Marc Gibernau | Université Blaise-Pascal, F- Clermont-Ferrand (original) (raw)

Papers by Marc Gibernau

Proceedings of the Royal Society B: Biological Sciences, 1998

Every dioecious species of ¢g is pollinated by a speci¢c wasp that only reproduces within the in£... more Every dioecious species of ¢g is pollinated by a speci¢c wasp that only reproduces within the in£orescences of male trees. Pollinators usually die within the closed urn-shaped in£orescence (¢g or syconium) they visit. Thus pollinators that enter female syconia allow seed production but die without reproducing. In a previous study, pollinators of one dioecious ¢g where male and female trees £ower synchronously, Ficus hispida, did not exhibit di¡erential attraction or choice between in£orescences of the two sexes. Here we show that Blastophaga psenes, the pollinator of another dioecious species of di¡erent lineage, the common ¢g (F. carica), signi¢cantly avoided female syconia, when we experimentally induced a situation of choice. Paradoxically, choosiness can be demonstrated in F. carica where usually wasps do not face a choice because male and female trees do not £ower synchronously. We discuss how the mutualism may be stable despite this discrimination and hypothesize why the two species of ¢g-pollinators exhibit di¡erent behaviour on dioecious ¢gs.

Comptes Rendus Biologies, 2009

We examined 424 nests belonging to 61 wasp species along 5 km of rainforest edges in French Guian... more We examined 424 nests belonging to 61 wasp species along 5 km of rainforest edges in French Guiana (ca. 15,235 plants monitored), and estimate that we recorded up to 73% of the local social wasp fauna. This baseline study was complemented by a long-term survey of the same area and the examination of isolated trees (permitting us to record two additional species, resulting in a total of 63 wasp species). Our results form a continuum from species avoiding nesting on any plant (6.5% of the wasp species) to species nesting on plants but avoiding those sheltering ant nests (82%), to, finally, wasps nesting in association with arboreal ants known to divert army ant raids (11.5%). Consequently, this study documents that most wasp species select plants possibly repulsive to arboreal ants, while associations with arboreal ants, although confirmed here, have been overrepresented in the literature. To cite this article: B. Corbara et al., C. R. Biologies 332 (2009).

Comptes Rendus Biologies, 2010

Mots cle´s : Vespidae Variation de la taille des populations Microé volution La Niña Guyane franç... more Mots cle´s : Vespidae Variation de la taille des populations Microé volution La Niña Guyane française A B S T R A C T After noting the forecast of a La Niña episode, associated with heavy rainfall in French Guiana, we monitored the fate of wasp nests before and during the 2006 short rainy season. The population of the most abundant epiponine wasp species, Polybia bistriata, decreased dramatically during the short rainy season (60.6% of the nests disappeared) then remained low for at least 18 months. Colonies that survived moved from the shelter of large, low leaves (a situation well adapted to the previous dry season) of the most frequent substrate tree, Clusia grandiflora (Clusiaceae), to upper leaves, better ventilated and whose orientation provides good protection from the rain. Therefore, the possibility of moving the nest higher during the first rains following the dry season seems very adaptive as colonies that do not do so are eliminated during the La Niña years, whose frequency will increase with global climate change. ß 2009 Acadé mie des sciences. Published by Elsevier Masson SAS. All rights reserved.

ABSTRACT The pollination success of the dead horse arum, Helicodiceros muscivorus, was studied in... more ABSTRACT The pollination success of the dead horse arum, Helicodiceros muscivorus, was studied in one Corsican population. This aroid species is pollinated by deception, attracting blowflies by mimicking the floral volatiles emitted by mammal cadavers. The reproductive individuals were taller and larger than non-reproductive ones, indicating that the plant vigor and thus the available amount of resources are important factors in the production of an inflorescence. The reproductive success of the dead horse arum increased with the size of the inflorescence, as judged by a positive linear correlation between the appendix length and the total number of flies trapped within the floral chamber. Larger inflorescences had a longer appendix and thus a better probability to attract and dupe pollinating flies. The absence of correlation between floral sex-ratio and the spadix size indicated that there was no expression of the size-advantage model in H. muscivorus apparent in some other Araceae. The most probable explanation is that pollination efficiency is high because of low diversity and high abundance of pollinating insects.

