1
|
Milligan PD, Martin TA, Pringle EG, Prior KM, Palmer TM. Symbiotic ant traits produce differential host-plant carbon and water dynamics in a multi-species mutualism. Ecology 2023; 104:e3880. [PMID: 36199213 DOI: 10.1002/ecy.3880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/28/2022] [Accepted: 07/28/2022] [Indexed: 02/01/2023]
Abstract
Cooperative interactions may frequently be reinforced by "partner fidelity feedback," in which high- or low-quality partners drive positive feedbacks with high or low benefits for the host, respectively. Benefits of plant-animal mutualisms for plants have been quantified almost universally in terms of growth or reproduction, but these are only two of many sinks to which a host-plant allocates its resources. By investigating how partners to host-plants impact two fundamental plant resources, carbon and water, we can better characterize plant-partner fidelity and understand how plant-partner mutualisms may be modulated by resource dynamics. In Laikipia, Kenya, four ant species compete for Acacia drepanolobium host-plants. These ants differ in multiple traits, from nectar consumption to host-plant protection. Using a 5-year ant removal experiment, we compared carbon fixation, leaf water status, and stem non-structural carbohydrate concentrations for adult ant-plants with and without ant partners. Removal treatments showed that the ants differentially mediate tree carbon and/or water resources. All three ant species known to be aggressive against herbivores were linked to benefits for host-plant resources, but only the two species that defend but do not prune the host, Crematogaster mimosae and Tetraponera penzigi, increased tree carbon fixation. Of these two species, only the nectivore C. mimosae increased tree simple sugars. Crematogaster nigriceps, which defends the tree but also castrates flowers and prunes meristems, was linked only to lower tree water stress approximated by pre-dawn leaf water potential. In contrast to those defensive ants, Crematogaster sjostedti, a poor defender that displaces other ants, was linked to lower tree carbon fixation. Comparing the effects of the four ant species across control trees suggests that differential ant occupancy drives substantial differences in carbon and water supply among host trees. Our results highlight that ant partners can positively or negatively impact carbon and/or water relations for their host-plant, and we discuss the likelihood that carbon- and water-related partner fidelity feedback loops occur across ant-plant mutualisms.
Collapse
Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya.,Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Timothy A Martin
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, Florida, USA
| | - Elizabeth G Pringle
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Kirsten M Prior
- Department of Biology, SUNY Binghamton, Binghamton, New York, USA
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya
| |
Collapse
|
2
|
Lloyd-Jones DJ, St Clair JJH, Cram DL, Yassene O, van der Wal JEM, Spottiswoode CN. When wax wanes: competitors for beeswax stabilize rather than jeopardize the honeyguide–human mutualism. Proc Biol Sci 2022; 289:20221443. [PMID: 36448420 PMCID: PMC9709655 DOI: 10.1098/rspb.2022.1443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Many mutualisms are exploited by third-party species, which benefit without providing anything in return. Exploitation can either destabilize or promote mutualisms, via mechanisms that are highly dependent on the ecological context. Here we study a remarkable bird–human mutualism, in which wax-eating greater honeyguides (
Indicator indicator
) guide humans (
Homo sapiens
) to wild bees' nests, in an exchange of knowledge about the location of nests for access to the wax combs inside. We test whether the depletion of wax by mammalian and avian exploiter species either threatens or stabilizes the mutualism. Using camera traps, we monitored feeding visits to wax comb made available following honey harvests. We found that greater honeyguides face competition for wax from conspecifics and nine exploiter species, five of which were not previously known to consume wax. Our results support the hypothesis that heterospecific exploiters stabilize the mutualism, because wax depletion by these competitors probably limits feeding opportunities for conspecific exploiters, favouring the early-arriving individual that guided humans to the bees’ nest. These findings highlight the importance of the ecological context of species interactions and provide further evidence for how mutualisms can persist because of, and not in spite of, exploitation by third-party species.
Collapse
Affiliation(s)
- David J. Lloyd-Jones
- FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town 7700, South Africa
| | - James J. H. St Clair
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK
- School of Biology, University of St Andrews, St Andrews KY16 9AJ, UK
| | - Dominic L. Cram
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK
| | - Orlando Yassene
- Mariri Environmental Centre, Concession L5 South, Niassa Special Reserve, Niassa Province, Mozambique
| | | | - Claire N. Spottiswoode
- FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town 7700, South Africa
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK
| |
Collapse
|
3
|
Djogbenou A, Azihou AF, Dassou AG, Assogbadjo AE, Kassa B, Gaoue OG. Limited ant co-occurrence and defensive mutualism in Acacia plants in a West African savanna. AOB PLANTS 2021; 13:plab036. [PMID: 34234937 PMCID: PMC8255073 DOI: 10.1093/aobpla/plab036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 06/02/2021] [Indexed: 06/13/2023]
Abstract
Our understanding of the role of fire and effect of ant species composition, beyond their diversity and abundance, on the effectiveness of mutualism defence is limited. Most of our knowledge of ant-plant defence in tropical Africa is biased towards East African savannas which have richer soil, higher primary productivity and a more diverse arthropods and mammal community than West African savannas. We assessed the diversity of ant species associated with Acacia species in the Pendjari Biosphere Reserve in the Dahomey Gap, and their impacts on elephant damage. Elephant damage, ant diversity and abundance were measured in stands of five Acacia species. Eleven ant species were identified in the Acacia stands. The composition of these ant communities varied across Acacia species. Pair of ant species co-occurred in only 2 % of sampled trees, suggesting a strong competitive exclusion. Within this annually burnt environment, ants were rare on small trees. The intensity of elephant-caused branch breaking did not vary between trees with ants and trees without ants, suggesting limited Acacia-ant mutualism. Such limited biotic defence may mask strong physical and chemical defence mechanisms of Acacia trees against elephant damage. Ant assemblages in West Africa, unlike those in the more productive East Africa, are particularly species-poor. However, there is a convergence between these two regions in low rate of ant co-occurrence which might indicate strong competitive exclusion. Our study suggests that such low ant species richness while limiting the efficacy of mutualism in controlling mega-herbivore damage may mask a strong defence syndrome.
