Fig. 5

Changes to biospeckle object shape after PEITC treatment. a Biospeckle objects rendered in 3D from stacks of optical sections. (i) and (ii) show examples typical of object shape pre-treatment with (i) showing the x–y plane and (ii) showing the x–z plane. (iii) shows objects detected 24 h after PEITC treatment. b Examples of convex hull shape applied to areas of biospeckle activity rendered in 3D. Increased curvature of the biospeckle area increases the circularity (Circ) of the fitted convex hull shape. A circularity of 1 describes a perfect circle. c Effect of PEITC on the circularity and the integrated density of nematode biospeckle shapes. The minimum circularities of 8 nematodes (4 showing clear activity in the absence of PEITC, and 4 with clearly definable biospeckle areas 24 h after the addition of PEITC) measured in the XY and YZ plane are given. Blue markers represent non-trichodorid plant feeders, while red and green markers represent bacterial feeders and Trichodorus nematodes respectively. Arrows indicate the difference in mean circularity and integrated density measured for treated as opposed to untreated nematodes. In the absence of chemical treatment (filled markers), circularity for bacterial and non-trichodorid plant feeders was lower than after 24 h in PEITC (open markers). On average, Trichodorus nematodes had greater circularity than either bacterial feeders or non-trichodorid plant feeders in the absence of treatment and did not show any significant increase in circularity once PEITC was applied