DOI: 10.5061/dryad.q573n5tq2
title: Data from: A dynamical model of growth and maturation in Drosophila

description: The decision to stop growing and mature into an adult is a critical point
 in development that determines adult body size, impacting multiple aspects
 of an adult’s biology. In many animals, growth-cessation is a consequence
 of hormone release that appears to be tied to attainment of particular
 body size or condition. Nevertheless, the size-sensing mechanism animals
 use to initiate hormone synthesis is poorly understood. Here we develop a
 simple mathematical model of growth cessation in Drosophila melanogaster,
 which is ostensibly triggered by attainment of a critical weight early in
 the last instar. Attainment of critical weight is correlated with
 synthesis of the steroid hormone ecdysone, which causes a larva to stop
 growing, pupate and metamorphose into the adult form. Our model suggests
 that, contrary to expectation, the size-sensing mechanism that initiates
 metamorphosis occurs before the larva reaches critical weight; that is,
 the critical-weight phenomenon is a downstream consequence of an earlier
 size-dependent developmental decision, not a decision point itself.
 Further, this size-sensing mechanism does not require a direct assessment
 of body size, but emerges from the interactions between body size,
 ecdysone and nutritional signaling. Because many aspects of our model are
 evolutionarily conserved among all animals, the model may provide a
 general framework for understanding how animals commit to maturing from
 their juvenile to adult form.
description: The experimental data were collected as
 detailed in B. C. Stieper, M. Kupershtok, M. V. Driscoll, A. W.
 Shingleton, Imaginal discs regulate developmental timing in Drosophila
 melanogaster. <em>Dev Biol</em>
 <strong>321</strong>, 18 26 (2008). The simulated data were
 generated using the deposited XPP-Auto and Simulink/Matlab
 scripts. 
description: # A dynamical model of growth and maturation in Drosophila
 The data comprise
 experimental data used to parametrize the model, and example simulations
 generated by the model. The experimental data are the relationship between
 body mass (mg) and time to pupariation (TTP) for fed and starved
 third-instar *Drosophila* larvae (experimental_data_fed.csv and
 experimental_data_stvd.csv). The simulated data are the simulated
 relationship between body mass and TTP for fed and starved larvae without
 scatter (simulated_data_fed_ln.csv and simulated_data_stvd_ln.csv) and
 with scatter (simulated_data_fed_sct.csv and simulated_data_stvd_sct.csv).
 ## Description of the data and file structure All the data files contain
 two columns: one for body mass and a second for the time to pupariation in
 hours. ## Code/Software The R-script (Tyson_et_al_analysis.R) is the code
 used to analyze these data using loess regression and segmented
 regression. Script was prepared and run on R version 4.0.3. The XPP code
 to generate the ecdysone and growth dynamics is provided in
 Tyson_et_al_XPP.txt. Script was prepared and run on XPPAUT 8.0. The
 MatLab/Simulink model has two forms: one that generates the relationship
 between body mass and TTP without noise/scatter (single_run.m) and one
 that generates the same relationship but with scatter (multi_run.m). Both
 use the same core Simulink model (Model_simulink.slx). The scripts also
 generate plots of simulated versus experimental data for the relationship
 between body mass and TTP with and without scatter. The experimental data
 for these plots is contained in RealDatalmort.mat and are the same as the
 data used for the R-analysis. The matlab_workspace.mat file contains
 initial parameter values for the model. Parameter values can be specified
 within the single_run.m and multi_run.m scripts prior to running. Script
 was prepared and run on Matlab R2022b update 1.