Crescimento de Aegla itacolomiensis (Crustacea, Decapoda) em um arroio da Mata Atlântica no sul do Brasil

Abstract

. The specimens were collected by dip net, sexed and after the cephalotorax measured, the animals were brought back to the stream. The growth estimated by cephalotorax length for males and females of A.itacolomiensis was analized by absolut distributional size-classes frequency. The modal frequency of cephalotorax lenght was calculated. The growth was estimated trought the modal progression. The growth curves in cefalotorax length for males and females are described respectively by the equations: C t = 23.21 [1-e -0.0094 (t + 7.03) ] e C t = 19.49 [1-e -0.0065 (t + 11.16) ]. Were found juveniles in the spring and summer. The males attained larger sizes and a higher growth rate than females. The estimated longevity was 2.2 years for males and 2.5 years for females.

Allometric growth, sexual maturity and reproductive cycle of Aegla castro (Decapoda: Anomura: Aeglidae) from Itatinga, state of São Paulo, southeastern Brazil

“…Conversely, the time at which the size at onset of morphometric maturity is attained may vary among species. In accordance to the somatic growth pattern data compiled by Silva-Gonçalves et al (2009), Cohen et al (2011 and Trevisan and Santos (2011), complemented by results obtained by Chiquetto-Machado et al (2016), species found in lower latitude locations (<25º) tend to grow more slowly and, thus, are expected to take longer to attain morphometric maturity than those found in higher latitude regions.…”

Morphological sexual maturity of the freshwater anomuran crab Aegla parana (Crustacea, Decapoda, Aeglidae) from Negro River Sub-basin, Upper Iguaçu Basin, southern Brazil

“…This occurrence of sexual dimorphism in structures which play important roles in sexual interaction might be a strong indication that sexual selection operates on the determination of body size difference between males and females of a population (Shine, 1989;Cohen et al, 2011). Mortality, migration, responses to environmental conditions (Gonçalves et al, 2006), and resource use (Silva-Gonçalves et al, 2009) have also been suggested.…”

Estrutura populacional, crescimento somático e alométrico, biologia reprodutiva e estimativa do tamanho populacional de Aegla perobae Hebling & Rodrigues, 1977 do município de São Pedro, estado de São Paulo

“…As curvas de crescimento de machos e fêmeas apresentaram-se diferentes. Assim como em A. platensis , A. longirostri (Silva-Castiglioni et al, 2006) A. jarai Bond-Buckup & Buckup , 1994(Boss Jr. et al, 2006 e A. itacolomiensis Bond-Buckup & Buckup , 1994(Silva-Gonçalves et al, 2009, a taxa de crescimento (k) é maior nos machos, enquanto A. leptodactyla (Noro & Buckup, 2003) (Hartnoll 1982(Hartnoll , 1985. Diferentes taxas de mortalidade entre os sexos (Wolf et al, 1975), migração (Montague, 1980), maior facilidade de um dos sexos suportar as adversidades ambientais, desequilíbrio espacial e temporal na utilização dos recursos e padrões comportamentais diferenciados entre os sexos (Giesel, 1972) podem ser alguns dos fatores que, também, influenciam na diferença de tamanho entre machos e fêmeas de uma determinada espécie.…”

“…itacolomiensis Bond-Buckup & Buckup , 1994(Silva-Gonçalves et al, 2009. Para essas espécies citadas, a taxa de crescimento (k) é maior nos machos que nas fêmeas, enquanto A. leptodactyla (Noro & Buckup, 2003) não apresenta diferença significativa no k entre os sexos.…”

“…É comum nos eglídeos, os machos apresentarem um tamanho assintótico maior que o das fêmeas. Tal fato ocorre em A. leptodactyla (Noro & Buckup, 2003), A. longirostri (Silva-Castiglioni et al, 2006), A. jarai Bond-Buckup & Buckup , 1994(Boss Jr. et al, 2006 e A. itacolomiensis Bond-Buckup & Buckup , 1994(Silva-Gonçalves et al, 2009. Apenas em A. platensis as fêmeas são maiores que os machos, entretanto, os autores atribuíram tal diferença ao fato de que machos maiores foram raros durante as amostragens.…”