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150 resultados encontrados para: AUTOR: Lachaud, Jean Paul
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1.
Artículo
Nest site selection during colony relocation in Yucatan Peninsula populations of the ponerine ants Neoponera villosa (Hymenoptera: Formicidae)
Rocha, Franklin H. (autor) ; Lachaud, Jean Paul (autor) ; Hénaut, Yann (autor) ; Pozo, Carmen (autora) ; Pérez Lachaud, Gabriela (autora) ;
Disponible en línea
Contenido en: Insects Volumen 11, número 3, 200 (March 2020), páginas 1-15 ISSN: 2075-4450
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Resumen en: Inglés |
Resumen en inglés

In the Yucatan Peninsula, the ponerine ant Neoponera villosa nests almost exclusively in tank bromeliads, Aechmea bracteata. In this study, we aimed to determine the factors influencing nest site selection during nest relocation which is regularly promoted by hurricanes in this area. Using ants with and without previous experience of Ae. bracteata, we tested their preference for refuges consisting of Ae. bracteata leaves over two other bromeliads, Ae. bromeliifolia and Ananas comosus. We further evaluated bromeliad-associated traits that could influence nest site selection (form and size). Workers with and without previous contact with Ae. bracteata significantly preferred this species over others, suggesting the existence of an innate attraction to this bromeliad. However, preference was not influenced by previous contact with Ae. bracteata. Workers easily discriminated between shelters of Ae. bracteata and A. comosus, but not those of the closely related Ae. bromeliifolia. In marked contrast, ants discriminated between similar sized Ae. bracteata and Ae. bromeliifolia plants, suggesting that chemical cues and plant structure play an important role. Size was also significant as they selected the largest plant when provided two dissimilar Ae. bracteata plants. Nest site selection by N. villosa workers seems to depend on innate preferences but familiarization with plant stimuli is not excluded.


2.
- Artículo con arbitraje
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Resumen en: Inglés |
Resumen en inglés

Ant parasitoidism has been reported in seven of the 26 recognized species of the mite genus Macrodinychus (Machrodynichidae). Macrodynichus sellnicki, previously reported as a parasitoid of the invasive ant Nylanderia fulva in Colombia, is now reported, in the same region, as attacking a native host, Ectatomma sp. 2 (E. ruidum complex). The mite develops within the protective silk cocoon of an Ectatomma pupa and waits for the emergence of the young ant before leaving the cocoon, unmolested. Overall nest prevalence was relatively high (34.6% of the 52 nests containing cocoons) but pupae prevalence was low (4.0%, n=1401 cocoons). Mite life-history (parasite or parasitoid) was context dependent, shifting according to the intensity of the attack on a same host. Contrary to the strictly parasitoidic association of M. sellnicki with N. fulva, single mite attacks against E. ruidum did not result in host killing and solitary M. sellnicki (78.6% of the cases) behaved as parasites. However, in 21.4% of the attacks (0.9% of all available host pupae) more than one mite was involved and behaved as parasitoids, draining the host of its internal fuids and killing it. This is the frst association of a macrodinychid mite with a species of the subfamily Ectatomminae, and the frst ant associated mite for which such a context dependent life-style shift is described.


3.
- Artículo con arbitraje
Fine-tuned intruder discrimination favors ant parasitoidism
Pérez Lachaud, Gabriela (autora) ; Rocha, Franklin H. (autor) ; Valle Mora, Javier Francisco (autor) ; Hénaut, Yann (autor) ; Lachaud, Jean Paul (autor) ;
Disponible en línea
Contenido en: PLoS One Vol. 14, no. 1, art. no. e0210739 (January 2019), p. 1-21 ISSN: 0187-6376
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Resumen en: Inglés |
Resumen en inglés

