Research Highlights
Understanding natural selection on floral scent; variation and phylogenetic patterns of scent evolution in genus Penstemon
Flowering plants are astonishingly diverse in their floral presentation, and this diversity is thought to evolve through selection by pollinators, promoting an array of “pollination syndromes”. Pollination syndromes can be defined as a suite of floral characters specialized in attraction of pollinators/pollen vectors and they can be understood by studying morphological and functional aspects of floral traits that comprise them. The majority of studies have focused on general floral features attractive to flower visitors such as flower number, flower size, display height or traits associated with breeding systems such as pollen presentation but have not measured either floral scent as an attractive trait or floral nectar resources as an attractive reward. In this Ph.D. project, I set out to examine the evolution of few understudied floral traits taking a holistic approach at three different levels under the supervision of Dr. Amy Parachnowitsch at the University of New Brunswick. The project will be carried out with a special emphasis on floral scent as an integral component of pollination syndromes. My first goal is to examine floral traits, including floral scents, to determine the targets of selection in bee-pollinated species using the genus Penstemon as a focal study system. My second goal is to examine floral scent across the diverse genus to determine the variation in scent production in Penstemon species that exhibit different pollinator syndromes such as bee pollination and hummingbird pollination syndrome. My third goal is to study the effect of different combinations of floral scent emission rates, colors, and nectar amount/concentration of individual flowers on pollinator behavior in a manipulative experiment. During these studies, I will compare floral scent bouquets and individual compounds found in various Penstemon species with different pollinator syndromes to assess how generalizable shifts in floral scents are. Thereby, I will be addressing fundamental ecological and evolutionary questions related floral scents in flowering plants.
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Relative importance in visual and odor cues in maintaining interactions with spore dispersing flies of two sympatric moss species in family Splachnaceae
My recent research is focus on spore dispersal of moss family Splachnaceae in Island Newfoundland, Canada. The moss family is known to be corprophilous and those two species I am working on is exclusively grows on moose dung as individual colonies as well as mixed colonies. I am curious about this substrate restriction because, moose is an introduced species to NL. But, Splachnaceae mosses are not. Thus, we are actively experimenting on the question of "how these substrate restriction occured in the first place?" .
The experiments was design to understand the relative importance of visual and odor cues in attracting flies to this brood-site deceptive system of mosses. Also, spore dispersal ability and efficacy will be weighed linking observed spore dispersers on carnivore, herbivore and omnivore dung piles. Further, use the network analysis to examine the relationship between individual fly taxa and experimental treatments to determine taxon-specific associations such as specializations and generalization level with each species of mosses, mixed-species populations and how the absence of olfactory signals influence those relationships. We hypothesized that flies associated with S.pensylvanicum to be tightly nested within fly fauna associated with Omnivore/Carnivore dung, and flies associated with S.ampullecium to be tightly nested within fly fauna associated with herbivore dung considering their odor chemistry. |
The Significance of Habitat Characteristics to the Spatial Distribution of Local Avian Assemblage at Gannoruwa Mountain Forest Reserve, Kandy, Sri Lanka
Distribution patterns corresponding to habitat characteristics in tropical forests have not been largely studied. Natural forest structure as well as the anthropogenic alterations to the forests equally affects the distribution patterns of wet zone avifauna. The study reveals the importance of % canopy closure, distance from the forest edge, tree density, diversity, and elevation to the community compositionof local forest birds inhabitingGannoruwa Forest Reserve, Sri Lanka.Themost important factors resulting in the study for shaping the avian distribution pattern are distance from the edge,elevation, and the % canopy closure. With the increase of favouring resources to the avian fauna at the edges and the juxtaposition of the edge, many forest loving species were observed to move towards the edge. The pattern is proven advantageous, but harmful in the long run. Thus, it is advisable that the
conservation plans should focus on habitat destruction and the anthropogenic disturbance along forest edges.
conservation plans should focus on habitat destruction and the anthropogenic disturbance along forest edges.
