H1 - Larger frugivores will consume heavier and larger fruits, and fruits with larger seeds. |
Larger frugivores are stronger (Sekar and Sucumar 2013Sekar, N.; Sukumar, R. 2013. Waiting for Gajah: an elephant mutualist’s contingency plan for an endangered megafaunal disperser. Journal of Ecology, 101: 1379-1388. ) and have larger gape sizes (Moran and Catterall 2010Moran, C.; Catterall, C.P. 2010. Can functional traits predict ecological interactions? A case study using rain forest frugivores and plants in Australia. Biotropica, 42: 318-326.; Burns 2013Burns, K.C. 2013. What causes size coupling in fruit-frugivore interaction webs? Ecology, 94: 295-300.; Galetti et al. 2013Galetti, M.; Guevara, R.; Côrtes, M.C.; Fadini, R.; Von Matter, S.; Leite, A.B.; et al. 2013. Functional extinction of birds drives rapid evolutionary changes in seed size. Science, 340: 1086-1090. ) allowing them to cope with heavier and larger fruits, and with fruits with larger seeds. |
H2 - Larger frugivores will prefer to feed on larger trees (larger DBH). |
Larger trees bear higher fruit abundance (Chapman et al. 1992Chapman, C.A.; Chapman, L.J.; Wangham, R.; Hunt, K.; Gebo, D.; Gardner, L. 1992. Estimators of fruit abundance of tropical trees. Biotropica, 24: 527-531. ), supplying more efficiently the higher energetic demand of larger frugivores (Hawes and Peres 2014Hawes, J.E.; Peres, C.A. 2014. Ecological correlates of trophic status and frugivory in neotropical primates. Oikos, 123: 365-377.). |
H3 - Larger frugivores will swallow the seeds more frequently than smaller ones. |
Gape size, which is related to frugivore size, limits the size of seeds that can be swollen by frugivores (Moran and Catterall 2010Moran, C.; Catterall, C.P. 2010. Can functional traits predict ecological interactions? A case study using rain forest frugivores and plants in Australia. Biotropica, 42: 318-326.; Galetti et al. 2013Galetti, M.; Guevara, R.; Côrtes, M.C.; Fadini, R.; Von Matter, S.; Leite, A.B.; et al. 2013. Functional extinction of birds drives rapid evolutionary changes in seed size. Science, 340: 1086-1090. ). |
H4 - Smaller fruits will have their seeds swallowed more frequently than larger fruits. |
Given the limiting effect of gape size in the ingestion of fruits (Moran and Catterall 2010Moran, C.; Catterall, C.P. 2010. Can functional traits predict ecological interactions? A case study using rain forest frugivores and plants in Australia. Biotropica, 42: 318-326.; Burns 2013Burns, K.C. 2013. What causes size coupling in fruit-frugivore interaction webs? Ecology, 94: 295-300.), more frugivores should be able to swallow the smaller fruits as a whole (Jordano 2000Jordano, P. 2000. Fruits and frugivory. In: Fenner, M. (Ed.). Seeds: the Ecology of Regeneration in Plant Communities. CABI Publishing, Wallingford, p.125-166.; Muñoz et al. 2016Muñoz, M.C.; Schaefer, H.M.; Böhning-Gaese, K.; Schleuning, M. 2017. Importance of animal and plant traits for fruit removal and seedling recruitment in a tropical forest. Oikos, 126: 823-832.). |
H5 - Fruits with smaller seeds will have their seeds swallowed more frequently than fruits with larger seeds. |
Larger seeds occupy more space within the frugivore gut (Jordano 2000Jordano, P. 2000. Fruits and frugivory. In: Fenner, M. (Ed.). Seeds: the Ecology of Regeneration in Plant Communities. CABI Publishing, Wallingford, p.125-166.), limiting the ingestion of fruit pulp. Thus, frugivores must avoid ingesting larger seeds. |
H6 - The richness and abundance of frugivores that visit a given fruit tree will be related to fruit traits, such as size, weight, as well as seed size. |
Fruit size and weight, as well as seed size may constrain the consumption of such fruits by some frugivore species (Moran and Catterall 2010Moran, C.; Catterall, C.P. 2010. Can functional traits predict ecological interactions? A case study using rain forest frugivores and plants in Australia. Biotropica, 42: 318-326.; Galetti et al. 2013Galetti, M.; Guevara, R.; Côrtes, M.C.; Fadini, R.; Von Matter, S.; Leite, A.B.; et al. 2013. Functional extinction of birds drives rapid evolutionary changes in seed size. Science, 340: 1086-1090. ; Blendinger et al. 2016Blendinger, P.G.; Martín, E.; Osinaga, A.O.; Ruggera, R.A.; Aráoz, E. 2016. Fruit selection by Andean forest birds: influence of fruit functional traits and their temporal variation. Biotropica, 48: 677-686. ). |
H7 - Larger trees will attract a large number of frugivore individuals and species. |
Larger trees may be more conspicuous and produce higher fruit abundance (Chapman et al. 1992Chapman, C.A.; Chapman, L.J.; Wangham, R.; Hunt, K.; Gebo, D.; Gardner, L. 1992. Estimators of fruit abundance of tropical trees. Biotropica, 24: 527-531. ). |
H8 - Frugivore richness and abundance in the focal trees will be higher in months with lower prevalence of ripe fruits. |
Frugivores will concentrate their feeding in the few trees bearing fruits in months with low fruit prevalence (Stevenson et al. 2000Stevenson, P.R.; Quiñones, M.J.; Ahumada, J.A. 2000. Influence of fruit availability on ecological overlap among four neotropical primates at Tinigua National Park, Colombia 1. Biotropica, 32: 533-544., Saracco et al. 2005Saracco, J.F.; Collazo, J.A.; Groom, M.J.; Carlo, T.A. 2005 Crop size and fruit neighborhood effects on bird visitation to fruiting Schefflera morototoni trees in Puerto Rico. Biotropica, 37: 81-87.). |
H9 - Taxonomic groups will differ in the time of arrival in the fruiting tree. |
Taxonomic groups differ regarding predation risk, and physiological constraints that may influence the time of activity onset (Taufique et al. 2006; Saggese et al. 2011Saggese, K.; Korner-Nievergelt, F.; Slagsvold, T.; Amrhein, V. 2011. Wild bird feeding delays start of dawn singing in the great tit. Animal Behaviour, 81: 361-365.). |