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Host preferences, colour patterns and distribution records of Pseudocryptochirus viridis Hiro, 1938 (Decapoda, Cryptochiridae)
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The coral gall crab Pseudocryptochirus viridis is an obligate symbiont of some species of the Indo-West Pacific coral genus Turbinaria. The colour pattern variation within the species is illustrated for the first time. Overviews of the coral host species and distribution records are provided, including new records from Indonesia, Malaysia and Australia.
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Latitudinal variation in the reproductive cycle and size of the northern rock barnacle Semibalanus balanoides (L.) (Cirripedia, Archaeobalanidae) in the Bay of Fundy
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The reproductive phenology and size of populations of Semibalanus balanoides were studied at four sites along a latitudinal gradient in the Bay of Fundy. Animals were collected from May 2006 through January 2007, their basal widths measured and the first appearance of immature oocytes, mature oocytes, brooded embryos, and sperm scored. Proceeding from south to north, there was a significant decline in the size of the barnacles and a delay in appearance of all stages. The possible effects of temperature and turbidity are discussed.
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Effects of substrate colour preference on growth of the shrimp Litopenaeus vannamei (Boone, 1931) (Decapoda, Penaeoidea)
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We tested the substrate colour preference and its effect on the specific growth rate (SGR), food intake and feeding efficiency (FE) of the shrimp Litopenaeus vannamei (Boone, 1931). Preference was tested in 50 cm diameter circular tanks divided into 4 lateral compartments, each filled with 2 cm depth of fine-grain, coloured sand (yellow, blue, green and red). The respective walls of each tank were also kept with the same colour, using coloured paper. Tanks were filled with 10 l of water (salinity of 4) and illuminated with fluorescent light ( n = 35 ). Tanks with natural sand (without a specific colour) were used as controls ( n = 6 ). Thirty-five shrimps were observed individually for three days at 7, 10, 13 and 16 h, for 20 min each time. Visit frequency to each compartment was registered every 2 min. Shrimps did not show any preference for a specific colour substrate for the first two days, however, there was higher preference for the yellow and red substrates on the third day. Control shrimps did not show preference for any compartment. To test the effects of substrate colour on feeding rate and growth, 25 shrimps were isolated for 60 days in a 15-l aquarium covered with coloured paper on the walls and filled with 2 cm of coloured substrate (yellow, blue, green, red and natural sand, n = 5 for each colour). Shrimps were fed daily and uneaten food removed and recorded. Shrimps were weighed every 10 days. Feeding rate was higher in the red environment than in blue or green environments, and FE was also higher for red than for blue shrimps group. SGR was higher in red and yellow environments. These results suggest that yellow and red substrate enhance the shrimps’ visual perception and food detection, and thus supports the finding that these substrate colours can improve FE and SGR of cultivated shrimps.
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Similar offspring production by normal and intersex females in two populations of Gammarus minus (Malacostraca, Amphipoda) with high levels of intersexuality
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Two Virginia (U.S.A.) populations of the freshwater amphipod Gammarus minus (Say, 1818) exhibit high frequencies of females with male genital papillae (60 to 75% in one population and 100% in the other) that have been observed for over 30 years. This observation is surprising because sex-allocation theory predicts that such intersex individuals should have lower evolutionary fitness than ‘normal’ males or females. Here we tested this theory by comparing a major component of reproductive fitness (offspring production, as estimated by number and total mass of offspring in a brood) between intersex and normal females. Although intersex females tend to brood slightly fewer, but larger embryos than those of normal females, these differences were not significant overall, and moreover they resulted in nearly identical mean production of total offspring mass per brood. Maternal somatic investment (body mass and body condition) during brooding also did not differ significantly between intersex and normal females. These results suggest that intersex females may not have lower reproductive fitness than that of normal females, which may help explain their high frequencies in the Virginia populations. Consistent with this hypothesis, available literature data on four amphipod species show a positive association between intersex frequency and the offspring production of intersex females relative to that of normal females. However, this hypothesis needs to be tested further by examining other reproductive and survival traits related to fitness, and by examining other amphipod populations with varying intersex frequencies. Moreover, the cause(s) of the intersex condition in the Virginia populations (and most other amphipod populations) remains largely unknown.
