Pub Date : 2026-01-05DOI: 10.1016/j.beproc.2026.105332
A. Sofía Flores , Carlos Flores , Julian C. Velasquez , L. Rebeca Mateos , Kenneth Madrigal , Cinthia M. Hernández-Escalante
Prior research has examined combined forms of behavioral recurrence, showing that relapse is greater when these forms occur together than when each is studied in isolation. However, this enhancement effect has not yet been explored in the joint expression of two phenomena: reinstatement, defined as the reappearance of extinguished behavior following response-independent or response-dependent exposure to consequences (or consequence-associated cues), and spontaneous recovery, defined as the recurrence of a response after an interval following extinction. The present study evaluated whether delaying the test phase enhances response-independent reinstatement in rats. After reinforcement and extinction of a response, subjects were assigned to one of two groups: Control Group, which was exposed to an immediate test with delivery of non-contingent reinforcement, or Delay Group, which was exposed to the same test after a seven-day delay. Results showed that reinstatement was higher in the Delay Group compared to the Control Group. These findings offer new support for enhanced recurrence paradigms, showing that reinstatement and spontaneous recovery jointly produce greater relapse.
{"title":"Combined effects of reinstatement and spontaneous recovery","authors":"A. Sofía Flores , Carlos Flores , Julian C. Velasquez , L. Rebeca Mateos , Kenneth Madrigal , Cinthia M. Hernández-Escalante","doi":"10.1016/j.beproc.2026.105332","DOIUrl":"10.1016/j.beproc.2026.105332","url":null,"abstract":"<div><div>Prior research has examined combined forms of behavioral recurrence, showing that relapse is greater when these forms occur together than when each is studied in isolation. However, this enhancement effect has not yet been explored in the joint expression of two phenomena: reinstatement, defined as the reappearance of extinguished behavior following response-independent or response-dependent exposure to consequences (or consequence-associated cues), and spontaneous recovery, defined as the recurrence of a response after an interval following extinction. The present study evaluated whether delaying the test phase enhances response-independent reinstatement in rats. After reinforcement and extinction of a response, subjects were assigned to one of two groups: Control Group, which was exposed to an immediate test with delivery of non-contingent reinforcement, or Delay Group, which was exposed to the same test after a seven-day delay. Results showed that reinstatement was higher in the Delay Group compared to the Control Group. These findings offer new support for enhanced recurrence paradigms, showing that reinstatement and spontaneous recovery jointly produce greater relapse.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105332"},"PeriodicalIF":1.5,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145916875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-03DOI: 10.1016/j.beproc.2026.105328
Hanlin Yan , Longwu Wang , Wei Liang
Brood parasitism can force hosts to evolve adaptive defense behaviors. To effectively prevent or mitigate reproductive losses caused by parasites, host birds can adjust their nest defense intensity at different breeding stages. In our study area, the oriental reed warbler (Acrocephalus orientalis) is a common host of the common cuckoo (Cuculus canorus). Previous studies have shown that this host exhibits strong aggressive behaviors toward common cuckoos. To test whether the intensity of nest defense by oriental reed warblers varies between different breeding stages, we compared their behavioral responses toward 3D dummies of the grey common cuckoo and oriental turtle dove (Streptopelia orientalis) during the early incubation and nestling stages. Results showed that there was no significant difference in the defensive behavior of oriental reed warblers against common cuckoos and oriental turtle dove dummies between early incubation and nestling feeding stages. Oriental reed warblers exhibited three different types of response behaviors during both early incubation and nestling feeding stages, which included attack, mobbing calls, and no response. We conclude that the nest defense intensity of oriental reed warblers against common cuckoos did not significantly change with different breeding stages between early incubation and nestling feeding stages. This may provide a new experimental case to fill a gap in understanding the coevolution between the oriental reed warbler (host) and the common cuckoo (parasite).
