Seed germination of a myrmecochorous plant endemic to the Brazilian semiarid region: the wolf is not so bad

Abstract

Studies about seed dispersal and germination are important to understand patterns of plant distribution and abundance, and help establish strategies for environmental conservation. We evaluated the role of two different dispersers, the ant Atta laevigata and the maned wolf Chrysocyon brachyurus, in the germination of Copaifera arenicola seeds, a characteristically myrmecochorous plant species. Germination was evaluated for seeds subjected to four treatments: (1) seeds manipulated by the ant, (2) seeds ingested by the maned wolf, (3) seeds that had the elaiosome removed manually, and (4) seeds with elaiosome (unmanipulated seeds). Seeds manipulated by the ant and seeds that had the elaiosome removed manually required less time to germinate and had higher germination percentages (98.6% and 95.8%, respectively) than the other treatments. However, seeds ingested by the maned wolf also had a high germination percentage (87.7%), above that of unmanipulated seeds (34.7%). Probably, elaiosomes of unmanipulated seeds and small remnants of this structure that resist digestion by maned wolf can decrease to some extent seed germination. We argue that dispersal of C. arenicola seeds by the ant and by the maned wolf result in different patterns of seed distribution in the environment and that they have complementary roles in structuring plant populations.

Contrasting patterns of host selection and performance of insect seed predators on three sympatric host plant species

“…The seeds are ovoid and have a shiny black integument partially covered by a nutrient‐rich orange elaiosome (Fagundes et al, 2021). Copaifera seeds are important key resources for several vertebrate and invertebrate species (Fagundes et al, 2022; Souza & Fagundes, 2017). In Brazil, the Copaifera genus is represented by 26 species broadly distributed through different biomes, such as Cerrado, Caatinga, Atlantic Forest, and the Amazon (Maruyama et al, 2021).…”

“…Rhinochenus brevicollis Chevrolat (Curculionidae: Cryptorhynchinae) is the main insect predator of Copaifera seeds. Females of these beetles lay their eggs directly on the fruit in initial stages of seed formation and only one larva develops inside the seed, feeding upon the cotyledons and often causing damage to the embryo (Fagundes et al, 2022). One unidentified species of beetle within the Apion genus (Brentidae: Apioninae) also feeds on Copaifera seeds, but information on the biology of this species is still very scarce (Ramirez & Arroyo, 1987).…”

“…Although some seeds are generally chemically and physically defended against attacks by insects such as moths and beetles (e.g., Wright 1994;Oliveras et al 2008;Mezquida et al, 2021), the number of insects preying upon them are generally high, particularly in the tropics (see Ramírez & Traveset, 2010;Souza & Fagundes, 2017;van Klinken, & White, A.J., 2014;Xu et al, 2015). Seed damage caused by insects varies from superficial damage to the tegument or cotyledons to severe damage to the embryo, resulting in seed death (Fagundes et al, 2022;Han et al, 2018;Perea et al, 2020;Silva & Rossi, 2019).…”

“…Although some seeds are generally chemically and physically defended against attacks by insects such as moths and beetles (e.g., Wright 1994; Oliveras et al 2008; Mezquida et al, 2021), the number of insects preying upon them are generally high, particularly in the tropics (see Ramírez & Traveset, 2010; Souza & Fagundes, 2017; van Klinken, & White, A.J., 2014; Xu et al, 2015). Seed damage caused by insects varies from superficial damage to the tegument or cotyledons to severe damage to the embryo, resulting in seed death (Fagundes et al, 2022; Han et al, 2018; Perea et al, 2020; Silva & Rossi, 2019). The specificity of the relationship between seed‐feeding insects and their hosts can range from polyphagy (i.e., an insect species that feeds upon seeds of several plant species) to monophagy (i.e., an insect species that feeds on seeds of one or a few phylogenetically related plant species) (Galfrascoli et al, 2022; Gripenberg et al, 2019; Janzen, 1980; Kergoat et al, 2004).…”

“…Species of Copaifera (Fabaceae) produce ovoid, shiny black seeds, partially covered by an orange elaiosome. These seeds are important food resources for several vertebrate and invertebrate species, acting as key resources in tropical savanna vegetation (Fagundes et al, 2022). We evaluated these plants as models to study the preference and performance of EPIs among three congeneric Copaifera species ( C. arenicola , C. langsdorffii , and C. oblongifolia ) that are sympatric but differ in the growth form and appearance to insects that use their seeds.…”