Insights into Super-host Plant Species of Galling Insects in the Neotropical Region

Abstract

Background: The term ‘super host’ plant is often used in the literature surrounding plant-galling interactions, but the different contexts in which the term is used generates doubt and confusion due to the absence of a systematic definition of the term’s meaning. Objective: In this study, we used 60 well-defined plant-galling assemblages to propose a systematic definition of super-host plants at the local and regional level. In addition, we investigated factors that explain the number of galling species per host plant at different geographic scales. Methods: Plant-galling assemblages were compiled from an extensive literature review on insect gall inventories carried out in Brazil. Results: We found 888 host plant species belonging to 94 families and 340 genera hosting 2,376 insect gall morphotypes. At a local scale, 33.2% of host plant species harbored one insect gall morphotype and 12.2% hosted two gall morphotypes, making up 45.4% of the host plant species in each locality. At the regional scale, 51.5% of host plant species harbored one insect gall morphotype, and 17.9% of host plant species hosted two gall morphotypes, corresponding to 69.4% of all host plant species. Based on the average number of galling species per plant species, we classified the plant species into: 1) Host species; 2) Multi-host species and 3) Super-host species. The super-host plant species that showed the greatest richness of gall morphotypes at the local level were Baccharis reticularia and Adenocalymma neoflavidu. Furthermore, we found a positive relationship between plant life-form architectural complexity and the number of galling species at the local level. At the regional scale, we registered five super-host species (Guapira opposita, Protium heptaphyllum, Copaifera langsdorffii, Myrcia splendens, and Byrsonima sericea) which hosted 21 or more insect gall morphotypes. The number of galling species per host plant species at the regional scale was influenced positively by geographic distribution rank and number of biomes in which each species of the plant occurs. Conclusion: The present study stands out as the first of its kind to provide a systematic standardization for the super-host plants and to investigate factors influencing these species.

Temporal resource partitioning and stochastic colonization explain the co‐occurrence of gall‐inducing insects in the super‐host plant Copaifera langsdorffii Desf. (Fabaceae)

“…Consequently, the high turnover among host plants generates a large regional pool of gall‐inducing species associated with the super‐host plant (but see Grandez‐Rios et al . 2020 for interpretations of α‐ and β‐diversities of galling insects associated with super‐hot plants at broad spatial scales). Taken together, our results indicate that the temporal resource partitioning and the relationship high β‐diversity among host plants are the main factors related to the high number of gall‐inducing insects associated with C. langisdorffii .…”

“…Estimates of the global richness of gallinducing insects indicate more than 132 000 species, with most of them occurring in the Neotropical region (Esp ırito-Santo & Fernandes 2007). Within this system, there are some species of plants, called super-hosts, that are capable of harbouring more than 20 species of gall-inducing insects (Veldtman & McGeoch 2003;Grandez-Rios et al 2020). The ecological role of super-host plants on the diversity of gall-inducing insect has been evaluated from two main perspectives.…”

“…Within this system, there are some species of plants, called super‐hosts, that are capable of harbouring more than 20 species of gall‐inducing insects (Veldtman & McGeoch 2003; Grandez‐Rios et al . 2020). The ecological role of super‐host plants on the diversity of gall‐inducing insect has been evaluated from two main perspectives.…”

“…multiple communities) levels (Grandez‐Rios et al . 2020). However, there is no study describing the relationship between regional richness (i.e.…”

“…alpha richness) at local level ( sensu Grandez‐Rios et al . 2020). Regional richness could be high while local richness of gall‐inducing species is low, indicating high compositional turnover (i.e.…”