Central Research Questions
This thesis is led by Ambre Genard and explores the ecology of Phengaris arion through the following questions: How is the distribution of P. arion related to different environmental gradients such as ground moisture levels, plants and tree cover? How does its host ant species, Myrmica, respond to these same environmental factors? How does the presence of Myrmica affect the distribution and density of P. arion? Is P. arion using recently restored/newly created areas? What are the oviposition preferences of P. arion? And what key ecological factors influence the habitat requirements and long-term persistence of P. arion on Gotland?
Background and Aims
The large blue butterfly, Phengaris arion, has experienced widespread decline across Europe, with Gotland serving as one of its remaining strongholds. Following the extreme drought of 2018, the population collapsed dramatically. Remarkably, the species has demonstrated impressive recovery in subsequent years. Its survival strategy appears linked to refugia in slightly more moist and shaded microhabitats. However, the precise relationships between its distribution, ground moisture levels, tree canopy cover, and the response of its host ant species to these environmental factors remain poorly understood.
The large blue butterfly has a unique lifecycle that relies on Myrmica ants. The larvae secrete a solution that attracts ants, tricking them into carrying the larvae into their nests. The butterfly larvae then feed on the ant larvae, and after pupating inside the nest, the adult butterflies emerge the following summer, completing their cycle. This complex interspecies interaction underscores the butterfly's dependence on the presence and health of specific Myrmica ant populations. Consequently, conservation efforts targeting P. arion must also prioritize the protection and management of suitable Myrmica habitats to ensure the butterfly's continued survival.
To ensure the long-term persistence of this unique butterfly, continued research and targeted conservation efforts are essential. This project aims to contribute to this knowledge by investigating key ecological factors influencing its distribution and habitat requirements.