Insect mandibular glands are exocrine organs that produce chemical substances known as pheromones that play an important role in intra-specific communication of insects. The mandibular glands of Apis mellifera, which are more highly developed in queens than in workers, present caste-specific polymorphism which seems to be regulated by the juvenile hormone (JH). These glands develop at the pupat...

During the lifespans of most animals, reproductive maturity and mating activity are highly coordinated. In Drosophila melanogaster, for instance, male fertility increases with age, and older males are known to have a copulation advantage over young ones. The molecular and neural basis of this age-related disparity in mating behavior is unknown. Here, we show that the Or47b odorant receptor is r...

The olfactory hypothesis for salmon imprinting and homing to their natal stream is well known, but the endocrine hormonal control mechanisms of olfactory memory formation in juveniles and retrieval in adults remain unclear. In brains of hatchery-reared underyearling juvenile chum salmon (Oncorhynchus keta), thyrotropin-releasing hormone gene expression increased immediately after release from a...

1. Corpora cardiaca (CC) from immature and adult Blaberus discoidalis Serville of both sexes contained approximately equal amounts of activity for the cytochromogenic hormone (CGH), a neurohormone which stimulates cytohaem synthesis in fat body mitochondria on day 4 of adult life. 2. CGH activity remained at a constant level in the CC of males during days 0 and 1 of adult life, decreased during...

We have used differential display to identify genes that are regulated by juvenile hormone in the epidermis of the beetle Tenebrio molitor. One of the genes encodes T. molitor chitinase 5 (TmChit5), a chitinase possessing an unusual structure. Sequence analysis of TmChit5 identified five 'chitinase units' of approx. 480 amino acids with similarity to chitinase family 18. These units are separat...

The roles of the ovary and egg case in the regulation of the development and activity of the corpora allata were studied in Blattella germanica adult females. The corpora allata of ovariectomized females exhibit a delayed pattern of development and activity compared with intact females. Implantation of a young ovary into ovariectomized females resulted in a faster activation of the corpora alla...

Ovarian development plays an important role in the life history of insects and is crucial for control of the insect population. The metamorphosis of an insect is precisely regulated by the interaction of the juvenile hormone and ecdysone. To understand the role of NlBr and NlKr-h1 in ovary development, we used RNA interference (RNAi) to down-regulate the expression of Broad-Complex (Br) and Krü...

Growth hormone (GH) is an important factor in the developmental adaptation to enhance P(i) reabsorption; however, the nephron sites and mechanisms by which GH regulates renal P(i) uptake remain unclear and are the focus of the present study. Micropuncture experiments were performed after acute thyroparathyroidectomy in the presence and absence of parathyroid hormone (PTH) in adult (14- to 17-wk...