Are insect pollinators more generalist than insect herbivores?

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.

Diversity of plant evolutionary lineages promotes arthropod diversity

“…In fact, phylogenetic structure of species interactions is not limited to consumer–resource interactions, but also occurs in mutualistic interactions (Fontaine et al . ; Gómez et al . ).…”

How many species of arthropods visit flowers?

“…However, most of the work on pollination networks has been carried out on herb communities, grasslands, or alpine meadows in the temperate zone (see data in (1980), e Lack and Kevan (1984), f Armstrong and Irvine (1989), g Armstrong and Drummond (1986) How many species of arthropods visit flowers? Fontaine et al 2009;Schleuning et al 2012). While these studies have revealed valuable insights into the structure, resilience, and function of pollinator communities, they cannot be easily extrapolated to forest habitats such as tropical rainforests, where there is a greater diversity of pollination systems (Ollerton et al 2006).…”

Effects of native pollinator specialization, self‐compatibility and flowering duration ofEuropean plant species on their invasiveness elsewhere

“…; Ollerton et al . ) or the number of links of a plant species with pollinators in a plant–pollinator network (Fontaine, Thébault & Dajoz ) may already serve as proxies of specialization. However, these metrics inevitably depend on observation frequency and, consequently, may be biased in that more common (or more attractive) species are regarded as more generalized (Blüthgen ).…”