Wojciech Czechowski

Territory Size of Wood Ants (Hymenoptera: Formicidae): A Search for Limits of Existence of Formica polyctena Först., An Inherently Polygynic and Polycalic Species

Abstract. n Wood ants are often absent on islands of the Gulf of Finland, even when seemingly suitable habitats are available. Their absence may partially be explained by the lack or rarity of ant species suitable as host during colonisation through temporary parasitism. To search for the limits of living conditions on islands, given colonisation constraints are overcome, we artificially established wood ant colonies on several islands constituting a series from suboptimal to extremely harsh living conditions. The case reported here showed that a barren < 0.2 ha islet, with aphids on its single pine tree the only permanent and relatively rich food source, has allowed the existence of an artificially introduced Formica polyctena Först. colony for 22 years. The ambient living conditions are probably close to the limit for the species, as evidently the colony does not produce sexual offspring. Thus the sustained existence of the colony is dependent on adoption of fertile gynes originating in colonies that live in more optimal conditions. We suggest that the polygynic social mode of the inherently polycalic F. polyctena is the key for its sustained existence on the islet, as polygyny together with receptivity to new, even alien queens keeps the colony alive in a sink habitat insufficient for production of own sexual offspring.

POLLENIVORY IN ANTS (HYMENOPTERA: FORMICIDAE) SEEMS TO BE MUCH MORE COMMON THAN IT WAS THOUGHT

Abstract. So far, besides some specialised Neotropical ant species of the genus Cephalotes Latr., the Palaearctic Myrmica schencki Viereck, M. rubra (L.) and Tetramorium cf. caespitum (L.) were known to be, at least facultative, pollen-eaters. The present paper reports on nine other common Palaearctic ant species occasionally feeding on pine pollen: Myrmica ruginodis Nyl., F. pratensis Retz., F. cinerea Mayr, F. clara For., F. sanguinea Latr., F. exsecta Nyl., Lasius niger (L.), L. platythorax Seifert, and L. fuliginosus (Latr.) and re-confirms pollenivory of M. schencki. Pollenivory of all these species was revealed based on the presence of pollen grains in the alimentary canal of the dissected workers. The possible role of pollen in the diet of ants as a generally omnivorous insect group is discussed.

Strikingly malformed host morphology: Myrmica rugulosa Nyl. and Myrmica sabuleti Mein. (Hymenoptera: Formicidae) parasitised by mermithid nematodes

A bstrac t: Mermithid nematode infestation o f M yrm ica rugulosa Nyl. and M . sabuleti Mein, is reported, and parasitogenic morphological anomalies o f these two ant species are described for the first time. Two infected M. rugulosa males and a female worker-like individual o f M . sabuleti were found outside their nests in the Pieniny Mts (southern Poland). The latter individual was recognised belonging to the gynaecoid mermithergate parasitogenic category caused by the mermithid parasitism. Mermithogenic malformation o f the infected M . sabuleti female is discussed in the context o f its developmental origin. Emphasis is also placed on possible taxonomic difficulties in the determination o f M yrm ica Latr. specimens infected by the mermithids as well as the risk o f erroneous descriptions o f taxa based on such parasitogenic forms.

Lasius niger (L.) Ants Invade the Web of an Agelenid Spider

ABSTRACT n Black garden ants Lasius niger (L.) were observed to invade a web of an agelenid funnel spider (Agelena labyrinthica Clerck or Allagelena gracilens C. L. Koch) and to take the entangled prey away, probably after driving the resident spider out of the web. The observation adds to a few examples of ants invading spider webs and suggests complex interactions between ants and funnel spiders which are known to feed on rather than being ousted by ants.

Wood Ants in the Białowieża Forest and Factors Affecting their Distribution

Wood ants are common in coniferous, mixed and deciduous forests of the Palaearctic ecozone. We conducted a survey of wood-ant mounds in an area of 1400 ha in the Białowieża Forest (NE Poland) and related physical mound characteristics to the surrounding forest properties. The overall density of inhabited wood-ant mounds was 0.13 per ha. Formica polyctena and F. rufa were the most abundant species, and the highest densities of their mounds were found in fresh mixed deciduous and fresh mixed coniferous forests. The physical mound properties, such as direction of the longest mound slope and the distance to the closest tree did not differ significantly between these two ant species. Amount of light significantly affected mound size and the distance to the closest tree distance: mound diameter, height and volume increased with increasing shade; and the distance to the closest tree with increasing amount of light. The results of our study suggest that coniferous forests with an admixture of deciduous trees are best for maintaining wood-ant populations.

New records of two alien mud daubers Sceliphron destillatorium (Ill.) and Sceliphron curvatum (Sm.) (Hymenoptera, Sphecidae) from Poland with comments on expansion of their ranges.

The paper presents information on two species of digger wasps, Sceliphron destillatorium (Illiger, 1807) and S. curvatum (Smith, 1870), alien for the fauna of Poland (within its present borders). Both species are presently spreading in the country. Sceliphron destillatorium, a South-Palaearctic species, has been observed in Poland since 1960. Sceliphron curvatum was introduced to Europe from Asia in the 1970s, and at present it is known from many South- and Central-European countries. The species was found for the first time in Poland in 2003. New localities of the two species in Poland are given and issues connected with their present distribution are discussed.