An animal defending against a predator may engage in either " fight or flight " or " tend and befriend " in response to predator attack or threat of attack, depending on its estimate of the predator's strength relative to its own. Alternative defenses include a range of antipredator adaptations , including alarm signals . An example of an alarm signal is nerol, a chemical which is found in the mandibular glands of Trigona fulviventris individuals.  Release of nerol by T. fulviventris individuals in the nest has been shown to decrease the number of individuals leaving the nest by fifty percent, as well as increasing aggressive behaviors like biting.  Alarm signals like nerol can also act as attraction signals; in T. fulviventris, individuals that have been captured by a predator may release nerol to attract nestmates, who will proceed to attack or bite the predator. 
I tried the cup of raisins before bed and woke up before dawn with an erection reminiscent of days gone by, that lasted for over an hour. Pretty awesome! Though peeing was a long and drawn out affair.
I just had my T checked as I was not getting them any more, neither was I much interested in sex. The test came back with a paltry 305 @ 46yrs old. Just a year ago my erections used to have a bitter sweet ache to them. After going close to zero carb I lost my power, my head hair, got rosacea, limp erections, and my nitric oxide plummeted. I stopped training as it was painful and although I was eager to exercise my body just didn’t seem up to it. ( come to think of it now after reading all these articles, it would seem that lower elasticity of my arteries(low NO) was the reason.)
Testosterone is a hormone, known as an androgen, responsible for the development and maintenance of reproductive function and sexual characteristics in men. In men with hypogonadism, testosterone levels are abnormally low, affecting normal sexual development and function. Testosterone-containing medicines work by replacing the missing testosterone, helping to restore normal testosterone levels to ensure normal sexual development and function in men. Possible signs and symptoms include incomplete sexual development, decreased sexual function, infertility, fatigue, depressed mood, mild anaemia, reduced muscle bulk and strength and increased body fat.