Zettel Jürg
Autecology of Formica selysi Bondroit 1918 (Hymenoptera, Formicidae) at different zonation types at Pfynwald (CH)
Project Number: CH-4989
| Project Type: |
Master |
| Project Duration: |
03/01/1998 - 06/30/1999 project completed |
| Funding Source: |
other , |
| Leading Institution: |
Universität Bern, Institut für Zoologie |
| Project Leader: |
Prof. em. Jürg Zettel
Biologe
Speichergasse 8
3150 Schwarzenburg
Phone: +41 31 971 34 44
|
Research Areas:
Disciplines:
Keywords:
Hymenoptera, Formicidae, Aphinidae, zonation, steppe, alluvial area, pioneer species, nest density, dynamic density, foraging area, feeding ecology, crop content analysis
Abstract:
The Rottensand at Pfynwald (CH) is the last remaining steppe area in the valley bottom of the Valais and is characterised by grassland on sandy soil. During a heavy flood in 1993, parts of the area were covered with sand and gravel deposit and different zonation types were created. In summer 1994, a long term research project was started to study arthropod succession at the newly created gravel area. Grossrieder and Zettel (1999) showed that the ant fauna at all zonation types was dominated by Formica selysi (Hymenoptera, Formicidae), with the species attaining its maximum nest density at the non-flooded steppe. Based on these results, we hypothesised that the steppe area would be used more intensively by F. selysi than the early successional stage.
Our results did not support this hypothesis. Although the density of F. selysi nests was higher at the steppe than at the gravel area, the dynamic density of foragers was significantly lower. Furthermore, the foraging distances were much smaller, and the foraging areas tended to overlap less between nearest-neighbour nests at the steppe than at the gravel area. At both study sites, F. selysi showed a clear preference for foraging in sectors of the home range containing trees or samplings with aphid colonies.
In the present study, we also examined the diet of F. selysi at one nest in the gravel area and one at the uninfluenced steppe. We hypothesised that the two nests would differ in their diet due to the limited availability of food in the relatively bare gravel area. At both study nests, aphids, parasitic wasps, ants, beetles and Heteroptera were the most commonly collected insects. The prey composition was similar at both study nests. At both colonies, more than half of the workers returned with honeydew in their crops, whereas protein solutions were found only rarely. The density of aphid colonies was higher in the gravel area than at the steppe. Furthermore, the number of infested plants remained constant throughout the season, whereas at the steppe it dropped to an extremely low level in July due to the drying out of the vegetation. These results suggest that the nutritional situation for species such as ants which depend on continuous food supplies from spring through autumn may be better in the gravel area than at the steppe.
Leading questions:
Do ants F. selysi use more intensively a mature steppe or an alluvial area? Do ants F. selysi have different diet depending on the localisation of their nest (mature steppe or alluvial area)?
Publications:
Keller I. 1999. Autecology of Formica selysi Bondroit 1918 (Hymenoptera, Formicidae) at different zonation types at Pfynwald (CH). Zoologisches Institut, Abteilung Synökologie, Universität Bern Keller I, Zettel J (2002): Contribution to the autecology of Formica selysi Bondroit 1918 (Hymenoptera, Formicidae) in a mature steppe and a newly created alluvial zone at Pfynwald: I. Feeding ecology. Mitt Schweiz Ent Ges 74: 183-193 Keller I, Zettel J (2002): Contribution to the autecology of Formica selysi Bondroit 1918 (Hymenoptera, Formicidae) in a mature steppe and a newly created alluvial zone at Pfynwald: II. Habitat use. Mitt Schweiz Ent Ges 74: 227-236
Last update: 12/29/16
Source of data: ProClim- Research InfoSystem (1993-2024)
Update the data of project: CH-4989
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