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Isolation of the C-type lectin like-domain cDNAs from the mud crab Scylla paramamosain Estampador, 1949, and its expression profiles in various tissues, during larval development, and under Vibrio challenge
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Scylla paramamosain Estampador, 1949 is one of the most precious marine crabs farmed in China. The crab is prone to infection by microbes at various stages during its growth, leading to high mortality. C-type lectin has a characteristic carbohydrate recognition domain and plays an important role in the immunity system. A cDNA library from the mud crab S. paramamosain was constructed using the SMART technique. Two complete cDNA sequences showing high identities with the C-type lectin gene were isolated from the library. The two full-length C-type lectin cDNAs of S. paramamosain (SpLec1 and SpLec2) consist of 746 and 834 bp, respectively. Quantitative real-time PCR analyses revealed that the C-type lectins were expressed mainly in haemocytes, muscle and hepatopancreas, with the highest expression level found in hepatopancreas. The C-type lectin mRNA expression in continuous developmental stages during zoeal phases were also examined by quantitative real-time PCR. After infection with Vibrio parahaemolyticus (Sakazaki, 1963) at a concentration of 2.3 × 106 cfu/ml, the temporal expression of SpLec1 and SpLec2 mRNA in the megalopa stage was first increased, reached a maximum, and then dropped to the original level again. The research of C-type lectins in Scylla paramamosain could shed new light on studies on immunity and moulting in the mud crab.
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Distribution and abundance of the knobby swimcrab, Macropipus tuberculatus (Roux, 1830) (Decapoda, Portunidae), in the northern and middle Adriatic Sea
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Data on distribution and abundance of the knobby swimcrab Macropipus tuberculatus were collected from the by-catch during fishery-biological investigations of the trawling grounds (“Pipeta” Expedition) in the area of the northern and middle Adriatic Sea from 1985 to 1994. The area investigated was approximately 59 000 km2 of the Adriatic continental shelf at predetermined, permanent stations along ten transects over different sediment types at depths of 10 to 430 m. The data obtained (abundance index: number of specimens per km2) were analysed in relation to depth, sediment type, time of day, and the stations where the species was recorded. The highest species abundance was recorded at depths greater than 200 m and in the area of clayey “relict” sand. In the area of investigation, M. tuberculatus was the most abundant on deeper parts of the continental shelf, and especially on the shelf border and upper slope bottoms in the southernmost part of the middle Adriatic Sea.
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Seasonal distribution of Ostracoda in Bandırma Bay and Erdek Bay, Sea of Marmara, Turkey
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A total of 112 species of Ostracoda was identified as a result of seasonal sampling (four periods a year corresponding to the seasons) at 16 stations in Bandırma Bay and Erdek Bay (Sea of Marmara, Turkey). Fifty-five of these represent new records for the fauna of the Sea of Marmara, and 18 are new records for the Recent marine fauna of Turkey. The number of ostracode species found in Erdek Bay was generally higher than that found in Bandırma Bay, except in spring. Herein the ostracode fauna of the region is documented and its structure discussed.
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Molecular phylogeny of the genera Palaemon and Palaemonetes (Decapoda, Caridea, Palaemonidae) from a European perspective
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A molecular phylogenetic study by Murphy & Austin (2003) showed that Australian representatives of three shrimp genera of the family Palaemonidae (Palaemon, Palaemonetes, and Macrobrachium) do not cluster according to their generic classification. According to their results, the monophyly of these genera is questioned and the generic classification of the subfamily Palaemoninae is at stake. A large number of representatives of Palaemon and Palaemonetes inhabit European waters, including the type species of each genus. To clarify the phylogeny of these species, and thus the position of the generic names Palaemon and Palaemonetes on a phylogenetic tree, we obtained DNA sequences of the same genetic markers (16S mtDNA) as used by Murphy & Austin (2003) and re-addressed the question of taxonomy and phylogeny of these two genera within the subfamily Palaemoninae. Our results confirm the paraphyly of Palaemon and Palaemonetes. In contrast, the resulting monophyletic clades reflect the geographic distribution of the species according to their respective continents: Africa-Europe, Asia, Australia, and America. With the exception of Palaemon elegans the Afro-European species cluster in a way that would support monophyly of the two genera, if representatives from other continents are excluded. Possible taxonomic solutions are discussed.
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Professor Jacques Forest (1920-2012)
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The spotfin burrfish (Chilomycterus reticulatus), a new host record for Cymothoa pulchra (Isopoda, Cymothoidae)
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