Papers by Nicolas Chaline
Animal Behaviour, Jul 1, 2022
Behavioural Brain Research, Jun 1, 2021
Judgment bias tests have become an important tool in the assessment of animals' affective sta... more Judgment bias tests have become an important tool in the assessment of animals' affective states. Subjects are first trained to discriminate between two cues associated with a positive and a less-positive outcome. After successful training, they are confronted with an ambiguous cue, and responses are used for judgment bias assessment. In spatial settings, ambiguous cue presentation is typically linked with novelty, i.e. to yet unexplored areas or areas to which the animal has a low degree of habituation. We hypothesized that in such settings, responses to ambiguity might be biased by the animals' perception of novelty. We conducted judgment bias tests in mound-building mice phenotyped for their exploration tendency. After subjects had learned to distinguish between the positively and less-positively rewarded arms of a maze, a new ambiguous middle-arm was introduced. During the first test trial, more exploratory, less neophobic individuals displayed higher bidirectional locomotion in the ambiguous arm, indicating intensive exploration. Although this resulted in longer latencies to the reward in more exploratory animals, we conclude that this did not reflect a 'more pessimistic judgment of ambiguity'. Indeed, during the following two trials, with increasing habituation to the ambiguous arm, the direction of the association was inversed compared to the first trial, as more exploratory individuals showed relatively shorter approach latencies. We suggest that in spatial test settings associating the ambiguous cue to novel areas, results can be confounded by subjects' personality-dependent motivational conflict between exploration and reaching the reward. Findings obtained under such conditions should be interpreted with care.
With urbanization increasing globally, conservation ecologists need to characterize the functioni... more With urbanization increasing globally, conservation ecologists need to characterize the functioning of ecosystems embedded in urban landscapes. Ubiquitous and hyperdiverse, ants are an ideal model taxon for this purpose. Here we compared diversity, richness, and abundance of ants in a forest fragment and a green urban area within the City of São Paulo, characterizing relationships among ant species. We found higher species abundance and richness in the urban area, whereas diversity was greater in the secondary forest fragment. Transect sampling revealed higher heterogeneity in the more urban area, with a number of species not found in the secondary forest. Bait sampling suggested that, in the urban area, dominance of one or a few species was stronger than in the secondary forest, possibly because dominant species outnumbered other species at resources and behaved aggressively. We found that a limited number of species dominated in both the forest and the urban area. Although this st...
The Science of Nature
Meliponine bees use chemical-based nestmate discrimination to protect their colonies from unrelat... more Meliponine bees use chemical-based nestmate discrimination to protect their colonies from unrelated intruders. However, species from the Amazon basin are relatively poorly known from this perspective. Here, we investigated Melipona paraensis nestmate discrimination in different contexts (nests vs. neutral arenas), testing aggression in bees facing other bees varying in age and origin (same/different colony or a different kleptoparasitic meliponine species) or experimentally treated with odors from unrelated colonies. As expected, M. paraensis did not discriminate against callow non-nestmate workers with weak/undifferentiated chemical signatures. Workers specialized in nest defense aggressed intruders more often than non-specialized workers, but were less aggressive in neutral arenas than in the nest. Our study provides novel behavioral information relevant for social insect research and meliponiculture.
From speciation to introgressive hybridization: the phylogeographic structure of an island subspe... more From speciation to introgressive hybridization: the phylogeographic structure of an island subspecies of termite, Reticulitermes lucifugus corsicus
microsatellite paternity analysis
Current Zoology, 2021
Ants show collective and individual behavioral flexibility in their response to immediate context... more Ants show collective and individual behavioral flexibility in their response to immediate context, choosing for example between different foraging strategies. In Pachycondyla striata, workers can forage solitarily or recruit and guide nestmates to larger food sources through tandem running. Although considered more ancestral and less efficient than pheromone trail-laying, this strategy is common especially in species with small colony size. What is not known is how the decision to recruit or follow varies according to the immediate context. That is, how fine adjustments in information transfer affect immediate foraging decisions at the colony level. Here, we studied individually marked workers and evaluated their foraging decisions when food items varied in nature (protein versus carbohydrate), size, and distance from the nest at different temperatures and humidity levels. Our results show that tandem run leaders and potential followers adjust their behavior according to a combinati...
