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1. Frugivory, seed dispersal, and seed predation by Bornean orangutans (Pongo pygmaeus wurmbii)

   Blackburn, A; Susanto, TW; Knott, CD (January 2020, 6th Annual Meeting of the Northeastern Evolutionary Primatologists)

   null (Ed.)

   Seed dispersal is important for forest growth, maintenance, and regeneration. Orangutans are large-bodied frugivores with ecological roles as seed predators and seed dispersers. However, little is known about orangutans’ ecological roles and how they relate to orangutans’ patterns of frugivory. We investigated Bornean orangutans’ (Pongo pygmaeus wurmbii) ecological roles at the Cabang Panti Research Station in Gunung Palung National Park, Indonesian Borneo. We collected orangutan feces (n=401) and analyzed them for intact seeds (August 2018 to March 2020). We observed orangutan fruit handling behavior for 306 feeding bouts for 53 fruit genera to measure how often orangutans swallow, spit, or predate seeds. We used Ivlev’s Electivity Index to analyze fruit preference using long-term feeding data and phenology data (2014-2019). Lastly, we combined fruit preference with fruit handling behavior using the seed dispersal effectiveness framework to identify which fruit taxa were most effectively dispersed. Orangutans dispersed seeds in 71.8% of fecal samples with a mean of 27.9 ±4.5 (SD=0.95) seeds (>2mm) per fecal sample. Orangutans predated seeds more often than spitting or swallowing seeds (predating= 42.1% of fruit feeding time; spitting= 21.8%; swallowing= 12.5%; mixed behaviors= 10.6%, not observed=12.0%). Additionally, the top five preferred fruit genera, (Dialium, Sindora, Scaphium, Magnifera, and Spatholobus) were highly predated (0 to 5% of seeds dispersed). We identified Alangium and Tetramerista as the most effectively dispersed genera, orangutans frequently dispersed and preferred these fruits. We found orangutans are frequent seed predators, but this overlaps with their seed dispersal role, and we describe orangutans’ seed dispersal contribution. Funders: NSF (9414388, BCS-1638823, BCS-0936199); National Geographic; USFish/Wildlife (F18AP00898, F15AP00812, F13AP00920, 96200-0-G249, 96200-9-G110); Leakey; Disney Conservation Fund; Wenner-Gren; Nacey-Maggioncalda; Conservation-Food-Health; Orangutan Conservancy; Woodland Park Zoo; Boston University GRAF 

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2. Interactions between large‐scale and local factors influence seed predation rates and seed loss

   https://doi.org/10.1002/ece3.10208  

   Calixto, Eduardo S; Maron, John L; Hahn, Philip G (June 2023, Ecology and Evolution)

   Abstract Herbivores often have highly variable impacts on plant fecundity. The relative contribution of different environmental factors operating at varying spatial scales in affecting this variability is often unclear. We examined how density‐dependent seed predation at local scales and regional differences in primary productivity are associated with variation in the magnitude of pre‐dispersal seed predation onMonarda fistulosa(Lamiaceae). WithinM. fistulosapopulations growing in a low‐productivity region (LPR), Montana, USA, and a high‐productivity region (HPR), Wisconsin, USA, we quantified the magnitude of pre‐dispersal seed predation among individual plants differing in seed head densities. Out of a total of 303M. fistulosaplants that were surveyed, we found half as many herbivores in seed heads in the LPR (n = 133 herbivores) compared to the HPR (n = 316). In the LPR, 30% of the seed heads were damaged in plants with low seed head density, while 61% of seed heads were damaged in plants with high seed head density. Seed head damage was consistently high in the HPR (about 49% across the range of seed head density) compared to the LPR (45% across a range of seed head density). However, the proportion of seeds per seed head that were destroyed by herbivores was nearly two times higher (~38% loss) in the LPR compared to HPR (22% loss). Considering the combined effects of probability of damage and seed loss per seed head, the proportion seed loss per plant was consistently higher in the HPR regardless of seed head density. Nevertheless, because of greater seed head production, the total number of viable seeds produced per plant was higher in HPR and high‐density plants, despite being exposed to greater herbivore pressure. These findings show how large‐scale factors can interact with local‐scale factors to influence how strongly herbivores suppress plant fecundity. 

