Marie-Claire Cammaerts's research while affiliated with University Hospital Brussels and other places

Publications (103)

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The workers of the ant Myrmica sabuleti detain numerosity abilities, have a notion of the running time, and can acquire operant conditioning. The present work examines if, according to these skills and through conditioning, the workers of this ant can associate a learned quantity of a given element with the time period of its occurrence. We collect...
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On the basis of what is known about the biology and the cognitive abilities of the workers of the ant Myrmica sabuleti studied at a collective level, we wondered if these ants could associate sighted cues with time periods of the day. Working on four colonies and using four different cues, we showed that, trained to one kind of cue from 8 to 19 o’c...
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Using ants as models, we studied until now the side effects of 47 products used by humans and, over these studies we published five summaries of our main findings. After that, we studied the side effects of six other drugs used by humans, and we here summarize these lastly obtained results. These six other drugs were dextromethorphan, amitriptylin,...
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Working on the numerosity ability of the ant Myrmica sabuleti, we have already summarized for the readers’ convenience our previous papers in two successive publications. Since that time, we have produced six more papers on the subject, and we thought it was time to present a summary of them. These studies deal with the ants’ ability in expecting t...
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Having shown that the ant Myrmica sabuleti can expect the following number in an arithmetic sequence of increasing or decreasing numbers, we here investigated on their ability in expecting the size of the following element in an increasing or decreasing geometric sequence of shapes, otherwise identical. We found that the ants could anticipatively c...
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It has previously been shown that Myrmica sabuleti ant workers trained to an increasing (1 to 4) or decreasing (5 to 2) arithmetic sequence can expect that the next quantity will be larger or smaller. Here we show that they anticipate the exact next quantity by correctly incrementing the last quantity of the learned sequence by +1 or -1 and not by...
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Workers of the ant Myrmica sabuleti have been previously shown to be able to add and subtract numbers of elements and to expect the time and location of the next food delivery. We wanted to know if they could anticipate the following quantity of elements present near their food when the number of these elements increases or decreases over time acco...
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It has been previously shown that workers of the ant Myrmica sabuleti can add up numbers of elements when seeing the result of the operation during training, can acquire multiple numerical symbolisms and can make additions using learned numeric symbols. They have also been shown to acquire the notion of zero through experiences. Here, we examined i...
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Numerosity ability is an important biological trait. We examined this trait in the ant Myrmica sabuleti over sixteen experimental works. A summary of the first nine works has been already published, and we provide here a summary of the last seven works. During these last-mentioned studies, we successively showed that ants natively possess a number...
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The workers of the ant Myrmica sabuleti were previously shown to be able to associate a given amount to its corresponding symbol, one symbol at a time. It was here examined if they can simultaneously learn to associate the amount 1 with a corresponding symbol, the amount 2 with another symbol, the amount 3 with a third symbol, and the amount 4 with...
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The workers of the ant Myrmica sabuleti have been shown to be able to add numbers of elements after having seen them simultaneously, side by side, during training, and to be able to acquire single as well as multiple symbolism. It was here examined if these ants could make additions using learned symbols. In fact, after having learned the required...
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On the basis of the known numerosity abilities of the ant Myrmica sabuleti, it was checked if workers of this species could associate a symbol with a number of elements through conditioning, an ability rarely encountered in invertebrates and never mentioned in ants. Working each time on two colonies, we observed that these ants could associate a pa...
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The distance effect (the fact that the individuals’ discrimination between two similar elements increases with the magnitude of the distance between them) as well as the size effect (the fact that the individuals’ discrimination between two similar elements decreases with the size of these elements) have been largely reported in vertebrates but not...
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Non-numerical distance and size effects have been previously observed in the ant Myrmica sabuleti. As such effects can be theoretically in line with Weber’s law, we presumed that this law, until now examined in vertebrates, could also apply to ants. Using operant conditioning we trained then tested M. sabuleti workers faced with black circles havin...
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It was previously shown that workers of the ant Myrmica sabuleti can discriminate small numbers of elements during testing when these elements were identical to those learned during training. Here we examine if this numerosity ability still subsists if the shape, color, size or location of the elements (dots) to count are modified between training...
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The ants Myrmica sabuleti Meinert 1861 can add numbers (as non-symbolic displayed elements) or odors when having perceived them simultaneously. Otherwise, (i.e. having perceived them consecutively), they cannot do so. They can subtract one visual element or an odor when perceiving the result of the subtraction. These ants present a concrete notion...
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The workers of the ant Myrmica sabuleti were previously shown to have a compressed left to right oriented mental number line. It remained to know if they detain this trait soon after their emergence, or if they have to acquire it in the course of their life. We worked on workers a few days to at most 5-6 weeks old, maintained in small artificial ne...
