AbstractsBiology & Animal Science

The Polar Palette - The role of flower colour in polar regions

by Lorna Little

Institution: University of Otago
Year: 0
Keywords: flower colour; polar regions; svalbard; subantarctic; insect attraction; seed production; genetics; thermal imaging
Record ID: 1305812
Full text PDF: http://hdl.handle.net/10523/4999


Flower colour throughout the world is generally linked to various functional purposes, pollinator attraction in particular. Current knowledge regarding the functional significance of flower colour is, however, mainly based on studies from boreal, temperate, and tropical regions. This knowledge is not readily applicable to polar regions. Similar to lower latitudes, flower colour is often observed in polar regions, as well as flower colour polymorphisms. Pollinator attraction are considered to be the main purpose of flower colour, and the lack of pollinators in polar regions, where many plant species produce coloured flowers, causes the significance of colour to be unclear. Further, flower colour pigments are often quite energy expensive to produce, and in polar regions, nutrients, light and resources are limited. Hence, the question; what is the role of flower colour in reproductive success in polar regions? This thesis addresses this question of ‘What is the role of flower colour in polar regions?’ through several studies related to various aspects of floral reproduction in polar regions. This is a broad topic, and little background knowledge exists. To deal with this, a broad approach was also used, covering different geographical scales, from bipolar (Chapter Three), arctic (Chapter Two) and regional (Svalbard; Chapter Six) scales, to the population scale (Chapter Four and Five). Information from literature on hundreds of species (Chapter Two) was compiled, field experiments and thermal imaging were completed on specific plant populations (Chapter Three - Five), and, at the genetic level, amplified fragment length polymorphism (AFLPs) were conducted within a species (Papaver dahlianum; Chapter Six). Except for one study (Chapter Four), which included results from Campbell Island (Subantarctic), most information is gathered from the Arctic, in particular from the high-arctic archipelago, Svalbard. The thesis is thus somewhat biased towards the Arctic. There were several initial hypotheses around why we observe flower colour polymorphism in polar regions. One possibility was that the few pollinators present may be more specific or more efficient than formerly believed, and sufficient to drive and sustain flower colour polymorphisms in polar regions (addressed in Chapters Two, Three, Five and Six). Alternatively, these colour morphs could be remnants from ancestor populations living under a different pollinator regime, and without any current function (historical patterns are partly addressed in Chapter Two and Six). However, as the polar climate is thermodynamically unfavourable and energy budgets are tight, flower colour pigments are often too costly to produce without being linked to a functional purpose. Hence, another possibility was that flower colour is linked to functions aside from signalling to attract pollinators (addressed in Chapter Four and Five). The diversity and distribution of blue-purple flowers in the Arctic were correlated with the diversity and distribution of specialist pollinators…