Effects of resource heterogeneity on egg-spacing behavior of Callosobruchus maculatus (Fab.).
Date Issued
2007
Date
2007
Author(s)
Chung, Way-Sing
DOI
zh-TW
Abstract
Insects perceive their environment following a hierarchy system. Structures of resources usually influence insects’ behavior and survival. Callosobruchus maculatus (Fab.) is an endoparastoid insect whose larvae is immobile, therefore, how a female bruchid’s eggs dispersed when they face heterogeneous enviornment temporally and spatially directly affects her fitness. In this study, searching behavior of female bruchids and the way they reacted to a patch enviornment was investigated. In order to understand their ability to perceive information from enviroment and their seaching behavior, I used video recorder to date their walking patterns, such as orientation, velocity, turn rate, and distance distribution as they leave from a given patch. From the result of V-test, bruchids’ walking orientations aggregated to the resource direction within the distance of 1.25 cm. In other words, female bruchids’ perceptual ability to locate host precisely between 1.25 and 2.25 cm. Besides, I found that bruchids exhibited an area-restricted search behavior, with which female bruchids intensively searched for hosts near the resource area searched before. More than 40% of their returns occured within 1 cm around a given resource patch, and their walking patterns within this area were lower locomotion rate and higher turn rate. These results could be used as a basis to judge if a group of resource can be looked as a basic spatial unit, patch, or not. Finally, female bruchids were limited to oviposit for 12 and 24 hours under different spatial configurations composed of 16 adzuki beans to examine oviposition performance, such as uniformity of eggs distribution and eggs number. The experiment was on purpose of verifing the definition of a patch that I assump and examing bruchids’ oviposition performance in space and time. Results from oviposition experiments had supported the definition of a “patch” for Callosobruchus maculatus (Fab.) and showed that bruchids’egg distribution wuold be affected by spatial configurations of resource only under the condition that time became a limited factor for female bruchids to oviposit. The effects of spatial hetergeneity became inconspicuous when they were allowed to oviposit longer. Hence, the scale of time we used to testify the effects of spatial configurations would be an important factor and might be correlated with characters of the material we used. Besides, results also surpported the definition of a “patch”, patchiness of resource seemed not affecting the eggs number laid by female bruchids but the ditribution of eggs temporally. Female bruchids tend to lay more eggs within a patch when the resource dispersed patchily, but it seemed that there was an upper limit of utilization for the resource that prevented female bruchids from over exploiting the resource patch.
Subjects
四紋豆象
資源異質性
搜尋行為
產卵分布行為
區塊
Callosobruchus maculatus
resource heterogeneity
searching behavior
egg-spacing behavior
patch
Type
thesis
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