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The workers of the ant Myrmica sabuleti have a concrete notion of zero and locate this zero at the lower end of their mental number line. Here we examined how they acquire such a notion: do they have it natively or do they learn it over their life? We worked on young ants a few weeks old, and used operant conditioning to zero, the latter being a wh...
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Patients suffering from urinary incontinence are still nowadays mostly treated with oxybutynin. Using ants as models, we found that this drug decreased their food consumption, orientation ability, tactile perception, cognition and memory, induced restlessness and stress, impacted their social relationships and leaded to dependence. No adaptation oc...
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Myrmica sabuleti ants have a mental number line on which numbers (non-symbolic displayed amounts) are ranked, the smaller on the left and the larger on the right. Here we try to know if the difference between two successive numbers is identically estimated all along this line or is less and less well estimated with increasing number magnitude. Ants...
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Myrmica sabuleti ants have a mental number line on which numbers (non-symbolic displayed amounts) are ranked, the smaller on the left and the larger on the right. Here we try to know if the difference between two successive numbers is identically estimated all along this line or is less and less well estimated with increasing number magnitude. Ants...
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Full-text available
Myrmica sabuleti ants have a mental number line on which numbers (non-symbolic displayed amounts) are ranked, the smaller on the left and the larger on the right. Here we try to know if the difference between two successive numbers is identically estimated all along this line or is less and less well estimated with increasing number magnitude. Ants...
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Artificial nocturnal lighting affects the nature, an impact best studied on vertebrates that are directly depending on the presence or absence of light. Here, we examined on an ant species taken as a model the effects of artificial nocturnal lighting on eleven physiological and ethological traits. Ant workers maintained under nocturnal lighting sho...
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Summing and discriminating odors may be useful for animals in their daily life. The workers of the ant Myrmica sabuleti rely essentially on odors for navigating and have a rather poor visual perception. It was previously shown that they can add and subtract visual elements when the result of the operation has been concretely presented to them, i.e....
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Trained to a smaller number of elements versus a larger one and then tested faced with the larger number and twice the smaller one, one set on the left and the other on the right of the larger number, the ants essentially reacted to the smaller number located on the left of the larger one. Trained to a larger number of elements versus a smaller one...
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When trained to a number of colored elements of which one was crossed, tested Myrmica sabuleti worker ants reacted essentially to that number of elements excluding the crossed one. They thus apparently subtracted the crossed element, moreover doing so better for fewer numbers of elements. When trained in the same way but tested in front of a number...
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Knowing that the workers of the ant Myrmica sabuleti have a concrete notion of zero, and that they can expect the time and the place of the next delivery of food, we experimentally examined if these ants could locate the zero at its due cardinal place. The ants were visually trained step by step to a continuous decreasing series of two amounts of e...
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The workers of the ant Myrmica sabuleti have been shown to be able to distinguish different numbers of elements and to be able to add them if seen side by side, at the same time. They have thus a concrete concept of numbers and of adding. It remained to know if they have an abstract mathematical concept of numbers and of their addition. For temptin...
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Knowing that the workers of the ant Myrmica sabuleti can distinguish different numbers of elements and have a basic notion of zero, we here examine if they can add two numbers of identical elements seen simultaneously. As soon as after three training days, the ants could respond significantly more to the sum of 1 + 1, 2 + 1, 3 + 1, and 3 + 2 elemen...
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Workers of the ant Myrmica sabuleti can acquire the notion of ‘nothing’, i.e. a basic concept of zero, through olfactory conditioning, the best when the odor is unpleasant (onion odor) and when the response to the absence of the odor is rewarded. With a pleasant odor (lavender, rosemary or vanilla odor), the ants learn best when the response to the...
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Homeopathic treatments are considered by the vast majority of the scientific community as non-effective, apart from a well-documented placebo effect. Nevertheless, some experimental results raise questions about their efficiency, and numerous practitioners still consider homeopathy as an efficient alternative treatment instead of usual pharmaceutic...
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The notion of zero is rarely apprehended by animals. We examined if ants possess this ability in four experiments, each time using two colonies and operant conditioning. Ants succeeded in significantly comprehending the absence of a cue, but not as well as learning an existing cue, and they soon lost their learning. Ants thus have a sensory notion...
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Can an act learned through conditioning be adequately presented in a subsequent different situation under which it may be useful to the individuals? We approached this question, working on ants, and staying at a level basic compared to the largely developed Applied Behavior Analysis (ABA) discipline. We simply conditioned the ants of both colonies...
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Having previously found that workers of the ant Myrmica sabuleti can acquire serial recognition when rewarded after having walked a correct visual sequence, we here examined if they can acquire this type of learning (that is recognizing a correct sequence presented together with wrong ones) without being rewarded. Using the same colonies two months...
