DOI: 10.5061/dryad.4tmpg4fd8
title: Natural history and ecological effects on the establishment and fate of Florida carpenter ant cadavers infected by the parasitic-manipulator Ophiocordyceps camponoti-floridani

description: 1. Ophiocordyceps fungi manipulate the behavior of their ant hosts to
 produce a summit disease phenotype, thereby establishing infected ant
 cadavers onto vegetation at elevated positions suitable for fungal growth
 and transmission. Multiple environmental and ecological factors have been
 proposed to shape the timing, positioning, and outcome of these
 manipulations. 2. We conducted a long-term field study of Ophiocordyceps
 camponoti-floridani infections of Camponotus floridanus ants – the Florida
 zombie ants. We propose and refine hypotheses on the factors that shape
 infection outcomes by tracking the occurrence of fungal growth from
 hundreds of ant cadavers. We modeled and report these data in relation to
 weather, light, vegetation, and attack by mycoparasites. 3. We
 investigated environmental factors that could affect the occurrence and
 location of newly manipulated ant cadavers. New cadavers were positively
 correlated with epiphytic Tillandsia bromeliads, canopy openness, and
 weather conditions (an interactive effect of temperature, humidity, and
 precipitation) with an increased occurrence during the sub-tropical
 summer. We further suggest that incident light at the individual cadaver
 level may reflect microhabitat choice by manipulated ants or selective
 pressure on cadaver maintenance for conditions improving fungal survival.
 4. We also sought to connect fungal fitness to environmental conditions.
 Continued fungal development of reproductive structures and putative
 transmission increased with moist weather conditions (interaction of
 humidity and precipitation) and canopy openness, while being reduced by
 attack by mycoparasites. Moreover, under the most open canopy conditions,
 we found an atypical Ophiocordyceps growth morphology that could represent
 a plastic response to conditions influenced by high light levels. 5. Taken
 together, we explore general trends and the effects of various ecological
 conditions on host and parasite disease outcomes in the Florida zombie ant
 system. These insights from the field can be used to inform experimental
 laboratory setups that directly test the effects of biotic and abiotic
 factors on fungus-ant interactions or aim to uncover underlying molecular
 mechanisms.
description: We collected data on <em>O</em>.
 <em>camponoti</em>-<em>floridani</em>-infected
 <em>C</em>. <em>floridanus</em> from three
 wilderness areas in Seminole County, Florida, USA between October 2018 and
 November 2019. We scouted each wilderness area to find
 <em>Ophiocordyceps</em> graveyards with few to no observable
 ant cadavers in the forest between them. We collected a
 diverse range of data over time to identify potential drivers of cadaver
 occurrence and placement, and, subsequent fungal development and
 transmission. We monitored graveyards over the course of 411 days with a
 median interval of 60 days between visits to the same graveyard. We
 characterized cadavers by their biting vegetation, ant caste, height above
 the forest floor, and, for a subset, incident light levels on the
 cadaver. To collect vegetation data for each graveyard,
 we conducted three line-intersect surveys spaced at even intervals
 perpendicular to the adjacent trail and spanning the 9 m length of the
 plot. Our line-intersect transects were two-dimensional as we observed
 variation in vegetation types at different heights. Along the 9 m length
 of each transect we measured vegetation between the
 25<sup>th</sup> quartile (81 cm) and the
 75<sup>th</sup> quartile value (169 cm) of all cadaver
 occurrence data. Pieces of vegetation of the same category were measured
 as continuous if the linear distance in the plane of the transect was ≤ 5
 cm. We obtained weather data from the National Centers
 for Environmental Information (NCEI), Land-Based Station
 WBAN:12815.
description: Microsoft Excel.