A Biological Note on Bledius salsus MIYATAKE (Coleoptera, Staphylinidae), the Species of Insect Most Injurious to the Clay-bed in Sloping Salt-fields
1964 Volume 8 Issue 3 Pages 251-256
Details
1964 Volume 8 Issue 3 Pages 251-256
Biology of Bledius salsus MIYATAKE, the most injurious species of insect in the clay-bed of the sloping salt-fields of Japan, was investigated.
1. This species of Staphylinid beetle usually has three generations a year, whereas a small number of individuals appears to have four generations. Overwintering is done in the adult stage with exceptional individuals hibernating in the pupal stage.
2. There are three egg laying periods as follow: the first period lasts from midApril to the end of May or the beginning of June, the second period from the latter part of June to the middle or end of July, and the third period from the latter part of August to the latter part of September.
3. The developmental stages are: egg 14∼20 days, larva 40∼50 days, prepupa 2∼4 days and pupa 6∼8 days under natural conditions.
4. Five instars are observed in the larval stage.
5. Length of the life for the adults of both sexes is 20∼40 days during the warm season and 2∼4 months or more in winter.
6. Egg laying seems to take place two to three times during the life of the female, only 5∼10 eggs each.
7. Most of the activities of the adult, such as flying, creeping, burrowing galleries in the clay-bed etc. take place at night. The beetles show a marked positive phototaxis, especially to a fluorescent lamp.
8. The copulation probably takes place in a characteristic breeding room of the gallery which is relatively larger than other chambers. Egg laying might also take place in these rooms.
9. The feeding habits of the adult and larvae have not been clearly determined, but abundant organic matter in the clay particles of the bed may be utilized as food.
10. All the developmental stages inhabited in the salt-fields particularly in the clay-bed near the sea-water supply.
11. Distribution of Bledius salsus is wide and cover all the existing salt-fields in Japan.
12. Damage of the clay-bed is due to the destruction of the surface conditions, and the clay-bed proper. This results in reduction of the salt-water concentrating efficiency, and leakage of the salt-water through the clay-bed.
