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Premise: Volatile emissions from flowers and fruits play a key role in signalling to animals responsible for pollination and seed dispersal. Here, we investigated the pollination biology and chemical ecology of reproduction in Apodolirion buchananii, an African amaryllid that flowers in a leafless state soon after grassland vegetation is burnt in the dry late-winter season., Methods: Pollinators were identified through field collection and pollen loads were quantified. Floral traits including spectral reflectance and scent chemistry were documented. Bioassays using cup traps were used to test the function of floral volatiles. Fruiting biology was investigated using controlled hand-pollination experiments and chemical analysis of fruit scent. Seed germination was scored in greenhouse trials. Seed dispersal was monitored using observations and camera trapping., Results: The sweetly scented white flowers of A. buchananii are pollen-rewarding and pollinated mainly by a diverse assemblage of bees. Cup-trap experiments demonstrated that pollinators are attracted to phenylacetaldehyde, the dominant volatile in the floral scent. Plants are shown to be self-incompatible, and the fleshy fruits were found to emerge from the soil six months after pollination during the peak of the summer rains. Fruits emit a diverse blend of aliphatic and aromatic esters and contain large fleshy recalcitrant seeds which germinate within days of fruits splitting open. Seed dispersal by ants was recorded., Conclusions: This first account of the reproductive biology of a species in the genus Apodolirion highlights an outcrossing mating system involving bees attracted to color and scent as well as the unusual fruiting biology and ant-mediated system of seed dispersal., (© 2024 The Author(s). American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)

Postfloral peduncle laying is regarded as an element of myrmecochorous syndrome, which is presumed to facilitate seed discovery by ants by presenting seeds on the ground. However, this presumption does not explain why the peduncles should lay down rather than dropping diaspores on the ground. In this study, an alternative hypothesis is proposed, the distance hypothesis, stating that peduncle laying extends the primary dispersal distance and thereby enhances myrmecochory or functions as an insurance against myrmecochory failure. To test the distance hypothesis, I focused on several myrmecochorous sedge species. First, the occurrence of postfloral peduncle elongation was examined, which contributes to the extension of primary dispersal distance and is not directly relevant to seed presentation on the ground. The primary dispersal distances relative to sedge canopy radius were quantified to infer the insurance function, that is, the extent to which peduncle laying and elongation alone isolate seedlings from the sedge canopy. The effect of primary dispersal distances on myrmecochory were examined in a field experiment. Postfloral peduncle elongation was observed in all species examined. The insurance function of peduncle laying and elongation was supported in a subset of sedge species, in which primary dispersal distances were approximately twice as long as the sedge canopy radius. The field experiment revealed that longer primary dispersal distances increased both the number of ant nests into which diaspores were transported and myrmecochorous dispersal distances. These results support the distance hypothesis and highlight the need to reconsider the function of peduncle laying in myrmecochores. [ABSTRACT FROM AUTHOR]

Placing traits into novel evolutionary contexts may profoundly alter their functional roles. Here, we investigated whether the elaiosome, a lipid‐rich appendage located on seeds, retained its role as a seed dispersal trait promoting mutualisms with insectivorous ants following human‐mediated introduction of the elaiosome‐bearing Carduus nutans into the Argentinean Caldenal. This system is located within the Neotropical region, an alleged myrmecochory cold spot. Specifically, we first tested the assumption that the elaiosome mediates the interaction between C. nutans and the native ant Pheidole bergi. Then, we explored the hypothesis that, instead of a mutualism, the elaiosome promotes an antagonism between these species because P. bergi predates on both insects and seeds. Finally, we assessed the possibility that the elaiosome is rare in our system, as predicted from its location within the Neotropics. By manipulating the presence/absence of C. nutans' elaiosomes, we demonstrated that P. bergi strongly prefers to collect seeds with versus without C. nutans' elaiosomes, indicating that the elaiosome indeed mediates the interaction between these species. While we detected no direct signs of predation on nor alteration of viability in seeds recovered from P. bergi's refuse dumps, 80% of offered C. nutans seeds remained inside P. bergi colonies, where they are likely consumed by ants, buried too deep for emergence or destroyed by pathogens. Importantly, by quantifying the outcome of the C. nutans–P. bergi interaction, we showed that this relationship is strongly antagonistic. Finally, by sampling taxa most likely to have elaiosomes, we identified eight native species with that trait, preliminary confirming that elaiosome‐bearing species are uncommon in the Caldenal. Taken together, our findings suggest that the elaiosome promotes an antagonism that deters invasion in a cold spot of myrmecochore diversity. The functions of phenotypic traits can thus vary according to the ecological and evolutionary contexts in which they operate. [ABSTRACT FROM AUTHOR]

