Spotting a fungal parasite on a globally invasive ladybug: explaining the global distribution and possible use as a biocontrol
Michiel de Groot
michiel.degroot@ugent.be
Promotor: Danny Haelewaters (UGent), Mieke Verbeken (UGent), Dirk Maes (INBO), Tim Adriaens (INBO)
Grant number FWO: 1142722N
This research seeks to unravel the intricate relationship between the globally invasive ladybird Harmonia axyridis and its fungal parasite Hesperomyces harmoniae. The research is pivotal in understanding the ecological dynamics of invasive species and the potential role of natural enemies in controlling them. The proposal is structured around three primary objectives:
Determining Infection Factors:
This aspect focuses on identifying the environmental and biological factors that influence the prevalence of H. harmoniae infections. Through a combination of controlled laboratory experiments and extensive field data collection, the research will examine how abiotic factors such as temperature, humidity, and habitat fragmentation affect the spread of the fungal parasite. Human-modified landscapes, including urbanized and agricultural areas, are particularly significant in understanding infection dynamics. The project will also investigate the interaction of the fungus with native and non-native ladybird species to uncover the conditions that promote or inhibit infection.
Exploring Global Spread:
The project will delve into the population genetics of H. harmoniae to trace its global distribution and historical pathways of spread. This involves sequencing the fungus's genome and analyzing genetic variations across populations worldwide. The research aims to determine whether the parasite's association with H. axyridis originated in its native range in Asia or was acquired elsewhere, such as in North America, where the ladybird was first introduced as a biocontrol agent. This investigation will provide insights into how parasitic fungi adapt to and spread with their hosts across diverse ecosystems.
Evaluating Biocontrol Potential:
The research will assess the efficacy of H. harmoniae as a biocontrol agent for managing H. axyridis populations, which have been known to outcompete native species and cause ecological and agricultural damage. Laboratory experiments will test whether the fungus negatively impacts the fitness, reproduction, and survival of H. axyridis. Additionally, the study will evaluate the compatibility of H. harmoniae with other locally occurring pathogens, determining its potential as part of an integrated pest management strategy. The research will also ensure that the fungal parasite does not harm native ladybird species.
The project incorporates fieldwork to collect specimens globally, lab-based molecular and experimental approaches, and citizen science initiatives for data gathering. Platforms like Beetlehangers.org will play a key role in engaging the public and facilitating large-scale data collection on fungal infections in ladybirds. By integrating these methods, the research aims to provide a comprehensive understanding of how H. harmoniae infections are influenced by ecological and anthropogenic factors, how the parasite spreads globally, and its potential as a sustainable biocontrol solution. This work is expected to contribute significantly to invasive species management, conservation strategies, and the broader understanding of host-parasite dynamics.
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