Computational protocol: Morphological and life-history responses of anurans to predation by an invasive crayfish: an integrative approach

Similar protocols

Protocol publication

[…] In order to examine tadpole morphology, five haphazardly selected tadpoles per container were photographed with a digital camera in side view against a grid background. Photographs were taken, depending on species, when tadpoles were between Gosner developmental stages 30 and 35 (see Table ). Images were loaded into MakeFan7 (Sheets ) to create a standardized template for digitizing the different landmarks. The body shape of tadpoles was captured by digitizing 20 landmarks on each individual (Fig. S1) using tpsDig2 software (Rohlf ). Some of the landmarks were chosen according to specific and easily identifiable anatomical points in the tadpole body (e.g., the center of the eye, the tip of the tail muscle and fin), while others were defined using proportional distances within a structure (Fig. S1). We conducted landmark-based geometric morphometrics analyses on these digitized landmarks; this method is a powerful tool for analyzing and visualizing morphological variation between individuals (Rohlf and Marcus ; Zelditch et al. ). Digitized landmarks were imported into tpsRelw (Rohlf), where a generalized least-squares Procrustes analysis was performed in order to standardize the size, translate and rotate the configurations of landmark coordinates (Rohlf and Slice ). We used the same software to extract relative warp scores, which were then used as shape variables in the analysis. Relative warp scores were estimated using the consensus (i.e., average) morphology for each experimental container in order to avoid pseudoreplication. Consensus conformations were estimated using tpsRelw (Rohlf ).At metamorphosis, tadpoles were blotted dry and weighed with a digital balance to the nearest 0.01 g (mass at metamorphosis). Time to metamorphosis was defined as the number of days elapsed between the beginning of the experiment (day of Gosner stage 25) and the onset of metamorphosis (day of Gosner stage 42). Growth rate was estimated as the quotient between mass at and time to metamorphosis. […]

Pipeline specifications

Software tools TpsDIG, TpsRelw
Application Macroscope & basic digital camera imaging
Organisms Procambarus clarkii