Résumé
Life history changes may change resource use. Such shifts are not well understood in the dung beetles, despite recognised differences in larval and adult feeding ability. We use the flightless dung beetle Circellium bacchus to explore such shifts, identifying dung sources of adults using DNA metabarcoding, and comparing these with published accounts of larval dung sources. C. bacchus is traditionally considered to specialise on the dung of large herbivores for both larval and adult feeding. We successfully extracted mammal DNA from 151 adult C. bacchus fecal samples, representing 16 mammal species (ranging from elephants to small rodents), many of which are hitherto undescribed in the diet. Adult C. bacchus showed clear dung source preferences, especially for large herbivores inhabiting dense-cover vegetation. Our approach also confirmed the presence of cryptic taxa in the study area, and we propose that this may be used for biodiversity survey and monitoring purposes. Murid rodent feces were the most commonly fed-upon dung source (77.5%) for adult C. bacchus, differing markedly from the large and megaherbivore dung sources used for larval rearing. These findings support the hypothesis of life history-specific shifts in resource use in dung beetles, and reveal a hitherto unsuspected, but ecologically important, role of these dung beetles in consuming rodent feces. The differences in feeding abilities of the larval and adult life history stages have profound consequences for their resource use and foraging strategies, and hence the ecological role of dung beetles. This principle and its ecological consequences should be explored in other scarabaeids.
Auteurs, date et publication :
Auteurs Graham I H Kerley , Marietjie Landman , Gentile F Ficetola , Frédéric Boyer , Aurélie Bonin , Delphine Rioux , Pierre Taberlet , Eric Coissac
Publication : Oecologia
Date : 2025
Volume : 188
Issue : 1
Pages : 107–115
Catégorie(s)
#CNRS #eDNARésumé
To better understand the evolutionary significance of symbiotic interactions in nature, microbiome studies can help to identify the ecological factors that may shape host-associated microbial communities. In this study we explored both 16S and 18S rRNA microbial communities of D. armigerum from both wild caught individuals collected in the Amazon and individuals kept in the laboratory and fed on controlled diets. We also investigated the role of colony, sample type, development and caste on structuring microbial communities. Our bacterial results (16S rRNA) reveal that (1) there are colony level differences between bacterial communities; (2) castes do not structure communities; (3) immature stages (brood) have different bacterial communities than adults; and 4) individuals kept in the laboratory with a restricted diet showed no differences in their bacterial communities from their wild caught nest mates, which could indicate the presence of a stable and persistent resident bacterial community in this host species. The same categories were also tested for microbial eukaryote communities (18S rRNA), and (5) developmental stage has an influence on the diversity recovered; (6) the diversity of taxa recovered has shown this can be an important tool to understand additional aspects of host biology and species interactions.
Auteurs, date et publication :
Auteurs Manuela O. Ramalho , Christophe Duplais , Jérôme Orivel , Alain Dejean , Joshua C. Gibson , Andrew V. Suarez , Corrie S. Moreau
Publication : Scientific Reports
Date : 2025
Volume : 10
Issue : 1
Pages : 7350
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Jean-François Humbert , Kamel Soudani , Gabriel Hmimina , Louise Audebert , Stéphane Buttigieg , Patrice Chatellier , Simon Chollet , Beatriz Decencière , François Derkx , Catherine Freissinet , others
Date : 2025
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
Abstract. The isotopic composition of dioxygen in the atmosphere is a global tracer which depends on the biosphere flux of dioxygen toward and from the atmosphere (photosynthesis and respiration) as well as exchanges with the stratosphere. When measured in fossil air trapped in ice cores, the relative concentration of 16O, 17O and 18O of O2 can be used for several applications such as ice core dating and past global productivity reconstruction. However, there are still uncertainties about the accuracy of these tracers as they depend on the integrated isotopic fractionation of different biological processes of dioxygen production and uptake, for which we currently have very few independent estimates. Here we determined the respiration and photosynthesis fractionation coefficients for atmospheric dioxygen from experiments carried out in a replicated vegetation-soil-atmosphere analog of the terrestrial biosphere in closed chambers with growing Festuca arundinacea. The values for 18O discrimination during soil respiration and dark respiration in leave are equal to −12.3 ± 1.7 ‰ and −19.1 ± 2.4 ‰, respectively. We also found a value for terrestrial photosynthetic fractionation equal to +3.7 ± 1.3 ‰. This last estimate suggests that the contribution of terrestrial productivity in the Dole effect may have been underestimated in previous studies.
