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Median, interquartile range, and outliers for relative concentrations of four elaiosome phytochemicals selected by all random forest models as important in distinguishing among species of Trillium (blue = least attractive species, pink = most attractive species). Statistical results of follow‐up ANOVA models are included at the top of each plot
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Abstract Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaios...
Citations
... For myrmecochorous plants, diaspore traits primarily determine ant foraging preferences. In general, ants preferentially interact with larger diaspores, diaspores with a higher elaiosome-to-seed ratio and those bearing elaiosomes with higher lipidic content (Boulay et al., 2006;Gómez et al., 2005;Leal, Neto, et al., 2014;Miller et al., 2020). Like in endozoochory, this preference is predicted by OFT because the higher the elaiosome-to-seed ratio, or elaiosome lipidic content, the higher the net energetic intake per diaspore (Bono & Heithaus, 2002;Byk & Del-Claro, 2011). ...
... In both myrmecochorous and endozoochorous plants, manipulation and consumption impacts post-dispersal seed performance (Giladi, 2006;Godínez-Alvarez et al., 2020;Jordano et al., 2007;Schurr et al., 2018). In myrmecochorous plants, for instance, the elaiosome physically prevents seed imbibition so germination is favoured when ants consume elaiosomes (Leal et al., 2007;Miller et al., 2020). Similarly, the fleshy tissue surrounding seeds of endozoochorous fruits, especially drupes and berries, often contains germination inhibitors while the fruit is still connected to the maternal plant (Robertson et al., 2006). ...
... This can happen because a decline in the elaiosome-to-seed ratio and/or elaiosome size increase the probability of interaction with low-quality or even granivorous ants (e.g. Leal, Neto, et al., 2014;Miller et al., 2020). These low-quality ant dispersers consume the elaiosome in situ, barely removing the diaspores and some even predate seeds while consuming the elaiosome (Giladi, 2006 and references therein). ...
Seed production and dispersal are crucial ecological processes impacting plant demography, species distributions and community assembly. Plant–animal interactions commonly mediate both seed production and seed dispersal, but current research often examines pollination and seed dispersal separately, which hinders our understanding of how pollination services affect downstream dispersal services. To fill this gap, we propose a conceptual framework exploring how pollen limitation can impact the effectiveness of seed dispersal for endozoochorous and myrmecochorous plant species. We summarize the quantitative and qualitative effects of pollen limitation on plant reproduction and use Optimal Foraging Theory to predict its impact on the foraging behaviour of seed dispersers. In doing so, we offer a new framework that poses numerous hypotheses and empirical tests to investigate links between pollen limitation and seed dispersal effectiveness and, consequently, post‐dispersal ecological processes occurring at different levels of biological organization. Finally, considering the importance of pollination and seed dispersal outcomes to plant eco‐evolutionary dynamics, we discussed the implications of our framework for future studies exploring the demographic and evolutionary impacts of pollen limitation for animal‐dispersed plants.
... Another important factor is the identity of both ant and plant species. The attractiveness of diaspores for ants is a complex characteristic and may be influenced by multiple factors such as elaiosome metabolite composition (Reifenrath et al., 2012), elaiosome mass (Levine et al., 2019;Wendt et al., 2022), diaspore mass (Miller et al., 2020), and/or elaiosome:seed mass ratio (Leal et al., 2014;Levine et al., 2019). The diaspore mass is the most used generative trait (called seed weight) to express the reproductive effort as a part of three basic leaf-height-seed plant measures by Westoby (1998) and is, unlike the other mentioned traits, available in databases for wide range of species. ...
