Molecular insights into an insect-plant interaction

Alansari, Rayan (2018) Molecular insights into an insect-plant interaction. PhD thesis, University of Nottingham.

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This project evaluates the phylogeographic patterns of an insect-plant interaction, using ecological and molecular data for the model system of Alkanna orientalis (Boraginaceae) and its solitary bee pollinator Anthophora pauperata (Anthophoridae) in the Middle East. Understanding the relationship between the plant and its pollinator will help with recommendations for conservation strategies.

The flowering time of the plant coincided with the appearance of its main pollinator. In the northern part of the western highlands of Saudi Arabia, A. pauperata was the most common visitor for both pollen and nectar, and was also an efficient pollinator, transferring pollen to the stigmas. The females foraged for nectar and pollen early and late in the day, while the males performed territory defence in between these times. Females were shown to be able to travel long distances regardless of the harsh landscape and high mountain barriers, and hence can facilitate genetic exchange of both bee and plant amongst wadis.

From a molecular point of view, I investigated genetic variation within and amongst populations of Alkanna orientalis at different spatial scales across the eastern Mediterranean and Middle East regions. I used biparentally inherited, nuclear ribosomal DNA (the ITS region) and maternally inherited, chloroplast DNA (the trnH-psbA region) to understand the rate of gene flow of pollen vs. seeds. The results showed evidence of spatial structure over a large geographical scale, which might be the consequence of historical series of expansions and constrictions. In addition to these large-scale patterns, there was evidence of spatial heterogeneity at smaller scales, which may describe more recent, localised events such as population extinction and recolonization from adjacent territories, or fluctuations in population size associated with random genetic drift when population size is small.

For the pollinator, Anthophora pauperata, I describe the genetic variation within and between the only two known populations, at Jabal El-Loz in northwest Saudi Arabia and the high massif of South Sinai in Egypt. For this, I sequenced a protein-coding region of mitochondrial DNA and genotyped ten hyper-variable microsatellite loci. The results showed evidence of significant genetic differentiation across the large geographical scale between the two populations, coupled with significant gene flow within populations over smaller geographical scales, such as between wadis.

One of the outcomes of this study is to suggest that some populations should be given higher priority in terms of conservation. This prioritisation is based on elements, such as the level of genetic diversity within each population, the distribution of unique genotypes, evidence that populations have been recently exposed to bottlenecks, populations that are potentially glacial refugia, and populations under extreme threat because of human activities.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Gilbert, Francis
Goodacre, Sara
Keywords: Alkanna Orientalis, Anthophora pauperata, pollination, solitary bee, territoriality, foraging, mating, genetic variation, phylogeography, conservation
Subjects: Q Science > QL Zoology > QL360 Invertebrates
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Life Sciences
Item ID: 52034
Depositing User: Alansari, Rayan
Date Deposited: 12 Jul 2018 04:41
Last Modified: 12 Jul 2020 04:30

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