Using devitalised seeds in myrmecological research

Abstract

Field studies of myrmecochory (seed dispersal by ants) can benefit from the use of devitalised seeds, particularly where these studies may involve invasive plants or plants outside of their natural range. Here, we test three different methods of seed devitalisation – gamma irradiation (10.6 kGy over 9.1 h at 23.7–25.4 °C), heating (150 °C for 30 min) and freezing (submerged in liquid nitrogen for 10 min) – in three different Australian plants: Acacia longifolia, Acacia melanoxylon and Kennedia rubicunda. We further test their suitability post-treatment as stimuli for use in field studies of myrmecochory. Gamma radiation and exposure to heat effectively inhibited germination, whereas freezing did not. The devitalisation treatments did not appear to affect the attractiveness of seeds to ants as there was no significant difference in daily collection rate of control seeds compared to devitalised seeds.