Naturwissenschaften, 2014

Staining and histochemistry of volatile organic compounds (VOCs) were performed at different infl... more Staining and histochemistry of volatile organic compounds (VOCs) were performed at different inflorescence developmental stages on nine aroid species; one temperate, Arum italicum and eight tropical from the genera Caladium, Dieffenbachia and Philodendron. Moreover, a qualitative and quantitative analysis of VOCs constituting the scent of A. italicum, depending on the stage of development of inflorescences was also conducted. In all nine species, vesicles were observed in the conical cells of either the appendix or the stamens (thecae) and the staminodes. VOCs were localised in intracellular vesicles from the early stages of inflorescence development until their release during receptivity of gynoecium. This localisation was observed by the increase of both number and diameter of the vesicles during 1 week before receptivity. Afterwards, vesicles were fewer and smaller but rarely absent. In A. italicum, staining and gas chromatography analyses confirmed that the vesicles contained terpenes. The quantitatively most important ones were the sesquiterpenes, but monoterpenes were not negligible. Indeed, the quantities of terpenes matched the vesicles&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; size evolution during 1 week. Furthermore, VOCs from different biosynthetic pathways (sesquiterpenes and alkanes) were at their maximum quantity 2 days before gynoecium receptivity (sesquiterpenes and alkanes) or during receptivity (isobutylamine, monoterpenes, skatole and p-cresol). VOCs seemed to be emitted during gynoecium receptivity and/or during thermogenesis, and FADs are accumulated after thermogenesis in the spadix. These complex dynamics of the different VOCs could indicate specialisation of some VOCs and cell machinery to attract pollinators on the one hand and to repulse/protect against phytophagous organisms and pathogens after pollination on the other hand.

Journal of Tropical Ecology, 2007

Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie, 2000

Despite the large specific diversity of equatorial rainforests, Caternaultiella rugosa (Heteropte... more Despite the large specific diversity of equatorial rainforests, Caternaultiella rugosa (Heteroptera; Plataspidae) was only noted on two euphorbiaceous trees (Bridelia micrantha and B. grandis) and was attended by two ant species, Camponotus brutus (Formicinae) and Myrmicaria opaciventris (Myrmicinae). We recorded semiochemical (attending workers palpated the dorsal abdominal glands of the nymphs) and semantic signals (nymphs ready to excrete honeydew raised their bodies; they alternated the extrusion and withdrawal of the first honeydew droplet when the workers did not immediately absorb the honeydew). Cat. rugosa was recorded in carton pavilions built by the ants at the base of the tree trunks. During proliferations of the population, clusters of nymphs and adults developed outside pavilions. In the latter case, M. opaciventris workers did not modify their rhythm of activity in order to attend these clusters, while Camp. brutus workers, normally nocturnal, attended them day and night. © 2000 Académie des sciences/Éditions scientifiques et médicales Elsevier SAS

Botany, 2008

Pollen viability and germination were observed in six species of neotropical Araceae. In Anaphyll... more Pollen viability and germination were observed in six species of neotropical Araceae. In Anaphyllopsis americana (Engl.) A. Hay, 50% of pollen grains remain viable after 70 h following dehiscence, and it takes over 210 h for total loss of viability to occur. In Montrichardia arborescens (L.) Schott, approximately 50% of pollen grains are not viable after 24 h, and no germination occurs after 36 h. Monstera adansonii Schott and Philodendron pedatum (Hook.) Kunth have the lowest initial pollen viability (40%-55%) and lose half of this viability after approximately 30 h. Pollen grains of Monstera adansonii remain viable for at least 60 h and that of P. pedatum for approximately 40 h, and constitute another group with a similar viability pattern. In Philodendron melinonii Brongn. ex Regel and Philodendron solimoesense A.C. Sm., pollen loses 50% of its viability after 24 h, but remains viable for at least 48 h. The percentage of viability decreases in a pattern from species having a long flowering cycle and small pollen grains (A. americana) to species with a short flowering cycle and large pollen grains (M. arborescens).

Canadian Journal of Botany, 2007

Floral cycles and spadix temperatures were recorded for two species of Syngonium: Syngonium schot... more Floral cycles and spadix temperatures were recorded for two species of Syngonium: Syngonium schottianum Wendl. ex Schott (section Cordatum) and Syngonium angustatum Schott (section Syngonium). Both species exhibited a 3day flowering cycle, beginning with stigma receptivity and opening of the spathe the first day, the female phase continues over the second day, and the male phase continues over the third day. These species displayed two distinct patterns of heat production during flowering. In S. schottianum, the spadix warmed up twice during the beginning of the second and third nights, but in S. angustatum, the spadix warmed up twice the second day, once the second night, and once the third day. These different thermogenic cycles are discussed in regard to other genera that are phylogenetically close or sharing similar flowering and thermogenic cycles.

