Mullens Bradley A, Soto Diane, Gerry Alec C
Department of Entomology, University of California, Riverside, CA 92521 (
J Med Entomol. 2016 May;53(3):703-706. doi: 10.1093/jme/tjv246. Epub 2016 Jan 7.
Horn flies, Haematobia irritans (L.), were photographed on cattle and then immediately estimated visually in the field on pastured beef cattle in southern California. Horn flies were counted in the pictures later on a computer screen. For 479 counts on individual cattle, the concordance correlation coefficient between the visual and photo-based assessments was 0.790, but was better for the higher half of the counts (0.732) than for the lower half of the counts (0.217). Major axis regression indicated that visual estimates were consistently higher than the number of flies counted in the pictures across the entire density range. Based on average raw means, the visual estimates averaged 21% higher than the photo counts. Visual estimates included flies on the belly and lower legs that could not be seen in a photo, and lower densities may have been more susceptible to such error. Where flies can be seen well, e.g. for very tame animals, the visual estimates were much faster and more cost-efficient and were sufficient to track relative horn fly abundance changes.
在加利福尼亚州南部的牧场肉牛身上拍摄了角蝇（Haematobia irritans (L.)），然后立即在野外对其进行目视估计。之后在电脑屏幕上对照片中的角蝇进行计数。对于对479头牛个体的计数，目视评估与基于照片评估之间的一致性相关系数为0.790，但计数较高的一半（0.732）比计数较低的一半（0.217）情况更好。主轴回归表明，在整个密度范围内，目视估计始终高于照片中计数的苍蝇数量。基于平均原始均值，目视估计比照片计数平均高21%。目视估计包括照片中看不到的腹部和小腿上的苍蝇，较低密度的情况可能更容易受到此类误差的影响。在苍蝇能被清楚看到的地方，例如对于非常温顺的动物，目视估计速度更快、成本效益更高，并且足以追踪角蝇相对丰度的变化。