diversity of arthropods (myrmecophiles) thrives within ant nests, many of them unmolested though some, such as the specialized Eucharitidae parasitoids, may cause direct damage to their hosts. Ants are known to discriminate between nestmates and non-nestmates, but whether they recognize the strength of a threat and their capacity to adjust their behavior accordingly have not been fully explored. We aimed to determine whether Ectatomma tuberculatum ants exhibited specific behavioral responses to potential or actual intruders posing different threats to the host colony and to contribute to an understanding of complex ant-eucharitid interactions. Behavioral responses differed significantly according to intruder type. Ants evicted intruders that represented a threat to the colony’s health (dead ants) or were not suitable as prey items (filter paper, eucharitid parasitoid wasps, non myrmecophilous adult weevils), but killed potential prey (weevil larvae, termites). The timing of detection was in accordance with the nature and size of the intruder: corpses (a potential source of contamination) were detected faster than any other intruder and transported to the refuse piles within 15 min. The structure and complexity of behavioral sequences differed among those intruders that were discarded. Workers not only recognized and discriminated between several distinct intruders but also adjusted their behavior to the type of intruder encountered.

Our results confirm the previously documented recognition capabilities of E. tuberculatum workers and reveal a very fine-tuned intruder discrimination response. Colony- level prophylactic and hygienic behavioral responses through effective removal of inedible intruders appears to be the most general and flexible form of defense in ants against a diverse array of intruders. However, this generalized response to both potentially lethal and harmless intruders might have driven the evolution of ant-eucharitid interactions, opening a window for parasitoid attack and allowing adult parasitoid wasps to quickly leave the natal nest unharmed.


4.
- Artículo con arbitraje
Opportunistic predation by leaf-Cutting Ants (Hymenoptera: Formicidae) on a Wounded Baird's Tapir (Mammalia: Perissodactyla: Tapiridae) in Mexico
Lachaud, Jean Paul (autor) ; Pérez Flores, Jonathan Sechaly (autor) ; Pérez Lachaud, Gabriela (autora) ;
Disponible en línea
Contenido en: Florida Entomologist Vol. 102, no. 1 (April 2019), p. 251-253 ISSN: 0015-4040
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Resumen en: Español | Inglés |
Resumen en español

A pesar de su dieta herbívora especializada, las hormigas cortadoras de hojas aprovechan también de manera oportunística fuentes temporales como carcasas de insectos o de vertebrados. Reportamos el primer caso de hormiga atine, Atta cephalotes (L.) (Hymenoptera: Formicidae), forrajeando sobre el tejido cicatricial de un vertebrado vivo, una hembra herida del tapir centroamericano, Tapirus bairdii (Gill) (Mammalia: Perissodactyla: Tapiridae). Se proponen 2 hipótesis, no mutuamente exclusivas, para explicar tal comportamiento: (1) el uso por parte de las hormigas cortadoras de hojas de estos tejidos como fuente de nutrientes esenciales escasos; (2) el muestreo oportunístico de comunidades polimicrobianas asociadas con la piel de animales heridos, en búsqueda de nuevas cepas de sus actinobacterias asociadas.

Resumen en inglés

Notwithstanding their specialized herbivorous diet, leaf-cutting ants opportunistically exploit temporary resources such as insect or vertebrate carcasses. We report on the first case of attine workers, Atta cephalotes (L.) (Hymenoptera: Formicidae), foraging on the scar tissues of a living vertebrate, a wounded female Baird’s tapir, Tapirus bairdii (Gill) (Mammalia: Perissodactyla: Tapiridae). We put forward 2, not mutually exclusive, hypotheses to explain such behavior: (1) utilization by the leaf-cutting ants of these tissues as a resource that provides rare essential nutrients, and (2) opportunistic sampling of polymicrobial communities associated with the skin of the wounded animal in search of new strains of their associated actinobacteria.


