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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Factors influencing the visual detection in territorial male butterfly Hypolimnas bolina kezia

Cheng, Chiung-chen 14 February 2008 (has links)
Early studies about territory defense of territorial male butterflies were focused on factors that may affect the outcome of contest. But rapid detection was so critical for territorial defense. The detection ability was correlated to visual system. Studies had focused on visual system such as the structure of eye optics and electrophysiology. However, it still existed one question about how do the owner detect intruder in the field. Some factors may affect the probability of detecting intruders from an owner, such as the distance, the size of the intruder, and background contrast. To determine what factor might affect detection ability of territorial male butterfly Hypolimnas bolina, two different sized butterfly models and four different luminance models were used to determine: 1. The reaction rate of the owner with differrent distances; 2. Test the detection ability at different relative position between intruders and owner (acute zone). 3. To test the visual angle hypothesis; 4. Test the luminance contrast effect. The results showed that the response rate decreased with distance but increased with model size. The owner had greater detection ability when the model was presented in the front rather than it on the side. Finally, the response rate was increased with model¡¦s low luminance. Besides, if the model was darker than its background, the owner¡¦s detection ability was greater. Previous studies indicated that a complex background may let the owner spend more time in detection. However, it was quite different with Hypolimnas bolina. In fact, the owner could quickly detect the model when the model was in a complex background, even there was without luminance contrast between the model and background.
2

Etude des réseaux de communications acoustiques chez un oiseau chanteur forestier, le Troglodyte mignon (Troglodytes troglodytes) / Study of the acoustic communication networks in a forest songbird, the Winter wren (Troglodytes troglodytes)

Camacho-Schlenker, Sol 09 December 2011 (has links)
Le troglodyte est un oiseau chanteur forestier qui défend son territoire par des chants discrets. Les mâles voisins ayant des territoires adjacents forment des réseaux de communication acoustique. La mise en place, la dynamique et l’évolution dans le temps de ces réseaux en conditions naturelles sont peu connus.Par des enregistrements ciblés et continus, un suivi sur plusieurs années, des analyses acoustiques et des expériences de propagation et de diffusions passives et interactives, nous avons montré que i) les chants suivent des règles de construction syntaxique complexes et présentent des microdialectes, ii) les mâles voisins ont de nombreux chants en commun, discriminent les chant du groupe vs des chants inconnus, iii) les mâles portent une signature acoustique individuelle complexe et utilisent différentes stratégies d’interaction acoustique entre eux, iv) les groupes de voisins sont des communautés pérennes perpétuant des traditions vocales. / The Winter wren is a forest songbird singing discrete songs for territorial defense and mate attraction. Neighbouring males defending adjacent territories form acoustic communication networks. Little is known about such networks concerning their onset, dynamics and evolution in time, under natural conditions.By means of focal and continuous recordings, a survey over several years, acoustic analyses as well as propagation and playback experiments, we showed that: i) songs follow complex syntactical rules and form microdialects, ii) neighbouring males share many songs and discriminate between songs from neighbours and strangers, iii) males have complex individual acoustic signatures and use differential singing strategies in interaction with each other, iv) groups of neighbours are perennial communities maintaining vocal traditions.

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