Diplochorous Seed Dispersal of Rafflesiaceae by Fruit‐Consuming Squirrels, Rats and Treeshrews, Then Seed‐Burying Dung Beetles

ABSTRACT

Understanding seed‐dispersal of Rafflesiaceae species is essential to conserve this extraordinary family of parasitic plants. We present evidence supporting diplochorous seed dispersal, involving primary endozoochorous dispersal by small mammals, followed by secondary exozoochorous dispersal by dung beetles. Methods employed included in situ live capture of small mammals in traps, placed over developing Sapria himalayana fruits, in situ observations of dung beetles handling the small dung pellets of primary dispersers and ex situ experiments with both dispersers. Dung pellet analyses (number, weight, expulsion time and ratio of undamaged to broken seeds) indicated that the most capable primary seed dispersers were the nocturnal rat Maxomys surifer (among four species studied) and, during daytime, the squirrel Dremomys rufigenis and, to a lesser extent, the treeshrew Tupaia belangeri . Dispersal distances were likely to encompass multiple host Tetrastigma spp. (lianas). Dung beetles served as secondary dispersers. They removed all faecal pellets of primary dispersers from the soil surface within 24 h, burying them up to 7 cm deep. The beetles also released seeds from the faecal matrix by microphagy, enabling the seeds to come into intimate contact with hosts' fine roots and root hairs, through which infection likely occurs. Forty‐one beetle species (including seven new species) were involved, with Ochicanthon thai and Onthophagus lindaae being the most abundant. Further research throughout the distribution of Rafflesiaceae species, particularly in the Philippines, regarded as a centre of Rafflesia diversity, is likely to add to primary and secondary disperser diversity.