SOME OBSERVATIONS ON BIOLOGY OF CATAGLYPHIS AENESCENS (NYL.) (HYM., FORM.) IN DELIBLATO SANDS (VOJVODINA, SERBIA)

Ivan Z. Petrov

Institute of Zoology, Faculty of Biology, Univesity of Belgrade, 11000 Belgrade, Serbia and Montenegro,

e-mail: bipetrov@bf.bio.bg.ac.yu

INTRODUCTION

            The distribution center of the genus Cataglyphis Foerster 1850  is the Sahara desert (Bernard,1968). Agosti (1990) stated that Cataglyphis species are distributed  exclusively in the Palearctic  realm.

            Until now, in Serbia and Montenegro, Cataglyphis aenescens, was registered in the Deliblato Sands (=Deliblatska pe{~ara) (Fig. 1) (Gradojevi} 1963, Petrov 1986) and Metohija (Collingwood pers. comm.), both in Serbia.

Fig. 1. Deliblato sands (B) and its position (DP)

in Serbia (A)

Cataglyphis aenescens can be characterized as the  most characteristic ant species of  Deliblato sands (Petrov (1994).

            In the Deliblato Sands, it was found in several localities (Petrov, 1986)  where arid, semidesert and desert habitats are present. In these localities prevails high, sometimes lethal temperature. To such a temperature, C. aenescens is adapted by certain morphological and ethological characteristics such as: long legs, somewhat upward raised gaster and by  extreme mobility.

Fig 2. Semidesert habitat in Deliblato Sands

Due to its own peculiarities, as well as due to the peculiarities of its habitat, C. aenescens arose interest of several authors (Cagniant, 1973, 1976, 1979, 1980a, 1980b, 1984; Dlussky, 1962, 1981; Marikovski, 1973; Reznikova, 1983;  Lenoir, 1987; Lenoir, et al. 1988; Schmidt-Hempel, 1987).

DESCRIPTION OF THE STUDIED AREA

            Deliblato Sands is situated in Serbia, about 70 km northeast from Belgrade (Fig. 1A) and belongs to the part  of the Pannonian Plain. It has an oval shape, in NW‡SE direction (Fig. 1B), covering about 25.000 hectares. Its altitude ranges from  75 m in the southeast part, near the river Danube (Dubovac) up to 193 m in the northwest part (Pluc) (Fig. 1B).

            It is of dune character. Dunes extend in NW‡SE direction too. They are of different height (2‡4 m up to 20‡30 m), and slopes.

            One of the peculiarities of the Deliblato Sands is its soil, consisting of sand, which is partly presented by a drifting sand. Actually, the Deliblato Sands represents an “oasis” of preserved desert and semidesert habitats (Fig. 2) and it offers optimal conditions for C. aenescens. Due to the natural successions and artificial afforestation, desert and semidesert habitats are small and rare today.

            The second peculiarity of the Deliblato Sands is its climate which is characterized by great diurnal and annual fluctuations of temperature and quantity and arrangement of rain fall during the year, that are different from those in the surrounding environment.

            The third peculiarity of the Deliblato Sands is the SE wind (“ko{ava”) which blows very often and can be of  storm strength.

THE SOCIETY OF CATAGLYPHIS AENESCENS

The society of C. aenescens is  monogynous and relatively small, consisting of one queen and several hundreds up to about 2.500 workers (Tab. 1) (Petrov, 1985). The size of the society  was measured by doing census.

      Table 1.  Number of workers (census)

                          in the society of C. aenescens

                               Date         No. of workers

CATAGLYPHIS AENSCENS

The worker

The body  of  the worker of C. aenescens  is shiny black which reflects the sun rays and so prevents overheating. The front tibiae are brownish. Tibial spines and a well developed  psamophore aid digging and removal of  sand.

            The body length of the worker ranges from 3.10 up to 8.00 mm (Tab. 2) (Petrov, 1985).

Table 2. Body length of workers of C. aenescens

ACTIVITIES OF WORKERS

Worker activity can be divided into activity inside and outside the nest. Activity inside the nest was indirectly shown by the number, and disposition of workers at different levels of the nest dependant on the activity of the society (Fig. 2). The depth at which the queen was found was also registered. At the same time the temperature at the each level of the dug out nest was measured. 

The society begins activity in spring (March, April) and reaches a maximum  during the hottest period of the year (July and August) and also in the hottest period of the day (noon and early afternoon) when the temperature of sand can reach 60^oC (Petrov, 1992).

             When the activity of the society begins, small number of workers is present at the upper levels of the nest. As the activity increases during the season, the number of workers in upper levels of the nest also rises. Even then a greater number of workers remain at lower levels of the nest (Fig. 2). This confirms the statement of Harkness (1977) that only a small  number of  workers leave the nest as foragers.

