Meeting Abstract

P3.149  Wednesday, Jan. 6  The calculation of the body surface area of Manduca sextalarvae using serial sections and computer reconstruction. TUN, K.M.*; FRUTIGER, A.E.; HOLDENER, J.A.; ITAGAKI, H.; Kenyon College; Kenyon College; Kenyon College; Kenyon College itagaki@kenyon.edu

We have continued our work in estimating the body surface areas (BSA) of 2nd, 3rd and 4th instar larvae of the sphinx moth, Manduca sexta, of various body weights (BW). The larvae were reared from eggs on a prepared diet, then frozen and embedded in Histoprep along with four external orientation markers to serve as reference points between sections. A cryostat was used to make transverse serial sections of each larva at 50um. Each section was digitized using a stereomicroscope equipped with a digital camera and polarization optics. The images of the sections were then imported into the NIH Image J program for analysis. The distances between each of the 4 orientation markers was measured and used to estimate the centroid of each section. A line drawn between the centroid and the upper left marker dot served as the reference axis between sections. For each section, 36 radial measurements were taken from the centroid to the surface in 10 degree increments. Each set of radii values was imported into MAPLE, in which a parametric model of the boundary curve was constructed. A second program in MAPLE was then used to create a parametric model of the body surface for each instar in addition to finding the surface area; the centroid for each section was used to determine a space curve that served as the generating curve for the body surface. Our data so far indicate that the BSA in these larvae scales to the 2/3 power with respect to the BW. This work was supported by the NSF(DMS-0827208) and the Kenyon College Summer Science Scholars Program.