Dragonfly observations in the Raka area, Lower , eastern

Slovenia, with a note on the behaviour ofSomatochlora meridionalis

Nielsen (Anisoptera: Corduliidae)

M. Kotarac

Marohovih 11, SLO-62000 Maribor.

Abstract – An annotated list is of 28 given spp. Introduction

from 17 localities in the area (alt. 150-300 m). During August 1-10. 1992. the traditional sum-

In Slovenia, S. meridionalis of was so far known mer workshop Biology students of the Univer-

from NW held the of Raka. a single specimen, taken in Islria in sity of was at village

the therefore the the 30 km early 19605. strong populations near Ljubljana-Zagrebhighway, some

here interest. with W reported are of some Coupled of the international border with . The

the from recent records northern Italy (Friuli), report ofthe small "odonatological team" is pre-

sented here. these could represent an additional evidence for Evaluating the data, it should be

the current northward extension of this that based brief range sp. emphasised they are on a very

Various of male behaviour outlined in few hours each types are survey, hardly a were spent on

sonic detail. one locality.

The exceptionally hot summer of 1992. the

hottest since decades, dried completely up most Noiul. Vol. No. June 1993 2 odonalol.. 4, I, pp. 1-20, I,

other bottom. of the irrigation ditches and small water 5-8 m, modest current, mostly loamy

6 In the bodies for a period ofat least weeks. The tem- shallow sections near the banks, there peratures were 30-35°C during the day, and close are long chains of green algae, reaching the to 25°C in the mornings and evenings. Conse- surface at the low water. The steep banks quently, in the "normal" years species distribu- are regularly cut, therefore there are no tion. abundance and population densities may bushes or trees. deviate considerably from the situation recorded. (7) HrvaSki brod, the Martinek and Racna

Some localities have not been checked for the streams, WL 28; 9-VIII-1992.

and the WL larvae. The comments onecology behaviour (8) Kostanjevica, stream, 37; 7-

where -VIII-1992. - are given considered of some interest. Same as (8).

(10)D.GradiSie, CadraSki potok,WL 27; 7-VIII-

— List of localities 1992. Lowland stream in a grassland,

The localities are situated at an altitude of 150- overgrown by trees.

-300 m a.s.l. (II)Ardro nr Raka. the Lokavec stream, WL 38;

(1) Stritovsko jezero, WL 28; 3-VIII-1992. - 5-VIII-1992. - Lowland stream with 2

lake 3 branches. The in the meadow forms Man-made eutrophic (depth m). in a one a

natural fed rain and where of and depression, by heavily pool, exuviae Aeshna cyanea

stocked with fish, without submerged Anax imperator were found. The other

vegetation. It is surrounded by a thick branch flows on the meadow/forest border.

vegetation wall, with the usual fishermen (12)-Koprivnik, the Lokavec stream. WL

10-30 intervals. - The first km entrances at m 38; 2-VIII-1992. (A) from

(2) Prilipe, backwaters of R., WL 58; 5- the villageof Mikote is an artificial, 2 yr old

-VIII-1992. - It is one of the few backwa- canal, of modest velocity and with some

2 floor ters of the Sava R. preserved in Slovenia, pools (depth 30 cm, width m). The

and consists of 2 parts (length 600 and 150 consists of small gravel, covered with mud

connected the bank. El chari and m. resp.), by a stagnant water near Typha sp., eo s sp.

time less than canal. At the of our visit, 10% Potamogeton natans stands occur locally.

of the surface covered with floa- The banks cleared water was are annually.

ting vegetation.The vegetation is typical of natural lower section of the stream runs

backwaters, submerged vegetation modest. through an oak forest, it is completely shaded

Dobra mlaka backwater of the and has (3) nr Skocjan, no aquatic vegetation.

Radulja R„ WL 28; 4/8-VII1-1992. - Ac- (!3)Klevevz (castle), Radulja rivulet, WL 18; 4-

chan- tually a series of pools, connected by -VIII-1992.

nels the between the of Brod- that are dry most of time, fed by (14)SenuSa stream, village

Radulja at floods only. Water depth varies -v-podbo£juand the R„ WL38;4-VIII-

with the seasons, the surface is covered with -1992.

of WL 39; 5-V1II-1992. Lemna sp.. and there is a strong growth (IS), fishpond,

submerged vegetation. (16)Krakovski gozd, southern part, WL 38; 3-

WL 4- -VIII-1992. — forest (4) DobovSki potok. fishery ponds, 17; Normally a marshy

-V1II-1992. - Over-populatedwith fish and with numerous small natural water bodies.

probably regularly emptied. Save for the 2 largest streams, it was comple-

the time of (5) V. Koren, flint sand pits, WL 38; 7-VIII- tely dry at our visit.

