  Trophic niche width, shift, and specialization of Dascyllus aruanus in Toliara lagoon, MadagascarFrederich, Bruno  ; ; Vandewalle, Pierre et alin Copeia (2010), 2010(2), 218-226 Intrapopulation diet specializations may result from the use of different dietary items or foraging tactics by individuals within a single population. The damselfish, Dascyllus aruanus, is a highly site ... [more ▼] Intrapopulation diet specializations may result from the use of different dietary items or foraging tactics by individuals within a single population. The damselfish, Dascyllus aruanus, is a highly site-attached coral reef fish living in size hierarchies among branched corals. The trophic niche width and feeding specialization of this species were explored using stable isotopes and stomach content analyses. Intra-group niche variation was mainly related to fish size. Within social groups, D. aruanus gradually shifted its foraging tactics according to size; smaller fish fed on benthic prey such as isopods and copepods, and the larger fish foraged in the water column on planktonic copepods and larger-sized prey. Group density was found to explain some variation in trophic niche characteristics; greater specialization on prey size was observed in the colony having the highest density. All members of the largest colony foraged more frequently in the water column. Knowing that planktonic copepods are more energy-rich than benthic ones, a positive group-size effect facilitating access to preferred prey is suggested. Group size and group density effects on trophic specialization did not have any impact on body condition, suggesting that the behavioral plasticity of D. aruanus in its foraging strategies permits compensation for the maintenance of body conditions. [less ▲] Detailed reference viewed: 61 (3 ULg)New host and geographical distribution for the pearlfish Carapus mourlani (Pisces, Carapidae) with a discussion on Carapini nomenclature and biogeographyParmentier, Eric ; ; in Copeia (2006), 2006 Specimens of the pearlfish Carapus mourlani (Carapidae) were observed for the first time in association with the sea cucumber Isostichopus fuscus (Holothuroidea: Echinodermata) along the coast of Ecuador ... [more ▼] Specimens of the pearlfish Carapus mourlani (Carapidae) were observed for the first time in association with the sea cucumber Isostichopus fuscus (Holothuroidea: Echinodermata) along the coast of Ecuador. Out of 4345 sea cucumbers collected from various depths between 5 and 60 m, 12 harbored a pearlfish either in the coelomic cavity, the respiratory tree, or the digestive tract, yielding a prevalence of ca. 0.0028. The presence of C. mourlani appeared to be detrimental to the holothurian host in some cases. Side effects resulting from coelomic cavity infections included less advanced gonad maturity (reduced gonadal tubule diameter and length, lower ratio of mature oocytes) and a significant proportion of necrotic and shriveled gonadal tubules, devoid of gametes. Aside from discussing this evidence, the present paper briefly describes the biology of the pearlfish, its relationship with the host, and its daily activity cycle. [less ▲] Detailed reference viewed: 21 (0 ULg)Encheliophis chardewalli: A new species of carapidae (Ophidiiformes) from French Polynesia, with a redescription of Encheliophis vermicularisParmentier, Eric in Copeia (2004), (1), 62-67 A specimen of Encheliophis was found in the coelomic cavity of a sea cucumber in Moorea (French Polynesia). The skeletal morphology (skull, girdles, vertebrae) reveal it to be a new species, described ... [more ▼] A specimen of Encheliophis was found in the coelomic cavity of a sea cucumber in Moorea (French Polynesia). The skeletal morphology (skull, girdles, vertebrae) reveal it to be a new species, described herein as Encheliophis chardewalli. It is separable from all described species of Encheliophis (except Encheliophis vermicularis) by the lack of pectoral fins and from E. vermicularis by the larger and fewer teeth on the lower jaw (14 vs more than 20 in E. vermicularis) and by seven branchiostegal rays (vs six in E. vermicularis). [less ▲] Detailed reference viewed: 11 (2 ULg)Effect of rival males on the courtship of paedomorphic and metamorphic Triturus alpestris (Amphibia : Salamandridae)Denoël, Mathieu in Copeia (2003), (3), 618-623 Current theories on the alternative mating tactics suppose that individuals may opt for particular behavioral patterns depending of their morphological status. Facultative paedomorphosis in newts and ... [more ▼] Current theories on the alternative mating tactics suppose that individuals may opt for particular behavioral patterns depending of their morphological status. Facultative paedomorphosis in newts and salamanders is a suitable process to explore this question because it implies the coexistence of two different morphological morphs differing by the presence of gills and epigamic traits. The aim of this study was to find out whether paedomorphs and metamorphs use similar tactics to attract mates in the presence of a rival and whether there are differences in sexual activity and success between alternative morphs. Sexual interactions in triadic encounters were staged and analyzed in a standardized experimental design. The two kinds of males did not differ in terms of sexual activity, spermatophore deposition or female responsiveness. Both rival paedomorphic and metamorphic males exhibited sexual interference, but in most encounters, intruders just disturbed the courting pair. Sperm transfer success was lower in triadic encounters than in dyadic encounters. These results illustrate that intermorph breeding also occurs in the presence of competitors but that the success rate of the newts is considerably decreased in such competitive situations. Moreover, newts do not use alternative reproductive tactics depending on their status (i.e., paedomorpho or metamorph). [less ▲] Detailed reference viewed: 84 (4 ULg) |
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