{"title":"Intensity of host nest defense against parasites does not change with different breeding stages","authors":"Hanlin Yan , Longwu Wang , Wei Liang","doi":"10.1016/j.beproc.2026.105328","DOIUrl":"10.1016/j.beproc.2026.105328","url":null,"abstract":"<div><div>Brood parasitism can force hosts to evolve adaptive defense behaviors. To effectively prevent or mitigate reproductive losses caused by parasites, host birds can adjust their nest defense intensity at different breeding stages. In our study area, the oriental reed warbler (<em>Acrocephalus orientalis</em>) is a common host of the common cuckoo (<em>Cuculus canorus</em>). Previous studies have shown that this host exhibits strong aggressive behaviors toward common cuckoos. To test whether the intensity of nest defense by oriental reed warblers varies between different breeding stages, we compared their behavioral responses toward 3D dummies of the grey common cuckoo and oriental turtle dove (<em>Streptopelia orientalis</em>) during the early incubation and nestling stages. Results showed that there was no significant difference in the defensive behavior of oriental reed warblers against common cuckoos and oriental turtle dove dummies between early incubation and nestling feeding stages. Oriental reed warblers exhibited three different types of response behaviors during both early incubation and nestling feeding stages, which included attack, mobbing calls, and no response. We conclude that the nest defense intensity of oriental reed warblers against common cuckoos did not significantly change with different breeding stages between early incubation and nestling feeding stages. This may provide a new experimental case to fill a gap in understanding the coevolution between the oriental reed warbler (host) and the common cuckoo (parasite).</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105328"},"PeriodicalIF":1.5,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145905543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.beproc.2026.105327
Gerson Yukio Tomanari
Food-deprived pigeons were given a random sequence of 50-s discrete trials, half of which ended with and half without response-independent food presentation. During a trial, pecking a white key could change its color to red or green, depending on whether food (S+ color) or no food (S- color) was scheduled. In the single stimulus-production condition (SSP), if the red or the green key color was produced, the key remained red or green, respectively, until the end of the trial. In the multiple stimulus-production condition (MSP), the duration of each green or red illumination was limited to a maximum of 10 s. After 10 s, the white light resumed and additional key-color changes (re-presentations of S+ or S-) were possible. Results showed that S+ and S- were produced equally often in SSP, as well as in the first stimulus production in MSP. The frequencies of S- re-presentations, however, were clearly and systematically higher than the frequencies of S+ re-presentations. These findings demonstrate that under certain conditions, a stimulus signaling the absence of primary reinforcement (S-) can maintain higher rates of observing behavior than a stimulus signaling its presence (S+).
{"title":"Observing responses maintained by re-presentations of S-","authors":"Gerson Yukio Tomanari","doi":"10.1016/j.beproc.2026.105327","DOIUrl":"10.1016/j.beproc.2026.105327","url":null,"abstract":"<div><div>Food-deprived pigeons were given a random sequence of 50-s discrete trials, half of which ended with and half without response-independent food presentation. During a trial, pecking a white key could change its color to red or green, depending on whether food (S+ color) or no food (S- color) was scheduled. In the single stimulus-production condition (SSP), if the red or the green key color was produced, the key remained red or green, respectively, until the end of the trial. In the multiple stimulus-production condition (MSP), the duration of each green or red illumination was limited to a maximum of 10 s. After 10 s, the white light resumed and additional key-color changes (re-presentations of S+ or S-) were possible. Results showed that S+ and S- were produced equally often in SSP, as well as in the first stimulus production in MSP. The frequencies of S- re-presentations, however, were clearly and systematically higher than the frequencies of S+ re-presentations. These findings demonstrate that under certain conditions, a stimulus signaling the absence of primary reinforcement (S-) can maintain higher rates of observing behavior than a stimulus signaling its presence (S+).</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105327"},"PeriodicalIF":1.5,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.beproc.2025.105326
Francisco Javier Zamora-Camacho
Animals are expected to adjust their decisions to different contexts so that their benefits outweigh the costs. For instance, the proximity of predators frequently leads to cautious behaviors, whereas competitors promote boldness. Foraging can be affected by these patterns, although to an extent that may depend on the individual’s need for food. In this work, I investigate the effect of chemical cues of non-gape-limited predators and intraspecific competitors on foraging rates of Iberian spadefoot toad (Pelobates cultripes) tadpoles either fed ad libitum or fasted for 24 h. Food restriction did not affect foraging rates, and neither did predator cues. These are large tadpoles that could have enough reserves to survive a 24-hour fast, and be difficult to handle by most predators. However, tadpoles ate more in the presence of competitor cues. Hoarding food under dispute could maximize its consumption before the competitor reduces the amount of it available, also limiting the access of the competitor to it, probably limiting its growth and its ability to compete in future encounters.
