580 per se. They suggested that in the testes there is a basal (endogenous) rate of mitosis that occurs even in the absence of hormones. Ecdysone increases the rate of division, whereas JH depresses it, though never below the basal level. Differentiation of the germ cells follows division, but its rate is constant (not directly affected by hormones) and species-specific. Thus, in early juvenile stages, the rate of division will be low, because of the presence in the hemolymph of JH as well as ecdysone. However, in the final larval and/or pupal stages when the corpora allata are inactive (Chapter 21, Section 6.1), ecdysone will accelerate spermatogonial division (reflected in the enormous growth of the testes seen at this time), which results in production of large numbers of mature sperm. In adults, spermatogenesis continues at the basal rate, despite the presence of JH in the hemolymph. The demonstration that ecdysteroids are produced by the testicular sheath and other tissues (Hagedorn, 1985; Loeb et al., 1996) provides, of course, a ready explanation for the continuation of spermatogenesis in mature males of some species.

The male accessory reproductive glands are fully differentiated at eclosion. During sexual maturation they become active and increase greatly in size as a result of the synthesis and accumulation of materials used in spermatophore and/or seminal fluid formation (Section 4.3.1). In some species, for example, the cockroach Leucophaea maderae, secretory activity of the accessory glands apparently is not under JH control; thus, allatectomized adult males are able to produce spermatophores throughout their life. In contrast, in many other species (including other cockroaches [Schal et al., 1997]) there is a clear correlation between the onset of corpus allatum activity and development of secretory activity in the accessory glands. Further, accessory glands of allatectomized males of these species remain small and show only weak secretory activity, effects that can be reversed by treatment with JH (Gillott, 1988; Gillott and Gaines, 1992). Though Engelmann (1970) suggested that the effect of JH on the secretory activity of the accessory glands may be indirect, stemming from a general endocrine control of protein metabolism, other authors, for example, Odhiambo (1966), Gillott and Friedel (1976), and Gillott (1996) argued that JH has a specific role, namely, to control the synthesis of specific accessory gland proteins. Indeed, studies of the production of accessory gland secretion in the male migratory grasshopper, Melanoplus sanguinipes, revealed some interesting parallels with the process of vitello-genesis (Friedel and Gillott, 1976; Gillott, 1996). Male M. sanguinipes are promiscuous insects. They may copulate several times on a single day and, on each occasion, transfer several spermatophores. Such promiscuity requires either extremely active accessory glands or the participation of other tissue(s) in the production of the necessary materials. It was shown that the fat body produces specific proteins that are accumulated by the accessory glands. Removal of the accessory glands led to accumulation of protein in the fat body and hemolymph. Furthermore, both synthesis of these proteins in the fat body and their accumulation by the accessory glands were prevented by allatectomy, an effect that could be reversed by treating operated insects with a JH mimic. Several other demonstrations of extraglandular synthesis of accessory gland proteins have been made, suggesting that the phenomenon may be a common occurrence among Insecta (Figure 19.9).

Ecdysteroids have been reported in adult males of a range of species and may also be involved in regulating accessory gland protein synthesis. For example, in vitro experiments with the accessory glands of M. sanguinipes have demonstrated that (3-ecdysone can promote or inhibit the production of specific proteins. Further, the level of ecdysteroids does vary during sexual maturation and is increased briefly after mating (Gillott, 1996).

The development and endocrine control of sexual behavior in male insects have been studied in detail in relatively few species, mostly Acrididae. As Engelmann (1970) noted,

FIGURE 19.9. Endocrine relationships in male insects. Note that some of these relationships may not exist in all species.
Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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