Collapse
Affiliation(s)
- Anyse Djogbenou
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526, Cotonou, Benin
| | - Akomian F Azihou
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526, Cotonou, Benin
| | - Anicet G Dassou
- Laboratory of Biotechnology, Genetic Resources, Plant and Animal Breeding, Faculty of Sciences and Technology of Dassa, National University of Sciences, Technology, Engineering and Mathematics, 01 BP 14, Dassa-Zoumè, Benin
| | - Achille E Assogbadjo
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526, Cotonou, Benin
| | - Barthelemy Kassa
- Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526, Cotonou, Benin
| | - Orou G Gaoue
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA
- Faculty of Agronomy, University of Parakou, BP 123, Parakou, Benin
- Department of Geography, Environmental Management and Energy Sciences, University of Johannesburg, APK Campus, Johannesburg, South Africa
| |
Collapse
|
4
|
Milligan PD, Martin TA, John GP, Riginos C, Goheen JR, Carpenter SM, Palmer TM. Mutualism disruption by an invasive ant reduces carbon fixation for a foundational East African ant-plant. Ecol Lett 2021; 24:1052-1062. [PMID: 33745197 DOI: 10.1111/ele.13725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 11/30/2022]
Abstract
Invasive ants shape assemblages and interactions of native species, but their effect on fundamental ecological processes is poorly understood. In East Africa, Pheidole megacephala ants have invaded monodominant stands of the ant-tree Acacia drepanolobium, extirpating native ant defenders and rendering trees vulnerable to canopy damage by vertebrate herbivores. We used experiments and observations to quantify direct and interactive effects of invasive ants and large herbivores on A. drepanolobium photosynthesis over a 2-year period. Trees that had been invaded for ≥ 5 years exhibited 69% lower whole-tree photosynthesis during key growing seasons, resulting from interaction between invasive ants and vertebrate herbivores that caused leaf- and canopy-level photosynthesis declines. We also surveyed trees shortly before and after invasion, finding that recent invasion induced only minor changes in leaf physiology. Our results from individual trees likely scale up, highlighting the potential of invasive species to alter ecosystem-level carbon fixation and other biogeochemical cycles.
Collapse
Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
| | - Timothy A Martin
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL, USA
| | | | - Jacob R Goheen
- Mpala Research Centre, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | | | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
| |
Collapse
|
5
|
Kulikowski AJ. Ant–scale mutualism increases scale infestation, decreases folivory, and disrupts biological control in restored tropical forests. Biotropica 2020. [DOI: 10.1111/btp.12786] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Andy J. Kulikowski
- Department of Environmental Studies University of California Santa Cruz Santa Cruz CA USA
| |
Collapse
|
6
|
Combining stable isotope analysis with DNA metabarcoding improves inferences of trophic ecology. PLoS One 2019; 14:e0219070. [PMID: 31329604 PMCID: PMC6645532 DOI: 10.1371/journal.pone.0219070] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 06/14/2019] [Indexed: 12/31/2022] Open
Abstract
Knowing what animals eat is fundamental to our ability to understand and manage biodiversity and ecosystems, but researchers often must rely on indirect methods to infer trophic position and food intake. Using an approach that combines evidence from stable isotope analysis and DNA metabarcoding, we assessed the diet and trophic position of Anthene usamba butterflies, for which there are no known direct observations of larval feeding. An earlier study that analyzed adults rather than caterpillars of A. usamba inferred that this butterfly was aphytophagous, but we found that the larval guts of A. usamba and two known herbivorous lycaenid species contain chloroplast 16S sequences. Moreover, chloroplast barcoding revealed high sequence similarity between chloroplasts found in A. usamba guts and the chloroplasts of the Vachellia drepanolobium trees on which the caterpillars live. Stable isotope analysis provided further evidence that A. usamba caterpillars feed on V. drepanolobium, and the possibilities of strict herbivory versus limited omnivory in this species are discussed. These results highlight the importance of combining multiple approaches and considering ontogeny when using stable isotopes to infer trophic ecology where direct observations are difficult or impossible.
Collapse
|
7
|
Haba Y, Herbert R, Yang L. An undescribed relationship between the knobthorn tree (
Senegalia nigrescens
), ants, and a lac scale insect in South Africa. Afr J Ecol 2019. [DOI: 10.1111/aje.12627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuki Haba
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey
| | - Ryan Herbert
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey
| | - Luojun Yang
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey
| |
Collapse
|