Wind pollination has evolved from animal pollination at least 65 times in flowering plants, but the reverse transition is rare. Wind pollination is usually accompanied by the loss of traits that attract pollinators, and re-evolving them may be difficult. This dissertation examines this rare transition using Artocarpus (ca. 70 spp., Moraceae), a genus of tropical trees with a center of diversity in Borneo. Chapter 1 presents a draft genome sequence for A. camansi and identifies 333 genes suitable for phylogenetic inference in Artocarpus. Chapter 2 uses those genes to reconstruct the phylogeny of Artocarpus, using DNA from museum specimens as much as a century old to achieve 96% taxon sampling. Chapter 3 uses field experiments, behavioral studies, and floral volatile chemistry to examine the interaction between jackfruit (A. heterophyllus) and a new species of pollinator, Clinidiplosis ultracrepidata, which uses fungus-covered male flower heads as brood sites and is attracted to female flower heads by floral scent consisting mainly of aliphatic esters. Chapter 4 reports pollination studies and floral volatiles analyses for six species and discusses their implications in the context of the phylogeny developed in Chapter 2, advancing a hypothesis that insect pollination evolved once in the most recent common ancestor of all Artocarpus followed by at least two transitions back to wind pollination. The midge-fungus mutualism is reported in three different clades of Artocarpus, and all of the likely insect-pollinated species produce floral volatiles that are largely the same between male and female flower heads. By contrast, wind pollinated species produce few volatiles in female flower heads and male and female volatiles differ markedly. Chapter 5 discusses the interplay of indigenous knowledge and scientific taxonomy in the context of a phylogenetic and population genetic study of a tree crop from Borneo, A. odoratissimus, concluding that molecular evidence supports the traditional Iban taxonomy. These findings counsel improved engagement with indigenous nomenclatures in developing taxonomic hypotheses.

Last modified

• 01/25/2019

Creator

• Elliot M. Gardner

DOI

• https://doi.org/10.21985/N2CF59

Subject

• Plant Biology and Conversation

Keyword

• Chemical ecology
• Moraceae
• Phylogenetics
• underutilized crops
• tropical biology
• Pollination

Date created

• 2017-01-01

Resource type

• Dissertation

Rights statement

• In Copyright