Myrmecochory commonly complements the advantages of ballistic dispersal in diplochorous species. We studied the role of the elaiosome in two populations of the two diplochorous Mediterranean spurgesEuphorbia boeticaandE. nicaeensis, which share an efficient ballistic dispersal mechanism followed by secondary removal by ants. They differ in elaiosome persistence, as mostE. boeticaseeds lose the elaiosome during explosive dispersal. Self-assessed dietary preferences with seeds with and without elaiosomes of each species showed differences in behaviour among and within ant species. In general, the absence of elaiosome entailed a decrease in the number of disperser ant species interacting with the seeds, whereas the number of predatory ants remains invariable. However, in one population ofE. nicaeensis, experimental elimination of the elaiosome did not affect seed removal by mutualistic ants. On the other hand, analysis of refuse piles of the granivorousMessor marocanusandM. bouvierisuggests that they act as seed predators inE. boetica,whereas unintentional dispersal can be important inE. nicaeensis. We suggest, therefore, that the presence of the elaiosome in the seeds of the studied spurges increases the interaction with disperser ant species, but the possible dispersal advantage is not apparent and is spatially variable. [ABSTRACT FROM AUTHOR]

Seed dispersal by ants (myrmecochory) is found worldwide, but the benefits that plants obtain from this mutualism remain uncertain. In the present study, we conducted laboratory experiments to demonstrate seed predator avoidance as a benefit of myrmecochory using the annual ant-dispersed herb Lamium amplexicaule, the disperser ant Tetramorium tsushimae, and the seed predatory burrower bug Adomerus rotundus. We compared the predation intensity of Lamium amplexicaule seeds by Adomerus rotundus under the presence or absence of Tetramorium tsushimae. Both the number of seeds sucked by Adomerus rotundus adults and the feeding duration of sucked seeds by nymphs were significantly reduced in the presence of ants. This effect was most likely due to the behavioral alteration of Adomerus rotundus in response to the ant presence, because ants seldom predated Adomerus rotundus during the experiment. Our results demonstrated that the presence of ants decreases post-dispersal seed predation, even when the ants do not bury the seeds. The present study thus suggests that the non-consumptive effects of ants on seed predators benefit myrmecochorous plants. [ABSTRACT FROM AUTHOR]

Seed dispersal by ants (myrmecochory) is found worldwide, but the benefits that plants obtain from this mutualism remain uncertain. In the present study, we conducted laboratory experiments to demonstrate seed predator avoidance as a benefit of myrmecochory using the annual ant-dispersed herb Lamium amplexicaule, the disperser ant Tetramorium tsushimae, and the seed predatory burrower bug Adomerus rotundus. We compared the predation intensity of Lamium amplexicaule seeds by Adomerus rotundus under the presence or absence of Tetramorium tsushimae. Both the number of seeds sucked by Adomerus rotundus adults and the feeding duration of sucked seeds by nymphs were significantly reduced in the presence of ants. This effect was most likely due to the behavioral alteration of Adomerus rotundus in response to the ant presence, because ants seldom predated Adomerus rotundus during the experiment. Our results demonstrated that the presence of ants decreases post-dispersal seed predation, even when the ants do not bury the seeds. The present study thus suggests that the non-consumptive effects of ants on seed predators benefit myrmecochorous plants.

Having a wide geographical distribution and, as an engineering species, actively transforming the landscapes they inhabit, ants have a significant impact on the environment, creating new biogenic landforms and changing a number of its parameters, including biotic ones. This review is devoted to the consideration of the diverse environment-forming activities of ants in different regions of the world. An analysis of the scientific literature carried out in this context revealed a clear disproportion between the fairly good knowledge of tropical regions and the insufficient knowledge of temperate latitudes. The environment-forming activity of ants actively populating grasslands removed from agricultural use: steppes, continental and floodplain meadows of temperate latitudes has been especially poorly studied, which determines the undoubted priority of this area of research.

A case of interference competition in which some ant species (Messor barbarus and Aphaenogaster senilis) rob seeds of Euphorbia characias from other ants (especially Tapinoma nigerrimum) is reported. Seed robbing is here regarded as a possible natural impediment to myrmecochory as it may interfere with the seedling recruitment process of the myrmecochorous plant.