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Generalisation within specialization: inter-individual diet variation in the only specialized salamander in the world.

Costa A, Salvidio S, Posillico M, Matteucci G, De Cinti B, Romano A - Sci Rep (2015)

Bottom Line: Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones.Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent.At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.

View Article: PubMed Central - PubMed

Affiliation: Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale (CNR-IBAF), Area di Ricerca Roma 1, Via Salaria km 29, 300-00015. Monterotondo (RM) (Italy).

ABSTRACT
Specialization is typically inferred at population and species level but in the last decade many authors highlighted this trait at the individual level, finding that generalist populations can be composed by both generalist and specialist individual. Despite hundreds of reported cases of individual specialization there is a complete lack of information on inter-individual diet variation in specialist species. We studied the diet of the Italian endemic Spectacled Salamander (Salamandrina perspicillata), in a temperate forest ecosystem, to disclose the realised trophic niche, prey selection strategy in function of phenotypic variation and inter-individual diet variation. Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones. Analyses of inter-individual diet variation showed that a subset of animals exhibited a broader trophic niche, adopting different foraging strategies. Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent. At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.

No MeSH data available.


Related in: MedlinePlus

Scatterplot of the probability of use of Collembola, obtained from resource selection probability functions (RSPF), in relation to body condition index (SMI).
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f4: Scatterplot of the probability of use of Collembola, obtained from resource selection probability functions (RSPF), in relation to body condition index (SMI).

Mentions: Collembola are little armored and therefore highly energetic17 but, at the same time, hard to catch because they evolved their furcula as an escape mechanism to avoid predators, being able to jump like “miniature kangaroos”18. Thus, our findings concerning the seasonality effect, which mainly deal with prey availability, and the phenotypic variation of salamanders, may be regarded as a balance between the energy content of a given food and the difficulty in obtaining it. Larger salamanders, and in a better physiological condition, have higher probabilities of consuming Collembola (Fig. 4), while smaller and under-performing individuals had high probabilities of selecting Acarina and Araneae.


Generalisation within specialization: inter-individual diet variation in the only specialized salamander in the world.

Costa A, Salvidio S, Posillico M, Matteucci G, De Cinti B, Romano A - Sci Rep (2015)

Scatterplot of the probability of use of Collembola, obtained from resource selection probability functions (RSPF), in relation to body condition index (SMI).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543951&req=5

f4: Scatterplot of the probability of use of Collembola, obtained from resource selection probability functions (RSPF), in relation to body condition index (SMI).
Mentions: Collembola are little armored and therefore highly energetic17 but, at the same time, hard to catch because they evolved their furcula as an escape mechanism to avoid predators, being able to jump like “miniature kangaroos”18. Thus, our findings concerning the seasonality effect, which mainly deal with prey availability, and the phenotypic variation of salamanders, may be regarded as a balance between the energy content of a given food and the difficulty in obtaining it. Larger salamanders, and in a better physiological condition, have higher probabilities of consuming Collembola (Fig. 4), while smaller and under-performing individuals had high probabilities of selecting Acarina and Araneae.

Bottom Line: Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones.Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent.At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.

View Article: PubMed Central - PubMed

Affiliation: Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale (CNR-IBAF), Area di Ricerca Roma 1, Via Salaria km 29, 300-00015. Monterotondo (RM) (Italy).

ABSTRACT
Specialization is typically inferred at population and species level but in the last decade many authors highlighted this trait at the individual level, finding that generalist populations can be composed by both generalist and specialist individual. Despite hundreds of reported cases of individual specialization there is a complete lack of information on inter-individual diet variation in specialist species. We studied the diet of the Italian endemic Spectacled Salamander (Salamandrina perspicillata), in a temperate forest ecosystem, to disclose the realised trophic niche, prey selection strategy in function of phenotypic variation and inter-individual diet variation. Our results showed that Salamandrina is highly specialized on Collembola and the more specialized individuals are the better performing ones. Analyses of inter-individual diet variation showed that a subset of animals exhibited a broader trophic niche, adopting different foraging strategies. Our findings reflects the optimal foraging theory both at population and individual level, since animals in better physiological conditions are able to exploit the most profitable prey, suggesting that the two coexisting strategies are not equivalent. At last this species, feeding on decomposers of litter detritus, could play a key role determining litter retention rate, nutrient cycle and carbon sequestration.

No MeSH data available.


Related in: MedlinePlus