| Records |
| Author |
Christensen-Dalsgaard, K.K.; Fournier, M.; Ennos, A.R.; Barfod, A.S. |
| Title |
Changes in vessel anatomy in response to mechanical loading in six species of tropical trees |
Type |
Journal Article |
| Year |
2007 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
176 |
Issue |
3 |
Pages |
610-622 |
| Keywords |
hydraulic architecture; hydraulic-mechanical trade-off; mechanical adaptation; rooting morphology; tropical trees; vascular anatomy |
| Abstract |
It is well known that trees adapt their supportive tissues to changes in loading conditions, yet little is known about how the vascular anatomy is modified in this process. We investigated this by comparing more and less mechanically loaded sections in six species of tropical trees with two different rooting morphologies. We measured the strain, vessel size, frequency and area fraction and from this calculated the specific conductivity, then measured the conductivity, modulus of elasticity and yield stress. The smallest vessels and the lowest vessel frequency were found in the parts of the trees subjected to the greatest stresses or strains. The specific conductivity varied up to two orders of magnitude between mechanically loaded and mechanically unimportant parts of the root system. A trade-off between conductivity and stiffness or strength was revealed, which suggests that anatomical alterations occur in response to mechanical strain. By contrast, between-tree comparisons showed that average anatomical features for the whole tree seemed more closely related to their ecological strategy. |
| Address |
Univ Manchester, Fac Life Sci, Manchester M60 1QD, Lancs, England, Email: karen@cd-mail.dk |
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Thesis |
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| Publisher |
BLACKWELL PUBLISHING |
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0028-646X |
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| Notes |
ISI:000250275000013 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
156 |
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| Author |
de Grandcourt, A.; Epron, D.; Montpied, P.; Louisanna, E.; Bereau, M.; Garbaye, J.; Guehl, J.M. |
| Title |
Contrasting responses to mycorrhizal inoculation and phosphorus availability in seedlings of two tropical rainforest tree species |
Type |
Journal Article |
| Year |
2004 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
161 |
Issue |
3 |
Pages |
865-875 |
| Keywords |
phosphorus; growth; efficiency; Paris-type arbuscular mycorrhizas; tropical rainforest; seedlings; Dicorynia guianensis; Eperua falcata |
| Abstract |
This work aimed at understanding the role of mycorrhizal status in phosphorus efficiency of tree seedlings in the tropical rainforest of French Guyana. Mycorrhizal colonization, growth, phosphorus content, net photosynthesis and root respiration were determined on three occasions during a 9-month growth period for seedlings of two co-occurring species (Dicorynia guianensis and Eperua falcata) grown at three soil phosphorus concentrations, with or without inoculation with arbuscular mycorrhizas. Seedlings of both species were unable to absorb phosphorus in the absence of mycorrhizal association. Mycorrhizal seedlings exhibited coils that are specific of Paris-type mycorrhizae. Both species benefited from the mycorrhizal symbiosis in terms of phosphorus acquisition but the growth of E. falcata seedlings was unresponsive to this mycorrhizal improvement of phosphorus status, probably because of the combination of high seed mass and P reserves, with low growth rate. The two species belong to two different functional groups regarding phosphorus acquisition, D. guianensis being an obligate mycotrophic species. |
| Address |
Univ Franche Comte, Lab Biol & Ecophysiol, F-25211 Montbeliard, France, Email: daniel.epron@scbiol.uhp-nancy.fr |
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| Publisher |
BLACKWELL PUBLISHING LTD |
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| ISSN |
0028-646X |
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| Notes |
ISI:000188646500022 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
239 |
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| Author |
Haettenschwiler, S.; Coq, S.; Barantal, S.; Handa, I.T. |
| Title |
Leaf traits and decomposition in tropical rainforests: revisiting some commonly held views and towards a new hypothesis |
Type |
Journal Article |
| Year |
2011 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
189 |
Issue |
4 |
Pages |
950-965 |
| Keywords |
energy starvation; French Guiana; litter quality; mycorrhizas; nutrient cycling; nutrient limitation; phosphorus; soil fauna |
| Abstract |
