Article

Ecological interactions are evolutionary conserved across the entire tree of life.

Departamento de Ecología, Universidad de Granada, E-18071 Granada, Spain.
Nature (Impact Factor: 42.35). 06/2010; 465(7300):918-21. DOI: 10.1038/nature09113
Source: PubMed

ABSTRACT Ecological interactions are crucial to understanding both the ecology and the evolution of organisms. Because the phenotypic traits regulating species interactions are largely a legacy of their ancestors, it is widely assumed that ecological interactions are phylogenetically conserved, with closely related species interacting with similar partners. However, the existing empirical evidence is inadequate to appropriately evaluate the hypothesis of phylogenetic conservatism in ecological interactions, because it is both ecologically and taxonomically biased. In fact, most studies on the evolution of ecological interactions have focused on specialized organisms, such as some parasites or insect herbivores, belonging to a limited subset of the overall tree of life. Here we study the evolution of host use in a large and diverse group of interactions comprising both specialist and generalist acellular, unicellular and multicellular organisms. We show that, as previously found for specialized interactions, generalized interactions can be evolutionarily conserved. Significant phylogenetic conservatism of interaction patterns was equally likely to occur in symbiotic and non-symbiotic interactions, as well as in mutualistic and antagonistic interactions. Host-use differentiation among species was higher in phylogenetically conserved clades, irrespective of their generalization degree and taxonomic position within the tree of life. Our findings strongly suggest a shared pattern in the organization of biological systems through evolutionary time, mediated by marked conservatism of ecological interactions among taxa.

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Available from: Francisco Perfectti, Aug 04, 2015
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    • "Given all the above, niche conservatism (i.e., the tendency of species to retain ancestral conditions, Wiens et al., 2010) seems the most plausible process to account for the observed distributional pattern of the two Lebbeus sister species. It is now well known that ecological interactions are evolutionarily conserved, both in cases of specialised and generalised interactions (Gómez et al., 2010), and that the evolution of specialisation, e.g., the adaptation to a specific environment, implies a covariation of the genotype with environmental performance (Poisot et al., 2011). "
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    ABSTRACT: We report a remarkable case of ‘bipolarism’, where two different polar species, namely Lebbeus polaris in the northern hemisphere and Lebbeus kiae n. sp., here described from the Southern Ocean, have been found to share similar ecologies. Despite the great geographical distance between the two species, both show high host fidelity in associations with two congeneric sea anemones: Bolocera tuediae and Bolocera kerguelensis, respectively. A close molecular phylogenetic relationship between the two Lebbeus species is indicated by COI data, which clearly show them as sister clades with respect to other congeners as well as a plurality of other Antarctic species. This is the first reported case of a defensive association in the Southern Ocean involving shrimps and sea anemones. The distribution of the new species, limited to seamount systems off the Ross Sea, may be the result of a specific colonisation/speciation event in the past, although more molecular data are needed to unravel the phylogenetic relationships within the genus Lebbeus. Despite this uncertainty, the persistence of ecological traits, i.e., the defensive association with sea anemones, indicates the presence of niche conservatism in this clade of shrimps.
    Hydrobiologia 07/2015; DOI:10.1007/s10750-015-2403-1 · 2.21 Impact Factor
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    • "The possibility remains that some key niche adaptations that are little conserved throughout the evolutionary history of the lineages may have produced extinction patterns resembling those produced by functional equivalences, even when they are not (see Appendix S4). However, evidence suggests that both life history (Davies et al., 2013) and ecological interactions (Gómez et al., 2010) exhibit phylogenetic conservatism in plants. "
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    05/2015; 24(7). DOI:10.1111/geb.12310
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    • "These conflicting ideas about what is and what is not PNC have resulted in a strong debate on its prevalence in nature. While some studies have reported support for PNC (Ackerly 2004; Gomez, Verdu & Perfectti 2010; Burns & Strauss 2011), others have provided counter-examples (Evans et al. 2009; Boucher et al. 2012; Pearman et al. 2014) and some studies have demonstrated its dependency on studied systems, time-scales and niche-related traits (Peterson, Soberon & Sanchez-Cordero 1999; Freckleton & Jetz 2009; Cooper, Freckleton & Jetz 2011). However, as the different studies define PNC differently and accordingly utilize different measures, they are not directly comparable (Revell, Harmon & Collar 2008; Ackerly 2009) and inevitably lead to inconsistent conclusions about the prevalence of niche conservatism (Losos 2008). "
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    ABSTRACT: 1. The prevalence of phylogenetic niche conservatism (PNC) in nature is still a conflicting issue. Disagreement arises from confusion over its precise definition and the variety of approaches to measure its prevalence. Recent work highlighted that common measures of PNC strongly depend on the assumptions of the underlying model of niche evolution. However, this warning has not been well recognized in the applied literature and questionable approaches are still frequently applied. 2. The aim of this paper is to draw attention to the assumptions underlying commonly applied simple measures of PNC. We used a series of simulations to illustrate how misleading results can be if assumptions of niche evolution are violated, that the violation of assumptions is a common phenomenon and that testing assumptions requires in-depth pre-test. 3. We conclude that the seemingly simple measures of PNC, such as phylogenetic signal and evolutionary rate, are not so easy to apply if one accounts for the necessity to test model assumptions. In addition, these measures can be difficult to interpret. The common assumption that strong phylogenetic signal indicates PNC will be often invalid. In addition, the interpretation of some measures, e.g. the conclusion that evolutionary rate is slow enough to indicate PNC, requires a comparison with another clade, another trait or well-developed null model assumptions and thus additional data. 4. We suggest that studies investigating PNC should always compare alternative evolutionary models, and that model comparisons should in particular include flexible niche evolution models such as multiple-optima OU models, although these are computational intensive. These models are directly inherited from the concept of macro-evolutionary adaptive landscape, and can indicate PNC either by relative few peak shifts or by narrow peaks in the adaptive landscape. A test of PNC thus requires comparing these parameters of the macroevolutionary landscape between clades or time periods. 5. The general prevalence of PNC in nature should be evaluated only based on studies keeping up to the high standards of communicating the used definition of PNC, testing the assumptions made in the modelling approaches and including newly developed models in a model comparison approach.
    Functional Ecology 05/2015; 29(5). DOI:10.1111/1365-2435.12388 · 4.86 Impact Factor
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