Denis Fournier

Denis Fournier
Université Libre de Bruxelles | ULB · Evolutionary Biology and Ecology Unit

PhD

About

155
Publications
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1,248
Citations

Publications

Publications (155)
Article
Full-text available
Sexual reproduction can lead to major conflicts between sexes and within genomes. Here we report an extreme case of such conflicts in the little fire ant Wasmannia auropunctata. We found that sterile workers are produced by normal sexual reproduction, whereas daughter queens are invariably clonally produced. Because males usually develop from unfer...
Article
Full-text available
1.Under polyandry, males are selected to produce more competitive ejaculates. Theoretical models have explored how the mechanism of sperm competition drives males to partition investment within an ejaculate between sperm quantity and quality. The raffle-based competition model predicts that increased level of sperm competition selects for larger nu...
Article
Termite colonies are typically founded by a pair of sexually reproducing dispersers, which can sometimes be replaced by some of their offspring. Some Reticulitermes and Embiratermes species routinely practice asexual queen succession (AQS): the queen is replaced by neotenic daughters produced by parthenogenesis, which mate with the primary king. He...
Article
Wolbachia has deeply shaped the ecology and evolution of many arthropods, and interactions between the two partners are a continuum ranging from parasitism to mutualism. Non-dispersing queens of the termite Cavitermes tuberosus are parthenogenetically produced through gamete duplication, a mode of ploidy restoration generally induced by Wolbachia....
Article
Hybridization may help drive biological invasions by reducing Allee effects, increasing genetic variation, and generating novel adaptive genotypes/phenotypes. Social insects (ants, bees, wasps, and termites) are among the world's worst invasive species. In this review, we study the relationship between hybridization and invasiveness in social insec...
Article
Full-text available
Termites are eusocial insects having evolved several feeding, nesting and reproductive strategies. Among them, inquiline termites live in a nest built by other termite species: some of them do not forage outside the nest, but feed on food stored by the host or on the nest material itself. In this study, we characterized some dimensions of the ecolo...
Article
Full-text available
While many bee species are experiencing population declines, some host plant generalist bees remain common in Europe, partly because they seem able to shift to new resources. However, foraging on a new alternative plant, such as an invasive species, can modify diet quality and have a potentially detrimental effect on bee health. Herein, we investig...
Article
Full-text available
Background A decade ago, the mixed reproductive strategy Asexual Queen Succession (AQS) was first described in termites. In AQS species, the workers, soldiers and dispersing reproductives are produced through sexual reproduction, while non-dispersing (neotenic) queens arise through automictic thelytokous parthenogenesis, replace the founding queen...
Article
Some species of termites evolved an outstanding reproductive strategy called asexual queen succession (AQS), in which the primary queen is replaced by multiple parthenogenetically produced daughters (neotenics) that mate with the primary king. When the primary king is eventually replaced, this time by sexually produced neotenic king(s), sex-asymmet...
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Full-text available
The Galápagos Islands constitute one of the most pristine tropical systems on Earth. However, the complex and fragile equilibrium of native species is threatened by invasive species, among which is one of the most successful ants in the world, the tropical fire ant, Solenopsis geminata. We characterized the genetic structure and diversity of popula...
Article
Chelonoidis land tortoises are iconic species endemic to the Galápagos Islands of Ecuador. Their populations have been dramatically reduced by human activities in the last three centuries, including indirect effects such as the introduction of invasive species. We investigated the mortality of eggs and hatchlings in 48 nests of Chelonoidis porteri...
Article
The insect fauna of the Galápagos Islands is considered among the most pristine in the world and is well-studied in the preserved areas. However, introduced species are numerous and damaging, particularly in disturbed areas such as agricultural zones. In this study, we examined the arthropod diversity in two agricultural sites on Santa Cruz Island,...
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Full-text available
1. Bumblebees are valuable pollinators of numerous wild and cultivated plants. They can forage on variable pollen resources. As some pollen species lack particular nutrients or have global low nutritional quality, it has been suggested that bumblebees mix their pollen incomes to ensure a global balanced diet. The hypothesis that a mixed pollen diet...
Article
Un mâle et une femelle unis pour procréer. Ce schéma n'était pas celui des origines de la vie, et il est aujourd'hui ignoré par plusieurs espèces. Il apparaît cependant comme la solution optimale pour produire une variété infinie d'individus différents.
Data
Matrix of agressiveness between colonies. (CSV)
Data
Areas of peaks identified as cuticular lipids. (CSV)
Data
Matrix of geographic distances between colonies (m). (CSV)
Article
Full-text available
In social insects, the evolutionary stability of cooperation depends on the privileged relationships between individuals of the social group, which is facilitated by the recognition of relatives. Nestmate recognition is based on genetically determined cues and/or environmentally derived chemical components present on the cuticle of individuals. Her...
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Full-text available
1. We investigated ant communities in all main vegetation zones of the model island of Santa Cruz in the Galápagos archipelago (155 collection points, spread over 21 sites; 28 ant species collected), and evaluated the distribution, coexistence, and effect of environmental factors in a community composed of endemic, probably endemic, and introduced...
Article
Full-text available
The use of Bombus terrestris L. commercial colonies for outdoor and greenhouse crop pollination is currently widespread. Colony breeding includes bumblebee feeding, mostly by using the honeybee pollen loads of diverse palynological composition. Because the chemical content of pollen is highly variable, the choice of commercial blend should not be r...