Species Composition and Visiting Frequencies of Flower Visitors of Chromolaena odorata (L.) in a Dry Zone Forest Patch of Sri Lanka
![Picture](/uploads/1/1/4/6/114658343/editor/20151026-132656.jpg?1510265235)
A native of Central and South America, Siam weed Chromolaena odorata (L.) King and H.E. Robins has spread throughout the tropical and subtropical areas of the world and is now a major weed in central and western Africa, tropical America, India and South-East Asia. This neotropical weed is being flagged as one of the most troublesome weeds in many humid tropical countries.
This study was conducted to account pollinators who visits widely dispersed Chromolaena odorata in tropical secondary dry forest patch in north central Sri Lanka with the intention to highlight the importance of this exotic invasive species as a forage source for native potential insect pollinators. The study also suggests the validation of visitation frequencies as a surrogate for measure the importance of flowering plant to the insect pollinators.
This study was conducted to account pollinators who visits widely dispersed Chromolaena odorata in tropical secondary dry forest patch in north central Sri Lanka with the intention to highlight the importance of this exotic invasive species as a forage source for native potential insect pollinators. The study also suggests the validation of visitation frequencies as a surrogate for measure the importance of flowering plant to the insect pollinators.
Plant frugivore network and avifaunal assemblage in dry zone secondary forest
Objectives of this study are to examine what are the key characteristic features of plant-frugivore mutualistic network in tropical dry evergreen forests, to understand how that network behave, identify what are the factors that determine the network type found in those areas, to identify how those interactions help in forming secondary forests which we can observe commonly in dry zone of Sri Lanka and as well as what are the trees that frugivores have utilized as food sources mostly.
Structure of a Plant-Flower Visitor network in a semi-evergreen dry forest in the dry zone of Sri Lanka
![Picture](/uploads/1/1/4/6/114658343/published/p5130025.jpg?1510265816)
Main objectives of this study are to examine what are the key characteristic features of plant flower-insect mutualistic network in tropical dry evergreen forests, to understand how that network behave, identify what are the factors that determine the network type found in those areas, to check whether any patterns can be found in specialization and generalization of plant and animal species, to identify any species if present act as network keystones i.e. having a disproportionately large role in maintaining community structure.
In our study, the interaction between plants and insects appeared to be asymmetrical. That is, while insects were less specialized on plants, plants tended to be more specialized on insects. Interaction asymmetry is probably the result of fewer complementary flowering plant species than insect species in the community forcing insects to visit all available flowering plants for survival. The low degree of modularity could be attributed to the low number of flowering plant species in the study area. Hymenopterans and Lepidopterans are the most important in the context of pollination in the study area. But groups such as dipterans are highly specialized but are not very important in the context of pollination. However, such specialized species are more vulnerable to extinction upon removal of their plant species.
Our study identifies insect groups that are probably critical to pollination and also groups that are highly specialized and vulnerable to extinction. Thus, network analysis is a useful tool to identify insects critical to pollination processes and also insects that have specific resource requirements and hence vulnerable to extinction.
In our study, the interaction between plants and insects appeared to be asymmetrical. That is, while insects were less specialized on plants, plants tended to be more specialized on insects. Interaction asymmetry is probably the result of fewer complementary flowering plant species than insect species in the community forcing insects to visit all available flowering plants for survival. The low degree of modularity could be attributed to the low number of flowering plant species in the study area. Hymenopterans and Lepidopterans are the most important in the context of pollination in the study area. But groups such as dipterans are highly specialized but are not very important in the context of pollination. However, such specialized species are more vulnerable to extinction upon removal of their plant species.
Our study identifies insect groups that are probably critical to pollination and also groups that are highly specialized and vulnerable to extinction. Thus, network analysis is a useful tool to identify insects critical to pollination processes and also insects that have specific resource requirements and hence vulnerable to extinction.