Mutualism as a Source of Evolutionary Innovation: Insights from Insect-Plant Interactions

Abstract

Mutualism is ubiquitous in nature and probably all species in the world are involved in some form of such ecological interaction. The evolution of mutualisms is often envisioned in a framework where individual selection leads to reciprocal exploitation that results in net benefits to all the interacting parties, i.e. in a framework in which individual selection intrinsically destabilises the mutualistic association. However, mutualisms are stable, and rarely turn into parasitism. At a macroevolutionary scale, mutualisms have been a source of major evolutionary innovations and have benefited all the species involved. Indeed, complementary traits of the partners enable them to colonise new ecological niches. In this chapter we discuss mutualism as a source of evolutionary innovation, using some insect-plant associations as examples. Firstly, we dedicate a topic to theoretical aspects and hypotheses on evolutionary forces stabilizing mutualisms (and their pitfalls). We present some examples of mutualisms that allowed insects and/or plants to expand their ecological niches. Finally, we focus on fig tree -animal interactions that, putatively, allowed this plant lineage to diversify in subtropical and tropical ecosystems and to form a group of keystone species for the functioning of many forest ecosystems. Learning objectives: After completing this chapter, you should understand the following:  To understand the evolution of mutualisms we need to look at natural selection operating at different levels  The general architecture of mutualistic associations  Mutualisms are ecologically and evolutionarily stable  Mutualistic associations may boost species diversification by creating new ecological opportunities (innovations) for the interacting species

Mutualist- and antagonist-mediated selection contribute to trait diversification of flowers

“…Mutualisms, defined as interspecific interactions that are beneficial to all the involved partners, have been a source of major evolutionary innovations ( Pereira & Kjellberg, 2021 ). Mutualists of flowers are usually grouped according to the types of resources and services exchanged: transportation, protection, or nutrition, including pollinators, predators, parasitoids and beneficial microorganisms ( Bronstein, Wilson & Morris, 2003 ; Rafferty, CaraDonna & Bronstein, 2015 ).…”

Genome analysis and genomic comparison of a fungal cultivar of the nonsocial weevil Euops chinensis reveals its plant decomposition and protective roles in fungus-farming mutualism

“…Many eusocial and subsocial insects such as ants ( Mueller et al, 2001 ), termites ( Aanen, 2006 ), and ambrosia beetles ( Kirkendall et al, 2015 ) exhibit sophisticated forms of mutualistic relationships with fungi (fungus-farming mutualisms) that allow these insects to cultivate their fungal crops on appropriate substrates, and in turn these insects obligatorily rely on consumption of their fungal crops for key nutrients and/or certain services such as protection from enemies ( Biedermann and Vega, 2020 ). Mutualisms between fungi and fungus-farming insects are model systems for studying co-evolutionary interactions between species ( Nygaard et al, 2016 ; Solomon et al, 2019 ; Biedermann and Vega, 2020 ; Pereira and Kjellberg, 2021 ). Compared to the well-documented fungus-farming mutualisms in some social insects, fungus farming by non-social organisms is uncommon, but includes some examples such as a lizard beetle Doubledaya bucculenta ( Toki et al, 2012 ), weevils in the genus Euops (Coleoptera: Attelabidae) ( Sawada and Morimoto, 1986 ; Kobayashi et al, 2008 ; Li et al, 2012 ), a marine snail ( Silliman and Newell, 2003 ), and several species of damselfish ( Hata and Kato, 2006 ).…”

Impacto de insetos herbívoros e do fogo no desenvolvimento vegetativo e reprodutivo de plantas de cerrado

“…As interações positivas beneficiam ambos os membros da interação e tendem a se manter mais facilmente na história evolutiva das espécies (PEREIRA; KJELLBERG, 2021). Já as interações negativas resultam em efeitos negativos para um dos membros da interação, enquanto conferem benefícios ao outro.…”