Figure 5.2 Nervous system of a praying mantis alcock9e-fig-05-02-0.jpg

Figure 5.4 The blowfly’s nervous system and digestive system alcock9e-fig-05-04-0.jpg

Figure 5.5 Record of neural and behavioral activity of a calling cricket alcock9e-fig-05-05-0.jpg

Figure 5.6 Circadian rhythms in cricket calling behavior alcock9e-fig-05-06-0.jpg

Figure 5.7 Early in the night, the long-winged, flight-capable form of Gryllus firmus has higher concentrations of JH than the short-winged form alcock9e-fig-05-07-0.jpg

Figure 5.8 The cricket nervous system alcock9e-fig-05-08-0.jpg

Figure 5.9 A master clock may, in some species, act as a pacemaker that regulates the many other mechanisms controlling circadian rhythms within individuals alcock9e-fig-05-09-0.jpg

Figure 5.10 The genetics of biological clocks in mammals and fruit flies alcock9e-fig-05-10-0.jpg

Figure 5.11 Mutations of the per gene affect the circadian rhythms of fruit flies alcock9e-fig-05-11-0.jpg

Figure 5.12 Expression of the gene that codes for PK2 in the SCN alcock9e-fig-05-12-0.jpg

Figure 5.13 Circadian control of wheel running by white rats changes when the brains of rats are injected with PK2 alcock9e-fig-05-13-0.jpg

Figure 5.14 Naked mole rats lack a circadian rhythm alcock9e-fig-05-14-0.jpg

Figure 5.15 Circannual rhythm of the golden-mantled ground squirrel alcock9e-fig-05-15-0.jpg

Figure 5.16 Circannual rhythm in a stonechat alcock9e-fig-05-16-0.jpg

Figure 5.18 A cycle of photo-sensitivity alcock9e-fig-05-18-0.jpg

Figure 5.19 A hormonal response to light alcock9e-fig-05-19-0.jpg

Figure 5.20 Changes in the song control regions of the rufous-winged sparrow’s brain occur after summer rainfall alcock9e-fig-05-20-0.jpg

Figure 5.22 Photoperiod affects testis size in the red crossbill alcock9e-fig-05-22-0.jpg

Figure 5.23 Dominant male odors change female mate preferences in the house mouse alcock9e-fig-05-23-0.jpg

Figure 5.24 Regulation of infanticide by male house mice alcock9e-fig-05-24-0.jpg

Figure 5.25 A hormonal effect on infanticidal behavior in laboratory mice alcock9e-fig-05-25-0.jpg

Figure 5.26 Testosterone and progesterone concentrations in three categories of male California mice alcock9e-fig-05-26-0.jpg

Figure 5.27 Testosterone and the control of sexual motivation in male Japanese quail (Part 1) alcock9e-fig-05-27-1.jpg

Figure 5.27 Testosterone and the control of sexual motivation in male Japanese quail (Part 2) alcock9e-fig-05-27-2.jpg

Figure 5.28 Female fruit flies mated to males unable to supply sex peptide are as likely to copulate again within 48 hours as are virgin females alcock9e-fig-05-28-0.jpg

Figure 5.29 An associated reproductive pattern in the green anole and a dissociated reproductive pattern in the red-sided garter snake alcock9e-fig-05-29-0.jpg

Figure 5.33 The chemical structure of testosterone and its diverse effects on physiology and behavior alcock9e-fig-05-33-0.jpg

Zysling et al. 2006

Figure 5.36 Testosterone and territorial behavior (Part 1) alcock9e-fig-05-36-1.jpg

Figure 5.36 Testosterone and territorial behavior (Part 2) alcock9e-fig-05-36-2.jpg

Figure 5.39 Testosterone and the long-term maintenance of mating behavior alcock9e-fig-05-39-0.jpg