Ants (Hymenoptera: Formicidae) of San Marino

A recent catalog of the ants of Europe and surrounding areas listed no ants recorded from San Marino. One afternoon of collecting in urban sites of San Marino yielded 23 ant species: Aphaenogaster subterranea, Camponotus aethiops, Camponotus fallax, Camponotus lateralis, Camponotus piceus, Crematogaster scutellaris, Formica cunicularia, Formica gagates, Hypoponera eduardi, Lasius emarginatus, Lasius lasioides, Lasius paralienus, Messor structor, Pheidole pallidula, Plagiolepis pygmaea, Tapinoma nigerrimum s.l., Temnothorax angustulus, Temnothorax flavicornis, Temnothorax italicus, Temnothorax lichtensteini, Temnothorax tergestinus, Temnothorax unifasciatus, and Tetramorium caespitum. Surprisingly, despite collecting in heavily disturbed urban sites, none of the ants known so far from San Marino are exotic to Europe.

Unusual Ant Hosts of the Socially Parasitic AntAnergates atratulus(Schenck, 1852) (Hymenoptera, Formicidae)

The extreme inquiline antAnergates atratulus(Schenck, 1852) (Hymenoptera, Formicidae) was collected in ant nests ofTetramorium moravicumKratochvil, 1941 in Bulgaria and ofT. chefketiForel, 1911 in Bulgaria and Turkey. The reported ant hosts belong to theTetramorium chefketispecies complex in contrast with the typical hosts fromTetramorium caespitum/impurumcomplex. This finding confirms the assumption that a broader range of host species for the socially parasitic speciesA. atratulusmay be expected. Present data on the new host species expand knowledge about biology of this rare ant species, included in the IUCN Red List of threatened species.

Distributed leadership and adaptive decision-making in the ant Tetramorium caespitum

In the ant species Tetramorium caespitum , communication and foraging patterns rely on group-mass recruitment. Scouts having discovered food recruit nestmates and behave as leaders by guiding groups of recruits to the food location. After a while, a mass recruitment takes place in which foragers follow a chemical trail. Since group recruitment is crucial to the whole foraging process, we investigated whether food characteristics induce a tuning of recruiting stimuli by leaders that act upon the dynamics and size of recruited groups. High sucrose concentration triggers the exit of a higher number of groups that contain twice as many ants and reach the food source twice as fast than towards a weakly concentrated one. Similar trends were found depending on food accessibility: for a cut mealworm, accessibility to haemolymph results in a faster formation of larger groups than for an entire mealworm. These data provide the background for developing a stochastic model accounting for exploitation patterns by group-mass recruiting species. This model demonstrates how the modulations performed by leaders drive the colony to select the most profitable food source among several ones. Our results highlight how a minority of individuals can influence collective decisions in societies based on a distributed leadership.

The Effect of Human Activity on Ant Species (Hymenoptera: Formicidae) Richness at the Mont St. Hilaire Biosphere Reserve, Québec

The ant (Hymenoptera: Formicidae) fauna of the Mont St. Hilaire Biosphere Reserve, Québec, was surveyed in 2002 and 2003. Although overall species richness was high, 10 of 40 total ant species collected were limited to anthropogenically disturbed habitats within the reserve. While only 2 of these 10 species (Tetramorium caespitum (L.) and Lasius niger (L.)) can definitively be considered introduced, areas altered by human activity (representing a small fraction of the reserve’s total area) possess nearly as many unique species as the reserve’s old-growth forest. Although further research will be necessary to determine the consequences of such changes in community structure, this study shows the importance of specifying the extent of biodiversity surveys within protected habitats to more accurately monitor the effectiveness of conservation efforts.