While pillaging the brood of other ant colonies, Eciton army ants accumulate prey in piles, or ca... more While pillaging the brood of other ant colonies, Eciton army ants accumulate prey in piles, or caches, along their foraging trails. Widely documented, these structures have historically been considered as byproducts of heavy traffic or aborted relocations of the ants’ temporary nest, or bivouac. However, we recently observed that caches of the hook-jawed army ant, Eciton hamatum, appeared independently from heavy traffic or bivouac relocations. In addition, the flow of prey through caches varied based on the quantity of prey items workers transported. As this suggested a potential adaptive function, we developed agent-based simulations to compare raids of caching and non-caching virtual army ants. We found that caches increased the amount of prey that relatively low numbers of raiders were able to retrieve. However, this advantage became less conspicuous - and generally disappeared - as the number of raiders increased. Based on these results, we hypothesize that caches maximize the ...
1. Universidade Federal do Espírito Santo, Centro de Ciências Exatas, Naturais e da Saúde, Depart... more 1. Universidade Federal do Espírito Santo, Centro de Ciências Exatas, Naturais e da Saúde, Departamento de Biologia, Laboratório de Ecologia e Comportamento Animal, Alto Universitário, s/n, Guararema, CEP: 29.500-000, Alegre, ES, Brasil, *E-mail: [email protected]; 2. Universidade de São Paulo, Instituto de Psicologia, Departamento de Psicologia Experimental, Laboratório de Etologia, Ecologia e Evolução dos Insetos Sociais, São Paulo – SP, Brasil.
As formigas poneromorfas do Brasil, 2015
All the contents of this work, except where otherwise noted, is licensed under a Creative Commons... more All the contents of this work, except where otherwise noted, is licensed under a Creative Commons Attribution 4.0 International license. Todo o conteúdo deste trabalho, exceto quando houver ressalva, é publicado sob a licença Creative Commons Atribição 4.0. Todo el contenido de esta obra, excepto donde se indique lo contrario, está bajo licencia de la licencia Creative Commons Reconocimento 4.0.
Boletim do Museu Paraense Emílio Goeldi - Ciências Naturais, 2020
A formiga de correição Eciton rapax é uma espécie de formiga ainda muito pouco conhecida quanto à... more A formiga de correição Eciton rapax é uma espécie de formiga ainda muito pouco conhecida quanto à sua história natural. Os hábitos de nidificação de E. rapax ainda permanecem pouco estudados, sendo uma importante lacuna para a compreensão da ecologia dessa espécie. Nosso estudo registrou e descreveu locais de nidificação de E. rapax. O estudo foi realizado em uma região de mata primária, no município de Bragança, no estado do Pará. Colunas de forrageio de E. rapax foram encontradas e seguidas até seu local de nidificação, entre julho de 2018 e janeiro de 2020. Foram encontrados 5 bivaques, que foram descritos e localizados. Quatro bivaques eram subterrâneos, embaixo de troncos caídos, buracos deixados por outros animais ou entre raízes aéreas de árvores. Um bivaque situava-se na parte oca de uma árvore, a aproximadamente 3 metros de altura. Nossos dados mostram que além de hábitos subterrâneos de nidificação já descritos na literatura para a espécie, Eciton rapax também pode nidific...
