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E. Naylor - One of the best experts on this subject based on the ideXlab platform.

  • the neurosecretory system of the eyestalk of Carcinus maenas crustacea decapoda
    Journal of Zoology, 2009
    Co-Authors: G. Smith, E. Naylor
    Abstract:

    The optic ganglia neurosecretory cells of male and female Carcinus maenas during intermoult are distinguishable into six types based on size, location, appearance and method of secretory material release from the perikaryon. Release occurs via the sinus gland and also, in one case, directly into blood capillaries among the neurosecretory cells themselves. The sinus gland consists of axonal extensions of the neurosecretory cells; no secretory granules are produced there and nuclei observed between the axonal endings are those of ill-defined glial cells.

  • synchronization of endogenous tidal vertical migration rhythms in laboratory hatched larvae of the crab Carcinus maenas
    Journal of Experimental Marine Biology and Ecology, 1996
    Co-Authors: Chaoshu Zeng, E. Naylor
    Abstract:

    Abstract Previous studies showed that freshly collected zoea-1 larvae of the shore crab Carcinus maenas from coastal waters possessed endogenous circatidal vertical migration rhythms. Present experiments demonstrate that zoea-1 larvae released by crabs which extruded eggs in the field but were then kept in laboratory constant conditions since collection, also exhibited endogenous circatidal vertical migration rhythms. Such rhythms were shown by newly hatched larvae from nearly all of 50 females which released larvae in the laboratory, some of which had carried eggs in the laboratory for up to 3–4 months. Thus, since entrainment by tidal variables could not have occurred during embryonic development in these cases, other synchronising factors must set the phase of the larval circatidal rhythms. Present results suggest that the hatching process itself is the main synchroniser; upward swimming occurred just after hatching and at 12.4 h intervals thereafter. This is consistent with previous observations of peak hatching in Carcinus primarily around nocturnal high tide, with larvae in the field exhibiting tidal vertical migration rhythms of ebb-phased upward swimming associated with dispersal during ebbing tides. The results appear to be the first to characterize a synchroniser for tidal swimming rhythms of planktonic larvae and to provide experimental evidence that the hatching process can serve as the synchroniser for a larval swimming rhythm.

  • Crab clockwork: the case for interactive circatidal and circadian oscillators controlling rhythmic locomotor activity of Carcinus maenas.
    Chronobiology international, 1996
    Co-Authors: E. Naylor
    Abstract:

    The circalunidian hypothesis that tidal rhythms in coastal animals are controlled by two lunar-day (c. 24.8 h) oscillators coupled in antiphase is challenged. Rhythmic locomotor activity patterns of the shore crab Carcinus maenas, and probably of some other species too, are more economically explained by interacting circadian (c. 24 h) and true circatidal (c. 12.4 h) physiological oscillators. A testable hypothesis is proposed that combines a circadian promotor and a circatidal inhibitor of locomotor activity.

  • Intraspecific morphological variation related to the moult-cycle in colour forms of the shore crab Carcinus maenas
    Journal of Zoology, 1992
    Co-Authors: Iain J. Mcgaw, E. Naylor, Michel J. Kaiser, Roger N. Hughes
    Abstract:

    The common shore crab Carcinus maenas exhibits a range of carapace colours from green through orange to red, green forms showing some differences of distribution from red/orange forms. To test the hypothesis that colour differences were moult-related, large numbers of Carcinus were collected intertidally and subtidally in summer when moulting is most prevalent, and their moult stages determined. Red and orange coloration was found only to occur in the larger size classes in crabs in prolonged intermoult, but not solely in the largest crabs in terminal anecdysis. Red crabs were characterized by a heavier load of epibionts and a strong, thicker carapace. In contrast, green crabs were found over the entire size range and appeared to be actively moulting forms; they carried fewer epibionts and had a thinner integument than red forms. The significance of morphological differences between red/orange and green forms of Carcinus maenas is considered in relation to previously reported behavioural, physiological and ecological differences between the colour forms.

Mairena-valdivia Álvaro - One of the best experts on this subject based on the ideXlab platform.

