Mating strategy and sexual dimorphism of morphological traits of the leucosiid crab Pyrhila pisum were elucidated by analysing relative growth patterns of chelipeds and abdomen, and gonad development patterns. Male adults had long chelipeds compared with juvenile males and females. Among male adults, two phases with different slopes could be found in the regression lines; their chelipeds growth pattern changed from negative allometry to positive and longer chelipeds developed in large adults. The growth is more markedly expressed in the merus than in the propodus. Female adults had wider abdominal segments and a thicker body compared with juvenile females and males. Abdomen of females was greatly enlarged by a puberty moult. Male adults had well-developed gonads similar to female adults, and the weights of male gonads were often larger than those of females of the same body size. For adult males, a negative correlation was detected between carapace width and the weight ratio of their gonads, but no significant relationship was detected for adult females. Females had large and well-bloated seminal receptacles, whose weight was nearly equal to gonad weight. There was little difference in the amount of seminal receptacles regardless of the body size of females. There is a trade-off relationship in the development between chelipeds and gonads in adult males. Probably young adult males compensate for the disadvantageous condition of guarding by increasing the number of spermatozoids, and old adult males invest more of their energy to their chelae for guarding while decreasing investment in sperm production.

In order to map quantitative trait loci (QTLs) for allometries of body compositions and metabolic traits in chicken, we phenotypically characterize the allometric growths of multiple body components and metabolic traits relative to BWs using joint allometric scaling models and then establish random regression models (RRMs) to fit genetic effects of markers and minor polygenes derived from the pedigree on the allometric scalings. Prior to statistically inferring the QTLs for the allometric scalings by solving the RRMs, the LASSO technique is adopted to rapidly shrink most of marker genetic effects to zero. Computer simulation analysis confirms the reliability and adaptability of the so-called LASSO-RRM mapping method. In the F2 population constructed by multiple families, we formulate two joint allometric scaling models of body compositions and metabolic traits, in which six of nine body compositions are tested as significant, while six of eight metabolic traits are as significant. For body compositions, a total of 14 QTLs, of which 9 dominant, were detected to be associated with the allometric scalings of drumstick, fat, heart, shank, liver and spleen to BWs; while for metabolic traits, a total of 19 QTLs also including 9 dominant be responsible for the allometries of T4, IGFI, IGFII, GLC, INS, IGR to BWs. The detectable QTLs or highly linked markers can be used to regulate relative growths of the body components and metabolic traits to BWs in marker-assisted breeding of chickens.

The present study reports morphometric relationships and discusses the relative growth in the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). A total of 11 morphometric parameters (eight linear variables: shell length, shell width, total aperture length, aperture length, aperture width, spire length, spire width and siphonal canal length; three ponderal variables: total weight, soft parts weight and shell weight) were analysed in both species. The analyses comprised numerous individuals of both sexes and with broad size ranges (H. trunculus: 10.7–82.8 mm shell length; B. brandaris: 14.6–107.7 mm shell length), fairly representative of the populations from the Ria Formosa lagoon. In general, B. brandaris exhibited greater morphological plasticity and higher variability in shell shape compared with H. trunculus. In both species, the vast majority of morphometric relationships displayed positive allometries, distantly followed by negative allometries and by isometries. Although H. trunculus and B. brandaris are known to lack external sexual dimorphism, several morphometric relationships revealed significant differences in the type of growth between sexes, which should be further confirmed using more powerful techniques, such as geometric morphometric analyses of shell shape.

The life history of the mud shrimp Axianassa australis, a common and widespread burrower inhabiting coastal mangroves and mud flats, is poorly known. This contribution presents the first information about the population structure, reproductive biology and fecundity of A. australis, based on individuals collected from September 2011 to December 2012 on Casa Caiada Beach, located in a densely urbanized area in north-eastern Brazil, using a yabby pump. The sex ratio did not depart significantly from the expected 1:1 proportion. A significant trend of left-handedness of the major cheliped was observed in the population. Females reached a larger maximum cephalothorax length (CL) than males. The differential growth between CL and the propodus of the major cheliped showed negative allometric growth for females and positive allometric growth for males, suggesting a trade-off between somatic growth and reproductive effort. Females bearing uneyed orange embryos predominated during all months in which ovigerous females were collected. Mean fecundity was 2379 eggs, ranging from 5 (7.55 mm CL) to 8300 (14.19 mm CL) eggs per female. About 71% of the variation in the number of eggs carried per female was explained by CL. The mean egg size correlated negatively with fecundity, indicating that large females of A. australis produce more and larger eggs than smaller females.

