Acorn removal and dispersal by the dung beetle Thorectes lusitanicus: ecological implications

Abstract

1. Plant–animal interactions, and in particular the processes of seed predation and dispersal, are crucial for tree regeneration and forest dynamics. A novel and striking case of interaction between a dung beetle (Thorectes lusitanicus) and two Quercus species (Q. suber and Q. canariensis) in forests of southern Spain is presented here.

2. During the autumn, T. lusitanicus beetles (endemic to the southern Iberian Peninsula) bury and feed on single-seeded fruits (acorns) of Quercus, with important ecological implications.

3. Field experiments found differences in the removal rate of acorns by T. lusitanicus, depending on the type of microsite within the forest, the species of oak, the exclosure of large herbivores, and the forest site.

4. Acorn consumption by T. lusitanicus was studied under laboratory conditions, confirming for the first time that this dung beetle is a legitimate seed predator.

5. In addition, some buried acorns can be abandoned partially predated or even intact, and emerge as seedlings; thus, T. lusitanicus also has a potential role as secondary seed disperser.