Seed source, seed traits, and frugivore habits: Implications for dispersal quality of two sympatric primates

Abstract

• Premise of the study: Frugivore selection of fruits and treatment of seeds together with seed deposition site are crucial for the population dynamics of vertebrate-dispersed plants. However, frugivore species may influence dispersal quality differently even when feeding on the same fruit species and, while animals disperse some seeds, others simply fall beneath the parent plant.• Methods: In southern Mexico, we investigated to see if within-species seed traits (i.e., length, width, weight, and volume) and germination success differed according to seed source. For five tropical tree species we obtained ingested seeds from two sources, howler monkey (Alouatta pigra) and spider monkey (Ateles geoffroyi) feces; and noningested seeds from two sources, the ground and tree crowns (with predispersed seeds used as control).• Key results: A principal components' analysis showed that traits of seeds ingested by howler monkeys differed from other sources while seeds ingested by spider monkeys were similar to noningested seeds. Howlers consumed on average the larger seeds in Ampelocera hottlei, Brosimum lactescens, and Dialium guianense. Both primate species consumed the smaller seeds in Spondias mombin, while no seed trait differences among seed sources were found in Spondias radlkoferi. For all five tree species, germination rate was greatest for seeds ingested by howler monkeys.• Conclusions: For the studied plant species, seed ingestion by howler monkeys confers higher dispersal quality than ingestion by spider monkeys or nondispersal. Dispersal services of both primate species, however, are not redundant and may contribute to germination heterogeneity within plant populations in tropical forests.

Isolation and characterization of polymorphic microsatellite loci in Spondias radlkoferi (Anacardiaceae)

“…The fruits of S. radlkoferi and S. mombin are highly consumed by many bird and mammal species. However, the seeds of both species are relatively large (mean ± SD: S. radlkoferi , 3.11 ± 0.43 cm; S. mombin , 2.10 ± 0.23 cm in length; Benítez‐Malvido et al, 2014), which implies that only a few large‐sized mammals, such as spider monkeys ( Ateles geoffroyi Kuhl), are able to swallow and disperse (through endozoochory) the seeds of these tree species (González‐Zamora et al, 2009, 2014; Chaves et al, 2011; Benítez‐Malvido et al, 2014). Nevertheless, to date it is largely unknown whether and how seed dispersal by spider monkeys affects the genetic structure and diversity of these tree species.…”

Can tortoises facilitate the germination of plants with dry fruits? A simulation of the effects of Chelonoidis carbonarius (Testudines: Testudinidae) on the germination of Leucaena leucocephala (Fabaceae)

“…The model had cumulative germination as a response variable and time (the number of days since the seeds were sowed), time 2 , treatment, time × treatment, time 2 × treatment as explanatory variables. This linear model provides three parameters for each treatment: 1) starting germination (the regression intercept), 2) initial germination rate, and 3) variation in germination rate; and we used Analysis of Deviance with chi-square tests to evaluate if these parameters varied among the treatments (Guillén et al 2009;Benítez-Malvido et al 2014). Differences among the treatments were evaluated using Z tests and a significance level of 5% (P < 0.05).…”

“…We evaluated differences in cumulative germination (cumulative proportion of seeds germinated in each day) among the four treatments using Generalized Linear Models (GLM) with Binomial error family and logit link function, because the response variable range between 0 and 1 (Guillén et al 2009;Benítez-Malvido et al 2014). The model had cumulative germination as a response variable and time (the number of days since the seeds were sowed), time 2 , treatment, time × treatment, time 2 × treatment as explanatory variables.…”

Global patterns of seed germination after ingestion by mammals

“…Many other seeds are defecated still viable and continue their recruitment process, although from then on they are affected by the structural changes previously suffered. For instance, defecated seeds that are highly scarified by GT can germinate faster than non-scarified seeds (Benítez-Malvido et al 2014).…”