Movements of fireflies visible on the surface of soil were measured under controlled laboratory conditions consisting of high and low ambient illumination. High illumination approximating the intensity of light prior to sunset constituted our light condition. Low illumination was consistent with ambient light levels after civil sunset, which we referred to as our dark condition. Surface movements were significantly more frequent during dark conditions compared to light conditions. Stemmata are the larval form of the insect eye and were the only identified visual organs present in Photuris larvae. We investigated whether stemmata provided larvae with the sensory information facilitating the light dependency of surface movements. We disrupted transmission of visual information from the larval eyes to the brain by severing the optic nerves. The amount of surface movement was compared between larvae with intact and severed optic nerves, under light and dark conditions. Light dependency of surface movements was preserved in larvae with cut optic nerves. The presence of the light dependency after cutting the optic nerves indicated that an alternative, extrastemmatal sensory pathway must be providing light intensity information to the animal. Light dependency was abolished upon removal of the head. Thus, these results suggested that the extraocular system providing light intensity information for regulating the frequency of surface movement was located in the head. The precise location of the suggested extraocular receptor and the nature of the associated sensory system remains unknown.

中文翻译：

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环境光照对 Photuris 萤火虫幼虫表面运动的影响不是由干细胞介导的

在由高和低环境照明组成的受控实验室条件下测量土壤表面上可见的萤火虫的运动。接近日落前光强度的高照度构成了我们的光照条件。低照度与民用日落后的环境光水平一致，我们称之为黑暗条件。与光照条件相比，黑暗条件下的表面运动明显更频繁。Stemmata 是昆虫眼睛的幼虫形式，是 Photuris 幼虫中唯一确定的视觉器官。我们调查了茎节是否为幼虫提供了促进表面运动的光依赖性的感官信息。我们通过切断视神经来破坏视觉信息从幼虫眼睛到大脑的传输。在明亮和黑暗条件下，比较具有完整和切断视神经的幼虫之间的表面运动量。在视神经被切断的幼虫中保留了表面运动的光依赖性。切断视神经后光依赖的存在表明，必须有一个替代的、干细胞外的感觉通路为动物提供光强度信息。去除头部后消除了对光的依赖。因此，这些结果表明，提供光强度信息以调节表面运动频率的眼外系统位于头部。建议的眼外受体的精确位置和相关感觉系统的性质仍然未知。在明亮和黑暗的条件下。在视神经被切断的幼虫中保留了表面运动的光依赖性。切断视神经后光依赖的存在表明，必须有一个替代的、干细胞外的感觉通路为动物提供光强度信息。去除头部后消除了对光的依赖。因此，这些结果表明，提供光强度信息以调节表面运动频率的眼外系统位于头部。建议的眼外受体的精确位置和相关感觉系统的性质仍然未知。在明亮和黑暗的条件下。在视神经被切断的幼虫中保留了表面运动的光依赖性。切断视神经后光依赖的存在表明，必须有一个替代的、干细胞外的感觉通路为动物提供光强度信息。去除头部后消除了对光的依赖。因此，这些结果表明，提供光强度信息以调节表面运动频率的眼外系统位于头部。建议的眼外受体的精确位置和相关感觉系统的性质仍然未知。干细胞外的感觉通路必须为动物提供光强度信息。去除头部后消除了对光的依赖。因此，这些结果表明，提供光强度信息以调节表面运动频率的眼外系统位于头部。建议的眼外受体的精确位置和相关感觉系统的性质仍然未知。干细胞外的感觉通路必须为动物提供光强度信息。去除头部后消除了对光的依赖。因此，这些结果表明，提供光强度信息以调节表面运动频率的眼外系统位于头部。建议的眼外受体的精确位置和相关感觉系统的性质仍然未知。