Khaldoun Ali

Ali picture

I moved to Canada and joined the Department of Plant Sciences at the University of Saskatchewan as a doctoral student after many years of graduate studies in the Middle East and Europe (UK). My overall expertise spans both insect and plant sciences and centers on Ecology and Evolution research. My doctoral work focuses seed predation interactions and offers some insights into the sensory, behavioral, and nutritional mechanisms that underlie seed discrimination and selective seed foraging in carabid seed predators. I am currently finalizing work on my doctoral thesis and will be taking up a Plant-Insect Ecology post-doctoral position afterwards.

Abstract: Carabid (ground) beetles are among the widely distributed groups of predatory insects in temperate arable lands. Carabid predators of numerous species are omnivorous and prey upon a wide range of pests and weed seeds. Carabids usually attack weed seeds after seed shed, and seed removal rates can reach upwards of 65-90% for certain seed species. Despite this, some core aspects of seed feeding ecology remain poorly understood for omnivorous carabids. It remains unclear why omnivorous carabid predators choose to include seed species in their diets when alternative foods are accessible, or why carabids prefer to consume seeds of certain species when seeds of different species are available. It is therefore essential to study the biology and ecology of seed preference in omnivorous carabids to better understand their potential as weed biocontrol agents in agro-ecosystems. Here, we show that carabids rely on olfactory perception of long-chain volatile chemicals derived from epicuticular lipids located on the seed coat surface to identify the seed species suitable for consumption. Seed volatiles seem to encode information about the lipid content of seed species. Testing this assumption via synthetic diets has revealed that fatty acids are generally more limiting than protein (amino acids) to nutrient foraging in carabids. Carabids as such seem to seek seed consumption to acquire essential lipids that are often scarce in prey items. Factors that reduce the quality of protein in the seed can restrain carabids from obtaining seed lipids, and thus may somewhat protect the seed against carabid predation. Seed chemistry can predict seed selection decisions in carabids only if the physical traits of seed species vary within certain limits, however. It could be concluded that, within certain limits of seed physical characteristics, lipid-rich seeds are more likely to incur intense carabid attacks in the field.

Supervisor Name: Dr. Christian J. Willenborg

Affiliation: University of Saskatchewan