Moth hormones

Behavioral and Hormonal Chemicals. Sex pheromones, which attract pests to traps, are used effectively to control some insect pests, like the grape berry moth (46) and cabbage looper. With other Insect pests, sex pheromones have been effectively used to monitor the size of pest insect populations to determine when pesticide treatments should be made. 

Abstract Pheromones are utilized by many insects in a complex chemical communication system. This review will look at the biosynthesis of sex and aggregation pheromones in the model insects, moths, flies, cockroaches, and beetles. The biosynthetic pathways involve altered pathways of normal metabolism of fatty acids and isoprenoids. Endocrine regulation of the biosynthetic pathways will also be reviewed for the model insects. A neuropeptide named pheromone biosynthesis activating neuropeptide regulates sex pheromone biosynthesis in moths. Juvenile hormone regulates pheromone production in the beetles and cockroaches, while 20-hydroxyecdysone regulates pheromone production in the flies. 

The gene encoding PBAN was first characterized from H. zea and B. mori [134,137,138,195]. The cDNA was found to encode the 33 amino acid PBAN plus four additional peptides with a common C-terminal FXPRL sequence motif, including that of the diapause hormone of B. mori (Fig. 6). Three additional peptides with the common C-termini and sequence homology to those of H. zea and B. mori have been deduced from cDNA isolated from pheromone glands of several other moths [194,196-200]. Studies conducted to find the post-translational processed peptides indicated that PBAN was found to a greater extent in the mandibular and maxillary clusters than in the labial cluster of neurons... 

The chemical communication system used to attract mates involves not only the overt chemical signals but also indirectly a great deal of chemistry in the emitter and receiver. As an example, in emitting female moths, this includes enzymes (and cofactors, mRNA, genes) of the pheromone biosynthetic pathways, hormones (and genes) involved in... 

JUNVENILE HORMONES. One of several hormones, that retard the development of insects in the larval stage. So called because they prevent the insect from maturing by maintaining its juvenile characteristics. Obtained naturally from silk moths various syntheses indicate possible use as insecticides, especially for fire ants. Composition of one type is C18H30O3. 

As we shall see, cyclization reactions of this general type seem to be important in terpene biosynthesis. The 6,7-trans-farnesol has been shown to have hormone action in some insects. It acts to regulate the changes from caterpillar to cocoon to moth. 

A number of compounds important to animal physiology have been identified as isoprenoid compounds. Notable examples are vitamin A, retinal (Section 28-7), and squalene (Table 30-1). Also, terpene hydrocarbons and oxygenated terpenes have been isolated from insects and, like famesol, show hormonal and pheromonal activity. As one example, the juvenile hormone isolated from Cecropia silk moths has the structure shown in 3 ... 

The structure was established by an impressive combination of chemical, spectroscopic, and synthetic methods with about 200/xg of pure compound isolated from the abdomens of a myriad of male moths.1 (Some aspects of synthetic work on juvenile hormone are incorporated in Exercise 30-9.)... 

Looking first at the C-2, C-3 double bond of the cecropia moth s growth hormone... 

Figure 1.1 The three major types of hormones that regulate pheromone production in insects. A Juvenile Hormone III (C16 JH), B 20-Hydroxyecdysone and C PBANs from the corn earworm, Helicoverpa zea (Raina et al., 1989), the silkworm moth Bombyx mori (Kitamura et al., 1989) and the gypsy moth, Lymantira dispar (Master et al., 1994). The minimum sequence (pentapeptide) required for activity is indicated.

Raina A. K Jaffe H Kempe T. G Keim P, Blacher R. W Fales H. M Riley C. T Klun J. A., Ridgway R. L. and Hayes D. K. (1989) Identification of a neuropeptide hormone that regulates sex pheromone production in female moths. Science 244, 796-798. 

Another technique that is utilized to help ensure that label is incorporated into the pheromone is to apply the precursor at the same time as pheromone biosynthesis activating neuropeptide (PBAN). PBAN is a peptide hormone that regulates pheromone biosynthesis in most, but not all, moths. So, first it must be demonstrated that PBAN regulates pheromone production. In the case of the cabbage looper,... 

Arima R., Takahara K., Kadoshima T., Numazaki F., Ando T., Uchiyama M., Nagasawa H., KitamuraA. and Suzuki A. (1991) Hormonal regulation of pheromone biosynthesis in the silkworm moth, Bombyx mori (Lepidoptera Bombycidae). Appl. Entomol. Zool. 26, 137-147. 

Cusson M. and McNeil J. N. (1989) Involvement of juvenile hormone in the regulation of pheromone release activities in a moth. Science 243, 210-212. 

Cusson M., Tobe S. S. and McNeil J. N. (1994) Juvenile hormones - their role in the regulation of the pheromonal communication system of the armyworm moth, Pseudaletia unipuncta. Arch. Insect Biochem. Physiol. 25, 329-345. 

Ichikawa T., Shiota T., Shimizu I. and Kataoka H. (1996b) Functional differentiation of neurosecretory cells with immunoreactive diapause hormone and pheromone biosynthesis activating neuropeptide of the moth, Bombyx mori. Zool. Sci. 13, 21-25. 

Jurenka R. A., Fabrias G. and Roelofs W. L. (1991a) Hormonal control of female sex pheromone biosynthesis in the redbanded leafroller moth, Argyrotaenia velutinana. Insect Biochem. 21, 81-89. 

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