Proper estimates of decomposition are essential for tropical forests, given their key role in the global carbon (C) cycle. However, the current paradigm for litter decomposition is insufficient to account for recent observations and may limit model predictions for highly diverse tropical ecosystems. In light of recent findings from a nutrient-poor Amazonian rainforest, we revisit the commonly held views that: litter traits are a mere legacy of live leaf traits; nitrogen (N) and lignin are the key litter traits controlling decomposition; and favourable climatic conditions result in rapid decomposition in tropical forests. Substantial interspecific variation in litter phosphorus (P) was found to be unrelated to variation in green leaves. Litter nutrients explained no variation in decomposition, which instead was controlled primarily by nonlignin litter C compounds at low concentrations with important soil fauna effects. Despite near-optimal climatic conditions, tropical litter decomposition proceeded more slowly than in a climatically less favourable temperate forest. We suggest that slow decomposition in the studied rainforest results from a syndrome of poor litter C quality beyond a simple lignin control, enforcing energy starvation of decomposers. We hypothesize that the litter trait syndrome in nutrient-poor tropical rainforests may have evolved to increase plant access to limiting nutrients via mycorrhizal associations. |
| Address |
[Haettenschwiler, Stephan; Coq, Sylvain; Barantal, Sandra; Handa, Ira Tanya] CNRS, CEFE, F-34293 Montpellier 5, France, Email: stephan.hattenschwiler@cefe.cnrs.fr |
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| Publisher |
Wiley-Blackwell |
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Edition |
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| ISSN |
0028-646x |
ISBN |
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Medium |
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Conference |
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| Notes |
ISI:000286940500009 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
296 |
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| Author |
Clair, B.; Ghislain, B.; Prunier, J.; Lehnebach, R.; Beauchene, J.; Alméras, T. |
| Title |
Mechanical contribution of secondary phloem to postural control in trees: the bark side of the force |
Type |
Journal Article |
| Year |
2019 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol |
| Volume |
221 |
Issue |
1 |
Pages |
209-217 |
| Keywords |
bark; Malvaceae; maturation stress; secondary phloem; tree biomechanics |
| Abstract |
Summary To grow straight, plants need a motor system that controls posture by generating forces to offset gravity. This motor function in trees was long thought to be only controlled by internal forces induced in wood. Here we provide evidence that bark is involved in the generation of mechanical stresses in several tree species. Saplings of nine tropical species were grown tilted and staked in a shadehouse and the change in curvature of the stem was measured after releasing from the pole and after removing the bark. This first experiment evidenced the contribution of bark in the up-righting movement of tree stems. Combined mechanical measurements of released strains on adult trees and microstructural observations in both transverse and longitudinal/tangential plane enabled us to identify the mechanism responsible for the development of asymmetric mechanical stress in the bark of stems of these species. This mechanism does not result from cell wall maturation like in wood, or from the direct action of turgor pressure like in unlignified organs, but is the consequence of the interaction between wood radial pressure and a smartly organized trellis structure in the inner bark. |
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| Publisher |
John Wiley & Sons, Ltd (10.1111) |
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Edition |
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| ISSN |
0028-646x |
ISBN |
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Conference |
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| Notes |
doi: 10.1111/nph.15375 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
853 |
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| Author |
Dejean, A.; Leroy, C.; Corbara, B.; Cereghino, R.; Roux, O.; Herault, B.; Rossi, V.; Guerrero, R.J.; Delabie, J.H.C.; Orivel, J.; Boulay, R. |
| Title |
A temporary social parasite of tropical plant-ants improves the fitness of a myrmecophyte |
Type |
Journal Article |
| Year |
2010 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
97 |
Issue |
10 |
Pages |
925-934 |
| Keywords |
Ant-plant relationships; Biotic defense; Parasites of mutualisms; Temporary social parasites; Azteca; Cecropia |
| Abstract |
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant-plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant-myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca-Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees' fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree. |
| Address |
[Dejean, Alain; Leroy, Celine; Roux, Olivier; Orivel, Jerome] CNRS, F-97379 Kourou, France, Email: alain.dejean@wanadoo.fr |
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SPRINGER |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000282094100006 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
