Host-plant leaps versus host-plant shuffle: a global survey reveals contrasting patterns in an oligophagous insect group (Hemiptera, Psylloidea)

Abstract

Global analyses of interspecific interactions are rapidly increasing our understanding of patterns and processes at large scales. Understanding how biodiversity assembles and functions on a global scale will increasingly require analyses of complex interactions at different ecological and phylogenetic levels. We present an analysis of host-plant associations in the sap-sucking Psylloidea (∼3,800 species) using the most comprehensive assemblage of host data for this group compiled from 66 % of published records. Psyllids are known for high levels of host specificity and host switching between related plants at local scales, but a global survey implicates historical processes that are not entirely consistent with those at local scales. In particular, saltationary host switching events appear to have been a key factor explaining the wide but patchy distribution of psyllid host-plants throughout the angiosperm phylogeny. Alternative explanations involving co-diversification with subsequent extinction seem implausible. At the seed plant family level, we compare associations for psyllids with those of their relatives the aphids, but, despite notable differences in biogeographic distributions, find few plant families (2%) that host only psyllids but not aphids, while a much larger percentage (31%) host aphids but not psyllids, and 43% of plant families distributed throughout the plant phylogeny host neither group.

Key words:

• centrality
• ecology
• global database
• host-plant
• network analysis
• phylogeny
• psyllid

Acknowledgements

We thank Angel Anta for developing and managing the Psyl'list database. We are grateful to Thierry Bourgoin and Aurélie Delavaud for assistance with Gephi software, and supporting the Database to Name and Taxa project (DBTNT-http://hemiptera-databases.org/dbtnt/). We thank Roger Blackman, Jon Martin and Takumasa Kondo for sharing information on aphids, whiteflies and scale insects, and Neil Brummit for information on plant distributions. We thank Quentin Cronk for comments on earlier manuscript drafts. We thank the Editor in Chief, the Associate Editor, and two anonymous reviewers for their valuable comments that contributed to improving the final version of our manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed here.

Associate Editor: Dimitar Dimitrov