Variability in reproductive cycles and fecundity of Neohelice granulata.

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

Neohelice granulata, a model species for studies on crustaceans

Cambridge Scholars Publishing

Año: 2020;

The study of the reproductive biology considering specific reproductive traits such as duration of the reproductive and ovarian cycles, receptivity, fecundity, number of broods in a single reproductive period, reproductive output, parental care or loss of eggs; are important in the understanding of the female reproductive strategies of brachyuran crabs used to increase their reproductive success and maximize the survival of the offspring in a particular habitat.The reproductive aspects are often considered as adaptive processes influenced by environmental conditions. Latitudinal and habitat-related intra-specific differences in the reproductive biology of decapods were often reported (e.g. Wehrtmann and Kattner 1998, Kyomo 2000, Lardies and Castilla 2001, Brante et al. 2004, Ouellet and Plante 2004). For example, in general terms, the reported average fecundity in different locations suggests a negative correlation with latitude. Such differences among conspecific populations are attributed to latitudinal temperature gradients (e.g. Lardies and Castilla 2001, Wehrtmann and López 2003), interannual temperature variation (e.g. Ouellet and Plante 2004, Brillon et al. 2005), regional variation in salinity, or other environmental factors (Mashiko 1990, Hancock et al. 1998). In addition, seasonal changes werereported to affect the number and size of eggs or the biochemical composition of the embryos in crabs (O?Leary Amsler and George 1984, Paschke et al. 2004). In the same way, interannual changes in egg size and larval condition have been reported in lobsters (Ouellet and Plante 2004).Neohelice granulata is a species with a great latitudinal distribution range, and there is growing evidence in the intra-specific variability among different reproductive traits, in which environmental conditions like season, temperature, salinity, photoperiod and available food, are important factors modulating the variability (e.g. Ituarte et al. 2006, Bas et al. 2007, Silva et al. 2009). For example, differences between marine and estuarine habitats regarding the maximum adult body size, egg size, the timing and duration of the reproductive season (e.g. Botto and Irigoyen 1979, D?Incao et al. 1992, Ruffino et al. 1994, Spivak et al. 1994, 1996, Luppi et al. 1997, López-Greco and Rodríguez 1999, Ituarte et al. 2004, Bas et al. 2005), or a continuous reproduction in tropical areas and a seasonal one in the temperate zones (César et al. 2005) were often reported.In this context, it is interesting to highlight the strong competition for resources between moulting/growth (increase in size/increase in energy stored) and reproduction that is often proposed in brachyuran crabs (Sastry 1983, Adiyodi and Subramonian 1983). This conflict is commonly assumed in studies of reproduction and life history patterns since it is important to define a reproductive season where the energetic investment is shifted from somatic growth to brood production. However, the allocation of resources to reproduction when they are scarce and to grow when they are abundant is not necessarily determined by resource competition or physiological antagonisms since, for example, female crabs incubate their eggs externally; thus, they cannot moult during the breeding period to avoid the loss of eggs (Nelson 1991).In this chapter we will focus on different reproductive traits of N. granulata, especially, considering and comparing latitudinal differences among the different populations along its distributional range, but also the intra-populational differences, associating them with the environmental conditions to try to explain the diverse reproductive strategies used by females to maximize their reproductive success in the different habitats.