CONTENT - International Society of Zoological Sciences

ICZ2008 – Abstracts S16
Mating biology of Leptothorax gredleri (Hymenoptera,
Formicidae)
Angelika Oppelt 1 , Klaus Hartfelder 2 and Juergen Heinze 1
1
Biologie I, Universität Regensburg,Universitätsstr.31, D-93040
Regensburg, Germany
2
Departamento de Biologia Celular e Molecular e Bioagentes
Patogênicos, Faculdade de Medicina de Ribeirão Preto,
Universidade de São Paulo, Brazil
Leptothorax gredleri is a European ant species, in which female
sexuals attract males by “female calling" and mating occurs on the
ground. This allows observing sexual behaviour in flight cages and
thus investigating the mating biology of ants, which previously has
often been neglected. We studied sperm transfer, mate choice,
and cuticular hydrocarbon profiles of sexuals in this species and in
addition investigated gene expression patterns to learn more about
the reproductive investment of males.
A topological approach to the characterisation of termite
nests
Andrea Perna 1 , Guy Theraulaz 1 , Pascale Kuntz 2 , Stéphane
Douady 3 and Christian Jost 1
1 Centre de Recherches sur la Cognition Animale, CNRS UMR
5169, Université Paul Sabatier, 118 route de Narbonne, 31062
Toulouse Cedex 4, France
2 Ecole Polytechnique de l’Université de Nantes, rue Christian
Pauc, La Chantrerie, 44306 Nantes, France
3 Laboratoire Matière et Systèmes Complexes, Bâtiment
Condorcet, Université Paris Diderot - CC7056, 75205 Paris cedex
13 France
Termites build some of the most complex nests observed in the
animal world. The nests can have elaborate and distinctive forms
typical of the species that produced them; sometimes, however,
strong similarities are found between nests built by
phylogenetically unrelated taxa, suggesting that genetically coded
behavioural rules strongly interplay with physical constraints
imposed by the building material and environment. Inside the nests
of most species are large mazes of interconnected chambers and
galleries : complex transportation networks spanning the three
dimensions.
How can the insects orient themselves inside these networks? Are
there central points where all the paths converge? How long is the
effective distance a termite has to cover from one particular point
to another?
The answers to these questions all depend on the particular
topology of the network of galleries. Starting from a topological
analysis of the gallery system of termites Cubitermes [Perna et al.
Naturwissenschaften DOI : 10.1007/s00114-008-0388-6] we will
proceed to discuss the potentialities of a “topological” approach to
better understand the internal organization of social insects nests.
In particular, by characterizing gallery networks with tools
developped in the field of graph theory, we can analyze the
functions of transport and exchange of information or material
associated to different nests. We can also obtain compact yet
informative descriptors of the complex arrangement of internal nest
structures. The level of description is su±ciently abstract to allow
direct comparisons between nests built by different species and
evaluate directly architectural similarities and differences.
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Evolutionary relationships within the Pachycondyla apicalis
species complex
Chantal Poteaux-Léonard, Ronara S. Ferreira and Dominique
Fresneau
Laboratoire d‘Ethologie Expérimentale et Comparée (LEEC),
CNRS UMR 7153 - Université Paris 13, 99, avenue J-B. Clément,
93430 Villetaneuse, France
Ponerines are considered as one of the oldest
phylogenetic ant assemblages. They are
characterised by high species diversity, a vast
geographic distribution area, and considerable
variations in their anatomical features. However,
they remain primitive in their general social
organisation. Because of misinterpretations of
the biological traits examined and biased
phylogenetic reconstructions based on
morphological data, the phylogeny of
“ primitive ” ants has been subject to reassessment
during the past decade. In the
Pachycondyla apicalis complex, ongoing speciation
has resulted in several closely-related,
sympatric taxa. Even though a recent taxonomic
revision has been published, species limits are
difficult to assess in P. apicalis due to their
conservative morphology. There is still
disagreement about the actual number of species
and their relationships. To clarify these
questions, we performed separate and combined
molecular phylogenetic analyses based on nuclear
and mitochondrial DNA sequences. Our aims are to
reconstruct a robust phylogenetic hypothesis
using a dense taxon sampling, and to investigate
the evolution of behavioural traits (e.g. social
structure, nest location, mating strategy, among
others) among the examined taxa.
Rescue behavior in Cataglyphis cursor ants: an altruistic
behavior or a simple reaction toward individuals in distress?
Alexandra Scohier and Elise Nowbahari
Laboratoire d’Ethologie Expérimentale et Comparée UMR CNRS
7153, Université Paris Nord, 93430 Villetaneuse, France.
Cooperation is an interaction between, at least, two individuals to
accomplish a task. Cooperation frequently involves altruistic
behavior. A particular pattern, the so-called nestmate rescue
behavior, is expressed by Cataglyphis ants when they are
collected in the field. In this research, we created an experimental
procedure, not only to study this behavior in the laboratory, but
also to determine whether it should be considered as real rescue
behavior toward nestmates or if it is only a reaction to an individual
in distress. Our results clearly show that C. cursor ants help only
their nestmates by employing specific behavioral strategies. When
nestmates are in distress, ants display a particular helping
behavior that is excavation, dragging the ant and moving sand.
However, when a stranger ant or a prey is encountered buried in
sand, ants exhibited agonistic behavior (i.e threatening, biting and
gaster flexion). Thus, C. cursor ants discriminate between different
distress situations and adapt their behavior accordingly. Future
exploration of this behavior, coupled with biochemical analysis (the
study of the alarm signal and of the cuticular hydrocarbons by gas
chromatography) is planned to determine the nature of the signal,
itself, as well as to determine whether all colony members can act
as helpers and whether all ants in the colony are helped equally.