Botanical Journal of the Linnean Society, 2008

The reproductive success of Arum italicum in south-western France showed a positive relationship ... more The reproductive success of Arum italicum in south-western France showed a positive relationship with plant vigour at both the plant (number of inflorescences) and inflorescence (number of seeds) levels. However, the infructescence and berry numbers were not related to the number of inflorescences, and two-fold more seeds were produced by individuals flowering several times than by those flowering just once. Moreover, the reproductive success of this species appeared to be limited by the high abortion rate (50%), strong predation pressure on the inflorescences (34%), and low seed set rate of nonpredated inflorescences (36%), suggesting pollination limitation. Nevertheless, a positive relationship was found between the mean number of Psychoda trapped per inflorescence and the number of maturing infructescences, particularly for the most abundant species, Psychoda crassipenis. Therefore, pollinator availability appeared to be an important limiting factor for fructification in the studied population, by contrast with other studies in which the fruit set appeared to be related more strongly to the density of inflorescences. Such different results may have been caused by the relatively low abundance of Psychoda in the present study.

American Journal of Botany, 2012

Many flowers are pollinated by potentially hungry insects, yet flowers also contain gametes and e... more Many flowers are pollinated by potentially hungry insects, yet flowers also contain gametes and embryos which must be protected from predation. Microscopic calcium oxalate crystals in plant tissues have been proposed to protect against herbivory. Aroids, which have an unusual diversity of such crystals, also exhibit diverse pollination strategies. Many species have pollinators that do not feed while visiting the flowers, while other species, especially those pollinated by beetles, offer sterile staminodia as food rewards. We examined flowers of 21 aroid species with various pollination strategies to test the hypothesis that crystals protect vital gametes and embryos while allowing consumption of food bribes. Aroid inflorescences collected from the field or from greenhouse material were sectioned, cleared, and examined by bright field and polarization microscopy. All species examined, regardless of pollination strategy, arrayed crystals around unshed pollen and ovules. Less vital tissues, such as odoriferous appendages, had few crystals. Staminodia offered as food to beetle pollinators, however, differed greatly between species in their crystal contents. Some had minimal crystals; some had crystals in patterns suggesting they limit beetle feeding; still others had abundant crystals in no obvious pattern. The results are consistent with crystals protecting against insect predation of gametes and embryos. However, the role of crystals in food-bribe staminodia is unclear. They may limit and direct feeding by beetles in some species, while in others they might have no protective role.

Oecologia, Jan 9, 2015

Hybridisation is common in plants and can affect the genetic diversity and ecology of sympatric p... more Hybridisation is common in plants and can affect the genetic diversity and ecology of sympatric parental populations. Hybrids may resemble the parental species in their ecology, leading to competition and/or gene introgression; alternatively, they may diverge from the parental phenotypes, possibly leading to the colonisation of new ecological niches and to speciation. Here, we describe inflorescence morphology, ploidy levels, pollinator attractive scents, and pollinator guilds of natural hybrids of Arum italicum and A. maculatum (Araceae) from a site with sympatric parental populations in southern France to determine how these traits affect the hybrid pollination ecology. Hybrids were characterised by inflorescences with a size and a number of flowers more similar to A. italicum than to A. maculatum. In most cases, hybrid stamens were purple, as in A. maculatum, and spadix appendices yellow, as in A. italicum. Hybrid floral scent was closer to that of A. italicum, but shared some co...

