title: Scale insect host ranges are broader in the tropics.
abstract: The specificity of the interactions between plants and their consumers varies considerably. The evolutionary and ecological factors underlying this variation are unclear. Several potential explanatory factors vary with latitude, for example plant species richness and the intensity of herbivory. Here, we use comparative phylogenetic methods to test the effect of latitude on host range in scale insects. We find that, on average, scale insects that occur in lower latitudes are more polyphagous. This result is at odds with the general pattern of greater host-plant specificity of insects in the tropics. We propose that this disparity reflects a high cost for host specificity in scale insects, stemming from unusual aspects of scale insect life history, for example, passive wind-driven dispersal. More broadly, the strong evidence for pervasive effects of geography on host range across insect groups stands in stark contrast to the weak evidence for constraints on host range due to genetic trade-offs.
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA n8@auburn.edu.
authors.forename: Nate B
authors.initials: NB
authors.lastname: Hardy
authors.affiliation: Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Peterson
authors.affiliation: Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Normark
mesh_terms: D000818:Animals; D005843:Geography; D006430:Hemiptera / Q000502:physiology*; D058507:Host Specificity; D008962:Models, Theoretical; D010802:Phylogeny; D010944:Plants / Q000469:parasitology*; D014329:Tropical Climate
keywords: insect–plant interactions; latitudinal gradients; phylogenetic generalized linear mixed models