Alexandra Magro

Toulouse University · Laboratory "Evolution et diversité biologique"

Palomena prasina, the green shield bug (GSB), is widely distributed in the Eurosiberian region. In the Southwest of France, it is considered as a serious pest of hazelnuts, its feeding punctures lead to blank hazelnuts and kernel necrosis, causing heavy losses in commercial orchards. To date, no Integrated Pest Management strategy is available to c...

Species in the genus Scymnus Kugelann are common, but there is little information available on their defence compounds. Pupae are covered with setae on tips of which there are small droplets of liquid. This study explored the patterns of the distribution of the droplets and the influence of diet on their production in five species of Scymnus. GC-MS...

Phytoma: Les punaises sont des insectes hautement polyphages et mobiles, elles peuvent causer des dégâts dans les noiseraies si aucun moyen de gestion n’est mis en place. Face à une lutte chimique de plus en plus complexe, la filière est à la recherche de solutions alternatives. Le projet Replik, financé par la région Nouvelle-Aquitaine, se termine...

While ecological interactions have been identified as determinant for biological control efficiency, the role of evolution remains largely underestimated in biological control programs. With the restrictions on the use of both pesticides and exotic biological control agents (BCAs), the evolutionary optimization of local BCAs becomes central for imp...

Evolutionary understanding is central to biology. It is also an essential prerequisite to understanding and making informed decisions about societal issues such as climate change. Yet, evolution is generally poorly understood by civil society and many misconceptions exist. Citizen science, which has been increasing in popularity as a means to gathe...

Des séquences décortiquées pour comprendre et utiliser l’Apprentissage par Projet et par Problème (APP). À l’heure des grands défis que posent une nécessaire transition écologique, on peut se demander comment outiller la réflexion des citoyens de demain afin de mieux les préparer à s’impliquer dans les débats et s’engager dans l’action. Les auteur...

• The balance between risk and benefit of exploiting resources drives life-history evolution in organisms. Predators are naturally recognized as major drivers of the life-history evolution of their prey. Although prey may also influence the life-history evolution of their predators in the context of an evolutionary arms race, there is far more evid...

Evolutionary understanding is central to biology as a whole. It is also an essential prerequisite to understanding issues in everyday life, such as advances in medicine and global challenges like climate change. Yet, evolution is generally poorly understood by civil society and many misconceptions exist. Citizen science, which has been increasing i...

A comprehensive annotated checklist of the ladybeetle species of Portugal, including the Azores and Madeira archipelagos, is presented. The Coccinellidae fauna comprises a total of 101 species: 83 from the Mainland, 39 from Madeira, and 32 from the Azores. The listed species are distributed among 2 sub-families and 13 tribes: within the subfamily M...

We reconstruct a comprehensively sampled molecular phylogeny for the second most species-rich tribe of the ladybird beetle family Coccinellidae, the charismatic Coccinellini. We analysed a dataset consisting of five nuclear and three mitochondrial gene fragments from 150 taxa to provide a detailed phylogeny and estimates of historical divergence ti...

1. The balance between risk and benefit of exploiting resources drives life history evolution. Predators are naturally recognized as major drivers of the life history evolution of their prey. The concept of an evolutionary arms race posits that prey also influence the life history evolution of their predators. There is far more evidence on the role...

Coccinellidae (Coleoptera), commonly known as ladybirds or ladybugs, are a highly diversified family comprising nearly 6000 described species (Vandenberg 2002) distributed in 2 subfamilies and 24 tribes (Seago et al. 2011). The genus Nephus Mulsant, 1846, present worldwide, is currently placed in the vast Coccidulini tribe (Seago et al. 2011). Ther...

We report here a new species belonging to Nephus (Nephus) Mulsant. Nephus (Nephus) apolonia sp. nov. was collected in the Reunion Island (Mascarene Archipelago, Indian Ocean). We describe this new species and redescribe and illustrate three other Nephus species already known from Reunion: Nephus (Nephus) oblongosignatus Mulsant, 1850, Nephus (Gemin...

Trophic cascades – the indirect effect of predators on non‐adjacent lower trophic levels – are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying e...

