Generalist flowers, biodiversity and florivory: implications for angiosperm origins

Abstract

A brief overview of arthropod/insect evolution with particular emphasis on herbivory provides the starting point for discussion of increased herbivory over time. The term "flower" is defined, and it is noted that angiosperm flowers are distinguished by their edibility. It is observed that the phenomenon of florivory is a primary plant-animal interaction, and pollination, as one possible outcome of the eating of flowers, is a secondary phenomenon. An hypothesis reconciling the facts that angiosperms are the most eaten of all plant groups and the most successful in term of number of species is proposed. From the perspective of a floral morphologist, I discuss what a generalist flower is and how archaic angiosperms are characterized by this flower type. Biodiversity arguments underpin a discourse on why researchers should investigate generalist flowers and florivory.

How many species of arthropods visit flowers?

“…Instead, evidence now suggests that the earliest angiosperms were generalised in their pollination syndromes (Bernhardt 2000;Hu et al 2008). The early emergence of specialised beetle pollination systems (Qiu et al 1999;Bernhardt 2000) suggests that beetles were among the most numerous and effective pollinators that visited the first generalised entomophilous flowers (Bernhardt and Thien 1987;Bernhardt 2000;Frame 2003). Indeed, species from one of the more archaic herbivorous beetle families, Nemonychidae, continue to feed on The weighted mean is the percentage of the total number of tree species pollinated by each group across the included studies a Momose et al (1998), b Kato (1996), c Kato et al (2008), d Hansman (2001), e Machado and Lopes (2004), f Gottsberger and SilberbauerGottsberger (2006), g Bawa et al (1985), h, i Frankie et al (2003), j Kress and Beach (1994), k Ramirez and Seres (1994), l Renner and Feil (1993) How many species of arthropods visit flowers?…”

“…Invertebrates visit flowers for their own interests (typically to find food or a mate), not to intentionally carry out pollination, which is rather a by-product of their foraging behaviour (Frame 2003). Flowers offer high-quality food resources in the form of nectar and pollen (Roulston and Cane 2000), while the flowers themselves may also represent less well-defended material for chewing herbivores compared to leaves (Carisey and Bauce 1997).…”

One-step identification of conserved miRNAs, their targets, potential transcription factors and effector genes of complete secondary metabolism pathways after 454 pyrosequencing of calyx cDNAs from the Labiate Salvia sclarea L

“…Special emphasis was originally placed on pollinating insect attraction and the intertwined co-evolution of insects and flower perianths' morphologies (Ehrlich and Raven, 1964). However, a growing body of research has recently suggested that floral adaptations also reflect resistance/tolerance to the feeding of insects on floral parts (florivory) and to flower larceny (Baldwin and Karb, 1995;Frame, 2003;Mccall and Irwin, 2006). Both events increase the cost of attracting pollinators and reduce plant fitness by direct damage and by indirect effects on pollinator behaviour.…”

“…The adaptive value of this floral trait has intrigued evolutionary biologists since the early 20th century. Using a wide variety of approaches, many authors have presented results suggesting that specialised and complex perianth morphologies have evolved in response to selective pressure from insects (Frame, 2003). Special emphasis was originally placed on pollinating insect attraction and the intertwined co-evolution of insects and flower perianths' morphologies (Ehrlich and Raven, 1964).…”

Olycella aff. junctolineella (Lepidoptera: Pyralidae) florivory on Opuntia microdasys, a Chihuahuan Desert endemic cactus

“…Although the effect of tissue herbivory on plant fitness has been extensively studied, little research has focused on florivory (i.e., bud or flower consumption prior to the formation of the seed coat, McCall and Irwin, 2006) even though the evidence indicates that florivory is a very specialized (Ferná ndez et al, 2008;Mann, 1969) and old interaction (Frame, 2003). In particular, Lepidoptera larvae have been recognized as major consumers of reproductive structures (i.e., flowers, fruits, or seeds) in certain families of plants (Ehlers and Olesen, 2003;Pratt and Pierce, 2001;Winotai et al, 2005).…”