  • Estudio Biométrico y ecológico del camarón de río (género Macrobrachium) en la parte baja de la cuenca del río Kukra
    'Latin America Journals Online', 2018
    Co-Authors: González-aleman Néstor, Mairena-valdivia Álvaro
    Abstract:

    The Macrobrachium Gender made up of more than 100 species, of which 26 belong to the american continent (Pascual, 2005), they commonly known as river shrimp and/or prawn. Due to his trascendency like fishing resource they are considered of great economic importance, principally Macrobrachium Carcinus and M. acanthurus, which are well known and exploited in the majority of the riverside communities throughout Latin America (García-Guerrero et al., 2013).During the period of study (2006-2007), a total of 1180 specimen were captured, of Macrobrachium acanthurus 447 individuals were captured, 622 of M. Carcinus and 111 of M. olfersii. All the captures were done with fishnets of bamboo of the Guadua specie of the Amplexifolia type that is the native one of Nicaragua.During the study the average temperature was 27.2 ± 1.25 °C (range: 25 - 29 °C), average transparency of 0.3 ± 0.17 m (range: 0.26 – 0.45 m) and the average depth of 3 ± 0,25 m (range: 2 -4.5 m). In the sexual proportion (female: male) there was dominance of males, for M. Carcinus the proportion was (1H: 0.9M) with a value of χ2 = 2.57 without significant difference, M. acanthurus presented a proportion of (1H: 1.66M) with a value of χ2 = 18.53 with significant difference and M. olfersii presented a proportion of (1H: 0.8M) whit a value of χ2 = 0.73 without significant difference. There is a significant difference when (χ2 < 3.84 and p > 0.05) (Vazzoler, 1996). M. Carcinus presented an average Total Length (LT) of 15.8 ± 4.5 cm (range: 3.6 - 24 cm) and a Total Weight (W) of 105.4 ± 82.5 g (range: 1.7 - 382 g). For the three species, the model that best fits the growth of the population is the polynomial model, in M. Carcinus (W = 1.6 LT2 - 28.2 LT + 118.6) it explains more than 90% of the relationship between W and LT (R2 = 0.9046). M. acanthurus presented average LT of 11.7 ± 4.9 cm (range: 4.3 - 26 cm) and W of 47.1 ± 66.2 g (range: 1.3 - 383 g), the model of growth of this population (W = 1.2 LT2 - 19.5 LT + 79.36) explains more than 93% of the relationship between W and LT (R2 = 0.9395). Finally, M. olfersii presented an average LT of 6.4 ± 1.3 cm (range: 3.5 - 9.6 cm) and W of 4.2 ± 1.8 g (range: 1.2 – 9.7 g), the growth model of this population (W = 0.22 LT2 - 1.8 LT + 6.5) explains more than 60% of the relationship between W and LT (R2 = 0.621) in females and less than 30% in males (R2 = 0.294).El género Macrobrachium comprende más de cien especies, de las cuales 26 pertenecen al continente americano (Pascual, 2005); comúnmente son conocidos como camarones de río y/o langostino. Debido a su trascendencia como recurso pesquero se les considera de gran importancia económica, principalmente Macrobrachium Carcinus y M. acanthurus, los cuales son bien conocidos y explotados en la mayoría de las comunidades ribereñas de toda Latinoamérica (García-Guerrero, Becerril-Morales, Vega-Villasante, & Espinosa-Chaurand, 2013).Durante el periodo de estudio (2006-2007) se capturó un total de 1180 ejemplares. De éstos, 447 individuos fueron Macrobrachium acanthurus; 622, M. Carcinus, y 111 fueron M. olfersii. Todas las capturas se realizaron con nasas de bambú de la especie Guadua del tipo Amplexifolia que es nativo de Nicaragua.Durante el estudio, la temperatura promedio fue 27,2 ± 1,25 °C (rango: 25 - 29 °C), transparencia promedio de 0,3 ± 0,17 m (rango: 0,26 - 0,45 m) y la profundidad promedio de 3 ± 0,25 m (rango: 2 - 4,5 m). En la proporción sexual (hembra/macho) hubo dominancia de machos. Para M. Carcinus la proporción fue (1H: 0,9M) con un valor de χ2 = 2,57, sin diferencia significativa; M. acanthurus presentó una proporción (1H: 1,66M) con un valor de χ2 = 18,53, con diferencia significativa, y M. olfersii mostró una proporción (1H: 0,8M) con valor de χ2 = 0,73, sin diferencia significativa. Existe diferencia significativa cuando (χ2 < 3,84 y p > 0,05) (Vazzoler, 1996).M. Carcinus presentó un promedio de Longitud Total (LT) de 15,8 ± 4,5 cm (rango: 3,6 - 24 cm) y un Peso Total (W) de 105,4 ± 82,5 g (rango: 1,7 - 382 g). Para las tres especies el modelo que mejor se ajusta al crecimiento de la población es el modelo polinómico, en M. Carcinus (W = 1,6 LT2 - 28,2 LT + 118,6) explica más del 90% de la relación entre el W y LT (R2 = 0,9046). M. acanthurus presentó LT promedio de 11,7 ± 4,9 cm (rango: 4,3 - 26 cm) y W de 47,1 ± 66,2 g (rango: 1,3 - 383 g), el modelo de crecimiento de esta población (W = 1,2 LT2 - 19,5 LT + 79,36) explica más del 93% de la relación entre W y LT (R2 = 0.9395).Finalmente, M. olfersii presentó LT promedio de 6,4 ± 1,3 cm (rango: 3,5 - 9,6 cm) y un W de 4,2 ± 1,8 g (rango: 1,2 - 9,7 g), el modelo de crecimiento de esta población (W = 0,22 LT2 - 1,8 LT + 6,5) explica más del 60% de la relación entre W y LT (R2 = 0,621) en hembras y menos del 30% en machos (R2 = 0,294)