« Le pourquoi du sexe » reste encore aujourd’hui une des grandes questions évolutives. La découverte de lignées asexuées chez des espèces animales considérées jusque-là comme étant strictement sexuées, ouvre la porte à des études pouvant éclairer cette question majeure. C’est le cas d’un travail publié dans la revue Journal of Zoological Systematic...

Parthenogenesis, the development of unfertilized eggs resulting in the exclusive production of female offspring, is rare in animals relative to sexual reproduction and is mainly reported in invertebrates. It has been hypothesized that polyploidy, hybridization and endosymbiont infections are its major causal events but the mechanisms triggering ase...

Increasing intrafield plant diversity has been shown to regulate pest populations in various agroecosystems. Among the suggested mechanisms for this bottom‐up pest control, the disruptive crop hypothesis states that herbivores' abilities to locate and colonize their host plants are reduced by the presence of non‐host plants. Under laboratory condit...

A bstract Trophic cascades—the indirect effect of predators on non-adjacent lower trophic levels—are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underl...

The role of intraspecific variation in the magnitude and direction of plastic responses in ecology and evolution is increasingly recognized. However, the factors underlying intraspecific variation in plastic responses remain largely unexplored, particularly for the hypothesis that the herbivores’ phenotypic response to predators might vary amongst...

The evolution of increased competitive ability (EICA) hypothesis (Blossey & Nötzold, 1995) postulates that escaping from coevolved enemies increases invaders fitness by energy reallocation from defenses and immunity to growth and reproduction. In this context, we evaluated the evidence of evolutionary change in invasive populations of Harmonia axyr...

Transgenerational phenotypic plasticity is a fast non-genetic response to environmental modifications that can buffer the effects of environmental stresses on populations. However, little is known about the evolution of plasticity in the absence of standing genetic variation although several non-genetic inheritance mechanisms have now been identifi...

Aggregation during diapause is a common phenomenon in arthropods that nevertheless remains poorly understood. The most commonly claimed benefit is that survival is higher in aggregations but animal aggregations could also be driven by sexual selection. In this perspective, we investigated whether aggregations in insects could be part of their matin...

Aggregations during diapause are common among terrestrial arthropod species. They are usually considered as a defense strategy or a way to resist unfavorable abiotic conditions. However, systematic studies on the abiotic conditions as close as possible to the arthropods in their aggregation sites (= microsites) and individual survival in the aggreg...

Harmonia axyridis (Pallas) is a coccinellid of Asian origin that has recently invaded substantial parts of Europe and is suspected to affect native coccinellid populations through intraguild predation and competition for food. Previous work has shown that two species from the Calvia genus appeared to be well protected against H. axyridis predation....

1. The protection of animals' aggregation sites is increasingly seen as a key conservation strategy. However, to efficiently protect aggregation sites, they need to be accurately located. Species distribution models ( SDMs ) are an important tool in biological conservation to predict spatial distribution of species and they are used here to predict...

Figure S1. Plots of population allele frequencies per locus represented by dots of varying size. The two populations from Algeria are clustered.

Figure S2. Results of the Bayesian structure analyses of Coccinella septempunctata populations across Palearctic, calculated with the program STRUCTURE.

Figure S3. DAPC assignment: posterior probability of assignment of each individual to the five DAPC clusters.

Table S2. Null allele frequencies estimated per locus and per population. “–” means that null alleles were not encountered.

Table S3. Genetic signatures of demographic changes in Coccinella septempunctata identified with BOTTLENECK, significant deficiency of heterozygotes are indicated as “expansion” and excess as “bottleneck”.

Table S1. F IS values, per population and per locus, and across all loci with the significant values indicated in bold.

Aphidophagous ladybirds of the Coccinellinae subfamily are deterred from oviposition in the presence of chemical cues deposited by conspecific larvae, therefore avoiding the detrimental effects of competition and cannibalism to their offspring. However, it is still unknown whether aphidophagous species from other Coccinellidae subfamilies similarly...

Population genetics and phenotypic structures are often predicted to vary along the geographic range of a species. This phenomenon would be accentuated for species with large range areas, with discontinuities and marginal populations. We herein compare the genetic patterns of central populations of Coccinella septempunctata L. with those of two phe...

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with co...

Modern agricultural landscapes favour crop pests: herbivores benefit from resource concentration and/or the absence of natural enemies in large areas of intensively farmed fields interspersed by small fragments of natural or non-crop habitats. Conservation biological control (CBC) aims at increasing the functional diversity of agricultural landscap...