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Aiming to define the ants’ cognitive abilities, we examined if they could learn a correct sequence and recognize it among others made of the same elements but otherwise ordered. We first trained them to a sequence of three elements. They could recognize the correct sequence from the two wrong sequences, reaching a score of 66.9% after 8 training da...
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Arthritis is one of the most spread illnesses and is treated using essentially glucosamine. Since some years, the efficiency and even the safety of this drug is debated. Indeed, a placebo has often an effect similar to that of glucosamine, and in some cases, this drug appeared to induce cells’ death. In the present work, we examined the ethological...
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The aim of this study was to define the limit of ant cognition, and we examined whether Myrmica rubra ants could use tools or learn to use them. We presented the ants with 1) a piece of mealworm inserted into a small tube tied to a thread that had to be pulled for easy access to the mealworm; 2) a plug that closed the entrance of the ant sugar wate...
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Aiming to know the extent of the ants’ cognitive abilities, we set Myrmica ruginodis workers in four problematic situations. We discovered that these ants could walk round a barrier, by foraging and navigating as usual, using known visual cues. They could walk preferentially on smooth substrates instead of rough ones, but did not memorize their cho...
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We aimed to investigate on the ability of the ant Myrmica sabuleti in learning a behavioral sequence. We created two sequences consisting in navigating through five successive elements on the way to the nest, and tried to learn them to foragers. They could progressively learn a sequence for which the different steps were presented in a backward ord...
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We examined if workers of the ant species Myrmica ruginodis would be able to localize a food source on the basis of its previous locations. To this end we progressively relocated food to predefined positions, both linearly, i.e., farther or nearer the nest entrance, and circularly, i.e., to the left or to the right of the nest entrance. After remov...
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Experiments made on ants as biological models revealed that a saccharose/sucralose 95.5/.05 mixture increased sugar water consumption, decreased general activity, precision of reaction, audacity, brood caring, cognition and ability in acquiring visual conditioning (short term memory), induced aggressiveness against nestmates, and slightly reduced t...
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Abstract This article tries to answer the review paper from Verschaeve (2014 ). This review paper attempted to dismiss every study that shows negative effects of microwave radiation on living organisms. His conclusions are not supported by scientific data and are mostly based on his claims for “inaccurate” dosimetry. This issue is not the case, e...
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Using ants as models, the glycoside rebaudioside A, a sweetener extracted from the plant Stevia rebaudiana and commercialized under the name 'stevia', was shown to have no effect on their food consumption, locomotion, precision of reaction, response to pheromones, brood caring, cognition, visual and olfactory conditioning and memory, although this...
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Sweeteners are presently largely consumed all over the world, essentially aspartame (North America, Europe) and stevia (South America, Asia). Aspartame has a pleasant taste but present some adverse effects; stevia has very few adverse effects but has not the sweetest taste. Using ants as biological models, we here examined if a 0.123% solution of s...
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Working on three ant species of the genus Myrmica , M. ruginodis , M. rubra , and M. sabuleti , we showed that foragers can expect the subsequent time at which food will be available on the basis of the previous times at which food was present. The ants acquired this expectative ability right after having experienced two time shifts of food deliver...
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Many species display local variations in pre-mating signals and in mating preferences. This may lead to discrimination against potential foreign mates that may ultimately lead to reproductive isolation. However, the extent to which population differentiation in mating cues affects the species recognition has received little empirical support. Here...
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One of the most common pharmaceutical substances present in natural water is carbamazepine, a drug given to persons suffering from epilepsies or pain in their cerebral nervous system, and eliminated intact by the kidneys through sewage systems into rivers. This substance may affect macroinvertebrates and vertebrates depending on watercourses. We th...
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Using ants as biological models, we showed that fluoxetine (the active substance of the most consumed antidepressants) largely affects the individual's physiology and behavior. It increases sinuosity of movement, decreases precision of reaction and response to pheromones, decreases food consumption and brood caring, and induces aggressiveness towar...
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Under high levels of radiation (70-100 µW/m2 =175 mV/m), seeds of Brassicaceae Lepidium sativum (cress d’Alinois) never germinated. In fact, the first step of seeds’ germination - e.g. imbibitions of germinal cells - could not occur under radiation, while inside the humid compost such imbibitions occurred and roots slightly developed. When removed...
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Young workers of the ant Myrmica sabuleti (Hymenoptera: Formicidae) Meinert 1861 perceived nestmate alarm pheromone but did not display normal alarm behavior (orientation toward the source of emission, increased running speed). They changed their initial behavior when in the presence of older nestmates exhibiting normal alarm behavior. Four days la...
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In the present work, firstly, ant emergence was observed: it is a long, stereotyped, precarious event which may require the help of congeners. Then, our experiments on Myrmica sabuleti Meinert 1861 callow ants emerging apart from or inside their colony showed the following points. 1. Newly emerged workers, even if having never olfactorily perceived...
