You stay, but I Hop: Host shifting near and far co‐dominated the evolution of Enchenopa treehoppers

Abstract

The importance and prevalence of phylogenetic tracking between hosts and dependent organisms caused by co‐evolution and shifting between closely related host species have been debated for decades. Most studies of phylogenetic tracking among phytophagous insects and their host plants have been limited to insects feeding on a narrow range of host species. However, narrow host ranges can confound phylogenetic tracking (phylogenetic tracking hypothesis) with host shifting between hosts of intermediate relationship (intermediate hypothesis). Here, we investigated the evolutionary history of the Enchenopa binotata complex of treehoppers. Each species in this complex has high host fidelity, but the entire complex uses hosts across eight plant orders. The phylogenies of E. binotata were reconstructed to evaluate whether (1) tracking host phylogeny; or (2) shifting between intermediately related host plants better explains the evolutionary history of E. binotata. Our results suggest that E. binotata primarily shifted between both distant and intermediate host plants regardless of host phylogeny and less frequently tracked the phylogeny of their hosts. These findings indicate that phytophagous insects with high host fidelity, such as E. binotata, are capable of adaptation not only to closely related host plants but also to novel hosts, likely with diverse phenology and defense mechanisms.

The nature of interspecific interactions and co‐diversification patterns, as illustrated by the fig microcosm

“…The prevalence host switching could reflect two nonexclusive influences. It should arise if hosts respond to diverse sets of specialized antagonists with batteries of defences (Jermy, ; Janz, ; Hardy & Otto, ), and is commonly observed for figs and galling wasps (Cook & Segar, ) and other antagonistic associations (Doña et al ., ; Hsu et al ., ; Purcell et al ., ). Host switching could also be promoted by competition among multiple galling species contesting for access to ovules of the same fig species (e.g.…”

No evidence for host plant associated genetic divergence in a population of Bullacris unicolor (Linnaeus, 1758) (Orthoptera: Pneumoridae)

“…Genetic and phenotypic differences between insects feeding on different species of host plants are well documented and consistent with theories of sympatric speciation (Diehl & Bush 1984;Fritz & Simms 1992;Via 2001;Drès & Mallet 2002;Hsu et al 2018). Host plant associated ecological divergence among insect populations is often assessed in terms of traits, such as feeding preferences, mate choice, growth, survivorship, performance and fecundity (Funk et al 2002).…”

“…The success of predators and parasitoids may also be affected by host plant characteristics (Matsubayashi et al 2010). Thus, the observed relationship between host plants and morphology may be the product of multiple mechanisms, such as selective predation, developmental plasticity, adaptive and non-adaptive processes (Augustyn et al 2017;Hsu et al 2018).…”

Evolutionary diversification of Japanese Stomaphis aphids (Aphididae, Lachninae) in relation to their host plant use and ant association

“…Similar evolutionary host shifting by phloem sap feeders has been shown in the treehopper Enchenopa binotata species complex; each host lineage in this complex is specific to a single plant species, but together the host lineages use various plant taxa (Wood and Guttman 1983). Wood and Guttman (1983) inferred that this pattern reflects, first, fidelity to a single plant species, which arises because specialization on a particular plant species is advantageous for each host lineage; second, a release from phylogenetic constraints that enables the occurrence of shifts between distantly related plant species (Wood and Keese 1990;Wood 1993;Hsu et al 2018).…”