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Pre-dispersal seed mortality caused by premature fruit drop is a potentially important source of plant mortality, but one which has rarely been studied in the context of tropical forest plants. Of particular interest is premature fruit drop triggered by enemies, which – if density-dependent – could contribute to species co-existence in tropical forest plant communities. We used a long-term (31 year) dataset on seed and fruit fall obtained through weekly collections from a network of seed traps in a lowland tropical forest (Barro Colorado Island, Panama) to estimate the proportion of seeds prematurely abscised for 201 woody plant species. To determine whether enemy attack might contribute to premature fruit drop we tested whether plant species abscise more of their fruit prematurely if they: (1) have attributes hypothesised to be associated with high levels of enemy attack, and (2) are known to be attacked by one enemy-group (insect seed predators). We also tested (3) whether mean rates of premature fruit drop for plant species are phylogenetically conserved. Overall rates of premature fruit drop were high in the plant community. Across all species, 39% of seeds were abscised before completing their development. Rates of premature seed abscission varied considerably among species and could not be explained by phylogeny. Premature seed abscission rates were higher in species which are known to host pre-dispersal insect seed predators and species with attributes that were hypothesised to make them more susceptible to attack by pre-dispersal enemies, namely species which (1) have larger seeds, (2) have a greater average height, (3) have temporally predictable fruiting patterns, and (4) are more abundant at the study site. Synthesis. Premature fruit drop is likely to be a major source of seed mortality for many plant species on Barro Colorado Island. It is plausible that pre-dispersal seed enemies, such as insect seed predators, contribute to community-level patterns of premature fruit drop and have the potential to mediate species co-existence through stabilising negative density dependence. Our study suggests that the role of pre-dispersal enemies in structuring tropical plant communities should be considered alongside the more commonly studied post-dispersal seed and seedling enemies.
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How Seeds Shape Our World
Have you eaten bread or rice recently? Or maybe something with oil in it? If you said yes, then you were likely eating foods made from seeds. Seeds are an important food source for humans and animals, and they make up our grains, lentils, nuts, and cooking oils. But seeds are also important for the plant itself, as they can be planted in the ground to grow new plants. In some plants, the seeds are covered with fruit. For example, the tomato fruit is full of seeds, and the avocado has a large seed inside. Other plants like pine trees have so-called naked seeds, with no fruit covering them. What exactly are seeds, and how do they make new plants? Why do seeds grow when you plant them and not in seed packets in the store? Keep reading and you will find these answers, and learn how fascinating, complex, and extraordinarily diverse seeds can be.
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- Award ID(s):
- 1758800
- PAR ID:
- 10562476
- Publisher / Repository:
- Frontiers
- Date Published:
- Journal Name:
- Frontiers for Young Minds
- Volume:
- 11
- ISSN:
- 2296-6846
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/frym.2023.1065280