The variability of shell morphology and relative growth of the invasive pearl oyster Pinctada radiata was studied within and among ten populations from coastal Tunisia using discriminant tests. Therefore, 12 morphological characters were examined and 34 metric and weight ratios were defined. In addition to the classic morphological characters, populations were compared by the thickness of the nacreous layer. Results of Duncan's multiple comparison test showed that the most discriminative ratios were the width of nacreous layer of right valve to the inflation of shell, the hinge line length to the maximum width of shell and the nacre thickness to the maximum width of shell. The analysis of variance revealed an important inter-population morphological variability. Both multidimensional scaling analysis and the squared Mahalanobis distances (D2) of metric ratios divided Tunisian P. radiata populations into four biogeographical groupings: the north coast (La Marsa); harbours (Hammamet, Monastir and Zarzis); the Gulf of Gabès (Sfax, Kerkennah Island, Maharès, Skhira and Djerba) and the intertidal area (Ajim). However, the Kerkennah Island population was discriminated by the squared Mahalanobis distances (D2) of weight ratios in an isolated group suggesting particular trophic conditions in this area. The allometric study revealed high linear correlation between shell morphological characters and differences in allometric growth among P. radiata populations. Unlike the morphological discrimination, allometric differentiation shows no clear geographical distinction. This study revealed that the pearl oyster P. radiata exhibited considerable phenotypic plasticity related to differences of environmental and/or ecological conditions along Tunisian coasts and highlighted the discriminative character of the nacreous layer thickness parameter.

Biometric relationships of size and weight were estimated for the Argentinean prawn (Artemesia longinaris), a new commercial penaeid prawn exploited in the south-western Atlantic. Morphometric and meristic traits were used to elucidate population structure of this species along its distribution area. The morphological relationships were estimated by a simple linear regression, considering total length (TL) as the dependent variable. The males collected in southern Brazil, an area under influence of the Subtropical Convergence, presented a slightly lower TL increment than females. A marked reduction in slopes of males between populations from southern Brazil was observed in autumn and winter. Additionally, relative growth in length of males from Argentina is similar to that observed during autumn and winter in southern Brazil. The other morphometric and meristic variables used also indicated higher similarities between southern Brazil and Argentina, which may be explained by relative growth associated to water temperatures or migration during winter, taking advantage of the oceanographic systems connecting both sites. Moreover, the population from Rio de Janeiro seems morphologically apart from the others, forming a separate unit stock.

Relative growth and reproductive biology of Munida rutllanti were investigated for the first time in the Adriatic Sea. A total of 938 individuals were analysed. Sex-ratio differed statistically from the expected 1:1. Six individuals exhibited secondary sex characteristics of both males and females. Carapace length of males ranged from 10.5 to 21.5 mm, while in females it ranged from 11.2 to 19.4 mm. Sexual dimorphism was observed in seven morphometric characters. Ovigerous females were first observed in summer and later in autumn with higher frequency. Realized fecundity showed wide variation (273–3250 eggs) and positive correlation between the brood and female size. An epicaridean isopod Pleurocrypta sp., parasitizing the gill chamber of both sexes was isolated and its effect on the oogenesis was studied by histological examination of host reproductive system. Growth inhibition, modification of secondary sex characteristics, as well as retardation of oogenesis and failure of oviposition, are repercussions of bopyrid infestation. Given the small prevalence (7.85%) of the bopyrid in the M. rutllanti Adriatic population, we assume that for the moment there is no severe effect on the host population dynamic.