Ants disperse seeds of many plant species adapted to myrmecochory. While advantages of this ant–plant mutualism for myrmecochorous plants (myrmecochores) have been previously studied in temperate region mostly in forests, our study system was a pasture. Moreover, we used a unique combination of observing the effect of ant‐activity suppression on ant dispersal and comparison of the contribution of ant and unassisted dispersal to the distance from mother plant. We established plots without and with ant‐activity suppression (enclosures). We offered diaspores of a myrmecochorous ( Knautia arvensis ), and a non‐myrmecochorous ( Plantago lanceolata ) species in a choice test and followed ants carrying diaspores during days and nights (focus of previous studies was on diurnal dispersal). We measured frequency and distances of ant dispersal and compared them with unassisted dispersal recorded using sticky trap method. The dispersal frequency was lower in enclosures (3.16 times). Ants strongly preferred diaspores of the myrmecochore to non‐myrmecochore with 586 and 42 dispersal events, respectively (out of 6400 diaspores of each species offered). Ant dispersal resulted in more even and on average longer distances (maximum almost tenfold longer, 994 cm) in comparison to unassisted dispersal. Ant dispersal altered the distribution of distances of the myrmecochore from roughly symmetric for unassisted dispersal to positively skewed. Ants dispersed heavier diaspores farther. Ants dropped the majority of diaspores during the dispersal (which reduces clustering of seeds), while several (11%) were carried into anthills. Anthills are disturbed microsites presumably favorable for germination in competitive habitats. Ants provided non‐negligible dispersal services to myrmecochorous K. arvensis but also, to a lesser extent, of non‐myrmecochorous P. lanceolata .
... The main chemical components of the capitulum include oleic acid, palmitic acid, linoleic acid, linolenic acid and stearic acid (Stanton et al. 2015). Similarly, the elaiosome contains a number of lipid species, with oleic acid, a chemical thought to induce corpse-carrying behaviour, being the most abundant (Boulay et al. 2006;Fischer et al. 2008;Miller et al. 2020). The chemicals present in the capitulum are thought to facilitate the dissemination and burial of eggs by providing a food reward to ants (Hughes and Westoby 1992a;Stanton et al. 2015;Robertson et al. 2018). ...
Myrmecochory is a widespread mutualism between angiosperm plants and ants, where seed dispersal is facilitated by a nutrient-rich appendage known as the elaiosome. Some species of phasmids (Phasmatodea) have convergently evolved an appendage, the egg capitulum, that is analogous to the elaiosome. Research into ant-mediated dispersal of phasmid eggs is limited. It is unknown whether there are species-specific interactions between ants and phasmid eggs, nor if this variation in ant species behaviour towards eggs parallels behaviour towards seeds. We observed the behaviour of five Australian ant species towards Extatosoma tiaratum eggs and Acacia longifolia seeds. We found that ant species show significant variation in the likelihood of dispersing phasmid eggs and plant seeds. Iridomyrmex purpureus removed the largest quantities of eggs and seeds. Rhytidoponera metallica also removed large amounts of seeds but less eggs. Three species did not remove any eggs but removed small amounts of seeds. We found a species-specific component to dispersal of phasmid eggs and seeds by ants, indicating that this mutualism may depend on partner identity and abundance. Although seeds and eggs have convergently evolved to exploit ant behaviours, they elicit different behaviours in certain ant species, highlighting the complex nature of this interaction.
... For myrmecochorous plants, diaspore traits are the main factors determining ant foraging preferences. In general, disperser ants interact preferentially with larger diaspores, diaspores with a higher elaiosome-toseed ratio, and those bearing elaiosomes with higher lipidic content (Gómez et al. 2005;Boulay et al. 2006;Leal et al. 2014b, a;Miller et al. 2020). Like in endozoochory, this preference is predicted by OFT because the higher the elaiosome-to-seed ratio, and/or the elaiosome lipidic content, the higher the net energetic intake for ants per diaspore removed (Bono & Heithaus 2002;Byk & Del-Claro 2011). ...
Seed production and dispersal are crucial ecological processes impacting plant demography, species distributions, and community assembly. Plant-animal interactions commonly mediate both seed production and seed dispersal, but current research often examines pollination and seed dispersal separately, which hinders our understanding of how pollination services affect downstream dispersal services. To fill this gap, we propose a conceptual framework exploring how pollen limitation can impact the effectiveness of seed dispersal for endozoochorous and myrmecochorous plant species. We summarize the quantitative and qualitative effects of pollen limitation on plant reproduction and use Optimal Foraging Theory to predict its impact on the foraging behavior of seed dispersers. In doing so, we offer a new framework that poses numerous hypotheses and empirical tests to investigate downstream effects of pollen limitation on seed dispersal effectiveness and, consequently, post-dispersal ecological processes occurring at different levels of biological organization. Finally, considering the importance of pollination and seed dispersal outcomes to plant eco-evolutionary dynamics, we discussed the implications of our framework for future studies exploring the demographic and evolutionary impacts of pollen limitation for animal-dispersed plants.
