Chromatic alteration in Arenaeus cribrarius (Lamarck) (Crustacea, Portunidae): an indicator of sexual maturity

Abstract

ABSTRACT. Some individuals of the species Arenaeus cribrarills (Lamarck, 1818) bear a characteristic pink abdomen, which is notably different Ii-OIn the usual white coloration. The incidence of this chromatic alteration was determined for a single population and its relation with other individual variables were examined. The individuals were monthly collected from May , 1991 to April, 1993, in Ubatuba, Sao Paulo, with the aid of a shrimp fi shelY boat provided with double-rig trawling nets. All specimens were sexed, measured (CW = carapace width), di stributed in 10-mm size classes and classified according to growth phase (juvenile and adult), molting condition and development stage of gonads. The occurrence of pink-colored morphs was also recorded. From a total of2,096 collected individuals, only 60 females (nine of those ovigerous) presented a pink-colored abdomen, which represents 2.9% of the whol e sample and 5.2% of the females. Almost all of them were inte1l110it individuals (96.6%) and 63.3% showed mature gonads. According to published data, size at the onset offunctional maturity in A. cribrarills females is around 60 mm CW, ti'om which the incidence of pink morphs and ovigerous crabs were recorded. The obtained results suggest that such a chromatic alteration is associated to sexual maturity in these females. This characteristi c may enhance the attraction potential for mating, shonly after the puberty molt. KEY WORDS . Brachyura , Portunidae, repro~ucti ol1 , coloration During the past few years, changes in the coloration patterns related to the breeding period of several animal species, and mainly its role in attraction for mating, have received the attention of many researchers . According to LUM-KONG

Biological associations of color variation in the Indo-Pacific swimming crab Charybdis hellerii

“…This variation found for C. hellerii suggests that the abdomen color is related to the sexual maturity of the females, which also suggests that it would be possible to know when the female is about to become an adult, as recorded for A. cribanarius, with a possible relationship to physiological maturity (Pinheiro and Taddei 2000). However, no relationship between color and physiological maturity was found for U. cordatus (Castilho et al 2011).…”

“…In crustaceans, morphological variations are used to study differences between sexes, reproduction and behavioral strategies, and sexual maturity, among other traits (Detto et al 2004, Hemmi et al 2006, Pinheiro and Taddei 2000, Reid et al 1997. For instance, some freshwater shrimps have a caste structure that may play an important role in their social system, since they have different morphotypes, each of which show a different behavior, size and phenotypic color pattern (Kuris et al 1987, MoraesRiodades andValenti 2004).…”

“…cryptic or camouflage colors (Hemmi et al 2006, Hultgren andStachowicz 2008), microhabitat use (Trivedi and Vachhrajani 2012), salinity, desiccation and carapace thickness (Reid et al 1997, Styrishave et al 2004, temperature (Silbiger and Munguia 2008) and sexual maturity (Pinheiro and Taddei 2000). In contrast, no relationship to carapace color and ovarian development was found for the mangrove crab Ucides cordatus (Linnaeus 1763) (Castilho et al 2011).…”

Color variation of the freshwater crab Dilocarcinus pagei Stimpson, 1861 captured in the Amazon region at Itacoatiara, Amazonas, Brazil

“…The abdomen experiences positive allometric growth because it has the function of incubation chamber during reproduction (Davanso et al, 2016). This positive allometric growth may alter the concentration of chromophores in the abdomen as observed in C. hellerii and A. cribrarius by Watanabe et al (2015) and Pinheiro and Taddei (2000), respectively. The color variation of the chelipeds and pereiopods of D. pagei shows the same pattern as the cephalothorax.…”