DOI: 10.5061/dryad.wh70rxwpg
title: Megafruit and megafauna diversity are positively associated, while megafruit traits are related to abiotic factors, in Tropical Asia

description: Aim For tens of millions of years, herbivorous megafauna were abundant
 across the globe, fulfilling important ecological roles including seed
 dispersal. Megafruits are very large fruits that are dispersed most
 effectively by megafauna. However, megafruits also occur in ecosystems
 where megafauna are extinct or were never present, emphasizing our
 incomplete understanding of megafauna-megafruit relationships. Here we use
 the complex biogeography of tropical Asia to investigate how megafruit
 diversity and traits are associated with the diversity of megafauna,
 smaller animals, and abiotic factors. Location Tropical Asia, from the
 Indian subcontinent in the west to tropical China in the north to the
 Maluku archipelago (Indonesia) in the east. Time period Late Pleistocene
 to the present day. Major taxa studied Megafauna (body weight &gt;500
 kg) that consume fruits, including stegodons, elephants, rhinoceroses,
 giant tapirs, and large bovids. Fleshy-fruited plant species across the
 region with a fruit width &gt;40 mm (i.e., megafruits). Methods We
 compiled a list of all megafruits along with selected plant, fruit, and
 seed traits in 16 subregions across tropical Asia. We explored
 biogeographic patterns in megafruit diversity and traits in relation to
 the diversities of past and present megafauna, large- and medium-sized
 animals and abiotic factors (mean temperature, mean precipitation,
 precipitation seasonality, insularity). Results We identified 496
 megafruits in tropical Asia. Megafruit diversity was highest in subregions
 with high megafaunal diversity, particularly extant species. Megafruit
 traits were influenced most strongly by abiotic factors (mainly
 temperature and land area), and weakly by megafauna and smaller
 dispersers. Main conclusions Our results are consistent with megafauna
 maintaining or responding to megafruit diversity, but variation in
 megafruit traits is primarily associated with abiotic factors. Given the
 massive megafaunal losses in tropical Asia since the Late Pleistocene, it
 is important to identify fruit traits that can increase
 megafauna-dependence and thus vulnerability to these losses.
description: Our
 study area encompassed the Indian subcontinent, north to tropical China
 and east to the Maluku Islands of Indonesia. We recorded megafruits,
 megafaunal animals, and other potential consumers of megafruits in these
 subregions. We use the term “diversity” to refer to the number of species
 for each of these. For each of these variables we gathered species lists
 from regional floras and published literature. We used
 personal experience and floras from across the region to identify
 megafruits. Our searches were exhaustive, but we could have missed a few
 species for which fruit trait information was not available. The criteria
 for inclusion were fruit width ≥40 mm (Guimarães et al., 2008) and having
 an edible fruit-part other than the seed. For genera with several species
 of megafruits, where some lacked size information, we used additional
 resources (internet searches, unpublished data) to obtain fruit
 descriptions. Sixty-nine of the 496 species of megafruits did not have
 fruit width information available but were included because the genera had
 many other megafruit species. Half of these species (<i>N</i>
 = 30) were in <i>Rafflesia, </i>whose dispersers are almost
 completely unknown (Hidayati and Walck, 2016). The presence or absence of
 all the megafruit species in our list was recorded for each of the 16
 biogeographic subregions.  The following details were
 recorded for the fruit when available: IUCN status, habitat type, growth
 form (climber, tree, palm, shrub, herb), tree height, fruit-type (berry,
 drupe, syncarp, syconium, capsule, pod, follicles) and fruit colour. Fruit
 colour was simplified to the main colour displayed (see below) and then
 condensed into two broad groups that reflected consumption by terrestrial,
 dichromatic mammals (Yokoyama et al., 2005) and megafauna (Bunney et al.,
 2019). Brown, green, yellow, or orange fruits were grouped as being
 primarily targeted towards these mammals (“megafauna-coloured”), either
 because the fruit had not invested resources in colours that are not
 perceived as distinct by dichromats, or because they had invested in odour
 instead (Valenta et al., 2018), or possibly because these dull colours
 allowed fruits to escape predation on the forest floor. The other colour
 grouping – red, black, purple, pink, white, and blue – were fruits that
 had invested in colours often associated with tetrachromatic birds and,
 possibly, also perceived by trichromatic primates. The measured
 characteristics were fruit length (longest axis) and width (second longest
 axis), seed length and width, and seed number per fruit. Data were
 collected from published floras from different subregions, journal
 publications, and other on-line sources (only when published information
 was unavailable). The references used are recorded in the
 database. The nomenclatures and
 distributions of the 495 species in our database were checked in Plants of
 the World Online database (POWO). Synonyms were removed and distributions
 changed to follow POWO in 105 of the 157 discrepancies that we observed.
 For the other 52 species, we followed recent publications and regional
 floras that were available on-line.  Literature
 cited Bunney, K., Robertson, M.
 & Bond, W. (2019). The historical distribution of megaherbivores
 does not determine the distribution of megafaunal fruit in southern
 Africa. <i>Biological Journal of the Linnean Society</i>
 <b>128</b>, 1039–1051. Guimarães, P. R., Galetti, M.
 & Jordano, P. (2008). Seed Dispersal Anachronisms: Rethinking the
 Fruits Extinct Megafauna Ate. <i>PLoS ONE</i>
 <b>3</b>, e1745 (2008). Hidayati, S. N. & Walck, J. L. (2016). A review of the biology of Rafflesia: what do we know and what’s next? <i>Bulletin Kebun Raya</i> <b>9</b>, 67–78. POWO. (2020). Plants of the World Online | Kew Science. <i>Plants of the World Online</i> http://www.plantsoftheworldonline.org/. Valenta, K., Kalbitzer, U., Razafimandimby, D., Omeja, P., Ayasse, M., Chapman, C. A., Nevo, O. (2018). The evolution of fruit colour: phylogeny, abiotic factors and the role of mutualists. <i>Scientific Reports</i> <b>8</b>, 14302. Yokoyama, S., Takenaka, N., Agnew, D. W. & Shoshani, J. (2005). Elephants and Human Color-Blind Deuteranopes Have Identical Sets of Visual Pigments. <i>Genetics</i> <b>170</b>, 335–344.
description: See README file.