. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 206 KENNETH D. ROEDER moth was approximately 90° to the sound path. Samples of echoes from other angles are shown in Figure 3C, where the moth is headed directly away from the sound source, and in Figure 4, where the course is about 135°. In the present experiments the moth was always mounted as if it were in level flight at the same altitude as the optical and acoustic system. Since the surface of the wings appears to be the main source of echoes, it is apparent from the photographs, particularly those of Figure 4, that max
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 206 KENNETH D. ROEDER moth was approximately 90° to the sound path. Samples of echoes from other angles are shown in Figure 3C, where the moth is headed directly away from the sound source, and in Figure 4, where the course is about 135°. In the present experiments the moth was always mounted as if it were in level flight at the same altitude as the optical and acoustic system. Since the surface of the wings appears to be the main source of echoes, it is apparent from the photographs, particularly those of Figure 4, that maximal echoes would be. FIGURE 4. Echo and attitude of A gratis ypsilon on course about 135° away from sound source. Other details as in Figure 2. A, early in downstroke. B, mid downstroke. C, early in upstroke. D, mid upstroke. returned from other wing positions and flight angles if the transmitter and micro- phone were aimed at the moth at various angles from above or below the plane of flight. These were not investigated. During a given run the peak echoes usually went off the oscilloscope screen (Fig. 3B) while minimum echoes sometimes disappeared in the noise level of the recording system. This made it difficult to estimate with any accuracy the intensity difference between maximum and minimum echo. In many cases it was certainly greater than 20 to 30 decibels. Distortions of the echo were also common. The echo shown in Figure 5A has essentially the same form as the outgoing pulse. The asymmetric peak in B was probably due to movement of the wings towards the attitude producing a maximum echo during the interval of time ( millisecond) that the pulse impinged upon them. The sharp peak shown in C indicates that the attitude. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory
Size: 1902px × 1314px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