Auteurs, date et publication :
Auteurs Clémence Paul , Clément Piel , Joana Sauze , Nicolas Pasquier , Frédéric Prié , Sébastien Devidal , Roxanne Jacob , Arnaud Dapoigny , Olivier Jossoud , Alexandru Milcu , Amaëlle Landais
Date : 2021
Catégorie(s)
#CNRS #Ecotron de MontpellierAuteurs, date et publication :
Auteurs Christian Pichot , Nicolas Beudez , Cécile Callou , André Chanzy , Alyssa Clavreul , Philippe Clastre , Benjamin Jaillet , François Lafolie , Jean-François Le Galliard , Chloé Martin , Florent Massol , Damien Maurice , Nicolas Moitrier , Ghislaine Monet , Hélène Raynal , Antoine Schellenberger , Rachid Yahiaoui
Date : 2022
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Patterns of size variation in fish are supposed to be generated by growth differences, not by egg or hatchling size variation. However, annual killifish live in temporary ponds with a limited time period available for growth and reproduction. It has therefore been hypothesized that among annual killifish, hatchling size variation should be of large relative importance to generate adaptive adult size variation. Using growth curves of 203 individuals from 18 Austrolebias species raised in a common environment, we demonstrate that hatchling size variation indeed is a main determinant of adult size variation in annual killifish, in agreement with the time constraint hypothesis. Furthermore, we find an increased early growth rate in piscivorous species augmenting their difference in size from small congeneric species. This should be adaptive if size differences determine predation success. Environmental effects of spatial location of the population of origin on hatchling size and growth suggest that the time constraint might be weakened in populations occurring near the Atlantic coast. Our study reveals how extreme environments demand specific life history solutions to achieve adaptive size variation and that there might be scope for local adaptations in growth trajectories.
Auteurs, date et publication :
Auteurs Andrew Helmstetter , Tom JM Van Dooren
Publication : bioRxiv
Date : 2019
Pages : 2019.12.31.891648
Catégorie(s)
#CNRS #ENS #PLANAQUAAuteurs, date et publication :
Auteurs Thibaud Decaëns , Frédéric Bénéluz , Liliana Ballesteros-Mejia , Diego Bonilla , Rodolphe Rougerie
Publication : ZooKeys
Date : 2025
Volume : 1031
Pages : 183
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Alexandra Pardow , Michael Lakatos
Publication : Biotropica
Date : 2025
Volume : 45
Issue : 1
Pages : 27-36
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Abstract Cold-adapted species escape climate warming by latitudinal and/or altitudinal range shifts, and currently occur in Southern Europe in isolated mountain ranges within “sky islands”. Here, we studied the genetic structure of the Apollo butterfly in five such sky islands (above 1,000 m) in France, and infer its demographic history since the last interglacial, using single nucleotide polymorphisms (ddRADseq SNPs). The Auvergne and Alps populations show strong genetic differentiation but not alpine massifs, although separated by deep valleys. Combining three complementary demographic inference methods and species distribution models (SDMs) we show that the LIG period was highly unfavourable for Apollo that probably survived in small population in the highest summits of Auvergne. The population shifted downslope and expanded eastward between LIG and LGM throughout the large climatically suitable Rhône valley between the glaciated summits of Auvergne and Alps. The Auvergne and Alps populations started diverging before the LGM but remained largely connected till the mid-Holocene. Population decline in Auvergne was more gradual but started before ($sim$7 kya vs. 800 ya), and was much stronger with current population size ten times lower than in the Alps. In the Alps, the low genetic structure and limited evidence for isolation by distance suggest a nonequilibrium metapopulation functioning. The core Apollo population experienced cycles of contraction-expansion with climate fluctuations with largely interconnected populations overtime according to a “metapopulation-pulsar” functioning. This study demonstrates the power of combining demographic inferences and SDMs to determine past and future evolutionary trajectories of an endangered species at a regional scale.
Auteurs, date et publication :
Auteurs Caroline Kebaïli , Stéphanie Sherpa , Delphine Rioux , Laurence Després
Publication : Molecular Ecology
Date : 2025
Volume : 31
Issue : 2
Pages : 448–466
Catégorie(s)
#CNRS #eDNAAuteurs, date et publication :
Auteurs Blanka Vlasáková
Publication : Journal of Tropical Ecology
Date : 2025
Volume : 31
Issue : 1
Pages : 95-98