None of the plant species noted in the present study (see Appendix) appears to possess specialised appendages that would attract harvester ants and encourage myrmecochory, but, as noted by Buckley (1982), elaiosomes are not a common feature of ephemeral plant species. In general, harvester ants are highly selective in the seed species they collect (MacMahon et al., 2000), and seed foraging behaviour is likely to be dependent on spatial and temporal patterns of seed availability (Wilby and Shachak, 2000).