Adaptive value, as used in the study of animal behavior, refers to a measure of what value a trait has.  Usual, it takes the form of an increase in the number of an individual's offspring surviving to mating.  This website will not spend time examining the question of whether every behavior must be adaptive (for more information on this question, see Gould & Lewontin's 1979 paper "Spandrels of St. Marco and the Panglossian Paradigm: a critique of the adaptionist program", and Mayr's 1983 paper "How to Carry out the Adaptionist Program?"). 


A female stomatopod with her eggs [2].

Much of the adaptive value of stomatopod reproductive behaviors is fairly self-evident.  For instance:

  • I a highly aggressive and territorial species such as the stomatopod, it makes sense to signal that an approach is for the purposes of mating, so as to avoid being attacked on sight (though some males still don't know when a female isn't interested
  • A male's reproductive fitness is increased if he does not oust his own mate from the breeding cavity while she is brooding their young [7]. 
  • In some species of stomatopod, the female will only admit smaller males as suitors, as larger males will sometimes attempt to evict a female rather than mating.  This leaves the female vulnerable to predation [10].

However, one aspect of stomatopod reproduction is harder to explain, that being the amount of control the female has over her mate.  In many species of crustaceans, there is a form of female choice of mates, but a significantly strong mate can often overrule a females choice.  In many other crustaceans, the female has very little choice in the matter[9].   Yet in stomatopods, the choice of who to mate with lies almost entirely with the female.   Indeed, in some species, the female not only chooses which male to mate with, but also initiates courtship.  This reversal has been attributed to the practice in Psudosquilla cliata of multiple matings by females between periods of egg laying, and to the high degree of aggression inherent in stomatopod courtship  [13].  




© 2012 Brendan Kohrn, Reed College