Mating system of Neohelice granulata: flexible reproductive strategies.

SAL MOYANO M. P.; GAVIO M. A.; LUPPI T. A.

Neohelice granulata, a model species for studies on crustaceans.

Cambridge Scholars Publishing

Año: 2020;

In a context of a limited set of ecological conditions such as the abundance and distribution of resources, the mating system of a population depends on the behavioural strategies of individuals to gain access to mates (Emlen and Oring 1977). Particularly, in brachyuran crabs, two main classifications of mating systems were based on a biological and an ecological approach. The biological one was stated by McLay and López Greco (2011) who stressed the importance of the seminal receptacle structure due to the competence among sperm of different males to fertilize the oocytes (see Chapter 9 Volume II). The ecological one was defined by Christy (1987) who classified the mating systems in three principal types: (1) ?female centred competition?, (2) ?resource centred competition? and (3) ?encounter rate competition? based on the competition among males for the access to females. In (1) males compete directly for females and defend them until mating, in (2) males compete for resources females use during breeding or refuges they occupy, and in (3) males search for or intercept receptive females but defend neither females nor resources.Burrows are resources used principally for shelter (Richardson 2007), although they can also be used for mating purposes (Seiple and SalmonChapter Sixteen3181982, Brockerhoff and McLay 2005). Neohelice granulata is a burrowingcrab that actively constructs burrows in the sediment whose main functionis shelter. However, more recently, the construction of burrows featuring achamber (hereafter chambered burrows) by large males was determined tobe used for mating activities (Sal Moyano et al. 2012a). Consequently, themating system of this crab can be classified as belonging to the ?resourcecentred competition? type.In addition, a specific mating system is modulated by the display ofdifferent guarding behaviours such as pre and post-copulatory ones, whichfavours males to increase their fitness (Parker 1970). Mate guarding is areproductive tactic widely observed in marine invertebrates, includingbrachyuran crabs, and has an important function in male reproductivesuccess (Ridley 1983, Smith 1984). Both pre and post-copulatory guardingallow males to guard females to assure the paternity of the offspring(Parker 1970). These behaviours are highly flexible depending onphenotypic or physiological traits of reproductive individuals (e.g. bodysize or female receptivity), the social context (e.g. the operational sexratio) or the physical habitats characteristics. In this way, individuals fromdifferent populations may display different guarding tactics.Other important factors shaping the mating systems of crabs are thedifferent strategies of the two sexes used to recognize a mate, thus, the useof distinct types of signals, for example, chemical, tactile, acoustic orvisual. The different sperm allocation strategies displayed by males maybe contemplated since they can vary according to individual and socialfactors. The size of females or males, the female receptivity duration andthe number of rival males constitutes important factors to be considered.