5.
- Artículo con arbitraje
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Resumen en: Inglés |
Resumen en inglés

Biological collections around the world are the repository of biodiversity on Earth; they also hold a large quantity of unsorted, unidentified, or misidentified material and can house behavioral information on species that are difficult to access or no longer available to science. Among the unsorted, alcohol-preserved material stored in the Formicidae Collection of the `El Colegio de la Frontera Sur' Research Center (Chetumal, Mexico), we found nine colonies of the ponerine ant Neoponera villosa, that had been collected in bromeliads at Calakmul (Campeche, Mexico) in 1999. Ants and their brood were revised for the presence of any sign of parasitism. Cocoons were dissected and their content examined under a stereomicroscope. Six N. villosa prepupae had been attacked by the ectoparasitoid syrphid fly Hypselosyrphus trigonus Hull (Syrphidae: Microdontinae), to date the only known dipteran species of the Microdontinae with a parasitoid lifestyle. In addition, six male pupae from three colonies contained gregarious endoparasitoid wasps. These were specialized in parasitizing this specific host caste as no gyne or worker pupae displayed signs of having been attacked. Only immature stages (larvae and pupae) of the wasp could be obtained. Due to the long storage period, DNA amplification failed; however, based on biological and morphological data, pupae were placed in the Encyrtidae family.

This is the first record of an encyrtid wasp parasitizing N. villosa, and the second example of an encyrtid as a primary parasitoid of ants. Furthermore, it is also the first record of co-occurrence of a dipteran ectoparasitoid and a hymenopteran endoparasitoid living in sympatry within the same population of host ants. Our findings highlight the importance of biological collections as reservoirs of hidden biodiversity, not only at the taxonomic level, but also at the behavioral level, revealing complex living networks. They also highlight the need for funding in order to carry out biodiversity inventories and manage existing collections.


6.
Artículo
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Resumen en: Inglés |
Resumen en inglés

The myrmecophile larva of the dipteran taxon Nothomicrodon Wheeler is rediscovered, almost a century after its original description and unique report. The systematic position of this dipteran has remained enigmatic due to the absence of reared imagos to confirm indentity. We also failed to rear imagos, but we scrutinized entire nests of the Brazilian arboreal dolichoderine ant Azteca chartifex which, combined with morphological and molecular studies, enabled us to establish beyond doubt that Nothomicrodon belongs to the Phoridae (Insecta: Diptera), not the Syrphidae where it was first placed, and that the species we studied is an endoparasitoid of the larvae of A. chartifex, exclusively attacking sexual female (gyne) larvae. Northomicrodon parasitism can exert high fitness costs to a host colony. Our discovery adds one more case to the growing number of phorid taxa known to parasitize ant larvae and suggests that many others remain to be discovered. Our findings and literature review confirm that the Phoridae is the only taxon known that parasitizes both adults and the immature stages of different castes of ants, thus threatening ants on all fronts.


7.
- Artículo con arbitraje
Macrodinychus mites as parasitoids of invasive ants: an overlooked parasitic association
Lachaud, Jean Paul ; Klompen, Hans (coaut.) ; Pérez Lachaud, Gabriela (coaut.) ;
Contenido en: Scientific Reports Vol. 6, no. 29995 (2016), p. 1-10 ISSN: 2045-2322
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Resumen en: Inglés |
Resumen en inglés

Mites are frequent ant symbionts, yet the exact nature of their interactions with their hosts is poorly known. Generally, myrmecophilous mites show adaptations for dispersal through phoresis, but species that lack such an adaptation may have evolved unusual specialized relationships with their hosts. The immature stages of Macrodinychus multispinosus develop as ectoparasitoids of pupae of the invasive ant Paratrechina longicornis. Feeding stages show regressed locomotor appendages. These mites complete their development on a single host, sucking all of its body content and therefore killing it. Locally high proportions of parasitized host pupae suggest that M. multispinosus could serve as a biological control agent. This is the ninth species of Macrodinychus reported as ant parasite, and the third known as parasitoid of invasive ants, confirming a unique habit in the evolution of mite feeding strategies and suggesting that the entire genus might be parasitic on ants. Several mites’ characteristics, such as their protective morphology, possible viviparity, lack of a specialized stage for phoretic dispersal, and low host specificity, combined with both the general low aggressiveness of invasive P. longicornis towards other ants and its possible susceptibility to generalist ectoparasites would account for the host shift in native macrodinychid mites.


