Trap‐building antlion larvae detect their prey according to the substrate vibrations produced during movement of the prey on the sand surface. Although most studies are devoted to surface vibrational waves, in the present study, we determine the role of vibrations travelling through deeper sand layers. A behavioural experiment confirms that vibrational stimuli from prey insects on the surface of the sand stimulate the antlions buried in deeper sand layers to move towards the surface. Sand depth and particle size both have a strong effect on signal transmission. The damping coefficient (α10) varies from 0.49 dB to 3.30 dB cm−1 and depends on frequency (in the range from 100 to 300 Hz), particle size (from finest to coarse sand) and distance from the source of the vibrations. The deeper the sand, the narrower the frequency range of the signal becomes. Sand is a filter for higher frequencies. The smaller the sand particles, the more intense the filtering becomes. Fine sand with a mean sand particle size of 360 μm is a more efficient filter than coarse sand; consequently, high frequencies (> 2.5 kHz) are eliminated at a depth of 3 cm. Mean frequency depends on both depth and particle size. However, low frequency signals still propagate at a certain distance, which is biologically important in prey detection. Although the most efficient signal propagation appears to occur in coarse sand, it contains overly large particles that are inconvenient for relatively small antlion larvae. Predators seek a compromise between fine and coarse sand choosing medium sand.

中文翻译：

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蚁狮的猎物检测：振动信号深入沙子的传播

诱捕蚁狮幼虫根据猎物在沙子表面移动时产生的底物振动来探测猎物。尽管大多数研究都致力于表面振动波，但在本研究中，我们确定了振动穿过更深沙层的作用。一项行为实验证实，沙子表面捕食昆虫的振动刺激会刺激埋在更深沙层中的蚁狮向表面移动。沙子深度和颗粒大小都对信号传输有很强的影响。阻尼系数 (α10) 从 0.49 dB 到 3.30 dB cm-1 不等，取决于频率（在 100 到 300 Hz 的范围内）、粒度（从细沙到粗沙）以及与振动源的距离。沙子越深，信号的频率范围变得越窄。沙子是更高频率的过滤器。沙粒越小，过滤越强。平均砂粒径为 360 μm 的细砂是比粗砂更有效的过滤器；因此，高频 (> 2.5 kHz) 在 3 cm 深度被消除。平均频率取决于深度和粒度。然而，低频信号仍会在一定距离内传播，这在猎物检测中具有生物学重要性。虽然最有效的信号传播似乎发生在粗沙中，但它包含过大的颗粒，这对于相对较小的蚁狮幼虫来说是不方便的。捕食者在选择中砂的细砂和粗砂之间寻求折衷。过滤变得越强烈。平均砂粒径为 360 μm 的细砂是比粗砂更有效的过滤器；因此，高频 (> 2.5 kHz) 在 3 cm 深度被消除。平均频率取决于深度和粒度。然而，低频信号仍会在一定距离内传播，这在猎物检测中具有生物学重要性。虽然最有效的信号传播似乎发生在粗沙中，但它包含过大的颗粒，这对于相对较小的蚁狮幼虫来说是不方便的。捕食者在选择中砂的细砂和粗砂之间寻求折衷。过滤变得越强烈。平均砂粒径为 360 μm 的细砂是比粗砂更有效的过滤器；因此，高频 (> 2.5 kHz) 在 3 cm 深度被消除。平均频率取决于深度和粒度。然而，低频信号仍会在一定距离内传播，这在猎物检测中具有生物学重要性。虽然最有效的信号传播似乎发生在粗沙中，但它包含过大的颗粒，这对于相对较小的蚁狮幼虫来说是不方便的。捕食者在选择中砂的细砂和粗砂之间寻求折衷。平均频率取决于深度和粒度。然而，低频信号仍会在一定距离内传播，这在猎物检测中具有生物学重要性。尽管最有效的信号传播似乎发生在粗沙中，但它包含过大的颗粒，这对于相对较小的蚁狮幼虫来说是不方便的。捕食者在选择中砂的细砂和粗砂之间寻求折衷。平均频率取决于深度和粒度。然而，低频信号仍会在一定距离内传播，这在猎物检测中具有生物学重要性。虽然最有效的信号传播似乎发生在粗沙中，但它包含过大的颗粒，这对于相对较小的蚁狮幼虫来说是不方便的。捕食者在选择中砂的细砂和粗砂之间寻求折衷。