title: Thrips pollination of Mesozoic gymnosperms.
abstract: Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopites pollen grains. These females bear unique ring setae interpreted as specialized structures for pollen grain collection, functionally equivalent to the hook-tipped sensilla and plumose setae on the bodies of bees. The most parsimonious explanation for this structure is parental food provisioning for larvae, indicating subsociality. This association provides direct evidence of specialized collection and transportation of pollen grains and likely gymnosperm pollination by 110-105 million years ago, possibly considerably earlier.
authors.affiliation: Museo Geominero,  Instituto Geológico y Minero de España, Madrid E-28003,  Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Peñalver
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Labandeira
authors.forename: Eduardo
authors.initials: E
authors.lastname: Barrón
authors.forename: Xavier
authors.initials: X
authors.lastname: Delclòs
authors.forename: Patricia
authors.initials: P
authors.lastname: Nel
authors.forename: André
authors.initials: A
authors.lastname: Nel
authors.forename: Paul
authors.initials: P
authors.lastname: Tafforeau
authors.forename: Carmen
authors.initials: C
authors.lastname: Soriano
mesh_terms: D000818:Animals; D005075:Biological Evolution; D032462:Cycadopsida / Q000145:classification / Q000469:parasitology / Q000502:physiology*; D005260:Female; D006790:Host-Parasite Interactions; D010163:Paleontology / Q000379:methods; D011058:Pollen / Q000502:physiology*; D054817:Pollination / Q000502:physiology*; D013030:Spain; D013045:Species Specificity; D061149:Thysanoptera / Q000033:anatomy & histology / Q000145:classification / Q000502:physiology*