Cabbage butterfly can be compared to other butterflies such as swallow tail etc. Swallow tail is bigger than cabbage butterfly, length is 80~120mm. Cabbage butterfly is about 55mm. Swallow tail is green, yellow and black spots color while cabbage butterfly is wing color is white but reverse side is thin black color. Front wing point is black and front wing and back wing have two black spots. Their eyes have compound eyes and heads have club feeler.
Butterflies have scales with their wings. Their scale shed water so if it rains , wings are all right. Scale come off by touching their wings. Therefore without scale ,their wings are ragged and they can not fly. Cabbage butterfly larva is green caterpillar. They grow 3~4 time a year.
Cabbage butterfly is white butterfly genus. They live mainly temperate zone to subtropical zone. Therefore in Japan, we can see them almost all areas. In Japan, cabbage butterflies are seen anywhere, mountains, forests, house neighboring areas. Probably they can be seen even city.
Larva lives mainly cabbage field. They love to eat cabbage leaves. Then they transform to pupa. During pupa, pupa eats nothing and doesn’t move. Also larva organ is retrogression and imago organ is growing. When regular time passes, pupa hatch to imago. Finally green caterpillar transform butterfly truth pupa.
Then they expand with human active zone spread because we can see them anywhere. Larva loves cabbage, and because of this, they are vermin for us. We can see cabbage butterfly March to October. Larva likes cabbage while cabbage butterfly likes nectar. First they stop at flower, then they stretch their mouth. Then they suck nectar from their mouth. In this way they ingest their nutrition.
We can not see ultraviolet ray while cabbage butterfly can see ultraviolet ray so they discern male from female. When male find female he chase her, but if female end copulation, she open her wing and lay a roe where reverse of leaves. Roe is yellow and about 1mm length and shape of bottle. Egg hatch about a week. Larva come from egg, first, they are yellow and don’t eat leaves. They eat their eggs which contain many nourishment . When larva eats leaves their body color change green. They molt 4 times to become pupa. Before 4 times molting their length about 4 cm. besides this season larva moves bitterly and looks for fitting place to become pupa. Then they find fitting point, they spin their thread and fasten their body. Pupa hatch 2 weeks to a month. Imago period 2 weeks to 3 weeks and copulate in this period.
They can be seen anywhere in Japan so probably we can see them anywhere in Kochi. Perhaps we can see in Kochi city. Their incident are 3~4 times while probably the best season is spring April to May. But maybe we can see them still in summer Larva can be seen in spring.