Fig. 2. Progression of melanization in a L. vannamei male from the mixed adult male/adult female population over a 9-week period. The pictures show the ventral side in the posterior region of the cephalothorax. First week: the spermatophores are white; third week: slight melanization (arrow) is visible in the most distal part of the left spermatophore, immediately next to the gonopore area; fifth week: melanin accumulation is clearly seen in the left spermatophore (arrows); ninth week: melanin has spread over the left spermatophore (arrows). Broken arrow indicates slight melanization in the right spermatophore.