CONTENT - International Society of Zoological Sciences

S18 ICZ2008 - Abstracts
Integrating ethological and morphological features, ecological
requirements and biodiversity across taxonomical groups to
found water quality bioindicators
Antonio Torralba-Burrial and Francisco J. Ocharan
Dpto. Biología de Organismos y Sistemas, Universidad de Oviedo,
E-33071 Oviedo, Spain
Rivers play a fundamental role in the global hydrological cycle, and
provide important services to humans and biodiversity. The search
of simple, easy to use and cheap rivers ecological status
bioindicators can contribute to their biodiversity conservation. Here,
dragonflies which presence was related with a high ecological
status rives were found. In the fluvial network of Aragon (NE Spain)
108 reaches were sampled. Reach ecological status was assigned
using IBMWP score (summatory of benthic macroinvertebrate
communities’ taxa richness weight to taxa pollution sensibility).
Using multivariate methods (IndVal, SIMPER) dragonfly species
related with high ecological status reaches were identified:
Cordulegaster boltonii (Donovan, 1807), Boyeria irene
(Fonscolombe, 1838) and Onychogomphus uncatus (Charpentier,
1840). Definitive choice of C. boltonii and B. irene was based on
their morphological features (size and colour patterns), behaviour
(adults patrolling river reaches persistently), distribution (wide in
Aragon) and low taxonomical diversity of genera in the area (only
one species of Boyeria in Continental Europe; two of
Cordulegaster in Iberian Peninsula, but Cordulegaster bidentata
with a very narrow distribution and habitat). These species can be
identified easily by trained voluntaries in almost all of their life cycle
phases (larvae, exuviae and imagines). Moreover, both species
shown indicator values to class I and II of ecological status
(allowed by European Water Framework Directive), reinforced their
bioindicator characteristic.
Coexistence of Aphidius species: Does interspecific
competition structure the parasitoid community?
Joan van Baaren 1 , Cécile Le Lann 1 , P. Le Guigo 2 , L. Krespi 2 ,
Yannick Outreman 3 , Jean-Sébastien Pierre 1 and Jacques van
Alphen 1
1 UMR CNRS ECOBIO, University of Rennes 1, France;
2 Ecobiologie des Insectes Parasitoïdes, University of Rennes 1,
France ; 3 UMR BIO3P, Agrocampus Rennes, France
Three species of Aphidius parasitoids exploit the wheat aphid
Sitobion avenae in western Europe. Aphidius rhopalosiphi is a
habitat specialist and the only species present in wheat fields in
winter. It is the commonest species throughout spring. Two
generalists, A. avenae and A. ervi, invade wheat fields by the end
of spring. Wheat aphids defence themselves actively when
attacked by parasitoids and emit alarm pheromone when attacked.
Behavioural analyses of interspecific host discrimination,
competition, patch exploitation were realized. A. rhopalosiphi is
sensitive to host defensive behaviour, and exploits host patches
only partially. Aphidius avenae displays a particular behaviour, with
wing fluttering before attacking a host, which results in suppression
of defensive behaviour. This allows them to exploit patches with
alerted aphids abandoned by A. rhopalosiphi. Aphidius ervi has a
fecundity twice that of A. rhopalosiphi, is less sensitive to the host
defence behaviour and is a better competitor than A. rhopalosiphi
in multi-parasitized hosts. Interactions between A. avenae and A.
ervi are limited due to the low densities of these species. When
females of the three species encounter each other in a host patch
they display no aggressive behaviour to each other.
We showed that the three species can coexist with little overlap in
host use, because they have different phenologies and densities,
different host exploitation strategies and different life histories.
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Behavioral and endocrine responses to environmental
challenges in water vole males (Arvicola terrestris)
Evgenii Zavjalov and Ludila Gerlinskaya
Institute of Systematics and Ecology of Animals, SB RAS, Frunze
street 11, Novosibirsk 630091, Russia
Nobody doubts that stress reaction to both non-social and social
stimuli plays a key role in the population responses to
environmental challenges. We studied the multi-annual changes of
food conditions, demographic and territorial structures, endocrine
status and immunocompetence of water vole males in local
population during 6 reproductive seasons. Multi-annual variations
of food conditions and demography let us to separate these 6
years on 3 time periods. Two years with minimum of available food
were combined in food shortage (FS) period. Shortage of
reproductive resources (SRR) embraced 2 years, when percent of
females in studied local populations dropped below than 20%.
Resources abundant (RA) period combined the 2 years when food
and reproductive resources were higher than multi-annual
averages.
At both periods of resource shortage the non-equal space
distributions of animals was observed in the local population. At
this time overlapping of individual home ranges increased in
comparison with RA. But the average home ranges size did not
change between selected periods. Remarkably, maximum of skin
wounds as index of aggression was found only in male trapped at
SRR. The fecal testosterone also was highest in this time. Highest
aggression in SRR period was coincided with minimal marking of
animals that was estimated by numbers of latrine. Fecal
corticosterone increased in both FS and SRR compare with RA.
Antibody titer (IgG) was higher in males of RA in comparison with
SRR and FS. Thus, ethological and physiological reactions of male
in local population are determined by environment conditions.