Effects of temperature,photoperiod and soil humidity on induction of pseudopupal diapause in the bean blister beetle Epicauta gorhami

Larvae of the bean blister beetle Epicauta gorhami Marseul (Coleoptera: Meloidae) feed on grasshopper eggs in soil and undergo hypermetamorphosis. This beetle undergoes larval diapause in the fifth instar as a pseudopupa, a form characteristic of hypermetamorphosis in meloid beetles. The effects of temperature, photoperiod and soil humidity on larval development of E. gorhami are examined in a population in Miyazaki, Japan, using egg pods of Locusta migratoria L. as food. At lower temperatures (20 and 22.5 °C), all larvae become pseudopupae, regardless of the photoperiod. By contrast, at higher temperatures (27.5 and 30 °C), almost all larvae pupate at the end of the fourth instar, again regardless of the photoperiod. A long‐day photoperiodic response occurs only at an intermediate temperature (25 °C): under an LD 12 : 12 h photocycle, all larvae enter diapause, although the diapause incidence tends to decrease as the day length becomes longer. Pseudopupae are immobile and remain in diapause for ≥120 days when they are kept under the same conditions, except that diapause terminates within a relatively short time at 30 °C. Although lower soil humidity retards post‐feeding development, soil humidity has no effect on the diapause incidence. On the basis of the short developmental period and diapause avoidance under summer conditions, it is suggested that this beetle partially produces two generations a year in southwestern Japan.     

Transdifferentiation between Mast Cell Subpopulations

Mast cells are progeny of multipotential hematopoietic stem cells. Although most of the progeny of stem cells leaves the hematopoietic tissue after maturation, undifferentiated precursors of mast cells leave the hematopoietic tissue. Morphologically unidentifiable precursors migrate in the bloodstream, invade the connective tissues or the mucosa of the alimentary canal, proliferate, and then differentiate into mast cells. Even after their morphological differentiation, some mast cells retain an extensive proliferative potential. There are at least two subpopulations of mast cells, a connective-tissue type and mucosal type. Connective tissue-type and mucosal mast cells can be distinguished by histochemical, electron microscopical, biochemical and immunological criteria, but these two types can interchange, and their phenotypes are determined by the anatomical microenvironment in which their final differentiation occurs.