Ground beetles are postdispersal weed seed predators, yet their role in
consuming buried seeds is not well studied. We conducted greenhouse
experiments to investigate how seed burial affects consumption of weed seeds
(volunteer canola) by adult ground beetles (Coleoptera: Carabidae). Seed
burial depth influenced seed consumption rates as demonstrated by a
significant interaction between seed burial depth, carabid species, and
gender of the carabid tested. We observed higher seed consumption by females
of all species, and greater consumption of seeds scattered on the soil
surface compared with seeds buried at any depth. However, there was evidence
of seed consumption at all depths. Adults of Pterostichus
melanarius (Illiger) and Harpalus affinis
(Schrank) consumed more buried seeds than did those of Amara
littoralis Mannerheim. Agricultural practices, such as tillage,
bury seeds at different depths and based on the results of this study, these
practices may reduce seed consumption by carabids. Soil conservation
practices that reduce tillage (conservation or zero tillage) will favor
greater weed seed predation due, in part, to the high availability of seeds
at the soil surface or at shallow soil depths.