8.
- Artículo con arbitraje
Uncovering species boundaries in the Neotropical ant complex Ectatomma ruidum (Ectatomminae) under the presence of nuclear mitochondrial paralogues
Aguilar Velasco, Reina Gabriela ; Poteaux, Chantal (coaut.) ; Meza Lázaro, Rubí (coaut.) ; Lachaud, Jean Paul (coaut.) ; Dubovikoff, Dmitry A. (coaut.) ; Zaldívar Riverón, Alejandro (coaut.) ;
Contenido en: Zoological Journal of the Linnean Society Vol. 178, no. 2 (October 2016), p. 226–240 ISSN: 1096-3642
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Nuclear mitochondrial (mt) paralogues (numts) are non-functional fragments of mtDNA integrated into the nuclear genome that can overestimate the number of species in analyses based on mtDNA sequences. As numts have relatively slow mutation rates, they can pass undetected by conventional procedures such as inspecting for internal stop codons, indels or apparent polymorphism in chromatograms. Species boundaries based on mtDNA markers therefore require a thorough assessment of numts, especially in insects, where this phenomenon appears to be relatively frequent. Ectatomma ruidum is a widely distributed Neotropical ant species that is distributed from northern Mexico to northern Brazil. Previous behavioural and molecular evidence suggests that this species actually represents a composite taxon. Here we assessed the species boundaries in E. ruidum based on two mt (COI, cyt b) and one nuclear (H3) marker, as well as on external morphology. Ancient and recent mt paralogues were detected in several specimens, although pre-PCR dilution of DNA template helped to recover most of the mt orthologues. Based on the congruence found between our species delineation obtained from the mt genealogies and the discriminated morphospecies, we propose that E. ruidum is actually composed of at least three species. Two of these species have a wide geographical distribution in the Neotropics, whereas the remaining one was restricted to localities situated near the Pacific coast in south-east Mexico. We also found extensive intra- and interspecific variation in the barcoding locus. Moreover, the nuclear evidence suggests the existence of hybrids between two of these species in Oaxaca, south-east Mexico. This study agrees with previous studies of other closely related animal taxa, which have revealed a complex evolutionary history and overlooked species diversity in the latter region.


9.
- Artículo con arbitraje
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Biogeography, cryptic diversity, and queen dimorphism evolution of the Neotropical ant genus Ectatomma Smith, 1958 (Formicidae, Ectatomminae)
Nettel Hernanz, Alejandro ; Lachaud, Jean Paul (coaut.) ; Fresneau, Dominique (coaut.) ; López Muñoz, Román A. (coaut.) ; Poteaux, Chantal (coaut.) ;
Contenido en: Organisms Diversity & Evolution Vol. 15, no. 3 (September 2015), p. 543-553 ISSN: 1439-6092
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Resumen en: Inglés |
Resumen en inglés

Due to its high biodiversity and its complex climatic and geological history, the Neotropical region has caught the attention of evolutionary and conservation biologists. The Neotropics have an understudied and probably extensive cryptic diversity, stemming from old lineages that have persisted through time with highly similar morphology or from new morphologically undifferentiated sibling species. The wide-ranging Neotropical ant genus Ectatomma currently has only 15 described species, some of which present limited distribution. These ants provide an excellent system for the study of diversification and cryptic diversity in the Neotropics. Ectatomma also displays queen-size dimorphism in some northern populations of its two most common species: a case of true microgyny and a recently described parasitic species. We performed a phylogenetic and biogeographic analysis of Ectatomma species using two mitochondrial genes and one nuclear gene. We also explored the relationship between the history of the genus and the appearance of miniaturized queens. Our analysis recovered a monophyletic Ectatomma that originated in the Parana region of South America. We recorded three likely events of colonization of the Caribbean–Mesoamerican region. We also detected ample evidence of cryptic divergence that deserves a full taxonomic revision of the genus. Miniature queens—microgynes and parasites—represent two independent evolutionary events that appeared in the recent history of the genus.


