Morphology of Mandible and Lateralia in Six Endemic Amphipods (Amphipoda, Gammaridea) from Lake Baikal, in Relation to Feeding

Mekhanikova, I. V.

doi:10.1163/001121610x504289

Cited by 25 publications

(16 citation statements)

References 28 publications

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“…Although grazer size had large effects on final plant biomass, it did not predict the identity of the grazer's alternative resources, and diversity in body mass was therefore not correlated with diversity in feeding niche. Similarly, while mouthpart morphology in amphipods can sometimes be linked to specialised diets (Mekhanikova ), mouthparts in our species do not have obvious morphological differences that might determine which types of macrophytes can be consumed. To accurately assess the effects of feeding trait diversity, there may not be an easy morphological substitute for the direct measurement of feeding rates.…”

Section: Discussionmentioning

confidence: 65%

Trait vs. phylogenetic diversity as predictors of competition and community composition in herbivorous marine amphipods

2012

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Field studies of community assembly patterns increasingly use phylogenetic relatedness as a surrogate for traits. Recent experiments appear to validate this approach by showing effects of correlated trait and phylogenetic distances on coexistence. However, traits governing resource use in animals are often labile. To test whether feeding trait or phylogenetic diversity can predict competition and production in communities of grazing amphipods, we manipulated both types of diversity independently in mesocosms. We found that increasing the feeding trait diversity of the community increased the number of species coexisting, reduced dominance and changed food availability. In contrast, phylogenetic diversity had no effect, suggesting that whatever additional ecological information it represents was not relevant in this context. Although community phylogenetic structure in the field may result from multiple traits with potential for phylogenetic signal, phylogenetic effects on species interactions in controlled experiments may depend on the lability of fewer key traits.

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Section: Discussionmentioning

confidence: 65%

Trait vs. phylogenetic diversity as predictors of competition and community composition in herbivorous marine amphipods

2012

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“…trophic position and basal food source, respectively) are influenced by largely separate mouthpart morphologies. Amphipods employ diverse, highly specialised feeding behaviours, including exoparasitism (Schell, Rowntree & Pfeiffer, 2000;Mekhanikova, 2010), endoparasitism (Laval, 1978;Mekhanikova, 2010), predation (Coleman, 1990), egg predation (Mekhanikova, 2010), scraping ice algae (Arndt et al, 2005) and necrophagy (Saint-Marie, 1984). Lower trophic level species, such as T. texensis, exhibited proportionally larger and more strongly dentate mandibles, suggesting an adaptation to mastication.…”

Section: Discussionmentioning

confidence: 99%

“…Based on field and laboratory observations (Saint-Marie, 1984;Coleman, 1990;Mayer et al, 2009;Mekhanikova, 2010), robust relationships between mouthpart morphology and specific feeding modes have been identified for epigean freshwater and marine amphipods. Based on field and laboratory observations (Saint-Marie, 1984;Coleman, 1990;Mayer et al, 2009;Mekhanikova, 2010), robust relationships between mouthpart morphology and specific feeding modes have been identified for epigean freshwater and marine amphipods.…”

Section: Introductionmentioning

confidence: 99%

Morphological and trophic specialization in a subterranean amphipod assemblage

2014

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Summary Sympatric species are expected to exhibit specialisation that reduces interspecific competition in environments with food resources that exhibit little spatial or temporal variation in availability, while sympatric species in more unpredictable environments should exhibit generalised feeding strategies to exploit a wide range of variable resources. We combined stable isotopes and quantitative mouthpart morphometric data to investigate trophic structure among sympatric species in a diverse subterranean amphipod assemblage in the Edwards Aquifer, Texas, U.S.A. Seven amphipod species occupied different regions of isotopic (δ13C and δ15N) space, suggesting the use of different food resources. Trophic position, measured as δ15N, was negatively correlated with planar area of the mandible and number of molar ridges, while it was positively correlated with incisor width. Reduced molar size and robust incisors are generally associated with predatory feeding strategies in non‐subterranean amphipods. δ13C exhibited non‐significant relationships with mouthpart morphology although one species, Texiweckeliopsis insolita, had significantly different mouthpart and δ13C values. Another species, Stygobromus russelli, had more generalised mouthparts, but isotope values indicate that it had a unique and unidentified feeding method and food source, illustrating the obfuscating effect of phylogeny on form–function relationships. Intraspecific relationships between body size and isotope values indicate that amphipod species showed little to moderate ontogenetic shifts in trophic position. Furthermore, body size did not predict trophic position when data were combined across species, suggesting that larger amphipods do not necessarily feed at higher trophic levels in this community. Our results indicate that sympatric subterranean amphipod species can exhibit specialised feeding strategies, suggesting that competition among species is driving niche partitioning. These results contradict the assumption that variable resource availability in groundwater habitats selects for trophic generalists among sympatric species.

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“…The apical parts of IN teeth bear the greatest load in crushing hard food, and, as shown in previous studies on different species, it is these parts that become worn down during intermolt periods in polyphages and spongiophiles [1]. In A. grewingkii, however, individuals with broken IN teeth occur very rarely.…”

Section: Discussionmentioning

confidence: 61%

“…Recent scanning and transmission electron microscopy studies on six species of endemic Baikal amphipods (Crustacea, Malacostraca) differing in habitat, mode of life, and diet have provided evidence for the relationship between the morphology of the mandible (MD) and the feeding strategy of the species [1].…”

Section: Introductionmentioning

confidence: 99%

Specific Features of Mandible Structure and Elemental Composition in the Polyphagous Amphipod Acanthogammarus grewingkii Endemic to Lake Baikal

et al. 2012

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BackgroundIn crustaceans, several mechanisms provide for the mechanical strength of the cuticular “tools” (dactyli, claws, jaws), which serve to catch and crush food objects. Studies on the mandibles of the endemic Baikal amphipod Acanthogammarus grewingkii by means of electron microscopy and elemental analysis have revealed specific structural features of these mouthparts.MethodologyThe fine structure of the mandible has been studied by means of SEM, TEM, and AFM; methods used to analyze its elemental and phase composition include XEPMA, XPS, SEM-EDS analysis, and XRD.ConclusionFunctional adaptations of the mandible in A. grewingkii provide for the optimum combination of mechanical hardness and fracture resistance, which is achieved due to a complex structure and composition of its cutting parts. Teeth of the mandible are covered by a thin layer of silica (10–20 µm). Their epicuticle is characterized by a high density, consists of three layers, and increases in thickness toward the tooth apex. The epicuticle is enriched with Br, while the concentrations of Ca and P reach the peak values in the softer internal tissues of the teeth. These data broaden the view of the diversity of adaptation mechanisms providing for the strengthening of cuticular “tools” in crustaceans.

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Morphology of Mandible and Lateralia in Six Endemic Amphipods (Amphipoda, Gammaridea) from Lake Baikal, in Relation to Feeding

Cited by 25 publications

References 28 publications

Trait vs. phylogenetic diversity as predictors of competition and community composition in herbivorous marine amphipods

Trait vs. phylogenetic diversity as predictors of competition and community composition in herbivorous marine amphipods

Morphological and trophic specialization in a subterranean amphipod assemblage

Specific Features of Mandible Structure and Elemental Composition in the Polyphagous Amphipod Acanthogammarus grewingkii Endemic to Lake Baikal

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