Host-use pattern and sexual dimorphism reveals the mating system of the symbiotic pea crabAustinixa aidae(Crustacea: Brachyura: Pinnotheridae)

2012 ◽  
Vol 93 (3) ◽  
pp. 715-723 ◽  
Author(s):  
Douglas F. Peiró ◽  
J. Antonio Baeza ◽  
Fernando L. Mantelatto
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Mating System ◽  
Reproductive Strategies ◽  
The Body ◽  
Host Use ◽  
Decapod Crustaceans ◽  
Body Coloration ◽  
Early Embryos ◽  
Use Pattern

Austinixa aidaeinhabits burrows of the ghost shrimpCallichirus majorat Perequê-açu beach, Ubatuba, Brazil. We described the host-use pattern and sexual dimorphism ofA. aidaeto test for monogamy given the generality of this mating system in the subfamily Pinnothereliinae (family Pinnotheridae) to whichA. aidaebelongs. Against expectations,A. aidaelives as solitary individuals within burrows more frequently than expected by chance alone. Additional observations suggested thatA. aidaeexhibits a polygynandrous mating system with males moving among burrows in search of receptive females. First, only 21% of the burrows harboured heterosexual pairs of crabs and the body size of paired crabs was poorly correlated. This suggests pair instability and frequent shifts among burrows by male and/or female crabs, as reported before for other symbiotic crustaceans in which the body size of paired crabs is poorly correlated. Second, males paired with females that were sexually receptive (without embryos) or that have been receptive recently (carrying early embryos) were found more frequently than expected by chance alone. The above agrees with that reported for species in which sexual pairing does not last long. Third, sexual dimorphism in terms of claw size and coloration was evident. Claws were larger in males than in females, a condition that argues in favour of male–male competition inA. aidae. In addition, the body coloration of males was more similar to the sand grains of the beach than that of females. This sex-specific coloration suggests that males are ‘better adapted' than females to roam on the surface of the beach in search of burrows because their coloration should diminish the risk of detection by predators. Experiments are needed to reveal the details of the polygynandrous mating system herein inferred forA. aidaeand to understand those conditions favouring particular reproductive strategies in symbiotic decapod crustaceans.

scholarly journals Sexual dimorphism in Amphisbaena nigricauda (Reptilia, Squamata, Amphisbaenidae) from Southeastern Brazil

2014 ◽  
Vol 104 (3) ◽  
pp. 299-307 ◽  
Author(s):  
Francco A. N. de Souza e Lima ◽  
João Luiz Gasparini ◽  
Antonio de Padua Almeida ◽  
Marcos V. C. Vital ◽  
Tamí Mott
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Morphological Characters ◽  
The Body ◽  
Southeastern Brazil ◽  
Meristic Characters ◽  
Single Male ◽  
Posterior Portion ◽  
Espírito Santo ◽  
Espirito Santo

Amphisbaena nigricauda Gans, 1966 is a small, poorly known amphisbaenid endemic to the restinga of the states of Espírito Santo and Bahia, Brazil. We analyze 178 specimens collected in Vitória municipality, state of Espírito Santo, Brazil, to investigate whether this species show sexual dimorphism in pre-cloacal pores and in morphological characters. Sex was determined by a ventral incision and direct inspection of gonads. A PCA analysis was performed to generate a general body size measurement. A T test and the non-parametric Mann-Whitney test were used to assess whether this species show sexual dimorphism on five morphometric and five meristic characters, respectively. Sex could not be determined in 36 specimens because they were mutilated in the posterior portion of their bodies. The diagnosis of the species is redefined based on this sample size: the smallest number of body annuli changes from 222 to 192, the number of dorsal and ventral segments in an annulus in the middle of the body changes to 9-11/13-16 (instead of 10/16), and the autotomic tail annulus lies between annulus 7-10 (instead of 6-9). The number of tail annuli remained within the known range of variation of the species (19-24). None of the 80 females analyzed showed pre-cloacal pores, whereas within males 59 out of 62 specimens displayed four and two specimens displayed five pre-cloacal pores. A single male did not possess pre-cloacal pores, but showed irregular scales on its cloacal region. Sex-based difference based on presence or absence of pre-cloacal pores as well as males with wider head was seen in other Neotropical amphisbaenids. However, a pattern of body size differences between males and females has not been identified so far in the few amphisbaenid species studied in this regard. Further studies on this taxonomic group are still needed to elucidate the existence of general patterns of sexual dimorphism and to identify the selective pressures driving these patterns.

scholarly journals Sexual Dimorphism in Anthonomus santacruzi (Coleoptera: Curculionidae): a Biological Control Agent of Solanum mauritianum Scopoli (Solanaceae)

