Cockroach Fight

The challenge hypothesis forms the cornerstone of modern behavioral endocrinology and states that a maximum physiological testosterone level in male avians is reached rapidly during interactions with other males or receptive females.  The basic tenets of this hypothesis have subsequently proven applicable to a wide array of vertebrate taxa, including humans.  In the invertebrate lobster cockroach, Nauphoeta cinerea, combined pheromone (exocrine) and hormone (endocrine) responses are induced by male-male or male-female social stimuli, leading us to propose a two-dimensional response to social contact.  Physiological responses to social stimuli can be induced by solely contacting an individual’s antenna with an isolated antenna of a male or female conspecific, indicating the responses are innately hardwired.  In N. cinerea, fighting and mating are tightly correlated, and utilization of the same physiological responses for both types of social stimuli appears to reflect a central dogma of sustaining aggression during social interactions.  We propose that the evolutionary force shapes responses to distinct social encounters, and as such, each social context may induce multiple behavioral and physiological responses that function together to reach a final purpose of increasing survival time and genetic fitness in the species.