10.
- Capítulo de libro con arbitraje
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Diversidade genética e fenotípica no gênero Ectatomma
Poteaux, C. ; Prada Achiardi, F. C. (coaut.) ; Fernández, F. (coaut.) ; Lachaud, Jean Paul (coaut.) ;
Contenido en: As formigas poneromorfas do Brasil Ilhéus, Bahia, Brasil : Universidade Estadual de Santa Cruz, Editora Editus, 2015 p. 127-144 ISBN:978-85-7455-398-6
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Resumen en inglés

Ectatomma is a genus of ants belonging to Ectatomminae, currently located in the Formicoid group. With 15 recognized species, the genus includes relatively large ants endemic to the Neotropical Region. These species are relatively common in diverse areas such as wet forest, savannah, and dry forest habitats below 1500 m in altitude. Most of them are generalist predators but they also consume fruit pulp, honey and plant nectars. The wide variation in their environmental performance, foraging strategies and diet explains their abundance in the Neotropics. The first review of this genus was done by William Brown Jr. in 1958, who recognized the difficulties in delimiting some Ectatomma species. Some of these problems were partly solved by Kugler and Brown, who suggested some synonymies and recognized 12 species. Arias-Penna re-described E. confine; Almeida described two species from Brazil, E. vizotoi and E. suzanae, and Feitosa et al. described the first social parasitic Ectatomma, E. parasiticum from Mexico. While there are currently 15 Ectatomma described species, recent studies have shown that this variability is underestimated due to cryptic species or insufficient sampling. In this chapter, we synthesize from the literature and our own experience data on phenotypic variation, ecological and life traits and genetics. Morphological variation is known for E. tuberculatum, E. goninion and E. ruidum over their geographic distribution. As in other ants, this kind of variation has been the principal source of taxonomic inflation. The challenge with this taxon is to find a correct delimitation of the species, using several sources of data, including morphology, chemistry, genetics and biology. Phenotypic variation can also be expressed by differences in behaviours or life history traits between species, and we here present some features common to or, by contrast, specific to some Ectatomma.

The nests of all the species of the genus Ectatomma are terricolous, even those of species exhibiting arboricolous habits. Generally, they exhibit the same pattern; a simple architecture with a single entrance hole opening directly on the ground surface and leading to a gallery, which connects with successive chambers (4-12 according to the species) deeper in the ground (0.68-3.60 m according to the species). The structure of the nests seems to vary depending on the environment and probably with the season, colony size and the structure of the soil. The patterns of nest distribution appear to vary according to the species (overdispersion; random distribution; aggregated pattern; patchy distribution). Polydomy occurs in E. tuberculatum and possibly in E. brunneum and E. opaciventre. Polygynous colonies have been detected in seven of the 15 Ectatomma species (E. ruidum, E. tuberculatum, E. parasiticum, E. brunneum, E. permagnum, E. planidens (referred to as E. edentatum), and E. vizottoi). However, data based on genetic markers to investigate details of the socio-genetic structure of the colonies have only been obtained in E. tuberculatum and E. ruidum, for which we developed specific microsatellite loci. Although Ectatomma is a widespread and common genus in the Neotropics, their taxonomy is surprisingly poorly known, with several issues unanswered, such as: the delimitation of some species or cryptic species complexes (as in E. tuberculatum and E. ruidum); the interpretation of infra- vs inter-specific variation (as in E. goninion); the problem of paraphyly (as in the E. tuberculatum / E. parasiticum pair); and also the status of species described by Almeida in (E. vizotoi and E. suzanae). Hopefully work in progress, including the molecular phylogeny of the genus, will throw light on species delimitation, biogeography, and evolution of some biological traits such as microgyny and parasitism.

