Subannual phenology and the effect of staggered fruit ripening on dispersal competition

Abstract

Seed dispersal mutualisms evolve in complex communities of plants and frugivorous animals, within which indirect interactions such as competition and facilitation can occur. Many tropical plants reproduce subannually in multiple episodes per year. Yet, the consequences of episodic reproduction on interactions with seed dispersers remain largely unexplored. We studied Guarea guidonia (Meliaceae), a subannually reproducing tree, to examine temporal variation in seed dispersal within a tropical forested landscape in the central Dominican Republic. We hypothesized that foraging by dispersers would (a) increase with daily ripe fruit set on focal trees, (b) decrease with increasing ripe fruit biomass of neighboring plants, and (c) decrease in response to the fruiting periods of other taxa at the landscape scale. Over 18 months, we tracked the phenology of 24 focal trees and quantified foraging during fruiting phases through repeated observations, simultaneously measuring seed dispersal in traps beneath isolated bird perches across the study landscape. Date was the only clear predictor of frugivore visitation, with early and late peaks in activity during the 5‐month fruiting period. The midseason decline in foraging at focal trees matched a decline in Guarea dispersal to seed traps independently of fruit abundance. Declines in Guarea dispersal were inversely related to peak dispersal of higher quality lipid‐rich fruiting species. Our results suggest that multiple flowering episodes and subsequent asynchronous fruit ripening of low‐quality fruits can reduce competitive pressure from other higher quality fruiting species, implying that this potential bet‐hedging strategy may be an overlooked factor in the evolution of subannual reproduction. Abstract in Spanish is available with online material.

Winter dry season reproductive phenology in Bahamian dry forest and implications for conservation

“…Year‐round reproduction by individuals or the population can aid colonization of newly disturbed sites as they appear on the landscape. Asynchronous and multi‐episodic reproduction can also reduce intraspecific competition for resources, including pollinators and dispersers (Rathcke & Lacey, 1985; Schubert & Walters, 2022), which may be important during the dry season given spatial and temporal variability in insect abundance (Wunderle Jr. et al., 2014).…”

Maturation and harvest time of Ateleia glazioveana Baill. seeds

“…To carry out the harvest in advance or at the point of physiological maturity, it is necessary to precisely know this event. The asynchronous maturation of hardy species (Schubert and Walters, 2022), such as A. glazioveana, makes it impossible to harvest a greater number of seeds within the same period at the same degree of maturation. Thus, the possibility of post-harvest maturation makes it possible to gather a greater number of seeds, which will be viable after a period of storage (Santos et al, 2019).…”

Drivers of intraspecific variation and phenotypic plasticity in fleshy-fruited plants

“…Despite these benefits, fleshy, nutrient-dense fruits are costly to produce and must be offset by an increase in plant fitness to be adaptive. In addition, many fruits have a short window between when they become ripe and attract frugivores and when they begin to rot (Gleditsch et al, 2017;Schubert & Walters, 2021). Thus, it would be advantageous for fleshy-fruited plants to optimize energy invested in fruits (Obeso, 2002;Thompson & Stewart, 1981).…”