... For myrmecochorous plants, diaspore traits are the main factors determining ant foraging preferences. In general, disperser ants interact preferentially with larger diaspores, diaspores with a higher elaiosome-toseed ratio, and those bearing elaiosomes with higher lipidic content (Gómez et al. 2005;Boulay et al. 2006;Leal et al. 2014b, a;Miller et al. 2020). Like in endozoochory, this preference is predicted by OFT because the higher the elaiosome-to-seed ratio, and/or the elaiosome lipidic content, the higher the net energetic intake for ants per diaspore removed (Bono & Heithaus 2002;Byk & Del-Claro 2011). ...
Seed production and dispersal are crucial ecological processes impacting plant demography, species distributions, and community assembly. Plant-animal interactions commonly mediate both seed production and seed dispersal, but current research often examines pollination and seed dispersal separately, which hinders our understanding of how pollination services affect downstream dispersal services. To fill this gap, we propose a conceptual framework exploring how pollen limitation can impact the effectiveness of seed dispersal for endozoochorous and myrmecochorous plant species. We summarize the quantitative and qualitative effects of pollen limitation on plant reproduction and use Optimal Foraging Theory to predict its impact on the foraging behavior of seed dispersers. In doing so, we offer a new framework that poses numerous hypotheses and empirical tests to investigate downstream effects of pollen limitation on seed dispersal effectiveness and, consequently, post-dispersal ecological processes occurring at different levels of biological organization. Finally, considering the importance of pollination and seed dispersal outcomes to plant eco-evolutionary dynamics, we discussed the implications of our framework for future studies exploring the demographic and evolutionary impacts of pollen limitation for animal-dispersed plants.
... Seeds are ellipsoidal, slightly curved/ concave in shape and having 1 £ 2 mm dimensions. Seeds also contains some elaiosome fatty acids which attract many ant species (Miller et al., 2020). These plants provide a food source for the ants and the ants pick up the seeds which helps in seeds dispersal mechanism of Trillium species (Pennisi, 2020). ...
... Seeds are ellipsoidal, slightly curved/ concave in shape and having 1 £ 2 mm dimensions. Seeds also contains some elaiosome fatty acids which attract many ant species (Miller et al., 2020). These plants provide a food source for the ants and the ants pick up the seeds which helps in seeds dispersal mechanism of Trillium species (Pennisi, 2020). ...
Trillium govanianum Wall. ex D. Don (Melanthiaceae) is a medicinally important herbaceous plant and its rhizomes
are claimed to have therapeutic effects in traditional health practices. In earlier reports, only rhizomes
have been well explored for chemistry and efficacy, while aerial tissues are still underutilized. Due to overexploitation
of T. govanianum for rhizomes, it is listed as extinct. To understand the potentials of aerial tissues in
comparison to rhizomatous tissues, the present study was focused to estimate polyphenols, flavonoids, and
saponin (Borassoside E) as well as in-vitro antidiabetic and antioxidant potentials. Ethanolic extract of fresh
tissues (roots, rhizomes, rhizomatous buds, stems, leaves, sepals, fruits, fruit pulp, and seeds) were analysed
to determine the total phenolics, flavonoids, and saponins content using spectrophotometric methods.
Whereas, Borassoside E and targeted polyphenols were determined using UPLC-PDA methods. Current findings
disclosed that phenolics and saponins were enriched in aerial tissues (sepals, fruits, and leaves) while
borassoside E was found only in underground parts. All samples showed free radical scavenging and a-amylase
inhibitory activity, while a-glucosidase inhibitory activity was present in all, except borassoside E. Both
aerial and underground tissues of T. govanianum contained valuable polyphenols including flavonoids, and
saponins. Borassoside E was found as a specific a-amylase inhibitor and will helps to prevent the degradation
of starch. Alteration of targeted metabolites and activities were also observed within plant tissues. These
results highlight the importance of aerial tissues for futuristic utilization and value addition. Further, study
will help in quality control, agrotechnological interventions for captive cultivations.
... Threats to T. discolor are largely from development, as much of the upper Savannah River drainage has experienced damming. Flowers are borne singly on plants from April to early May, and capsules with ant-dispersed seeds (Miller and Kwit, 2018;Miller et al., 2020) set in June and July. Petals are adaxially white to cream while abaxial petal color varies from white to maroon at the petal base (M. ...
