Invertebrate Reproduction and Development, 43:1 (2003) 19-26 19 Balaban, Philadelphia/Rehovot 0168-8170103/$05.00 © 2003 Balaban Fecundity ofthe mangrove crab Ucides cordatus (Linnaeus, 1763) (Brachyura, Ocypodidae) MARCELO ANTONIO AMARO PINHEIRO', MARISTELA D'ANDREA BAVELONI and OSWALDO DA SILVA LEME TERCEIRO Departamento de Biologia Aplicada, FCA V. Universidade Estadual Paulista rUNESP) Campus de Jaboticabal, Via de Acesso Prof Paulo Donato Castellane, sin CEP 14884-900, Jaboticabal, SP, Brazil Tel. +55 (/6) 3209-2620; Fax +55 (/6) 3202-4275; email:[email protected] Received 14 November 2001; Accepted 1November 2002 Summary Females ofthe mangrove crab Ucides cordatus were collected in a monthly basis along a 2-year period at the mangrove areas ofIguape, SP, Brazil. Ovigerous individuals were measured (CW, carapace width) and weighed (WW, wet weight). Each brood was weighed (WWE, wet weight ofeggs), dried (DWE, dry weight ofeggs) and the number ofeggs (EN) was recorded. Scatter plots for the relationships EN/CW, EN/WW and EN/WWE were produced, and the data were subjected to regression analysis. Relative average fecundity (F') was calculated in different seasons and compared to verify ifthere were any temporal variation ofreproductive intensity. Fecundity in U cordatus varied from 36.081 to 250.566 eggs according to the size-dependent 2 2 relationship EN = 15.27CW ,24 (N = 66; R = 0.69; p<O.OO 1). The other expressions obtained for 813 2 the relationships were: EN =3797.6WW0 (N= 56;R = O.72;p<O.OOI); EN =29226WWEo 775 (N= 54; R2 = 0,70;p<0,001); and EN = 1093586DWE0 769 (N= 66; R2 = 0.86;p<0.001). Ovi­ gerous females were found only during spring and summer, and relative average fecundity differed between these seasons. Relative average fecundity was higher in spring and relative frequency ofovigerous females was higher during summer. Overall reproductive intensity was similar between these seasons. The observed trends are regarded to be related to temperature and photoperiod variations. Key words: Fecundity, reproduction, Ucides, Ocypodidae, crab Introduction natural populations (Mantelatto and Fransozo, 1997), The reproductive strategy of brachyuran crusta­ providing essential information for studies ofenviron­ ceans is extremely diversified, ultimately shaped to mental impact, management of stocks exposed to maximize egg production and offspring survivorship, fishing pressure and to evaluate the potential ofa given thus favoring the preservation ofthe species (Hartnoll species for aquaculture production. and Gould, 1988). The estimation offecundity and the Fecundity is a species-specific factor, not only delimitation ofthe breeding season are important tasks regarding the number of eggs extruded in a single to achieve forecasting of the turnover capacity of batch but also the frequency of brood production 'Corresponding author. 20 MA.A. Pinheiro et at. /1RD 43 (2003) 19-26 during the breeding season or life span (Sastry, 1983). Materials and Methods According to Bourdon (1962), fecundity is defined as Specimens of U. cordatus were monthly collected the number of eggs produced in each batch, usually at the mangrove areas of Barra de Icapara increasing with the female body size (Pinheiro and (24°41 '9.2"S), Iguape (SP), during the period from Fransozo, 1995; Costa and Negreiros-Fransozo, 1996; Pinheiro and Terceiro, 2000) and decreasing with egg September, 1998, to August, 2000. In each month the size or volume (Hines, 1982). Fecundity may also be individuals were captured manually in their open and closed burrows by two crab men in a rectangular affected by exogenous and/or endogenous factors 2 (Jensen, 1958; Sastry, 1983), varying interspecifically mangrove area (SOx 10m = 500 m ), disposed perpen­ among populations from different areas. dicularly from the shore to mangrove apicum. Size-specific fecundity has been assessed by using Individual females (nonovigerous and ovigerous) were different regression models, including non-linear put in plastic bags to avoid the loss of eggs and h appendages, and frozen until further analysis. relationships, such as the power function y = ax (Thomas, 1964; Haynes et aI., 1976; Somerton and Approximately ten eggs from each individual brood Meyers, 1983; Pinheiro and Fransozo, 1995; Pinheiro were examined under a dissecting microscope to deter­ and Terceiro, 2000), and the volumetric model y = mine the embryonic stage of eggs, classified whether a+bx3 (Jensen, 1958; Alma~a, 1987; Flores, 1993; as initial, intermediate or final, corresponding, Leme and Negreiros-Fransozo, 1998). Therefore, intra­ respectively, to the stage ranges 1-4, 5-8 and 9-10 specific fecundity comparisons, either seasonal within proposed by Boolootian et al. (1959). Only females a given population or spatial among different popula­ incubating initial