Are insect pollinators more generalist than insect herbivores?

NERC Centre for Population Biology, Division of Biology, Imperial College London, , Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 07/2009; 276(1669):3027-33. DOI: 10.1098/rspb.2009.0635
Source: PubMed

ABSTRACT Recent community-level studies have acknowledged that generalist species are more widespread than previously thought and highlighted their preponderant impact on community functioning and evolution. It is suggested that the type of interaction, trophic versus mutualistic, should affect species generalization level; however, no direct comparison has been made yet. Here, we performed such a comparison using 44 plant-insect networks describing either pollination or herbivory communities. Our analysis shows that the type of interaction does indeed have an impact on various aspects of species generalism, from the distribution of generalism in the community to the phylogenetic diversity of the plants with which a given insect species interacts. However, the amplitude of the observed differences depends on the aspect of species generalism studied. While the non-quantitative and quantitative measures of generalism suggest that pollinators interact with more plant species and more evenly than herbivores, phylogenetic measures clearly show that herbivores interact with plant species far more closely related to each other than pollinators. This comparative approach offers a promising perspective to better understand the functioning and evolution of multispecies assemblages by pointing out some fundamental singularities of communities depending on the type of interaction considered.

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    • "Methods, taxonomic coverage, and level of resolution vary widely among recent studies, with the resultant data points being heavily biased toward low and intermediated latitudes (Fontaine et al. 2009; Schleuning et al. 2012; Morris et al. 2014). Yet, with Zackenberg as the only data point north of the arctic circle, they seem to jointly attest against any general simplification of biotic interaction structure toward the poles (but see Schleuning et al. 2012). "
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    Ecology and Evolution 08/2015; 5(17):3842-3856. DOI:10.1002/ece3.1647 · 2.32 Impact Factor
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    • "Nevertheless, one mechanism that could explain the high specialisation of rare species is the constant co-evolution of defences and counter-defences, such as those between animals and plants (Thompson 2005), as observed in other antagonistic networks (Thompson 1994; Fontaine et al. 2009). In the case of plants, the putative defences "
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    ABSTRACT: Background: Antagonistic interactions, such as parasitism and herbivory, are generally specialised and have a strong phylogenetic signal for specialisation. As lianas and trees interact antagonistically, we expect to find phylogenetic signal for specialisation. Aims: We aimed to answer the following questions: (1) Is the liana–tree network specialised? (2) Is the specialisation of liana–tree network related to the abundance of both the life forms? (3) Is liana and tree specialisation related to species phylogeny? (4) Do phylogenetically related liana species occupy phylogenetically related tree species, and vice versa? Methods: For three areas in southern Brazil, we calculated the specialisation value of each liana and tree species (d') and of the entire network (H2′). Binomial regression and null models were used to test the role of abundance on d' and H2′, respectively. We searched for the presence of phylogenetic signal with phylogenetic independent contrasts for d'. We also compared the similarity of species sets and their interaction with phylogenetic distance between them using Mantel test. Results: All three networks had significant values of H2′, but the values of d' did not have significant phylogenetic signals. Closely related lianas did not share similar host-tree assemblages and vice versa. Rare species were more specialised than abundant species, and abundance did not influence H2′. Conclusions: Our study indicates that the significant H2′ may be due to co-evolution in some lineages of lianas and trees. Nevertheless, the abundance of species may also play an important role in species interaction, mainly rare species.
    Plant Ecology & Diversity 01/2015; 8(3). DOI:10.1080/17550874.2015.1004561 · 1.77 Impact Factor
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    • "For both plant-pollinator and plantherbivore networks asymmetric specialization in terms of the number of links per species is significant but most of the pollination networks are highly asymmetric and most of the herbivory networks are weakly asymmetric (Thébault and Fontaine 2008). Pollinators interact with more plant species and more evenly than herbivores but herbivores interact with plant species far more phylogenetically related to each other (Fontaine et al. 2009). Building a population dynamics model, Thébault and Fontaine (2010) found that higher diversity and connectance promote persistence and resilience of mutualistic networks but destabilize trophic networks. "
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    Population Ecology 01/2015; 57(1). DOI:10.1007/s10144-015-0482-5 · 1.57 Impact Factor
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