Premise:
Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor.
Methods:
I measured pollen limitation in T. discolor across two years, and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits.
Results:
Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits.
Conclusions:
Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits. This article is protected by copyright. All rights reserved.
... Gradations in partner attractivity have been tested in ant mutualisms as well. Workers of an ant colony show marked preferences for seeds of myrmecochorous plants (Leal et al. 2014;Miller et al. 2020) or for tending lycaenid caterpillars (Stadler et al. 2003). Ant visitation of aboveground aphids is also not random, with some aphids being much more tended than others (Fischer et al. 2001;Woodring et al. 2004;Akyildirim et al. 2014;Pålsson et al. 2020). ...
Mutually beneficial associations are widespread in ecological networks. They are typically assembled as multispecies guilds of symbionts that compete for one or more host species. The ant Lasius flavus engages in an intriguing and obligate mutualistic association with a community of aphids that are cultivated on plant roots in its nests. The ant displays a repertoire of amicable behaviours towards the aphids, including their transport. I examined whether L. flavus preferentially carried some of the root aphids. Using a no-choice and a choice experiment, I comparatively analysed the transport rate of five obligate and one loosely associated species back to the ant nest and used the transport rate of the ant larvae as a reference. All associated root aphids were carried back to the nest, but in a clear preferential hierarchy. Geoica utricularia, Forda Formicaria and Trama rara were rapidly transported, but slower than the own larvae. Tetraneura ulmi and Geoica setulosa were collected at a moderate rate and the loosely associated Aploneura lentisci was slowly retrieved. In contrast, different species of unassociated aphids were not transported and even provoked aggressive behaviour in L. flavus. This study revealed that co-occurring symbionts may induce different degrees of host attraction, which ultimately may affect the coexistence and assembly of ant-symbiont communities.
... due to differences in foraging, handling, and seed deposition behaviors (Prior et al. 2014(Prior et al. , 2015Meadley-Dunphy et al. 2020). Plant community composition is also altered by ant partner seed preference, which is influenced by elaiosome oleic acid content and plant species commonness (Gorb et al. 2000;Prior et al. 2015;Miller et al. 2020). Finally, aggressive behaviors between co-occurring ant partners also affect seed dispersal as ants alter foraging behavior in the presence of other ant partners (Aranda-Rickert and Fracchia 2012;Meadley-Dunphy et al. 2020;Prior et al. 2020). ...
... Instead, they both preferred species of seeds with high elaiosome to seed ratios (see Peters et a. 2003;Reifenrath et al. 2012). In Prior et al. (2015), the two ant species also preferred seeds with high concentrations of oleic acid, which is a known primary compound that seed-dispersing ants respond to (Turner and Frederickson 2013;Miller et al. 2020). The two preferred plant species in this study have seeds with the highest concentration of oleic acid-T. ...
Generalized mutualisms, such as seed dispersal by ants (myrmecochory), involve guilds of mutualistic partners that exchange services. Partners within guilds vary in traits that affect the quality of mutualistic services. Research aimed at uncovering within-guild variation in partner quality primarily considers the identity of partner species. However, mutualism-related traits vary within species, especially for populations in states of incomplete speciation where the distinction between intra- and interspecific variation is not well defined. Ants in the genus Aphaenogaster are mutualists and the major disperser of seeds of understory plants adapted to dispersal by ants (myrmecochores) in eastern North American forests. A. rudis and A. picea are polyphyletic with overlapping morphological features. We ask if functional variation partitions discretely between named species or along a continuum in this species complex. We collected replicate colonies of three populations, each of the named species. We performed 2D morphometrics on the thorax to quantify complex morphological variation among colonies. We performed lab behavioral trials, measuring behaviors that influence seed dispersal quality such as foraging, seed dispersal rate and preference, and intra- and interspecific aggression. Morphometrics revealed differences between species but also continuous variation in diagnostic features. We found behavioral differences between species, with A. rudis being a better disperser and having higher intraspecific aggression and A. picea being a more active forager and dominant over A. rudis. Behavior also varied along a continuum between species corresponding with colony morphometrics, with intermediate phenotypes having intermediate behavior. This work shows that it is important to consider partner identity in species complexes of mutualistic partners at multiple levels of biological organization.