77 |
| Permanent link to this record |
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| Author |
Dejean, A.; Grangier, J.; Leroy, C.; Orivel, J. |
| Title |
Predation and aggressiveness in host plant protection: a generalization using ants from the genus Azteca |
Type |
Journal Article |
| Year |
2009 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
96 |
Issue |
1 |
Pages |
57-63 |
| Keywords |
Aggressiveness; Ant-plant relationships; Biotic defence; Predation |
| Abstract |
In studying the ant genus Azteca, a Neotropical group of arboreal species, we aimed to determine the extent to which the ants use predation and/or aggressiveness to protect their host plants from defoliating insects. We compared a territorially dominant, carton-nester, Azteca chartifex, and three plant-ant species. Azteca alfari and Azteca ovaticeps are associated with the myrmecophyte Cecropia (Cecropiaceae) and their colonies shelter in its hollow branches; whereas Azteca bequaerti is associated with Tococa guianensis (Melastomataceae) and its colonies shelter in leaf pouches situated at the base of the laminas. Whereas A. bequaerti workers react to the vibrations transmitted by the lamina when an alien insect lands on a leaf making it unnecessary for them to patrol their plant, the workers of the three other species rather discover prey by contact. The workers of all four species use a predatory behaviour involving spread-eagling alien insects after recruiting nestmates at short range, and, in some cases, at long range. Because A. alfari and A. ovaticeps discard part of the insects they kill, we deduced that the workers' predatory behaviour and territorial aggressiveness combine in the biotic defence of their host tree. |
| Address |
[Dejean, Alain; Leroy, Celine] CNRS, UMR Ecol Forets Guyane 8172, F-97379 Kourou, France, Email: alain.dejean@wanadoo.fr |
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SPRINGER |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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Medium |
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Conference |
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| Notes |
ISI:000261791000006 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
125 |
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| Author |
Grangier, J.; Dejean, A.; Male, P.J.G.; Orivel, J. |
| Title |
Indirect defense in a highly specific ant-plant mutualism |
Type |
Journal Article |
| Year |
2008 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
95 |
Issue |
10 |
Pages |
909-916 |
| Keywords |
Allomerus decemarticulatus; Hirtella physophora; indirect defense; myrmecophytes; optimal defense theory |
| Abstract |
Although associations between myrmecophytes and their plant ants are recognized as a particularly effective form of protective mutualism, their functioning remains incompletely understood. This field study examined the ant-plant Hirtella physophora and its obligate ant associate Allomerus decemarticulatus. We formulated two hypotheses on the highly specific nature of this association: (1) Ant presence should be correlated with a marked reduction in the amount of herbivory on the plant foliage; (2) ant activity should be consistent with the “optimal defense” theory predicting that the most vulnerable and valuable parts of the plant are the best defended. We validated the first hypothesis by demonstrating that for ant-excluded plants, expanding leaves, but also newly matured ones in the long term, suffered significantly more herbivore damage than ant-inhabited plants. We showed that A. decemarticulatus workers represent both constitutive and inducible defenses for their host, by patrolling its foliage and rapidly recruiting nestmates to foliar wounds. On examining how these activities change according to the leaves' developmental stage, we found that the number of patrolling ants dramatically decreased as the leaves matured, while leaf wounds induced ant recruitment regardless of the leaf's age. The resulting level of these indirect defenses was roughly proportional to leaf vulnerability and value during its development, thus validating our second hypothesis predicting optimal protection. This led us to discuss the factors influencing ant activity on the plant's surface. Our study emphasizes the importance of studying both the constitutive and inducible components of indirect defense when evaluating its efficacy and optimality. |
| Address |
[Grangier, Julien; Dejean, Alain; Male, Pierre-Jean G.; Orivel, Jerome] Univ Toulouse 3, Lab Evolut & Diversite Biol, CNRS, UMR 5174, F-31062 Toulouse 9, France, Email: grangier@cict.fr |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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Conference |
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| Notes |
ISI:000259737600002 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
207 |
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| Author |
LaPierre, L.; Hespenheide, H.; Dejean, A. |