Entomologia Experimentalis et Applicata, 2018
Various organisms emit malodorous secretions against competitors, and the potential use of these ... more Various organisms emit malodorous secretions against competitors, and the potential use of these secretions in pest management should be investigated. For example, some ant species feed on similar resources as dung beetles, which might have led to counter chemical defences in dung beetles. We tested whether pygidial secretions of the dung beetle Canthon smaragdulus (Fabricius) (Coleoptera: Scarabaeidae, Scarabaeinae) alter the locomotor behaviour of the exotic urban pest ant Tapinoma melanocephalum (Fabricius) (Hymenoptera: Formicidae), specifically whether these secretions repel those ants. We also tested whether the disturbance in the locomotor behaviour of T. melanocephalum increases with the amount of pygidial secretion. We found that individual T. melanocephalum displayed changes in their locomotor behaviour when exposed to pygidial secretions of coupled dung beetles, single males, and single females. Additionally, the pygidial secretions from male and female dung beetles could repel ants. The change in the locomotor behaviour of T. melanocephalum increased with the amount of pygidial secretion. Our results suggest that the pygidial secretions of dung beetles have potential as a biological repellent of T. melanocephalum. Hence, pygidial secretions from dung beetles may be used in the future for the development of urban pest management strategies.
Biochemical Systematics and Ecology, 2018
We investigated the possible origin of the specific odor of the terricolous ant Myrmecina gramini... more We investigated the possible origin of the specific odor of the terricolous ant Myrmecina graminicola by elucidating its pattern of volatiles. It appeared to have a very large hypertrophied poison gland reservoir, which contains copious amounts of acetate and propionate esters that are also present on the cuticule. The poison gland was previously reported as the source of sex pheromone, but the finding that queens and workers exhibited the same ester patterns tends to refute their role in sex attractants, and their biological significance remains elusive. The composition of cuticular hydrocarbons in this species is also highly original as it mostly comprises alkadienes and alkatrienes (70%), which is unusual and may be an adaptation to subterranean life. Neither the esters nor the cuticular hydrocarbons vary qualitatively and quantitatively between various localities in France, including Corsica.
Proceedings of the Royal Society B: Biological Sciences, 2013
Restricted reproduction is traditionally posited as the defining feature of eusocial insect worke... more Restricted reproduction is traditionally posited as the defining feature of eusocial insect workers. The discovery of worker reproduction in foreign colonies challenges this view and suggests that workers’ potential to pursue selfish interests may be higher than previously believed. However, whether such reproductive behaviour truly relies on a reproductive decision is still unknown. Workers’ reproductive decisions thus need to be investigated to assess the extent of workers’ reproductive options. Here, we show in the bumblebee Bombus terrestris that drifting is a distinct strategy by which fertile workers circumvent competition in their nest and reproduce in foreign colonies. By monitoring workers’ movements between colonies, we show that drifting is a remarkably dynamic behaviour, widely expressed by both fertile and infertile workers. We demonstrate that a high fertility is, however, central in determining the propensity of workers to enter foreign colonies as well as their subse...
PLoS ONE, 2012
Context-dependent decision-making conditions individual plasticity and is an integrant part of al... more Context-dependent decision-making conditions individual plasticity and is an integrant part of alternative reproductive strategies. In eusocial Hymenoptera (ants, bees and wasps), the discovery of worker reproductive parasitism recently challenged the view of workers as a homogeneous collective entity and stressed the need to consider them as autonomous units capable of elaborate choices which influence their fitness returns. The reproductive decisions of individual workers thus need to be investigated and taken into account to understand the regulation of reproduction in insect societies. However, we know virtually nothing about the proximate mechanisms at the basis of worker reproductive decisions. Here, we test the hypothesis that the capacity of workers to reproduce in foreign colonies lies in their ability to react differently according to the colonial context and whether this reaction is influenced by a particular internal state. Using the bumble bee Bombus terrestris, we show that workers exhibit an extremely high reproductive plasticity which is conditioned by the social context they experience. Fertile workers reintroduced into their mother colony reverted to sterility, as expected. On the contrary, a high level of ovary activity persisted in fertile workers introduced into a foreign nest, and this despite more frequent direct contacts with the queen and the brood than control workers. Foreign workers' reproductive decisions were not affected by the resident queen, their level of fertility being similar whether or not the queen was removed from the host colony. Workers' physiological state at the time of introduction is also of crucial importance, since infertile workers failed to develop a reproductive phenotype in a foreign nest. Therefore, both internal and environmental factors appear to condition individual reproductive strategies in this species, suggesting that more complex decision-making mechanisms are involved in the regulation of worker reproduction than previously thought.
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Papers by Nicolas Chaline