The relative growth and population structure of the terebellid Nicolea uspiana were investigated in the intertidal zone of a rocky shore on the south-east coast of Brazil, from May 2006 to May 2007. Eight hundred and forty-seven individuals of N. uspiana were analysed: 391 males, 163 females, and 293 immatures. Although significant differences in some morphometric parameters were found, there was no sexual dimorphism between males and females. There were differences in total length, width of segment 5, and length of the notopodial region between matures and immatures. The negative allometry of the total length in relation to five other parameters showed that this feature is a good measure for estimating the individual size, which was then used in the analysis of population structure. This population of N. uspiana showed a bimodal size–frequency distribution, with immature and mature individuals found during the entire year. This pattern indicates continuous reproduction, with each cohort growing for at least three to four months and being responsible for two consecutive settlement peaks.

Biometric relationships were recorded for 2431 male and female Panulirus echinatus sampled at Tamandaré coastal reefs, Pernambuco, Brazil. The following body measurements were taken: carapace length and width, abdomen length and width, total length, third and fifth pereiopod length, cephalothorax–abdomen and total weight. Twelve relationships were studied to compare the biometric characteristics of males and females. Eleven of them showed difference between the sexes. Comparing sexes with the same carapace length, males have a heavier cephalothorax and longer third and fifth pereiopods than females, whereas females are longer, wider, and have a heavier abdomen than males. For genders with the same total length, males are heavier and have a longer carapace than females, while females have a larger abdomen. For genders with the same abdomen length, males have a heavier abdomen than females. The relationships TWg/TL and AWg/AL showed positive allometric growth for the males. All other relationships involving weight, presented negative allometric growth for both sexes.

The small intertidal New Zealand crab, Halicarcinus cookii undergoes a terminal pubertal moult, but this moult takes place over a wide range of pre-moult sizes. Relative growth of the abdomen width in immature females is positively allometric, but negatively allometric in mature females. Male abdomen growth is negatively allometric. Growth of the cheliped propodus in males is positively allometric, but in females it is negatively allometric or isometric. Overlap in the size-range of mature and pre-pubertal immature female H. cookii is 72% and in other hymenosomatids it can be as high as 87%. This overlap is probably the result of crabs having a variable number of pre-pubertal instars, but seasonal change in water temperature, with crabs moulting to a smaller final size during colder months and to a larger size during the warmer months is also possible. The net reproductive rate (Ro) of early and delayed moulters is compared and for H. cookii Ro e / Ro d = 1.0 so the size overlap is stable. Most hymenosomatids have determinate growth, but Hymenosoma orbiculare and Elamenopsis lineata continue to moult after maturity and have retained the ancestral link between moulting and mating.

Ommastrephid squids undergo remarkable morphological change during the transition from planktonic paralarvae to adults. These changes are characterized by changes in the relative growth of body dimensions and mark phases and stages in post-embryonic development. The following morphometric characters of paralarval and juvenille Illex argentinus ranging in size from 1–55 mm ML were measured: dorsal mantle length (ML), mantle width (MW), head width (HW), eye diameter (ED), right arm lengths (AIL) (AIIL) (AIIIL) (AIVL), proboscis length (PL), proboscis division (PD), fin length (FL), fin width (FW), right tentacle length (TL), club length (CIL), dactylus length (DL) and carpus + manus length (CML). The relative growth of AIL, AIIL, AIIIL, HW and ED, showed discontinuities at c. 14 mm ML, while AIL, AIIL, AIIIL, AIVL, FL, and TL showed other discontinuities at c. 28 mm ML. These discontinuities seem to be related to the activity and ability of the animal to obtain food and survive in different environments. At an early phase (1–14 mm ML), there is a rapid development of the arms, suckers and fins. In the second stage (14–28 mm ML) there is a rapid development of the tentacles and clubs. In the third (>28 mm ML), the juvenile grows more in length in relation to other body parts. No morphological change, besides the proboscis division, takes place at the end of rhynchoteuthion stage. This may indicate the necessity for re-evaluation of the paralarval phase in Ommastrephidae.