Frugivory and Seed Dispersal by Large Herbivores of Asia

Spitting Seeds From the Cud: A Review of an Endozoochory Exclusive to Ruminants

“…Given the abundance of wild and free-living domestic ruminants and their high rate of food consumption, it can be suspected they are able to mobilize great numbers of seeds during rumination. Recent reviews on frugivory and seed dispersal by vertebrates in tropical Asia have recognized the importance of this type of endozoochory (Sridhara et al, 2016;e.g., Corlett, 2017), but in general it has been overlooked in many other reviews, even devoted to tropical areas (e.g., Parolin et al, 2013) or specifically to ungulates (e.g., Miceli-Méndez et al, 2008;Albert et al, 2015a). The difficulty in monitoring rumination, a process that usually occurs in sheltered and quiet places, may explain why this modality of endozoochory has been overlooked so far.…”

“…According to Prasad et al (2006), fruit traits of species dispersed while ruminating "appear to converge toward being green or brown, drupaceous, with fibrous pulp and strong seed protection." Sridhara et al (2016) found more variation in the fruits consumed by wild large ruminants in Asia, 36.7% being yellow and most of them drupes (50.3%) and berries (27.2%). In contrast, seeds dispersed through defecation usually correspond to fruit without pulp ( Figure 1B).…”

“…Some recent reviews on frugivory and seed dispersal in tropical areas have considered this type of endozoochory (e.g., Forget et al, 2007), especially in Asia (Corlett, 2011(Corlett, , 2017Sridhara et al, 2016). However, other reviews refer only to seed regurgitation by birds, primates and fish (e.g., Parolin et al, 2013), mention ungulates mainly as seed predators (e.g., Stoner et al, 2007) or refer exclusively to plant species identified in dung, overlooking spat seeds (e.g., Miceli-Méndez et al, 2008, which introduced the term "bovinochory" to refer to seed dispersal by cattle in the Neotropics).…”

“…For instance, through the review of 52 studies, Albert et al (2015a) concluded that plants dispersed by ungulates are mainly grasses typical of open habitats (93%), while most (but not all) species dispersed from the cud are forest trees ( Figure 1A and Table S1). Also, most (85.2%) of the fruit consumed by wild ruminants in Asia, according to the review carried out by Sridhara et al (2016), corresponded to trees.…”

“…In their forestomach, sized particles are stratified into small and large, and the latter are regurgitated and then remasticated to smaller, easier-todigest particles (Schwarm et al, 2008). In this way, hard small seeds can pass directly all along the gut and be defecated, relatively soft seeds are crushed or digested, and well-protected large ones must be regurgitated at the cud (one or several times), to be expelled from the mouth or swallowed again and destroyed by rumen microbes (Bodmer, 1991;Sridhara et al, 2016). In addition to the typically large size of regurgitated seeds, this modality of seed dispersal is likely characterized by other parameters, such as retention time, dispersal distance, condition of seed deposition (e.g., level of aggregation), seed survival, and germination success, which must differ from those of seeds dispersed through defecation (Sridhara et al, 2016).…”