CONTENT - International Society of Zoological Sciences

S17 ICZ2008 - Abstracts
Nest biology of Monoeca haemorrhoidalis (Smith, 1854)
(Apidae) at the Atlantic Rainforest of Southern Brazil
Léo Correia da Rocha-Filho 1 and Gabriel A. R. Melo 2
1 Departamento de Biologia, Universidade de São Paulo, Av.
Bandeirantes 3900, Monte Alegre, 14040-901, Ribeirão Preto, SP,
Brazil ; 2 Departamento de Zoologia, Setor de Ciências Biológicas,
Centro Politécnico, Universidade Federal do Paraná, 81531-990,
Curitiba, PR, Brazil
The genus Monoeca is distributed over almost the entire
Neotropical region, with ten described species. The nesting biology
of a few species, Monoeca sp., M. schrottkyi, M. lanei and M.
xanthopyga, has been studied by previous authors. The aim of this
study was to investigate the nesting ecology of M. haemorrhoidalis.
This study was conducted between Setember/2005 and
January/2007, in an area of Atlantic Rainforest. Four nest
aggregations were studied, as well as other smaller aggregations
of M. haemorrhoidalis also found along the reserve trail. M.
haemorrhoidalis females construct their nests in clay soil, in dense
aggregations, with density values varying from 4 to 27 nests/m 2 .
The period of nest construction and cell provisioning started at the
end of October/2005 and stopped by the end of February/2006.
During this period, plant species of the families Orchidaceae,
Styracaceae and, mainly, Malpighiaceae, were the most important
pollen and floral oils resources that were utilized in brood cell
provisioning. Males and females gathered nectar in a great variety
of plant species. M. haemorrhoidalis is a univoltine and seasonal
species and its nest habits are similar to those already observed
for other Monoeca species.
Natural enemies and other species associated with Monoeca
haemorrhoidalis (Smith, 1854) (Apidae)
Léo Correia da Rocha-Filho 1 and Gabriel A. R. Melo 2
1 Departamento de Biologia, Universidade de São Paulo, Av.
Bandeirantes 3900, Monte Alegre, 14040-901, Ribeirão Preto, SP,
Brazil
2 Departamento de Zoologia, Setor de Ciências Biológicas, Centro
Politécnico, Universidade Federal do Paraná, 81531-990, Curitiba,
PR, Brazil
The bee species Monoeca haemorrhoidalis, the largest one in the
genus, occurs in the Atlantic rainforest of southeastern and
southern Brazil. This study focused in the interactions between M.
haemorrhoidalis and its natural enemies and associates. Nest
aggregations were studied in an area at the transition between
Dense and Mixed subtropical Rainforest, in southern Brazil. During
the nest activities, between October/2005 and February/2006,
thirty-two animal species were observed at the nesting sites.
Nonetheless, association with M. haemorrhoidalis was confirmed
only for the cleptoparasitic species Protosiris gigas (Apidae),
Heterostylum maculipennis (Bombyliidae) and Megaselia sp.
(Phoridae), Tetraolytta gerardi and Tetraonyx distincticollis
(Meloidae), the predators Pyrogaster moestus (Lampyridae) and
Pachycondyla harpax (Formicidae), the cleptobiont species
Acromyrmex niger (Formicidae) and the parasitoids Physocephala
bipunctata (Conopidae), Pseudomethoca melanocephala e
Hoplocrates specularis (Mutillidae). Moreover, pathogenic fungi
developed in stored food of brood cells and in M. haemorrhoidalis
cocoons and Meloidae larvae, causing the death of these species.
The cleptoparasitic bee P. gigas was one of the main causes of M.
haemorrhoidalis mortality. During the peak of activity of P. gigas, M.
haemorrhoidalis had a substantial decrease in its nest construction.
This can be an important adaptation of the host species against its
cleptoparasite.
- 58 -
Phenotypic plasticity, genotype x environment interaction,
and the (un)reliability of animal mating signals
Michael D. Greenfield
IRBI (Institut de Recherche sur la Biologie de l’Insecte), CNRS
UMR 6035, Université François Rabelais, Parc de Grandmont,
Tours 37200, France
The potential for animals to ‘deceive’ one another via ‘dishonest’
signals remains a major question in behavioral ecology. The
current view, that on average an individual’s signals are reliable
indications of potential ability, is based on the argument that
receivers would be selected to ignore signals that are habitually
unreliable, which, in turn, would select against the production of
such signals. Formal analyses as well as observations and
experimental findings are largely consistent with this generalization.
A very different, and more insidious, problem for reliable
communication, particularly in mating, is posed by the plasticity of
signal traits across environments: Because genotypes may
respond in different ways to environmental changes across space
or time, a given genotype may exhibit the ‘superior’ (mating) signal
in one environment but the ‘inferior’ one in another. Thus, (mating)
signals may not be reliable indications if the environment changes
across generations or offspring disperse to different environments.
This conundrum does not necessarily challenge the primacy of
signal reliability, but it points out fundamental weaknesses in our
understanding of signal evolution that result from ignoring
unpredictable environmental variation. Here, I present findings on
genotype x environment interaction (gei) in the male courtship
song of the ultrasonic pyralid moth Achroia grisella. I show how
signal unreliability can arise and discuss the restricted
circumstances under which reliability might yet persist. I then
present recent findings on genetic variance, phenotypic plasticity,
and gei in female response and preference in A. grisella, and I
show how reliability in animal communication can increase or
decrease when both male signal and female response traits are
subject to gei.
Prenatal stress influences behavioural features in young birds
Floriane Guibert 1 , Cécilia Houdelier 1 , Sophie Lumineau 1 , Kurt
Kotrschal 2 , Erich Möstl 3 and Marie-Annick Richard-Yris 1
1
UMR CNRS 6552 Ethologie animale et humaine, Université de
Rennes 1, 35042 Rennes, France
2 Konrad-Lorenz-Forschungsstelle, University of Vienna, A-4645
Grünau, Austria
3
University of Veterinary Medicine, Department of Natural
Sciences, Biochemistry, Veterinärplatz 1, A-1210 Vienna, Austria
The individual’s behavioural development is notably influenced by
his social environment and particularly by his mother. This
maternal effect occurs after youngster’s birth but also before. In
mammals, prenatal maternal stress influences the setting up of
youngster’s behaviour; this influence results from the modulation of
the mother’s plasmatic levels of steroid hormones. In birds, a
similar maternal influence also exists, implicating a modulation of
steroids levels in the egg. Indeed, egg’s hormonal levels are
influenced by laying females’ environment and an artificial steroids’
enrichment of eggs modulates the behavioural phenotype of
resulting chicks. However, no study has investigated yet the whole
mechanism of maternal prenatal influence in birds (i.e. from the
mother to the offspring). Thus, our aim was to analyse the impact
of stress on the laying female on her eggs’ hormonal composition
and on the behavioural features of her offspring. Therefore, we
applied stressors on laying females in a precocious bird, the
Japanese quail. Our results showed that the prenatally stressed
chicks appeared to be more emotive with a higher social
motivation and also a slight increase of steroids in the eggs of
stressed females. Thus, in this study, we show for the first time
that, in birds, stress on the laying female has a significant impact
on the behaviour of her offspring via a hormonal change in her
eggs.