Schultz T D, Hadley N F
Department of Zoology, Arizona State University, 85287, Tempe, AZ, USA.
Oecologia. 1987 Sep;73(3):363-370. doi: 10.1007/BF00385252.
The daily movements of two co-occurring tiger beetle species were monitored in conjunction with changes in microclimate along streams in Northeast Arizona. Cicindela oregona and C. tranquebarica temporarily segregated across areas of beach exhibiting different microclimates. C. oregona progressively moved from the dry upper beach to the wet stream edge as beach temperatures increased and humidity decreased. The actively foraged throughout the day in this moist habitat at air temperatures between 25 and 38°C. C. tranquebarica remained on the dry, upper portions of the beach and shuttled between sun and shade at air temperatures above 35°C. Only when stream edge temperatures exceeded 30°C was tranquebarica found in this subhabitat. Both species exhibited physiological tolerances in the laboratory that were consistent with their microhabitat preferences in the field. Although both species had similar high lethal temperatures (47-48°C) in saturated air, oregona died at lower temperatures (39-43°C) than tranquebarica (46-47°C) under dry (0% RH) conditions. C. oregona was considerably more active than tranquebarica at body temperatures below 30°C and exhibited higher levels of active metabolism between 25 and 40°C. In addition, C. tranquebarica exhibited significantly lower water loss rates than oregona at 30, 35 and 40°C.
在亚利桑那州东北部，结合溪流沿岸小气候的变化，对两种共生的虎甲物种的日常活动进行了监测。俄勒冈虎甲（Cicindela oregona）和金斑虎甲（C. tranquebarica）在呈现不同小气候的滩涂区域暂时隔离。随着滩涂温度升高和湿度降低，俄勒冈虎甲逐渐从干燥的上部滩涂迁移至湿润的溪流边缘。在25至38°C的气温下，它全天都在这个潮湿的栖息地积极觅食。金斑虎甲则留在滩涂干燥的上部区域，在气温高于35°C时在阳光和阴影之间穿梭。只有当溪流边缘温度超过30°C时，才会在这个亚栖息地发现金斑虎甲。这两个物种在实验室中的生理耐受性与其在野外的微生境偏好一致。尽管在饱和空气中，两个物种的致死温度都较高（47 - 48°C），但在干燥（0%相对湿度）条件下，俄勒冈虎甲在比金斑虎甲更低的温度（39 - 43°C）下死亡（金斑虎甲为46 - 47°C）。在体温低于30°C时，俄勒冈虎甲比金斑虎甲活跃得多，并且在25至40°C之间表现出更高水平的活跃代谢。此外，在30、35和40°C时，金斑虎甲的失水率明显低于俄勒冈虎甲。
