Zombie ant graveyard dynamics in Gunung Mulu National Park

Abstract

Ophiocordyceps is a genus of pathogenic fungi, which predominantly parasitise insects. This study investigates the spatial dynamics of zombie ant graveyards, and explores the optimal height for Ophiocordyceps unilateralis spore dispersal in a Bornean rainforest. While there is considerable research derived from alternative tropical regions, there is limited documentation of Ophiocordyceps fungi in Borneo. This paper aims to build on the current body of knowledge, focusing on the spatial dynamics of zombie ant graveyards, and in particular the height at which infected ants are found. In the present study, an area of Gunung Mulu National Park was searched for O. unilateralis-infected ants. Once an infected ant was located, the surrounding area was methodically searched to allow for the height and location of all surrounding ants to be recorded. Infected ants were found at variable heights between the four sites (means of 28.9–57.6 cm) above the expected height laid out in similar studies (approximately 25 cm). It is suggested that these heights may correspond to locations at which temperature and humidity are optimal for spore dispersal and fungal growth and that these heights differ depending on unique features of the environment.