Fig. 2. Distribution of workers and queen in the nest of C. aenescens (A‡ levels (cm), B ‡ temperature (^oC) C‡ number of workers, Q‡ level with the queen

The activity of workers outside the nest begins half an hour or one hour after Sunrise, when the temperature of the soil is about 20^oC. The maximum is reached about noon, or early afternoon, when the temperature of soil may reach 50‡60^oC (Petrov, 1992) (Fig. 3).

Fig 3. Exits and entries of workers of C. aenescens

during the day (thick line ‡ temperature, thiner line ‡

exits, broken line ‡ entries)

During their foraging trips, workers of C. aenescens leave the nest 10 to 12 times during the day, reaching the maximum distance of about 10 m from the nest, and showing site‡fidelity by going always in the direction chosen by the first exit (Fig. 4) (Petrov, 1993).

 Fig. 4. Route shape and the site‡fidelity by exits of workers

C. aenescens is a diurnal scavenger. Its diet mainly consists of dead arthropods (chiefly insects). Sometimes it behaves as predator attacking caterpilars and honey bees overloaded by pollen and exhausted by heat. Plant material and plant juices account for smaller portion of dietary resources of C. aenescens (Petrov, 1990).

The queen

The queen is bigger than the worker. Its length ranges from 8.24 mm up to 10.00 mm (Petrov, 1985). Its colour is entirely silvery‡whitish, because of the presence of fine hairs.

Disposition of the queen in the nest was variable (Tab. 3). Generally, it was always found at lower levels of the nest. Only once, the queen was found at the upper level. The temperature in the chamber with the queen was variable too, but in late spring and summer, the temperature became more balanced (Tab. 3).

The queen was always surrounded by several hundreds of workers. (Tab. 3) (Petrov, 1998).

Table 3. Position of queen in the nest

The male

The male has the same colour of the head and thorax as the worker. The thorax is without fine silvery hairs. The abdomen is not shiny. It is pale (reddish), more or less pale dorsally and darker on each side. Genitalia are pale brown and massive. The length of the male ranges from 7.66 mm to 9.96 mm (Petrov, 1985).

Alate queens and males appear in the nest at the end of May and at the beginning of June. Alate queens and males mostly wandered over the ground within very short flying distances. Mating occurs on the ground, like in other Cataglyphis  species.

THE NEST

            The nest of C. aenescens is monocalic. Its above ground part is smaller, and appears  like a bulwark (Fig. 5). Its diameter ranges from a few centimeters in younger to 30 centimeters in older nests, while its height ranges from a few centimeters in younger nests up to 15‡20 centimeters in older nests. The width of the entrance is about 1 cm.

Fig. 5. The above ground part of the

nest of C. aenescens

The nest was often situated in the turf of Festuca vaginata (Fig. 5) which gives the support to the nest.

            Usually, there is only one entrance into the nest (Fig. 5), but nests with two or more entrances were found too.

            The subterranean part of the nest is relatively shallow (30‡40 centimeters, up to 1 m) (Petrov, 1985, 1998). In younger nests it is constructed like a subsurface horizontal gallery (Fig. 6A), or in older nests like a subsurface horizontal system (Fig. 6B).

Fig. 6. Subsurface horizontal gallery (A) and subsurface

horizontal system (B) (ENT‡entrance)

From the subsurface part of the nest, there stretches one vertical passage, which is about 1 centimeter in diameter. Around it, chambers have a relatively spiral arrangement (Fig. 7 A, B) (Petrov, 1992, 1998). Such an arrangement shows an adaptation to loose soil (sand) (Petrov, 1992).

A                                             B

Fig. 7 A, B. The subterranean part of the nest

Distribution of nests on the plot studied showed a contagious type of distribution, which is a consequence of environmental heterogenity  (Fig. 8) (Petrov and GallÕ 1986).

C. aenescens overwinters in an adult stage. Clusters of workers, together with a queen were found in 2‡3 chambers, at the depth of about 70‡80 cm and a temperature of about 7‡8^oC (Petrov, 1985).

Since desert and semidesert habitats in Deliblato sands are disappearing because of natural successions, artificial afforestation, this species seems to be an endangered species in that area.

REFERENCES

Agosti, D. (1990). Review and reclassification of Cataglyphis (Hymenoptera, Formicidae). Journal of Natural History 24, 1457-1505.

Bernard, F. (1968). Les Fourmis (Hymenoptera, Formicidae) D'Europe occidentale et septentrionale. Masson et C^ie. Editeurs, Paris , 1’411.

Cagniant, H., (1973). Apasition d'ouvriers a partir d'aefus pondus par des ouvrieres chez la Fourmi Cataglyphis cursor Fonscolombe (Hymenoptera, Formicidae). C. A. Acad. Sci. 277, D-2197, Paris.

Cagniant, H., (1976). Cycle Biologique de la Fourmi Cataglyphis cursor Fonscolombe (Hymenoptera, Formicidae). Vie et Milieu, 24 (2 C), 277-281.