Predators of aphids exploit ephemeral but abundant resources. Aphid colonies are ephemeral because they hardly last longer than the time it takes the consumers to develop from egg to adult. Aphid colonies are also boom and bust resources that reach high numbers before collapsing. Many predators feed on these resources when they are abundant and as...

Les Sciences de la Nature ont cette dualité contradictoire de pouvoir être terriblement rébarbatives quand abordées uniquement de façon théorique et d’être absolument fascinantes quand elles bénéficient du temps de l’observation, du questionnement et de l’expérimentation sur les phénomènes qui nous entourent. Cette fascination est le moteur de l’ap...

Du terrain au laboratoire, expérimenter pour comprendre l'écologie scientifique. Enseignement secondaire.

Acyrthosiphon pisum Harris (Aphididae: Hemiptera), the pea aphid, is an important pest in organic farming systems. In this work, the objective was to gather empirical field data on the associational resistance of durum wheat–winter pea intercrops towards the pea aphid, compared with pure stands of winter pea. Our results showed that intercropping w...

To survive unfavorable periods, ladybird beetles form conspicuous aggregations in specific microsites, with these locations remaining the same year after year. This constancy of location leads to the hypothesis that semiochemicals are involved in the attraction and aggregation of ladybirds to the microsite. In this study, we identified two types of...

The concept of intraguild predation (IGP) appeared in 19871989 to describe trophic interactions within a guild of arthropods inhabiting a sand dune desert: consumers B prey on consumers A and both of them prey on a common resource. Theory predicts that the two types of consumers should only coexist if consumer A is more efficient in the conversion...

Invasive species are distinguished by their rate of spread and this is thought to be associated with the ability to produce many offspring. However, it is possible that many studies do not succeed in highlighting a positive correlation between invasiveness and reproductive rate because they lack an allometric perspective. Information on the ladybir...

Myrmecophiles are species that usually have developed specialized traits to cope with the aggressiveness of ants enabling them to live in their vicinity. Many coccinellid species are predators of Hemiptera; the latter is also often protected by ants. Therefore these ladybirds frequently interact with ants, and some species have become myrmecophilou...

We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline the nature and quantification of its chemical defence, and discuss the protection this provides against natural enemies, particularly intraguild predators....

Environmental constraints can be determinant key factors conditioning predator life history evolution. Prey seems to have conditioned life history evolution in their ladybird predator, with the predators of aphids apparently presenting faster development, greater fecundity and shorter longevity than species preying on coccids. However a rigorous co...

We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline the nature and quantification of its chemical defence, and discuss the protection this provides against natural enemies, particularly intraguild predators....

So far, only a few studies have explicitly investigated the consequences of admixture for the adaptative potential of invasive populations. We addressed this question in the invasive ladybird Harmonia axyridis. After decades of use as a biological control agent against aphids in Europe and North America, H. axyridis recently became invasive in four...

Chapitre 1-Education à l'écologie, éducation à l'environnement, éducation au développement durable : une perspective critique. 1. Education critique en des temps difficiles Nous traversons sans doute une époque critique car notre mode de vie est remis en cause par les signes avant-coureurs d'une possible crise écologique matérialisée, notamment, pa...

Marin, J., Crouau-Roy, B., Hemptinne, J.-L., Lecompte, E. & Magro, A. (2010). Coccinella septempunctata (Coleoptera, Coccinellidae): a species complex? —Zoologica Scripta, 39, 591–602.Coccinella septempunctata L., the seven spot ladybird is widely distributed across the Paleartic region. Based on a few morphological characteristics and geographical...

Faced with an ephemeral prey, aphidophagous ladybirds rely on the hydrocarbons present in the tracks of their larvae to choose an unoccupied patch for egg laying. Although both conspecific and heterospecific larval tracks might deter females from oviposition, the response to the later is often less striking. Several explanations have been suggested...

The Coccinellidae (ladybirds) is a highly speciose family of the Coleoptera. Ladybirds are well known because of their use as biocontrol agents, and are the subject of many ecological studies. However, little is known about phylogenetic relationships of the Coccinellidae, and a precise evolutionary framework is needed for the family. This paper pro...

