Morphological deformities of the gastrolith can be seen in crayfish injected with both GAP 65 dsRNA and ecdysone (Fig. 5A), whereas, in crayfish injected with only ecdysone and thedsRNA vehicle, the gastrolith appeared normal, with no deformities. In the control group, the gastrolith appeared to be undeveloped. In crayfish injected with both GAP 65 dsRNA and ecdysone, regions containing less dense mineral can be seen (arrows), although the gastrolith disk shape structure was retained. In the ecdysone- and dsRNA vehicle-injected crayfish, the gastroliths appeared normal with no effect on mineral densities (Fig. 5 B and C).