Microanalysis of courtship behaviour in Drosophila melanogaster
B. I. Arthur1, Jr. and M. S. Magnusson2
1Zoologisches Museum, Universitaet Zuerich,
Zurich, Switzerland
2Human Behavior Laboratory, University of Iceland, Reykjavik,
Iceland
The essential progressive sequence of fixed action patterns in the courtship
behavior of Drosophila melanogaster is well established. However, given
the small dimensions of the fly and the rapidity of its actions the finer
structure of its behavior and interactions is less known. We therefore
video-recorded the courtship of male-female pairs at a frame rate of 30/s
and with image quality allowing visual identification of minute behavioral
elements. This enabled us to identify and register precisely the times
of occurrence of known elements of courtship behavior, but also of new
behavioral elements invisible to the unaided eye. The coding thus resulted
in real-time behavior records of considerable complexity. Previous studies
of Drosophila melanogaster courtship behavior have mostly reported only
the coarse elements of male activity and totally neglected female activity
and the interactive nature of courtship. We guessed that the finer structure
of such behavior might involve hidden patterns of value in courtship interaction.
We therefore searched for possible hidden intra- and inter-individual
temporal patterns using the Theme program to process the data from all
the male-female dyads. It performs an intensive search for a particular
but very large class of temporal patterns called t-patterns. This pattern
type was specially developed for the detection of hidden structure in
real-time behavior and interaction records. We detected special patterns
characteristic of female receptivity that were dependent on their reproductive
status and also of abnormal courtship displayed by a male carrying a mutant
allele of the fruitless gene compared to normal male patterns. These analyses
have revealed patterns whose appearance and disappearance typify the development
of female sexual behavior and its subsequent modification after mating.
Additionally, we found that patterns from dyads with fruitless mutant
males showed less interaction with partner compared to normal males. T-patterns
provide a promising approach to the usually elusive phenotyping of behavior
and will facilitate studies into its molecular genetics basis.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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