Resumen en portugués

O gênero de formigas Ectatomma (Ectatomminae) está atualmente situado no clado Formicoide. Este gênero possui 15 espécies reconhecidas e inclui formigas relativamente grandes e endêmicas da Região Neotropical. Estas espécies são relativamente comuns em diversas áreas (habitats como florestas secas, florestas úmidas e savanas) abaixo de 1500m de altitude. A maioria dessas formigas é predadora generalista, mas também podem se alimentar de polpa de frutas, mel e néctar. A ampla variação de seu desempenho ambiental, estratégias de forrageio e dieta justificam a sua abundância na Região Neotropical. A primeira revisão do gênero foi realizada por William Brown Jr. em 1958, que enfrentou dificuldades em delimitar algumas espécies de Ectatomma. Alguns destes problemas foram parcialmente resolvidos por Kugler; Brown, que sugeriram algumas sinonímias e reconheceram 12 espécies. Arias-Penna redescreveu E. confine; Almeida descreveu duas espécies do Brasil, E. vizottoi e E. suzanae. Feitosa et al. descreveram E. parasiticum, a primeira Ectatomma parasita social, originária do México. Embora existam atualmente 15 espécies de Ectatomma descritas, estudos recentes mostraram que esta diversidade é subestimada devido a espécies crípticas ou amostragem insuficiente. Neste capítulo, sintetizamos da literatura e de nossa própria experiência dados de variação fenotípica a partir de características morfológicas, ecológicas, características de vida e genéticas (citogenética e estrutura populacional). A variação morfológica foi registrada em E. tuberculatum, E. goninion e E. ruidum ao longo de sua distribuição geográfica. Porém, assim como em outras formigas, este tipo de variação foi a principal fonte de inflação taxonômica, com muitos nomes desnecessários propostos anteriormente na história do gênero.

O desafio neste táxon é encontrar uma delimitação correta das espécies, usando várias fontes de dados como morfologia, química, genética e biologia (e.g. comportamento de nidificação). A existência de espécies crípticas em E. tuberculatum e E. ruidum, por exemplo, foi recentemente observada a partir de um estudo de filogenia molecular. A variação fenotípica também pode ser expressa baseada em alterações comportamentais ou em características da história de vida das espécies. Decidimos apresentar apenas algumas características comuns, ou por outro lado, específicas de algumas espécies de Ectatomma como a arquitetura de ninho, distribuição de ninhos e organização social. Os ninhos de todas as espécies do gênero Ectatomma são terrícolas, mesmo aqueles de espécies que demonstram hábitos arborícolas como E. tuberculatum. Geralmente os ninhos apresentam o mesmo padrão: uma arquitetura simples com um único orifício de entrada e uma abertura direta na superfície do solo, conduzindo a uma galeria que se aprofunda conectando-se a consecutivas câmaras (de quatro a 12, de acordo com a espécie) variando de 0.68 a 3.60m, de acordo com a espécie. A estrutura dos ninhos parece variar dependendo do ambiente e provavelmente da estação. No entanto, a variação também pode ocorrer de acordo com o tamanho da colônia (ou estado de desenvolvimento) e estrutura do solo. O padrão de distribuição de ninhos também parece variar de acordo com a espécie (sobreposição, distribuição aleatória, padrão agregado, distribuição em manchas). Além disso, a polidomia, que é a formação de ninhos múltiplos e separados que permitem intercâmbio entre eles, de operárias e da prole ocorre em E. tuberculatum e foi sugerida para E. brunneum e E. opaciventre.

A organização social foi estudada em diferentes espécies de Ectatomma e colônias poligínicas foram identificadas em sete das 15 espécies (E. ruidum, E. tuberculatum, E. parasiticum, E. brunneum, E. permagnum, E. planidens (referida como E. edentatum), e E. vizottoi). Entretanto, dados baseados em marcadores genéticos usados para investigar em detalhes a estrutura sociogenética das colônias foram realizados apenas com E. tuberculatum e E. ruidum, as quais desenvolvemos loci microssatélites específicos. Embora Ectatomma seja um gênero muito difundido e comum na Região Neotropical, sua taxonomia é pouco conhecida, com várias questões não respondidas, como a delimitação de algumas espécies ou complexos de espécies crípticas (como em E. tuberculatum e E. ruidum), a interpretação da variação intra vs interespecífica (como em E. goninion), o problema da parafilia (como no par E. tuberculatum / E. parasiticum) e também o status de espécie descrito por Almeida (E. vizottoi e E. suzanae). Esperamos que estudos em andamento, incluindo a filogenia molecular do gênero, possam elucidar a delimitação de espécies, biogeografia e evolução de algumas características biológicas como microginia, parasitismo e preferência de habitats.