened dome or truncate dorsal area, with a distinct posterior edge falling sharply to the junction with the postpetiole. Postpetiole wider than long from above, clearly higher than long in profile (ratio 10.7).................................................................................................. 9

9 (8) Antennal scape with massively developed lateral extension at bend; petiole in profile a flattened dome (Figs. 34, 39)............................. 8. sabuleti Meinert

Antennal scape simply but sharply angled or with inconspicuous semicircular extension at bend; petiole with distinct truncate dorsal area (Figs. 33,37) 9. scabrinodis Nylander

Queens

1 Antennal scape simply curved near base, without angle or lamellar outgrowth........................................................................................................ 2

Antennal scape bent at an angle near base, with or without a lamellar outgrowth at bend....................................................................................................... 6

2 (1) Antennal scape long and slender, gently curved near the base; frontal triangle entirely smooth and shining.......................................................................... 3

Antennal scape abruptly curved near base; frontal triangle at least in part striated or sculptured................................................................................... 4

3 (2) Propodeal spines long and coarse; infra-spinal area transversely striate; petiole and postpetiole sculptured ................................. 6. ruginodis Nylander

Propodeal spines short; infra-spinal area smooth; petiole and postpetiole shining without sculpture...................................................... 5. rubra (Linne)

4(2) Frontal triangle completely and coarsely striate; petiole in profile an irregular dome......................................................................... 12. sulcinodis Nylander

Frontal triangle in part smooth and shining; petiole either simply angled or clearly truncate in profile............................................................................. 5

5 (4) Postpetiole cubical in profile, not higher than long. Petiole simply angled with very short dorsal area .................................................... 7. rugulosa Nylander

Postpetiole distinctly higher than long in profile. Petiole with distinct truncate dorsal area...................................................................... 3. gallieni Bondroit

6(1) Antennal scape with upright lamelliform flange appearing as a vertical tooth in profile..................................................................................................... 7

Antennal scape either simply angled or with a lateral extension at bend .......... 8

7 (6) Postpetiole distinctly higher than long in profile; frontal ridges not closely approximated, frontal lobes strongly developed; predominant colour brownish black ...................................................................... 4. lobicornis Nylander

Postpetiole low in profile; frontal ridges closely approximated with frontal lobes narrow and widely divergent; predominant colour reddish brown 10. schencki Emery

8 (6) Petiole in profile with dorsal surface curving evenly into posterior surface without a distinct posterodorsal edge, narrowly rectangular from above 11. specioides Bondroit

Petiole in profile with dorsal surface flattened and a distinct posterodorsal edge, broadly quadrate from above .............................................................. 9

9 (8) Petiole with anterior and dorsal surfaces meeting at a blunt angle. Antennal scape with a lateral projection at bend and a distinct ridge running forward from the bend ........................................................................................... 10

Petiole with anterior and dorsal surfaces meeting at a sharp angle. Antennal scape simply angled or with small semi-circular extension without a distinct ridge running forward from the bend ........................... 9. scabrinodis Nylander

10(9) Head width 1.15 mm or greater, postpetiole narrower than maximum width across frontal laminae....................................................... 8. sabuleti Meinert

Head width less than 1.12 mm; postpetiole wider than maximum width across frontal laminae................................................................ hirsuta Elmes

Males

1 Antennal scape long, reaching or overreaching occipital border..................... 2

Antennal scape short, not reaching beyond ocelli .......................................... 5

2 (1) Antennae slender with gentle curvature near base; frontal triangle smooth 3

Antennae sharply bent or curved near base; frontal triangle at least in part sculptured................................................................................................... 4

'. 3 (2) Central area of head between frontal ridges longitudinally rugulose. Hind tibiae with long projecting hairs (Fig. 53)................................ 5. rubra (Linne)

Central area of head between frontal ridges smooth. Hind tibiae with sparse short hairs (Fig. 52)....................................................... 6. ruginodis Nylander

4 (2) Mesoscutum in front of notauli rugose; frontal triangle coarsely striated. Antennal scapes simply curved (Fig. 44)....................... 12. sulcinodis Nylander

Mesoscutum in front of notauli smooth; frontal triangle in part smooth. Antennal scape bluntly angled near base (Fig. 45).......................... 4. lobicornis Nylander

5(1) Antennal scapes at least at long as first four funicular segments together (Fig. 50).................................................................................................... 10

Antennal scapes not longer than first three funicular segments together.......... 6

6 (5) Body and appendage hairs abundant and long. Longest hairs are longer than maximum width of hind tibiae (Fig. 55)........................ 9. scabrinodis Nylander

Appendage hairs not as long as maximum width of hind tibiae........................ 7

7 (6) Second funicular segment more than twice as long as wide; scape angled near base (Fig. 51). Median area of head in front of occellus narrowly depressed 10. schencki Emery

Second funiculus segment less than twice as long as wide; scape not angled near base. Dorsum of head without depression.............................................. 8

8 (7) Petiole low with anterior and dorsal faces meeting at a gently rounded obtuse angle. Postpetiole in profile longer than high (Fig. 63)

11. specioides Bondroit

Petiole high with anterior and dorsal faces meeting at a right angle. Postpetiole in profile as high or higher than long.................................................. 9

9 (8) Mesoscutum in front of notauli finely sculptured ............... 3. gallieni Bondroit

Mesoscutum shining without sculpture (Fig. 3).............. 7. rugubsa Nylander

10 (5) Petiole and postpetiole conspicuously hairy with long setae exceeding maximum appendage width (Fig. 68).......................................................... hirsuta Elmes

Petiole and postpetiole with scattered short setae not exceeding maximum appendage width (Fig. 66)................................................. 8. sabuleti Meinert