2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

S�29 Davide Dominoni M 629 / 14:30
Effects of artificial light at night on daily cycles of songbirds
Author: Davide Dominoni 1
Affiliation: 1 Max Planck Institute for Ornithology, Migration and Immuno-Ecology
We live in the urban millennium, the age of cities and urbanization. Animals which
attempt to settle in such man-made ecosystems must cope with novel environmental
conditions. One of the most apparent environmental factors in cities is artificial light
at night. The goal of our research was to investigate how urban sprawl has change the
temporal life of European blackbirds (Turdus merula), and to correlate this change
with light pollution. We quantified daily activity patterns of blackbirds along an
urban/rural gradient in Munich, Germany, with the use of an automated telemetry
system. Simultaneously we tagged the same individuals with micro light loggers to
measure light irradiance to which the birds were exposed to. Diurnal and nocturnal
noise levels were also recorded in the territory of each individual. In my contribution I
will discuss the relative role of light at night, noise and weather conditions on the
daily cycles of European blackbirds and discuss fundamental questions about the
fitness consequences of light pollution.
S�30 Malika Ihle M 629 / 14:45
Does hatching failure breed infidelity?
Author: Malika Ihle 1
Affiliation: 1 Max Planck Institute for Ornithology Seewiesen
In socially monogamous species, the reasons for female infidelity are still
controversial. It has been suggested that females could seek extra-pair copulations as
an insurance against hatching failure caused by male infertility or incompatibility. In
species where couples breed repeatedly, females could use previous hatching success
as a cue to assess their partner's infertility (or incompatibility). Hence, it has been
predicted that females should increase their infidelity after experiencing hatching
failures, but to our knowledge this hypothesis has never been tested experimentally.
We manipulated hatching success of pairs in a captive population of zebra finches
(Taeniopygia guttata), a species that forms lifelong pair-bonds, and measured female
willingness to engage in extra-pair copulation. By experimentally cross-fostering
fertile and infertile eggs, couples either experienced 100% or about 35% hatching
success in each of three consecutive clutches. Contrary to our prediction, females
that experienced repeated hatching failure did not increase their responsiveness
towards extra-pair males relative to those females with 100% hatching success.
Moreover, there was no difference in female calling rate for the partner after male
removal and no occurrence of divorce when the opportunity was given. These
findings seem to contradict the common view that reproductive failure weakens the
pair bond. Furthermore, a critical review of the literature suggests that there is no
convincing evidence supporting this hypothesis in other species either. We therefore
highlight that this fundamental area of behavioural ecology research is still much in
need of specific experimental work that controls for confounding factors.
255