Background

It is well known that despite other factors, the composition of the surrounding extracellular matrix (ECM) is of great relevance for proper organ functionality. Changes in its composition can ultimately lead to organ malfunction or failure. Using the muscles of third instar wandering larvae as a model, we can assess the influence of the concentration of single ECM proteins on meshwork flexibility or strength with larval locomotion behavior as a readout. In general, this is also possible for first or second instar larvae, but we decided to use wandering third instar larvae due to their large body size. For precise aging of Drosophila larvae, we refer to the descriptions given by Demerec (1950).

A wide range of methods for measuring Drosophila melanogaster larvae crawling has arisen in recent years. Techniques such as FIM2c (Risse et al., 2017) enable the user to study locomotion in a detailed manner; however, they require a specialized set of equipment. The simple test described herein allows the recording of differences in crawling speed and muscle contractibility with tools that can most likely be found in every laboratory or students classroom. The method is based on a protocol published by Nichols et al. (2012). However, instead of using agar-filled plates, we conducted our experiments in humidified, empty Petri dishes. Thereby, we eliminate the problem of larvae digging into the agar, which can negatively influence the measurement of Z-direction crawling, leading to a loss of information.