  • “Estudio Biométrico y ecológico del camarón de río (género Macrobrachium) en la parte baja de la cuenca del río Kukra”
    'Latin America Journals Online', 2018
    Co-Authors: González-aleman Néstor, Mairena-valdivia Álvaro
    Abstract:

    El género Macrobrachium comprende más de cien especies, de las cuales 26 pertenecen al continente americano (Pascual, 2005); comúnmente son conocidos como camarones de río y/o langostino. Debido a su trascendencia como recurso pesquero se les considera de gran importancia económica, principalmente Macrobrachium Carcinus y M. acanthurus, los cuales son bien conocidos y explotados en la mayoría de las comunidades ribereñas de toda Latinoamérica (García-Guerrero, Becerril-Morales, Vega-Villasante, & Espinosa-Chaurand, 2013). Durante el periodo de estudio (2006-2007) se capturó un total de 1180 ejemplares. De éstos, 447 individuos fueron Macrobrachium acanthurus; 622, M. Carcinus, y 111 fueron M. olfersii. Todas las capturas se realizaron con nasas de bambú de la especie Guadua del tipo Amplexifolia que es nativo de Nicaragua. Durante el estudio, la temperatura promedio fue 27,2 ± 1,25 °C (rango: 25 - 29 °C), transparencia promedio de 0,3 ± 0,17 m (rango: 0,26 - 0,45 m) y la profundidad promedio de 3 ± 0,25 m (rango: 2 - 4,5 m). En la proporción sexual (hembra/macho) hubo dominancia de machos. Para M. Carcinus la proporción fue (1H: 0,9M) con un valor de χ2 = 2,57, sin diferencia significativa; M. acanthurus presentó una proporción (1H: 1,66M) con un valor de χ2 = 18,53, con diferencia significativa, y M. olfersii mostró una proporción (1H: 0,8M) con valor de χ2 = 0,73, sin diferencia significativa. Existe diferencia significativa cuando (χ2 0,05) (Vazzoler, 1996). M. Carcinus presentó un promedio de Longitud Total (LT) de 15,8 ± 4,5 cm (rango: 3,6 - 24 cm) y un Peso Total (W) de 105,4 ± 82,5 g (rango: 1,7 - 382 g). Para las tres especies el modelo que mejor se ajusta al crecimiento de la población es el modelo polinómico, en M. Carcinus (W = 1,6 LT2 - 28,2 LT + 118,6) explica más del 90% de la relación entre el W y LT (R2 = 0,9046). M. acanthurus presentó LT promedio de 11,7 ± 4,9 cm (rango: 4,3 - 26 cm) y W de 47,1 ± 66,2 g (rango: 1,3 - 383 g), el modelo de crecimiento de esta población (W = 1,2 LT2 - 19,5 LT + 79,36) explica más del 93% de la relación entre W y LT (R2 = 0.9395). Finalmente, M. olfersii presentó LT promedio de 6,4 ± 1,3 cm (rango: 3,5 - 9,6 cm) y un W de 4,2 ± 1,8 g (rango: 1,2 - 9,7 g), el modelo de crecimiento de esta población (W = 0,22 LT2 - 1,8 LT + 6,5) explica más del 60% de la relación entre W y LT (R2 = 0,621) en hembras y menos del 30% en machos (R2 = 0,294)

