The Dispersion of Diaspores of Protium icicariba (Burseraceae) - a Networked or Multifactorial System?

• Published in: Journal of chemical ecology 2020-02, Vol.46 (2), p.163-175
• Main Authors: Pereira, Izalnei Feres, Costa, Ana Paula Ferreira da, Srbek-Araujo, Ana Carolina, Guimarães, Lílian Jardim, Merencio, André Falcão, Silva, Ary Gomes da
• Format: Article
• Language: English
• Subjects: Adaptive radiation; Adaptive systems; Agriculture; Angiosperms; Animals; Anthills; Ants; Ants - physiology; Biochemistry; Biological Microscopy; Biomedical and Life Sciences; Burseraceae; Burseraceae - chemistry; Burseraceae - metabolism; Caves; Chemical composition; Clumps; Defecation; Diaspore; Dispersion; Ecology; Entomology; Essential oils; Fruit - chemistry; Fruit - metabolism; Gas chromatography; Gas Chromatography-Mass Spectrometry; Gastric juice; Germination; Ingestion; Life Sciences; Lizards; Lizards - metabolism; Mass spectrometry; Mass spectroscopy; Models, Theoretical; Oils & fats; Oils, Volatile - analysis; Oils, Volatile - chemistry; Pericarp; Plant Oils - analysis; Plant Oils - chemistry; Plant species; Pyrene; Pyrenes; Regurgitation; Seed Dispersal; Seedlings; Seeds; Species; Stomach; Stomach - chemistry; Substrates; Vertebrates; Weight; Workers (insect caste)
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1007/s10886-019-01140-x

The adaptive radiation of the angiosperms was strongly affected by fruit and seed dispersal since the establishment of the seedlings is a fundamental process for the recruitment of juveniles to the populations. Among the species of Burseraceae, seeds with fleshy attachments and high caloric value suggest mammaliochory as an ancestral dispersal way. In Protium icicariba , at the same time as there is a visual pattern typical of ornithochory, with a report of effective demonstration, the diaspores present the highest levels of essential oils of the whole plant, suggesting other dispersion processes by olfactory guided vectors. This work aims to monitor the diasporic dispersal process in P. icicariba in situ, aiming to identify dispersers and to investigate the role of the essential oil in the dispersion of diaspores of this plant species. The natural dispersion was monitored in situ, in weekly campaigns throughout eight months, using visual and photographic records, in daily shifts of six hours, distributed along the dawn, morning, afternoon, dusk, and night. We used both direct observation and continuous picture capturing along 43 days with photographic traps. Mature diaspores removed from pseudocapsules were pooled to determine potential dispersers. Artificial models of the diaspores, in white and green colors, were also used to test hypotheses on the role of scent in the dispersion, added 1%, weight/weight, of the essential oil extracted from the mature diaspores, which chemical composition determined by gas chromatography coupled to mass spectrometry. Besides, the analysis of stomach contents of lizards collected in adjacent area was also performed. In daytime and nighttime monitoring in nature, no vertebrates were recorded dispersing diaspores. The most common was the primary wind-facilitated autochory of diaspores to the substrate, near the plant matrices. Secondarily, workers of the ant species Atta robusta can remove the pseudoarils or move the pyrenes to the anthills. The lizard species Tropidurus torquatus ingests pyrenes with the pseudoarils, and the sclerified pericarp of the pyrene is potentially resistant to chemical action of the digestive juices. Ants and lizards have also accessed the caves with natural diaspores. Concerning the artificial diaspore models, ants accessed, indistinctly, white and the green models that contained essential oils. The lizards accessed the white models, with or without essential oils, and showed insignificant acces