A variety of arthropods, particularly insects, have developed myrmecophilous interactions with ants to gain access to resources and/or for protection. Among these myrmecophiles, only a few examples have been documented in the Coccinellidae, most of them involving species able to feed on ant-tended Hemiptera. We report here a new case of obligate my...

Les territoires ruraux et périurbains connaissent depuis plusieurs décennies des évolutions importantes qui marquent profondément les paysages. Face à ces transformations rapides, de nouveaux modes de gestion et de valorisation des espaces sont mis en oeuvre, poussés par de nouvelles manières de penser et de gérer durablement les territoires, marqu...

Aphid colonies can reach high levels of abundance but last for short periods of time. The larvae of aphidophagous ladybirds (Coleoptera: Coccinellidae) that feed on these colonies might therefore suffer from starvation, which favours the occurrence of cannibalism and intraguild predation. Thus, the assessment of patch quality becomes crucial and it...

Intraspecific and interspecific predation of eggs is a well documented phenomenon amongst aphidophagous coccinellids. The invasive species Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is known to be a top intraguild predator and reported to attack the eggs of many coccinellid species both in a laboratory setting and in the wild. A previou...

Intraspecific and interspecific predation of eggs is a well documented phenomenon amongst aphidophagous coccinellids. The invasive species Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is known to be a top intraguild predator and reported to attack the eggs of many coccinellid species both in a laboratory setting and in the wild. A previou...

Dysaphis plantaginea is one of the major pests of apple trees in Western Europe. It is usually recommended that apple trees be sprayed with insecticide as soon as the first aphid is recorded. Thus, orchards are sprayed with insecticide almost every year although aphids rarely remain abundant for several successive growing seasons. Consequently sign...

In a previous paper on the lack of motivation for ecology by most pupils of agricultural schools in France, Magro et al. (2001) suggested that this problem exists because teaching is not changing at the same pace as the "scientific knowledge". Furthermore, they have shown that teaching is based on descriptions and definitions and is therefore not v...

The prey of coccidophagous ladybird beetles has a slower rate of development and is less mobile than that of aphidophagous ladybirds. These differences are paralleled by a suite of characters suggesting that coccidophagous species live at a slower pace than aphidophagous species. Data in the literature tend to indicate that coccidophagous ladybirds...

Les professeurs de Biologie-Ecologie de l’Enseignement Agricole français considèrent que l’écologie est difficile à enseigner et se sentent souvent frustrés car ils ont peine à motiver leurs élèves. Depuis 1999 un projet de recherche est développé à l’ENFA pour essayer de comprendre et résoudre ce problème. Ces difficultés découleraient, à notre av...

Mills (1982) formulated the satiationhypothesis in order to explain why ladybirdsare generally more effective in the biologicalcontrol of coccids than of aphids:aphidophagous ladybirds are supposedly lessefficient because they become more rapidlysatiated than coccidophagous ladybirds. If thisis true, the former should spend less timeeating than the...

The teaching of ecology in the agricultural secondary curricula in France is relatively new. The displaying of the curricula has been causing some problems to the teachers (general frustration and difficulties to motivate their pupils). In order to identify the cause of the problems, analysis of curricula, teachers conceptions about ecology and the...

The teaching of ecology in the agricultural secondary curricula in France is relatively new. The displaying of the curricula has been causing some problems to the teachers (general frustration and difficulties to motivate their pupils). In order to identify the cause of the problems, analysis of curricula, teachers conceptions about ecology and the...

Integrated Pest Management programmes in Portugal pay main attention to coccids. The study of coccinellids for the biological control of those pests was undertaken. This paper aimed firstly to determine which coccidophagous ladybirds are more likely to control coccids by examining Dominance, Constancy and Persistence along the year. A second goal w...

Coccinellids were sampled in 88 citrus groves from the centre / south of continental Portugal. Analysis of distribution were performed by the usual indices but also with the help of a new method - SADIE. 38 species were identified, 36 of which are predators. Five coccinellids seem to have aggregated distributions ; UTM maps of those species distrib...

Samples of ladybirds were collected in two citrus groves near Setúbal from July to September 1990 and 1991. Twenty-four species belonging to seven tribes were identified. The most important is Scymnini with ten species which represents 91% of total captures. The three most abundant species are Scymnus (Scymnus) interruptus, S. (Oullus) mediterraneu...