-1992. - The depressions in the abandoned (17)Arto, Stagina stream, upward the village.

rain WL 39; 6-VIII-1992. sections were filled by water (depth 30-

-40 cm. surface up to 200 nr). Potamogeton

natans and Eleocharis sp. occur in some of Annotated list of species

50 - = "immense densi- the puddles. Young Libellulidae inslars were (x = > individuals; xx

recovered from the bottom mud. ty"!

Dobra mlaka nr rivulet. — 4 6 (6) Skocjan. Radulja Calopteryx splendens (Harr.) ssp. (1): ,

- — 4 — WL 28; 4-VI11-I992. Depth 70cm, width 3 9; (2): cj; (4): x 6. x 9, all at inlet Noinl. Vol. No. 1-20. June I. 3 odonalol.. 4. I. pp. 1993

and outlet; - (6): x 3, x 9; - (7): x 3, x 9; activity of adults on this particular stretch ofthe

- - - - (8); x 3, x 9: (9); 2 3: (10): 6

- The slow modest and suit- (12): x 3. x $: (14): x 3. x 9. uniform, to velocity

— — 3. $: (7): able bottom allow the larvae C. virgo (L.) ssp. (6): x x x structure to spread

3. x 9: - (9): 7 3. 3 9: - (10): 10 3, 4 9: out, the competition is lower and the survival - - Since the this and in (11) x larvae, x 3, x 9: (12): x 3, x 9: rate higher. development in

the former takes than 2 it - (13): I larva, x 3. x 9. species more years,

Platycnemis pennipes (Pall.). — (I): x cT.x remains to be seenwhether this process will result

— 9. 2 - (2): <3. 9.x (3): in in the cop.; x x cop.; x high emergence rates forthcomingyears.

— 9. 3. x 9, I cop.; (6) xx 3. xx xx cop., xx The 2 exuviae were clinging vertically to grass

— 3. 9: — (12): 3. few above the At the ovip.; (7): x x x larvae, x stems, a cm water. spot, no - - 9: 3, 9,x horizontal suitable for x 9; (13): x 3. x (14): x x structures, eedysis. arc — cop., x ovip,; (16): xx 3 juv., xx 9 juv. available.

Cercion lindenii (Sel.). — (6): 7 <5: — (14): - At (10). (1 and (12 B) Cordulegaster sp. 1 )

I 6. the adults were sighted, at (17) a copula was

- 7 noticed. No voucher could be secured. Coenagrion paella (L.). (1): X 6. î. 3 specimens

- d: - 9 7 d Somatochlora - cop.; (2): x (3): 5 (4-VIII), (7- flavomaculata (Vander L.).

-VIII). (2): X S: - O): I à. - viridulum — (2): x 6 S. meridionalis Nielsen. 5 d. 1 Erythromma (Charp.). . (3): cop.;

I I — 2 - - - - x 9, cop., ovip.; (3): x <3. ovip. (4- (4): 10 ó: (5): Id: (10): 7 â: (II):

— -Vlll), x d (7-VI11); — (6): x d. 4 ovip. 5 â: - (12): 4 â. I 9; - (13): 6 6: - (14):

Found only at the 2 backwaters. Those observed S â. — So far a single 5 of this species has

at (6) have surely migratedfrom (3). as they have been brought on record from Slovenia, taken in

it. been concentrated at the place nearest to 1961 near the city of Piran in NW Istria

— 8 At that that far Enallagmacyathigerum(Charp.). (5); 3, (KI ALITA. 1963). time, was by

1 ovip. the northernmost locality known. Recently, how-

— 3, Ischnura elegans (Vander L,). (I); x x ever, a number of populations were reported

— 3, 9, 5 cop., 5 ovip.; (2) x exuviae, xx x from northern Italy, notably also from the pro- — - - 3; 9, x ovip.; (5): I cop.; (6): I (12); vince of Friuli. N of Udine, where the species

