Transfer and fate of male ejaculate in female Queensland fruit flies

Abstract Insect seminal fluid commonly comprises a complex cocktail of proteins and other biochemical components that migrate away from the female reproductive tract to sites elsewhere in the female body and elicit changes in female reproductive behaviour. The transfer of male seminal fluid molecules to reproductive and somatic tissues of the female Queensland fruit fly (‘Q‐fly’) Bactrocera tryoni is examined and some putative target sites identified. Male Q‐flies are fed a diet containing radiolabelled (³⁵S) amino acids, which are incorporated into male accessory gland products. Radioactivity diminishes within the accessory glands and increases in all assessed parts of the female body during copulation, indicating the transfer of these products into the female soma via the reproductive tract. There are significant changes in the absolute and proportional radioactivity profiles among female tissues over the next 22 h, with substantial reductions in the thorax and increases in the head. This is consistent with accumulation of behaviour‐modifying male products at binding sites in the female head. Parallels can be drawn between the data in the present study and seminal fluid distribution profiles and receptor binding documented in other insects.     

Cardiac Responsiveness to Chronotropic Agents in the Cobra, Naja naja L.: Effect of Temperature and Thyroid Hormones

Cardiac responsiveness to isoproterenol, phenylephrine and parathyroidhormone have been studied in isolated cobra snake atria. Thepositive chronotropic responses to these agents are increasedunder elevated metabolic conditions: high temperature and tri-iodothyroninetreatment. The enhanced cardiac reactivity provides greatercardiac output in animals with increased metabolic demands.In view of the different receptors being stimulated by theseagents, theenhanced cardiac responsiveness is a general oneand, most likely, a result of increased metabolism.