Cagniant, H., (1979). La partÕnogÒnÒse thelytoque et arrenotoque chez la Fourmi Cataglyphis cursor (Hym., Form.). Cycle biologique et elevage des colonies avec reine et des colonies sans reine. Insect. Soc. 26, 51-60.

Cagniant, H., (1980a). La partÕnogÒnese thelytoque des ouvriÒres de la Fourmi Cataglyphis cursor Fonscolombe. Insect. Soc. 27, 157-174.

Cagniant, H., (1980b). Etude des stades larvaires, de la ligne Ailes et de lignee des ouvriÒres des colonies avec reine et des colonies sans reine chez la fourmi Cataglyphis cursor Fonsc. (H., F.). Bull. Soc. Hist. nat. 116, 192-206.

Cagniant, H., (1984). Influence de la reine sur l'aparition des sexes et sur la ponte des ouvriÒres chez la fourmi Cataglyphis cursor Fonscolombe (Hymenoptera, Formicidae). Bull. Soc. Hist. nat. 120, 99-102.

Dlussky, G. M., (1962). Muravi severnovich sklonov talaskogo Altana. Trudi Inst. Zool., 18, 177-188.

Dlussky, G. M., (1981). Muravi pustinj. Akad. Nauk. USSR, Moskovskoe         Obs~estvo Ispititatelei prirodi, Sekcija zoologii, "Nauka", Moscow, 1-228.

Gradojevich, Z., (1963). Naselje artropoda travnih zajednica Delibatske peshchare i         njihova sukcesija. Doktorska disertacija, Prirodno-matematichki fakultet, Beograd, 1-233.

Harkness, R. D., (1977). Quantitative observations on the foraging of nests of an ant (Cataglyphis bicolor F.) in Greece. Acta Entomologica Jugoslavica, 13, 21-33.

Lenoir, A., 1987. Factors determining polyethism in social insects. Experientia Supplementum, 54. Pp 219-240 - In: Pasteels, J.M. and Denebourg, J-L (eds.): From Individual to Collective Behavior in Social Insects. Birkhauser Verlag, Basel, Boston -433.

Lenoir, A., Querard, L. , Pondiq, N. and Berton F, (1988). Reproduction and dispersal in the ant Cataglyphis cursor (Hymenoptera, Formicidae). Psyche, 95, 21-44.

Marikovski, P. I. 1973. O muravjah. Priroda, Moscow, 8, 82-91.

Petrov, I. (1985). Idioekolo{ka studija vrste Cataglyphis cursor Fonscolombe (Hymenoptera, Formicidae) na Deliblatskoj pe{~ari. Prirodno–matematichki fakultet, Beograd. Magistarski rad, 1–96

Petrov, I. Z., 1986. Distribution of species of the genus Cataglyphis Foerster 1850 (Formicidae, Hymenoptera) in Yugoslavia. Arch. Biol. Sci., Beograd, 38, 11P-12P.

Petrov, I. Z. (1990). Observations on the feeding strategy in the desert ant Cataglyphis cursor  Fonscolombe (Hymenoptera, Formicidae). Arch. Biol. Sci., Beograd, 42, (1–2), 83–90.

Petrov, I., Z. (1992). Nest structure and activities of Workers of Cataglyphis cursor  Fonscolombe (Hymenoptera, Formicdae). Proceedings of the 4th ECE/XIII SIEEC, Gödöllö, Hungary, 2, 766–776.

Petrov, I., Z. (1993). Some remarks on the foraging strategy in Cataglyphis aenescens  Nyl. (Hymenoptera, Formicidae). Tiscia 27, 23–28.

Petrov, I., Z. (1994). Contribution to the myrmecofauna (Formicidae, Hymenoptera) of Deliblatska pe{~ara (Deliblato Sandy Area) (Serbia). Bios (Macedonia, Greece), 2, 251–256.

Petrov, I. Z.  (1998). Organization of the society and biology of Cataglyphis aenescens (Nyl.) (Hymenoptera, Formicidae) in the Deliblato Sands (Serbia). Arch. Biol. Sci., Belgrade, 50 (4), 243–248.

Petrov, I. Z., Gallé, L. (1986). Nest distribution of the Cataglyphis c. aenescens (Nyl.) (Hymenoptera, Formicidae) in Deliblato Sandy Area (Yugoslavia). Ekologija, Beograd, 21, 2, 135–148.

Reznikova, @., 1983. Me`vidovie otno{enia muravev. AN USSR, Izdateljstvo "Nauka" Sibirskoe otdelenie, Novosibirsk.

Schmidt-Hempel, P., 1987. Foraging characteristcis of the desert ant Cataglyphis. Experientia supplementum 54. Pp 43-62 - In: Pasteels, J.M. and Denebourg, J-L. (eds.): From individual to collective behavior in social insects. Birkhauser Verlag Basel, Boston, 1-433.