We examined age-related biochemical and histological changes in the fat bodies and hemolymph of Osmia rufa males and females. We analysed solitary bees during diapause, in October and in April; as well as the flying insects following diapause, in May and June. The trophocyte sizes, as well as the numbers of lipid droplets were the greatest at the beginning of diapause. Subsequently, they decrea...

BACKGROUND As a response to harsh environments, the crustacean artemia produces diapause gastrula embryos (cysts), in which cell division and embryonic development are totally arrested. This dormant state can last for very long periods but be terminated by specific environmental stimuli. Thus, artemia is an ideal model organism in which to study cell cycle arrest and embryonic development. PR...

Embryonic diapause is a reproductive strategy widespread in the animal kingdom. This phenomenon is defined by a temporary arrest in blastocyst growth and metabolic activity within a quiescent uterus without implantation until the environmental and maternal milieu become favorable for pregnancy to progress. We found that uterine Msx expression persists during diapause across species; their inact...

The chalcid wasp Chouioia cunea Yang (Hymenoptera: Eulophidae) is one of the most dominant pupal parasitoids of Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), an invasive pest of many forestry trees and agricultural crops. For mass rearing C. cunea for biological control purposes, the pupae of Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Saturniidae) have been widely used as a substitu...

Embryonic diapause (ED) is a temporary arrest of embryo development and is characterized by delayed implantation in the uterus. ED occurs in blastocysts of less than 2% of mammalian species, including the mouse (Mus musculus). If ED were an evolutionarily conserved phenomenon, then it should be inducible in blastocysts of normally non-diapausing mammals, such as domestic species. To prove this ...

The release of prothoracicotropic hormone, PTTH, or its blockade is the major endocrine switch regulating the developmental channel either to metamorphosis or to pupal diapause in the Chinese silk moth, Antheraea pernyi. We have cloned cDNAs encoding two types of serotonin receptors (5HTRA and B). 5HTRA-, and 5HTRB-like immunohistochemical reactivities (-ir) were colocalized with PTTH-ir in two...

The role of the two distinct retinal photoreceptor organs in photoreception for photoperiodism was examined in the carabid beetle, Leptocarabus kumagaii, by surgical removal. This beetle shows long-day and short-day photoperiodic responses in the larval and adult stages, respectively. Larval diapause in the final instar is induced under short-day conditions whereas pupation occurs without diapa...

Trehalose and trehalose metabolism are crucial for insect development. We measured the content of polyhydric compounds in the hemolymph of diapause- and nondiapause-destined individuals of Helicoverpa armigera. We found that the trehalose content is much higher in diapause-destined individuals than that in nondiapause individuals. The activity of trehalose-6-phosphate synthase (TPS) during H. a...

Respiration rate increases 6.3-fold during 15 days of post-oviposition development in embryos of the Southern ground cricket, Allonemobius socius. This ontogenetic increase in metabolism of non-diapause insects is blocked during diapause, such that metabolic rate is only 36% of the rate measured for 15 days developing embryos. Surprisingly, however, there is not an acute metabolic depression du...

Diapause prepares insects and other arthropods to survive in harsh environments. To explore the molecular basis of winter (WD) and summer diapauses (SD), we screened for diapause-specific genes in the onion maggot, Delia antiqua, that diapauses as a pupa in both summer and winter. A diapause-induced transcript, DaTrypsin, was identified through differential display, and examined by Northern blo...