This study explores the floral biology and reproduction mode of Ambrosina bassii L. that belongs ... more This study explores the floral biology and reproduction mode of Ambrosina bassii L. that belongs to a monospecific genus of the subfamily Aroideae (Araceae).The species has a limited distribution and the number of mature plants within natural populations is low. Reproductive success of this species is limited due to low fructification and seed rates, however there is a positive relationship

Volatile compounds emitted by the appendix of Arum italicum in South of France were analysed. Thr... more Volatile compounds emitted by the appendix of Arum italicum in South of France were analysed. Three chemotypes were found. The first was rich in fatty acid derivatives (about 75%) but was found in only one individual and needs to be confirmed. A second profile (4 individuals) showed a high proportion (57 -84 % of the blend) of monoterpenes (ßcitronellene and 3,7-dimethyl-1-octene, its reduced chemical form). The third profile (2 individuals sampled twice) was rich (79 -85% of the blend) in sesquiterpenes, particularly two isomers (? and ? ) of caryophyllene. Moreover p-cresol and 2-heptanone were also present in the blend. Further work is needed to resolve whether these odor differences are different chemotypes of Arum italicum, temporal variation during the flowering season or analytical and experimental biases.

The 28 species of the genus Arum (Araceae) attract and temporarily trap insects (mainly flies, an... more The 28 species of the genus Arum (Araceae) attract and temporarily trap insects (mainly flies, and beetles in a few cases) during a complex pollination process. At anthesis, the appendix of the inflorescence produces heat and emits a specific odour which attracts insects. The lured insects are trapped within the floral chamber when stigmas are receptive. They will be released

Annales de la Société Entomologique de France, 2011

The pollination of the genus Arum (Araceae) is mainly achieved by deception, the fl oral odour mi... more The pollination of the genus Arum (Araceae) is mainly achieved by deception, the fl oral odour mimicking the pollinator ovipositing site. In order to discover the sensory organs involved in this attraction, we have studied the antennae of fi ve species of psychodine moth-fl ies (former Psychoda sensu lato = Psychodini), pollinators of Arum spp. The antennae of the fi ve Psychodini reveal seven types of sensilla: multiporous tribranched sensilla basiconica (sensilla ascoidea), multiporous sensilla basiconica, multiporous sensilla coeloconica, multiporous sensilla auricillica, uniporous sensilla basiconica, aporous sensilla chaetica, aporous Böhm's sensilla. Each species possesses three, fi ve or six of these sensillum types. All the multiporous sensilla are probably olfactory receptors while the uniporous sensilla basiconica must possess a contact chemoreceptive function. The multiporous tribranched sensilla basiconica (s. ascoidea), present in all the species, are the best candidates for the reception of the odours given off by the ovipositing sites and the infl orescences of Arum. The multiporous sensilla basiconica and the multiporous sensilla coeloconica may be involved respectively as CO 2 receptors or thermoreceptors. Psychoda phalaenoides, which is the main pollinator of A. maculatum, is the species which possesses the largest number of antennal sensilla. The sexual dimorphism, studied only in Psycha grisescens, as concerns the number of sensilla and the absence of a sensillum type which differ according to sex, is diffi cult to interpret.

Willdenowia, 2012

Barabé D., Lacroix C. & Gibernau M.: Developmental floral morphology of Syngonium in the context ... more Barabé D., Lacroix C. & Gibernau M.: Developmental floral morphology of Syngonium in the context of the tribe Caladieae (Araceae). -Willdenowia 42: 297 -305. December 2012. -online issn 1868-6397; © 2012 BGBM Berlin-Dahlem. stable urL: http://dx.doi.org/10.3372/wi.42.42216

Annals of Botany, 2005

Backgrounds and Aims Thermogenesis in reproductive organs is known from several plant families, i... more Backgrounds and Aims Thermogenesis in reproductive organs is known from several plant families, including the Araceae. A study was made of the relationship between temperature increase and spadix size in the subfamily Aroideae in order to determine whether the quantitative variation of heat production among species and inflorescences of different sizes follows a physical law of heat transfer.

Human Evolution, 1996

... Hominid evolution began about four million years (my) ago in East Africa with australopitheci... more ... Hominid evolution began about four million years (my) ago in East Africa with australopithecine ... a faunistical change in the micromammals along this sequence, moreover 50% of large ... is found, whereas more evolved forms are present at Turkana (Paranthropus boisei), and at ...

Aroideana, 2003

Pollen-loaded insects are not obligatorily captured rapidly by odoriferous inflorescences after t... more Pollen-loaded insects are not obligatorily captured rapidly by odoriferous inflorescences after their escape from a 'pollen-donor' inflorescence, but may be caught two or three days later. In such a situation, can these insects be considered as pollinators (i.e.. pollen vectors) or just visitors? Our results confirm that pollen grains in both species Arum italicum and A. maculatum quickly lose their viability.