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3. Predation risk and personality influence seed predation and dispersal by a scatter‐hoarding small mammal

   https://doi.org/10.1002/ecs2.4377  

   Merz, Margaret R.; Boone, Sara R.; Mortelliti, Alessio (January 2023, Ecosphere)

   Small mammals are key scatter hoarders in forest ecosystems, acting as both seed predators and dispersers. The outcome of their interactions (i.e., predation vs. dispersal) is determined by a series of decisions made by small mammals, such as the choice of seed, whether the seed is immediately consumed or cached, and where it is cached. These decisions are influenced by a variety of factors, including the intrinsic traits of the seed, the individual personality of the scatter hoarder, and the perceived risk of predation while foraging. Furthermore, these factors may all interact to dictate the fate of the seed, with consequences for forest regeneration. Nevertheless, the ways in which perceived predation risk and personality interact to affect the seed dispersal decisions of scatter hoarders are still poorly understood. To contribute in filling this knowledge gap, we tested the hypotheses that southern red‐backed voles (Myodes gapperi), an important scatter hoarder in forest ecosystems, would exhibit personality‐mediated foraging and that predation risk would alter associations between personality and seed dispersal. We conducted a large‐scale field experiment, offering seed trays at stations with altered risk levels and recorded foraging decisions of free‐ranging voles with known personalities. We found that personality and perceived predation risk influenced decisions made by foraging voles. Specifically, docility, and boldness predicted foraging site selection, boldness predicted seed species selection and the number of seeds individuals selected, and the tendency to explore of an individual predicted whether voles would remove or consume seeds. Predation risk, mediated by the amount of cover at a site and by moon illumination, affected which foraging site individuals chose, seed species selection, and the probability of removal versus consumption. We did not find support for an interaction between personality and predation risk in predicting foraging decisions. These findings highlight the importance of scatter hoarder personality and perceived predation risk in affecting foraging decisions, with important consequences for seed dispersal and implications for altered patterns of forest regeneration in areas with different small mammal personality distributions or landscapes of fear. 

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4. Bornean orangutan (Pongo pygmaeus wurmbii) patterns of frugivory and the relation to seed dispersal and seed predation

   Blackburn, A; Susanto, TW; Knott, CD (January 2021, American journal of physical anthropology)

   null (Ed.)

   Seed dispersal is important for forest growth, maintenance, and regeneration. Orangutans are large-bodied frugivores with ecological roles as seed predators and seed dispersers. However, little is known about orangutans’ ecological roles and how they relate to orangutans’ patterns of frugivory. We investigated Bornean orangutans’ (Pongo pygmaeus wurmbii) ecological roles at the Cabang Panti Research Station in Gunung Palung National Park, Indonesian Borneo. We collected orangutan feces (n=401) and analyzed them for intact seeds (August 2018 to March 2020). We observed orangutan fruit handling behavior for 306 feeding bouts for 53 fruit genera to measure how often orangutans swallow, spit, or predate seeds. We used Ivlev’s Electivity Index to analyze fruit preference using long-term feeding data and phenology data (2014-2019). Lastly, we combined fruit preference with fruit handling behavior using the seed dispersal effectiveness framework to identify which fruit taxa were most effectively dispersed. Orangutans dispersed seeds in 71.8% of fecal samples with a mean of 27.9 ±4.5 (SD=0.95) seeds (>2mm) per fecal sample. Orangutans predated seeds more often than spitting or swallowing seeds (predating= 42.1% of fruit feeding time; spitting= 21.8%; swallowing= 12.5%; mixed behaviors= 10.6%, not observed=12.0%). Additionally, the top five preferred fruit genera, (Dialium, Sindora, Scaphium, Magnifera, and Spatholobus) were highly predated (0 to 5% of seeds dispersed). We identified Alangium and Tetramerista as the most effectively dispersed genera, orangutans frequently dispersed and preferred these fruits. We found orangutans are frequent seed predators, but this overlaps with their seed dispersal role, and we describe orangutans’ seed dispersal contribution. Funders: NSF (9414388, BCS-1638823, BCS-0936199); National Geographic; USFish/Wildlife (F18AP00898, F15AP00812, F13AP00920, 96200-0-G249, 96200-9-G110); Leakey; Disney Conservation Fund; Wenner-Gren; Nacey-Maggioncalda; Conservation-Food-Health; Orangutan Conservancy; Woodland Park Zoo; Boston University GRAF 

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5. Predispersal Seed Predation Obscures the Detrimental Effect of Dust on Wildflower Reproduction

   https://doi.org/10.1086/713440  

   Price, Mary V.; Waser, Nickolas M.; Lopez, David A.; Ramírez, Victor D.; Rosas, Carol E. (May 2021, International Journal of Plant Sciences)