broods (late blastula to early gastrula) tions, are not always possible. The structure of the were used for egg counts to minimize the error due to compared populations should be similar and the egg loss during subsequent stages (Pinheiro and mathematical and statistical treatment of data need to Terceiro, 2000). be standardized (Pinheiro and Terceiro, 2000). The wet weight (WW) of each ovigerous female There is a general lack of information on the and their brood (WWE) was recorded using an fecundity patterns of seniterrestrial mangrove brachy­ analytical balance to the nearest 0.01 g. The carapace urans from which grapsids were more frequently width (CW) ofexamined females was measured with a studied (Pillay and Ono, 1978; Seiple and Salmon, vernier caliper to a precision of 0.05 mm. For each 1987; Kyomo, 1988; Dfaz and Conde, 1989; Ruffino et specimen, the relative brood weight (SW%) was aI., 1994; Schuh and Diesel, 1995a, 1995b; Cobo and obtained by the percentage of egg wet weight in com­ Fransozo, 1998; Leme and Negreiros-Fransozo, 1998). parison with total wet weight of the female. The Regarding ocypodids, there are a few accounts on correlation between SW% and CW was tested at the species of the genus Uca, e.g., a revision by Hines, 5% significance level. 1982, and Ucides (e.g., Rujel-Mena, 1996 on U. occi­ The pleopods of each female were removed with dentalis and Mota-Alves, 1975, and Costa, 1979, on scissors and stored in 70% ethanol, which was replaced Ucides cordatus). with absolute ethanol 24 h after for better dehydration. Ucides cordatus (Linnaeus, 1763) is a semi­ For analysis, the excess of ethanol was discarded and terrestrial crab belonging to the Ocypodidae family, the broods were placed in Petri dishes to separate the distributed along the western Atlantic from Florida eggs. After isolation, the egg mass ofeach female was (USA) to Santa Catarina (Brazil) (Melo, 1996). This dried in a stove at 60°C for 48 h to achieve weight species is restricted to mangrove areas, where it feeds stability. on leaves and digs galleries in the sediment, being The dry weight ofeggs (DWE) ofeach female was considered one of the key-role mangrove species recorded in an analytical balance to the nearest (Koch, 1999). 0.0001 g, and three subsamples of about 3 mg were The purpose ofthe present study is to estimate the separated to estimate fecundity. In each subsample, potential fecundity, the relative average seasonal eggs were counted under a microscope supplied with a fecundity (F' ) and the reproductive intensity (lR) ofU. computer analysis system (software KS-lOO 3.0, cordatus as a means to evaluate its reproductive Zeiss). To determine the fecundity of each female strategy. In addition, it is also presented a revision of (EN), the mean of the three subsamples was extra­ the literature containing information on the egg polated to DWE, resulting in individual fecundity. production of this species, which is compared to the After the input of data, the scatterplots of the values obtained for other mangrove brachyurans. relationships ENxCW, ENxWW, ENxWWE and MA.A. Pinheiro et al. / /RD 43 (2003) /9-26 21 shap~ 320,000 224 ENxDWE were visually analyzed to observe the EN = 15.3 CW A ofthe scatter and then choose the mathematical model R2 = 0.69 0 providing the best fit. Since in most relationships the 240,000 N = 66 h power function y = ax renders an excellent fit 0 Z "0 0 0 (Pinheiro and Fransozo, 1995), it was possible to w 160,000 0° 00 0 calculate the relative average seasonal fecundity (F' ), ocP'o according to Pinheiro and Terceiro (2000), 80,000 0 F' =!t NE; b 30 40 50 60 70 80 n 1=1 Cw I CW(mm) where F'is relative average fecundity, n is the total 320,000 EN = 3797.6 Wwo e:3 B number ofovigerous females in the sample, NE; is the 2 R = 0.72 0 number of eggs ofthe ith female, b is the constant of 240,000 N = 56 h the function y = ax for the relationship ENxCW, and 0 o 0 0 0 Z 0 CW!-is the carapace width ofthe ith female. w 160,000 '0 0 F' was calculated for each season to assess repro- 0 8 0 ductive potential and intensity. Data were subjected to 80,000 an ANOVA and the contrast among average values was tested by a Tukey test (ex. = 0.05). 0 The percentage ofovigerous females was calculated 10 40 70 100 130 160 for each season based on the relative frequency of WW(g) breeding individuals within the total female in each season. The proportions were compared at the 5% 320,000 EN = 29226 WWE 0.775 C statistical significance level by the x-square test, 2 240,000 R = 0.70 0 according to Zar (1999). N = 54 The 'reproductive intensity (lR) was calculated for Z 160,000 0 each season as the F' value multiplied by the seasonal W proportion ofovigerous females. 80,000 o . Results o 2 4 6 8 10 During the period from September, 1998, to WWE (g) September, 2000, 276 U.