Shawn M C Robinson - One of the best experts on this subject based on the ideXlab platform.

Herbert Boyle - One of the best experts on this subject based on the ideXlab platform.

  • Phylogeny and taxonomy of powdery mildew fungi of Erysiphe sect. Uncinula on Carpinus species
    Mycological Progress, 2006
    Co-Authors: Uwe Braun, Saranya Limkaisang, Vasyl P. Heluta, Susumu Takamatsu, Rangsi Divarangkoon, Roger Cook, Herbert Boyle
    Abstract:

    A phylogenetic analysis of the Erysiphe with uncinuloid ascoma appendages ( Erysiphe section Uncinula , Erysiphales, Ascomycota ) on Carpinus spp. was done using sequences of the rDNA ITS regions and the D1/D2 domains of the 28S rDNA. These results, combined with morphological data, revealed a complex consisting of several distinct taxa. These included the already described Erysiphe carpinicola on C. japonica distinguishable from the Erysiphe sp. on C. betulus and C. tschonoskii as well as the one on C . laxiflora . Thus, it was shown that Oidium carpini , described from Europe on Carpinus betulus , the powdery mildew with uncinula-like ascomata, recently found in Europe on this host, as well as an Erysiphe on C. tschonoskii in Japan, described previously as E. carpinicola , all belong to a single new species, named E. arcuata in this paper. As the powdery mildew on C. laxiflora was also distinct from other known species, it is named E. carpini-laxiflorae in this paper. The already described E. pseudocarpinicola and Erysiphe sp. on Carpinus cordata are two additional taxa, which are morphologically and genetically distinguished from the other species of Erysiphe sect. Uncinula on Carpinus spp.

R. Seed - One of the best experts on this subject based on the ideXlab platform.

  • Foraging behavior of juvenile Carcinus maenas (L.) and Cancer pagurus L.
    Marine Biology, 2001
    Co-Authors: Maite Mascaró, R. Seed
    Abstract:

    Information concerning the way juvenile crabs choose their diet from a variety of prey types can be useful for a better understanding of community dynamics, as well as for the adequate management of natural resources. Prey size and species selection by juvenile Carcinus maenas (15–35 mm carapace width, CW) and Cancer pagurus (20–40 mm CW) feeding on four bivalves of contrasting shell morphology were investigated. When offered a wide size range of Mytilus edulis, Ostrea edulis, Crassostrea gigas, and Cerastoderma edule presented individually, crabs generally showed evidence of size-selective predation. Cancer pagurus selected larger mussels relative to the size of their chelae (relative prey size, RPS) than did Carcinus maenas of similar and even larger carapace width. However, the RPS of selected O. edulis and Cerastoderma edule were similar for all crabs, suggesting that certain prey features constitute effective barriers even to the powerful chelae of Cancer pagurus. When offered a wide size range of mussels and oysters simultaneously, all crabs consistently selected mussels. When offered O. edulis and Crassostrea gigas, crabs consumed both these oyster species in similar numbers. Carcinus maenas consumed similar numbers of mussels and cockles; Cancer pagurus, however, showed no preference for either prey in the smaller size classes but selected more mussels than cockles as prey increased in size. Although previous studies report that adult Carcinus maenas select prey species according to their profitability (amount of food ingested per unit of handling time, milligrams per second), consumption rates of the size classes of prey selected by juvenile shore crabs did not always parallel prey value. Although variations in crab strength can account for many of the differences between the foraging strategy of juvenile and adult C. maenas, our results suggest that juvenile crabs are less species selective than adults as a result of the restrictions imposed on small individuals that have limited access to larger prey.