CONTENT - International Society of Zoological Sciences

ICZ2008 – Abstracts S18
Important stopovers and limit of both breeding populations of
Black storks in Europe
Damien Chevallier, Yvon Le Maho and Sylvie Massemin-Challet
IPHC, Département d’Ecologie, Physiologie et Ethologie, CNRS,
ULP, 23 rue Becquerel, F-67087 Strasbourg Cedex 02, France
Sixteen black storks (Ciconia nigra) were tracked by satellite
during autumnal and spring migration in order to identify their
important stopover sites. They were followed between breeding
site in Europe and wintering site in West Africa from 1998 through
2006. The data obtained during the migration have permitted to
describe movement patterns, timing of migration, routes followed,
speed, stopovers and their connections between them, in Europe
and Africa. Among 29 important stopover sites identified, 5 were
considered as important ones.
It is known that the west and east breeding populations of black
storks in Europe pass by two ways to go the African continent,
Gibraltar for the first one and Bosphore Detroit for the second one.
Our results show that birds start the spring migration from Africa,
travel a distance equal to the “accessibility distance” (maximum
distance covered without stopover) until Spain, stay on one
stopover and go directly on a breeding ground. This “accessibility
distance” used one or two times by birds corresponds exactly at
the separation line between these two populations.
This study highlights the importance of stopover location on the
migration way for black storks. The protection of the most
important stopovers seems to be essential in black storks and
other bird species to assure good nutritional conditions during the
migration.
How physical oceanography helps in understanding the
foraging ecology of the southern elephant seal
Anne-Cécile Dragon 1 , Frédéric Bailleul 1 , Young-Hyang Park 2 and
Christophe Guinet 1
1
Centre d’Etudes Biologiques de Chizé, CNRS, 79360 Villiers-en-
Bois, France
2
Laboratoire d’Océanographie Physique, Muséum National
d’Histoire Naturelle, 43 rue Cuvier, 75005 Paris, France
Studies of predator movements contribute in understanding
individual foraging processes. In the ocean, those spatial
processes result from individual decisions taken in response to
physiological but also environmental constraints. In the Southern
Ocean polar frontal zone, where deep diving female southern
elephant seal concentrate their foraging activity, mesoscale eddies
structure and enhance the primary production with a likely effect
on the spatial structure of top predator’s prey fields. The optimal
foraging theory predicts that predators should adjust their
movement’s pattern in relation to prey density. The aim of this
study was to investigate the change in the movement and diving
patterns of 4 adult female southern elephant seals equipped with
temperature and salinity satellite-relayed data loggers. Argos
tracks were analysed using a hidden Markov model: each step and
turn of the animals’ trajectories was thus assigned to a behavioural
state between two statistically distinct states: travelling and
foraging. The first passage time technique applied on the duration
of the bottom part of the dive allowed to identify favourable
foraging zone at a finer scale. These favourable foraging zones
were all found to be part of portion of the trajectory classified as in
a foraging state. We finally correlated the detected foraging zones
with several hydrographical variables such as sea level anomalies
and the loggers’ temperature and salinity profiles. The most
favourable foraging zones were related to the presence of both
cyclonic and anticyclonic eddies. Elephant seals used the centre
and edges of cyclonic eddy but only the edges of the anti-cyclonic
ones and adjusted their diving behaviour accordingly
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Mimetic interactions shape the ecological structure of
butterfly communities
Marianne Elias 1,2 , Zach Gompert 3 , Keith Willmott 4 , Julia Robinson-
Willmott 4 and Chris Jiggins 2
1 Institute of Evolutionary Biology, University of Edinburgh, West
Mains Road, Edinburgh EH9 3JT; 2 Department of Zoology,
University of Cambridge, Downing Street, Cambridge CB2 3EJ; 3
Department of Botany, University of Wyoming, 1000 E. University
Avenue, Laramie, WY 82072, USA; 4 McGuire Center for
Lepidoptera Research, Florida Museum of Natural History,
University of Florida, Gainesville FL, USA
Niche phylogenetic conservatism is common at broad scales.
Conversely, fine scale niche at community level is much more
labile, due to complex interplay between common ancestry and
interspecific interactions such as competition, predation, parasitism
or mutualism. Yet surprisingly few studies have examined fine
niche structure in communities of related, interacting species in a
phylogenetic context. Here we use a multifaceted approach putting
ecological data from a highly diverse community of mimetic
butterflies in the upper Amazon into a phylogenetic perspective.
Müllerian mimetic butterflies, where several unpalatable species
have converged in wing patterns that advertise their toxicity to
predators, are one of the most spectacular examples of mutualistic
ecological adaptation. While the adaptive value of mimicry has
been clearly demonstrated in the field and in the lab, an
outstanding puzzle remains: up to ten distinct mimicry complexes
may occur in the same community. If selection is so strong, why do
communities not converge on a single colour pattern? Using
microhabitat measurements for butterflies and their avian
predators and a phylogeny of local butterfly species we show that
1) mimicry complexes and their avian predators are partitioned in
the ecological space in a similar way, and 2) community niche
structure is likely the result of predation-driven selection, which
overcomes common ancestry. Niche partitioning mediated by
predation and possibly competition thus maintain species and
mimetic diversity at the community level. We discuss the role of
mimicry in diversification of groups of mimetic butterflies in light of
these and recently published results.
The Space-Lifetime Hypothesis: viewing organisms in four
dimensions, literally.
Lev Ginzburg and John Damuth
100 North Country Road, 11733, Setauket, NY, USA
Much of the debate about alternative scaling exponents may result
from unawareness of the dimensionality appropriate for different
data and questions; in some cases, analysis has to include a
fourth temporal dimension, and in others, it does not. Proportional
scaling simultaneously applied to an organism and its generation
time, treating the latter as a natural fourth dimension, produces a
simple explanation for the 3/4 power in large-scale interspecies
comparisons. Analysis of data sets of reduced dimensionality (e.g.,
data sets constructed such that one or more of the four dimensions
are fixed), results in predictably lower metabolic exponents of 2/3
and 1/2 under one and two constraints, respectively. Our spacelifetime
view offers a predictive framework that may be useful in
developing a more complete mechanistic theory of metabolic
scaling.