5 PE- 3. co-occurs with S. metallica {Vander L.) (cf.

I. — pumilio (Charp.). (5): x 3. I 9. CILE, 1988). Since the Friulian fauna has been

Lestes (Flans.). — I 3 in the 1960s and meridiona- sponsa (2): juv., 1 9. thoroughlysurveyed

L. — I has been found il is that viridis (Vander L.). (4): I cop.. ovip. lis noi there then, likely

— I 3 Aeshna cyanea { Mull.). (II): exuviae, this is another (of the rather numerous) odonate

I 9 exuviae; — (16): I 9 juv. species that are currently expanding their range

A. grandis (L.). — (1): 2 3; — (2): 13; — northward. Its abundance in the Raka area could

(3): 2 3 exuviae, 1 9 exuviae, 2 ovip. be significant also from this point of view. —

A. mixta Latr. — is often (16); 1 9. Breeding sites of S. meridional are asso-

(L.). — (12 A): 4 ciated with slow the Gomphus vulgatissimus running streams, on grass-

F-0 larvae. land/forcst border. Allrecords given here, except

Onychogomphus f. forcipatus (L. ). — (I): 19 for localities (3) and (4), would fall within this

- 1 - 10 - males juv.; (2): 3; (6): 3, I 9: frame, although were not always sighted

2 1 — (12A): xx larvae, exuviae, x 3, 9; (13): near the water. Males at such localities were beha-

— 3. — whole stretch 1 larva, 2 3; (14): 3 In the clean gravel, ving in 3 ways. viz. (a) If the of

in the middle 2-3 larvae ofa stream at (12), were stream was shaded, they slowly patrolled, at a

2 counted per dm . Near the bank, where gravel is height ofca 80 cm, upstream or downstream, for

covered with 3 of larvae distances up to cm mud, 5-10 over 50 m. Occasionally they made a

2 were found per dm . Apparently,water manage- stop at the same spot for a couple of seconds,

ment measures (low bank vegetation and full for closer inspection of areas under overhanging

sunshine the have led Ifthere throughout year) to a higher branches. were any sunny spots, the males 4 Vol. No. Nolul. odonatoi. 4. I, pp. 1-20, June I, 1993

somehow them. this tried to avoid If was impossi- insect was ever seen settling down

turned L. - 10 3 ble, they around to fly back, or they over- Libellula depressa (5): d, cop., 3

— flew the place with much greater speed to ovip.; - (8): 1 9; - (13): 1 <3; - (16): 1 3.

slow in - down the next shade, (b) The majority Orthetrum albistylum (Sel.), — (1): x

ofmales 50-250 2 - — d. was patrolling at cm height over 9, cop., 10 ovip.; (6): 3d; (15): 1

meadow shaded line oftrees. If undis- O. brunneum — edges by a (Fonsc.). (2): xx d, 3 cop.;

turbed, they stayed at the same place (10-30 m) — (5): 10 d, I 9,3 cop., 3 ovip.; — (6); x d,

for time. 3 imme- 10 10 10 — 1 9. a very long Any intruding was 9, cop., ovip.; (12 A): x d,

— 1 diately attacked, and this always resulted in a O. cancellatum (L.). (1): x d, 9,2 cop.,

of After 10 — — furious chase to heights 20 m or more. ovip.; (6): 3d; (15): I d.

a couple of seconds one of the males usually O. coerulescens (Fabr.). — (12 A); 2 d. returned to the same place. — (c) On locality Crocothemis erythraea (Brulle). — (1): 2 d;

(3), the males were patrolling close to the shaded - (2): 4 d; - (15): 1 d.

bank, and carefully examined spots under bran- Sympetrum sanguineum (Mull.). — (1): 5 d,

ches of and bushes. 2 2 — 5 — overhanging trees Sunny pla- 9,1 cop., ovip.; (2): x d, cop.; (3):

returned. — I — 5 1 ces were "jumped over", or the males x d, 2 ovip.; (7): d; (10): d, 9.

The other bank When vul 1 I sunny was ignored. a fe- S. gatum (L.). (3): d, cop.

male attempted to oviposit, she was immediately

the - seized by one of males, and the couple flew References KIAUTA, B„ 1963, Beitr. naturk.

— It Forsch. SW-Deutschl. 22 65-66; - away. was cloudy on locality (4) duringour (1): PECILE,

visit. The males much 10: were flying more over I„ 1988, Gortania 193-204.

open water, the chasing after intrudingmales was

less furious, and a defending male after a few Received October 23. 1992

metres returned to continue his route.Not a single