| Title |
Wasps robbing food from ants: a frequent behavior? |
Type |
Journal Article |
| Year |
2007 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
94 |
Issue |
12 |
Pages |
997-1001 |
| Keywords |
cleptobiosis; social wasps; charterginus; polybioides; plant-ants |
| Abstract |
Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought. |
| Address |
CNRS Guyane, UPS2561, UMR5174, F-97300 Cayenne, France, Email: llapierre@lowercolumbia.edu |
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| ISSN |
0028-1042 |
ISBN |
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Medium |
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Conference |
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| Notes |
ISI:000250980800006 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
153 |
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| Author |
Dejean, A.; Grangier, J.; Leroy, C.; Orivel, J.; Gilbernau, M. |
| Title |
Nest site selection and induced response in a dominant arboreal ant species |
Type |
Journal Article |
| Year |
2008 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
95 |
Issue |
9 |
Pages |
885-889 |
| Keywords |
ant-plant relationships; biotic defense; induced responses; predation |
| Abstract |
It is well known that arboreal ants, both territorially dominant species and plant ants (e.g., species associated with myrmecophytes or plants housing them in hollow structures), protect their host trees from defoliators. Nevertheless, the presence of an induced defense, suggested by the fact that the workers discovering a leaf wound recruit nestmates, is only known for plant ants. Based on the results from a field study, we show here (1) that colonies of Azteca chartifex, a territorially dominant, neotropical arboreal ant species, mostly selected Goupia glabra (Goupiaceae) trees in which to build their principal carton nests and (2) that plant signals induced workers to recruit nestmates, which patrol the leaves, likely providing the plant with a biotic defense. Furthermore, the number of recruited workers was clearly higher on G. glabra, their most frequently selected host tree species, than on other tree species. These results show that contrary to what was previously believed, induced responses are also found in territorially dominant arboreal ants and so are not limited to the specific associations between myrmecophytes and plant ants. |
| Address |
[Dejean, Alain] CNRS Guyane, UPS 5621, F-97300 Cayenne, France, Email: alain.dejean@wanadoo.fr |
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SPRINGER |
Place of Publication |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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| Notes |
ISI:000258675700013 |
Approved |
no |
| Call Number |
EcoFoG @ eric.marcon @ |
Serial |
209 |
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| Author |
Sobotnik, J.; Sillam-Dusses, D.; Weyda, F.; Dejean, A.; Roisin, Y.; Hanus, R.; Bourguignon, T. |
| Title |
The frontal gland in workers of Neotropical soldierless termites |
Type |
Journal Article |
| Year |
2010 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
| Volume |
97 |
Issue |
5 |
Pages |
495-503 |
| Keywords |
Frontal gland; Workers; Soldierless termites; Apicotermitinae; Anoplotermes; Aparatermes |
| Abstract |
The presence of the frontal gland is well established in termite soldiers of Rhinotermitidae, Serritermitidae, and Termitidae. It is one of their main defensive adaptations or even an exclusive weapon. The gland was also occasionally reported in alate imagoes, but never in the worker caste. Here, we report the first observation of a frontal gland in workers of several Neotropical and one African species of Apicotermitinae. The ultrastructure of Aparatermes cingulatus and Anoplotermes nr. subterraneus is described in detail. In these two species, the gland is well-developed, functional and consists of class 1 secretory cells. The presence of envelope cells, wrapping the gland, is an unusual feature, as well as the presence of several zonulae adherens, connecting neighbouring glandular cells. The frontal gland of workers is homologous to this organ in soldiers and imagoes, as evidenced by the same position in the head and its connection to the same muscle. However, the defensive role of the frontal gland in workers remains to be confirmed. |
| Address |
[Sobotnik, Jan; Sillam-Dusses, David; Hanus, Robert] Acad Sci Czech Republic, Inst Organ Chem & Biochem, Res Team Infochem, CR-16610 Prague 6, Czech Republic, Email: robert@uochb.cas.cz |
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Series Issue |
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Edition |
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| ISSN |
0028-1042 |
ISBN |
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Medium |
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Conference |
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| Notes |
ISI:000277318800007 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
285 |
| Permanent link to this record |
