pupates, it goes through a stage called the pre-pupa, where it shrinks considerably and prepares to pupate. Often people mistake this stage for a dead or dying caterpillar. Pupa The pupal stage lasts approximately 18 days under laboratory conditions (17 hours light, 7 hours dark, 27 °C). When reared on a short-day photoperiod (12 hours light, 12 hours dark), pupae enter a state of diapause that can last several months. During the pupal stage, structures of the adult moth form within the pupal case, which is shed during eclosion (adult emergence). Adult Adult M. sexta have narrow wings with a wing span of approximately 100 mm. M. sexta moths are nectarivorous and feed on flowers, demonstrating a remarkable ability to hover. Adults are sexually dimorphic. Males are identifiable by their broader antennae and the presence of claspers at the end of the abdomen. Female moths are typically ready to mate one week after eclosion, and do so only once. Males may mate many times. Mating generally occurs on a vertical surface at night, and can last several hours, with the male and female facing in opposite positions, their posterior ends touching. After mating, females deposit their fertilized eggs on foliage, usually on the underside of leaves. Laboratory rearing Like Drosophila melanogaster, M. sexta is commonly used as a model organism for experiments. They are frequently studied in the laboratory due to their large size and relative ease of rearing. They may be reared on host plants, such as tobacco and tobacco relatives, tomato plants, or wheat-germ-based artificial diet. Their rearing is straightforward, provided they receive a long daylight cycle (e.g., 14 hours) during development to prevent diapause. Eggs are rinsed for one to five minutes in dilute household bleach for disinfection. Eggs are placed on diet cubes or host plants. The eggs hatch and develop at different speeds depending on temperature. The larvae are moved to a fresh diet or leaves as their food spoils or is consumed. When they start to "wander", they are about to pupate, so are placed in a pupation chamber. Pupation chambers are holes drilled into a wood board. The Manduca larvae are sealed in the chamber using a stopper and allowed to pupate. After pupation, the pupae are placed in a breeding or colony chamber to eclose. Providing a cup of sugar water and a tobacco (or related) plant will allow mated females to