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This paper summarizes our findings on the eye morphology, visual perception, learning abilities, navigation system and recruitment strategy of three Myrmica species, pointing out the agreement between each species' morphological, physiological and behavioral characters as well as the accordance between these characters and each species' environment...
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Nicotine is one of the most consumed alkaloids. Its effects still lead to mixed conclusions. Having recently observed that ants could be used as biological models, we examined several physiological and ethological effects of nicotine using the ant Myrmica sabuleti as a biological model. We pointed out that nicotine increases the individuals’ locomo...
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Well-controlled electromagnetic exposure conditions were set up at a representative societal GSM radiation intensity level, 1.5 V/m, which is the legally allowed level in Brussels. Two nests of the ant species Myrmica sabuleti were repeatedly irradiated during 10 min. before their behavior was observed, based on the analysis of the ant trajectories...
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Aiming to check if ants can be used as biological models, we studied the effects of four alkaloids on the ant Myrmica sabuleti . Caffeine and theophylline increased the ants’ linear speed, decreased their precision of reaction and their food consumption, did not affect their response to pheromones, nor their audacity, largely increased their condit...
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Myrmica ruginodis Nylander 1846 workers either of different ages, or having their food at different distances from the nest, or receiving different diet were submitted to identical operant conditioning. Very young ants (callow ants) could not be visually conditioned. Ants one to two years old rapidly acquired visual conditioning, presenting a score...
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Conditioning of isolated ants was attempted in the ant Myrmica sabuleti. Isolated ants did not die and could be visually as well as olfactorily conditioned. They acquired and kept ‐ or partly lost ‐ their visual ‐ or their olfactory ‐ conditioned responses as do ants living in a colony. Each individual of an ant colony is thus able to learn and mem...
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Young workers, experimentally removed from their nest and set in front of it, are not very good at finding the nest entrance and entering the nest. I examined how young ants learn their nest entrance characteristics, dealing only with the entrance sensu stricto, not with its vicinity. I observed that young ants have the innate behavior of trying to...
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Abstract Society is confronted with an increasing number of applications making use of wireless communication. We also notice an increasing awareness about potentially harmful effects of the related electromagnetic fields on living organisms. At present, it is not realistic to expect that wireless communication will decrease or disappear within the...
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We used the ant species Myrmica sabuleti as a model to study the impact of electromagnetic waves on social insects' response to their pheromones and their food collection. We quantified M. sabuleti workers' response to their trail, area marking and alarm pheromone under normal conditions. Then, we quantified the same responses while under the influ...
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Using collective differential operant conditioning, it could be shown that workers of the species Myrmica rubra distinguish different filled shapes of similar size (e.g. a black square from a black circle, a black triangle from a black circle, and a black triangle from a black square). They are unable to discriminate hollow shapes (e.g. a rectangle...
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Ants use chemical trails, laid down on the ground, for recruiting congeners and helping them to return to the nest. The present work shows that young ants, less than one year old, though obviously reacting to the trail pheromone, are unable to efficiently follow a trail. These young ants begin to better walk along a trail when being in presence of...
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Myrmica ruginodis workers are able to distinguish black or white circles from black or white squares, black or white ellipses from black or white rectangles as well as hollow circles or ellipses from hollow squares or rectangles. They can also distinguish differently oriented elements as well as objects containing a various number of elements. Thes...
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The kinetics of the acquisition and loss of the use of olfactory and visual cues were previously obtained in six experimental colonies of the ant Myrmica sabuleti meinert 1861, under normal conditions. In the present work, the same experiments were conducted on six other naive identical colonies of M. sabuleti, under electromagnetic radiation simil...
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Myrmica ruginodis NYLANDER, 1846 foragers were differentially conditioned to two olfactory and two visual cues. The ants were then placed in mazes provided with either olfactory cues, or visual cues, or with successively or alternatively set visual and olfactory cues. In the latter case, the ants scored consistently higher in front of visual cues....
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Foragers of Myrmica rubra were differentially conditioned to two olfactory and two visual cues. Their response to the visual cues was slight under light conditions at 110 lux. Conditioned workers negotiated mazes that were adequately provided with either olfactory or visual, or two kinds of cues. Under low light intensity, they performed better in...
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Males of Bombus terrestris (L.) adopt a patrolling behaviour during their nuptial parade using cephalic labial gland (CLG) secretions containing sexual pheromones to attract conspecific virgin queens. The changes in chemical composition of their CLG secretions with age are quite well known. In this study, we investigate the evolution of CLG secreti...
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The protozoan Paramecium caudatum was examined under normal conditions versus aside a switched-on GSM telephone (900 MHz; 2 Watts). Exposed individuals moved more slowly and more sinuously than usual. Their physiology was affected: they became broader, their cytopharynx appeared broader, their pulse vesicles had difficult in expelling their content...