Article
Full-text available
The use of Bombus terrestris L. commercial colonies for outdoor and greenhouse crop pollination is currently widespread. Colony breeding includes bumblebee feeding, mostly by using the hon-eybee pollen loads of diverse palynological composition. Because the chemical content of pollen is highly variable, the choice of commercial blend should not be...
Article
Full-text available
Eighteen microsatellite markers from the humivorous termite Cavitermes tuberosus (Isoptera: Termitidae: Termitinae) were developed using a procedure of microsatellite-enriched libraries pyrosequencing. They were optimized in four multiplex PCR sets, and tested on 38 individuals collected in French Guiana. The number of alleles per locus ranged from...
Article
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Presence of diploid males in wild bees reflects inbreeding and provides information about the health status of a colony or population. Detection of diploid males, and discrimination from haploid males and workers, has, however, been limited to molecular diagnostics. Here we present a novel method based on differences in wing shape, e.g., venation p...
Article
Full-text available
Presence of diploid males in wild bees reflects inbreeding and provide information about the health status of a colony or population. Detection of diploid males, and discrimination from haploid males and workers has, however, been limited to molecular diagnostics. Here we present a novel method based on differences in wing shape, e.g. venation patt...
Article
Full-text available
Tropical fire ant (TFA), Solenopsis geminata (Fabricius, 1804), is considered as one of the most serious threats to the terrestrial fauna of Galápagos, yet little is known about its distribution and impact in the archipelago. We reviewed literature, studied museum specimens and sampled over 62 sites on ten islands and islets in order to update the...
Article
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Biological invasions are recognized as a major cause of biodiversity decline and have considerable impact on the economy and human health. The African big-headed ant Pheidole megacephala is considered one of the world's most harmful invasive species. To better understand its ecological and demographic features, we combined behavioural (aggression t...
Data
Details in lateral views of hairs present on the petiole. Magnification and scale bar are indicated for each scanning electron microscopic image. The terminal part of the hairs forms a point in P. megacephala var. 1 (A) and a brush in P. megacephala var. 2 (B). (TIF)
Data
Minor of P. megacephala var. 1 (A) and P. megacephala var. 2 (B) in lateral views. Magnification and scale bar are indicated for each scanning electron microscopic image. (TIF)
Data
Lateral views of the propodeum showing shorter spines in P. megacephala var 1. than in P. megacephala var. 2 (B). Magnification and scale bar are indicated for each scanning electron microscopic image. (TIF)
Article
Full-text available
In social insects, the high variability in the number of queens per colony raises fundamental questions about the evolution of altruism. It is hypothesized, for instance, that nestmate recognition should be less efficient in polygynous than in monogynous colonies because the presence of several breeders increases the diversity of genetically determ...
Article
Full-text available
Background: Biological invasions are recognized as a major cause of biodiversity decline and have considerable impact on the economy and human health. The African big-headed ant Pheidole megacephala is considered one of the world's most harmful invasive species.
Article
The invasive ant species Wasmannia auropunctata displays both ecologically dominant and non-dominant populations within its native range. Three factors could theoretically explain the ecological dominance of some native populations of W. auropunctata: (i) its clonal reproductive system, through demographic and/or adaptive advantages; (ii) its unico...
Article
Recent work has shown that, in the Amazonian fungus-growing ant Mycocepurus smithii, queens use exclusively asexual reproduction and the male sex seems to have disappeared from the species. This finding illustrates the remarkable diversity of reproductive systems in ants.
Article
Full-text available
Abstract 1. The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions.2. The present study focuses on the little fire ant Wasmannia auropunctata, a species native to Central and Sou...
Article
Cooperative colony founding (pleometrosis) in social insects is an ideal model for investigating how cooperation and competition shape social behaviour among unrelated individuals. In many ant species, foundress associations are more competitive and the colonies survive better compared with single-queen colonies. However, cooperation among queens b...
Article
Introduced species often become ecologically dominant, displacing native species and posing a serious threat to ecosystem function and global biodiversity. Ants are among the most widespread and damaging alien species; introductions are often accompanied by population-level behavioural and genetic changes contributing to their success. We investiga...
Article
Full-text available
In social Hymenoptera, within-colony relatedness is usually high due to the haplodiploid sex-determining system. However, factors such as the presence of multiple reproductive queens (polygyny), multiple queen matings (polyandry) or worker reproduction result in decreased relatedness among workers and the brood they rear, and consequently dilute th...
Article
We report the characterization of eight microsatellite markers in the big-headed ant Pheidole megacephala, a pest ant registered in the list of '100 of the world's worst invasive alien species'. An enrichment protocol was used to isolate microsatellite loci, and polymorphism was explored with 36 individuals collected in an invasive population from...
Article
Understanding the adaptive significance of multiple mating (polyandry) by females has long been a challenge in evolutionary biology. Several genetic and nongenetic benefits have been proposed to explain the evolution and maintenance of polyandry. In eusocial Hymenoptera, a prominent hypothesis is that increased genetic diversity within colonies res...
Article
Full-text available
Reproduction systems are controlling the creation of new genetic variants as well as how natural selection can operate on these variants. Therefore, they had historically been one of the main foci of evolutionary biology studies. The little fire ant, Wasmannia auropunctata, has been found to display an extraordinary reproduction system, in which bo...