2020 ◽  
Vol 49 (6) ◽  
pp. 840-850
Author(s):  
Archbold Sasa ◽  
Rafał Gosik ◽  
Ed T. F. Witkowski ◽  
Marcus J. Byrne ◽  
Miłosz A. Mazur
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Body Length ◽  
Biological Control Agent ◽  
Abdominal Tergite ◽  
Total Body Length ◽  
The Body ◽  
Body Structure ◽  
Solanum Mauritianum ◽  
Total Body

AbstractThere is evident variation in body size amongst Anthonomus santacruzi Hustache, 1924, weevils. The aims of this study were to assess if the variation in body size in A. santacruzi weevils is a result of sexual dimorphism and what features can be used to distinguish males from females. The weevils were collected from field sites in Mpumalanga, South Africa, where they were introduced as biocontrol agents of Solanum mauritianum Scopoli. Body structures and the presence/absence of the tergal notch was examined under an optical stereomicroscope and SEM to assess differences between sexes. The morphometric analysis of the body structures included rostrum length (base–apex and antennal insertion–apex), elytral length and width, pronotum length and width, first tarsus length, first tibia length, funiculus length and total body length. Rostrum length, elytra length and width and total body length were significantly larger in females than in males. A tergal notch in the 8th abdominal tergite was present in males and absent in females. The body structure; of rostrum length, elytra length and width and total body length overlapped between sexes in some specimens. The abdominal tergal notch was found to be the most useful body structure to distinguish males from females in A. santacruzi.

scholarly journals Morphology and Morphometry of Caeca in the Tufted Duck Aythya Fuligula

2009 ◽  
Vol 54-55 (1-4) ◽  
pp. 21-31
Author(s):  
Ewa Działa-Szczepańczyk ◽  
Anna Charuta
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Fluctuating Asymmetry ◽  
The Body ◽  
Asymmetry Coefficient ◽  
Tarsus Length ◽  
Tufted Duck ◽  
Morphology And Morphometry ◽  
Sternum Length

Morphology and Morphometry of Caeca in the Tufted Duck Aythya Fuligula In this study, we examined the caeca of 44 individuals of Tufted Duck (Aythya fuligula): 29 males (23 adult and 6 young) and 15 females (8 adult and 7 young). We analyzed the correlations between lengths of left (CLL) and right (CRL) caeca vs. the dimensions of the bird's body: body weight (BW), body length (BL), sternum length (SL) and tarsus length (TL), in relation to the sex of the animals. We also analyzed the asymmetry of caeca and determined its direction and strength, using a fluctuating asymmetry coefficient. Despite the observed sexual dimorphism in the body size, we found neither sex-related differences in the length of caeca, nor any significant correlation between the CLL and CRL vs. body size (BW, BL, SL, TL). 42 birds (94.5%) were asymmetrical with respect to the length of caeca, and in 37 (84.1%) the left caecum was longer. The fluctuating asymmetry coefficient for the length of these organs in the examined group was 0.413.

scholarly journals Host-use pattern of the shrimp Periclimenes paivai on the scyphozoan jellyfish Lychnorhiza lucerna: probing for territoriality and inferring its mating system

2017 ◽  
Vol 71 (1) ◽  
Author(s):  
J. Antonio Baeza ◽  
Samara de Paiva Barros-Alves ◽  
Rudá Amorim Lucena ◽  
Silvio Felipe Barbosa Lima ◽  
Douglas Fernandes Rodrigues Alves
Keyword(s):  
Mating System ◽  
Host Use ◽  
Use Pattern ◽  
Scyphozoan Jellyfish

Growth dynamics of young mink of the albino-pastel breed in postnatal ontogeny

2021 ◽  
Vol 1 (4) ◽  
pp. 56-62
Author(s):  
O. I. Fedorova ◽  
◽  
E. A. Orlova ◽  
I. D. Antonova ◽  
◽  
...  
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Growth Dynamics ◽  
Postnatal Period ◽  
The Body ◽  
Postnatal Ontogeny ◽  
Hair Colour ◽  
Males And Females ◽  
Further Development

Coloured minks are widespread – more than 200 colour variations in hair colour are known. Currently, breeding in fur farming continues. One of the most recent breeding achievements is the albino pastel mink. An important characteristic of the new breed is the body size and growth of the organism during the postnatal period, which does not occur evenly but goes through certain phases. In different periods of growth, the organism requires appropriate conditions, in the presence of which further development occurs. As a result of studies of mink growth from birth to adulthood, data necessary for the correct organization of measures for rearing and feeding the animals are accumulated. When analysing the growth dynamics of young animals, it has been established that sexual dimorphism in body weight of males and females of the albino-pastel genotype is absent at one day of age. The most intensive increase in body weight in female and male albino-pastel minks occurs from day 50 to day 80. The increase in body weight continues after 3–4 months of life, with males more intense than females.

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