{"title":"I call dibs on it! Chemical cues of intraspecific competitors potentiate food consumption in anuran tadpoles","authors":"Francisco Javier Zamora-Camacho","doi":"10.1016/j.beproc.2025.105326","DOIUrl":"10.1016/j.beproc.2025.105326","url":null,"abstract":"<div><div>Animals are expected to adjust their decisions to different contexts so that their benefits outweigh the costs. For instance, the proximity of predators frequently leads to cautious behaviors, whereas competitors promote boldness. Foraging can be affected by these patterns, although to an extent that may depend on the individual’s need for food. In this work, I investigate the effect of chemical cues of non-gape-limited predators and intraspecific competitors on foraging rates of Iberian spadefoot toad (<em>Pelobates cultripes</em>) tadpoles either fed <em>ad libitum</em> or fasted for 24 h. Food restriction did not affect foraging rates, and neither did predator cues. These are large tadpoles that could have enough reserves to survive a 24-hour fast, and be difficult to handle by most predators. However, tadpoles ate more in the presence of competitor cues. Hoarding food under dispute could maximize its consumption before the competitor reduces the amount of it available, also limiting the access of the competitor to it, probably limiting its growth and its ability to compete in future encounters.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105326"},"PeriodicalIF":1.5,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-29DOI: 10.1016/j.beproc.2025.105324
Rui Han , Jun Zhang , Xin-Hui Chen , Jing-Wen Duo , Yi-Yi Li , Yi-Ran Chen , Si-Tong Chen , Lin-Xiang Liu , Xiang-Haoran Lin
Mating behaviour plays a key role in animal reproduction and profoundly affects the physiological state and behavioural performance of individuals. Although numerous studies have focused on the behavioural responses of single-sex groups of Drosophila melanogaster under mating contexts, systematic comparisons of male and female fruit flies across different mating contexts are still relatively limited. This study investigated the locomotion of 86 male and female fruit flies under different mating contexts, including virgin, continuously exposed to the opposite sex (mated), beginning cohabitation with the opposite sex on the 8th day of the experiment (virgin-mated), and opposite-sex cohabitation on the 8th day and switching to same-sex cohabitation (mated-deprived). The results showed that virgin males exhibited the highest overall movement speed and that continuous exposure to the opposite sex led to a transient reduction in male movement speed. In contrast, females displayed a temporary increase in movement speed under opposite-sex cohabitation but rapidly returned to levels comparable to virgins. These sex-specific and time-dependent changes indicate that mating context exerts dynamic effects on movement speed. Moreover, in contrast to the negative effects of social isolation reported in previous studies, our findings suggest that mating status and social environment jointly shape locomotor performance under non-isolated conditions. Overall, this study highlights how males and females dynamically adjust locomotor strategies in response to changing reproductive and social contexts, providing an evolutionary perspective on behavioural plasticity and sex-specific trade-offs in insects.
{"title":"Sex differences in locomotor recovery across mating contexts in Drosophila melanogaster","authors":"Rui Han , Jun Zhang , Xin-Hui Chen , Jing-Wen Duo , Yi-Yi Li , Yi-Ran Chen , Si-Tong Chen , Lin-Xiang Liu , Xiang-Haoran Lin","doi":"10.1016/j.beproc.2025.105324","DOIUrl":"10.1016/j.beproc.2025.105324","url":null,"abstract":"<div><div>Mating behaviour plays a key role in animal reproduction and profoundly affects the physiological state and behavioural performance of individuals. Although numerous studies have focused on the behavioural responses of single-sex groups of <em>Drosophila melanogaster</em> under mating contexts, systematic comparisons of male and female fruit flies across different mating contexts are still relatively limited. This study investigated the locomotion of 86 male and female fruit flies under different mating contexts, including virgin, continuously exposed to the opposite sex (mated), beginning cohabitation with the opposite sex on the 8th day of the experiment (virgin-mated), and opposite-sex cohabitation on the 8th day and switching to same-sex cohabitation (mated-deprived). The results showed that virgin males exhibited the highest overall movement speed and that continuous exposure to the opposite sex led to a transient reduction in male movement speed. In contrast, females displayed a temporary increase in movement speed under opposite-sex cohabitation but rapidly returned to levels comparable to virgins. These sex-specific and time-dependent changes indicate that mating context exerts dynamic effects on movement speed. Moreover, in contrast to the negative effects of social isolation reported in previous studies, our findings suggest that mating status and social environment jointly shape locomotor performance under non-isolated conditions. Overall, this study highlights how males and females dynamically adjust locomotor strategies in response to changing reproductive and social contexts, providing an evolutionary perspective on behavioural plasticity and sex-specific trade-offs in insects.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105324"},"PeriodicalIF":1.5,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145877629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1016/j.beproc.2025.105323
Chris T. Tromborg, Richard G. Coss, Kenneth R. Henry
California ground squirrels (Otospermophilus becheeyi) exhibit adaptive variation to their local environments based on antipredator, immunological, and social-communication evaluations. The following pair of experiments investigated the acoustic and behavioral responses of California ground squirrels from the higher-elevation Sierra Valley (alt. ∼1900 m) and from the lower-elevation Sunol region (alt. ∼270 m). Analyses of their genetic distance suggest that these populations diverged during the Late Pleistocene. The first experiment compared small groups from these populations on the basis of their auditory brainstem responses (ABR) to a range of sound frequencies. The ABR audiograms of Sierra Valley squirrels showed greater acoustic sensitivity to frequencies lower than 4 kHz than the Sunol squirrels. Both groups exhibited similar audiograms for higher frequencies. Such an adaptation would be useful for coping with dangerous circumstances possibly masked by inclement weather. The second experiment compared the squirrel groups for several 9-hr observation periods focusing on the number of egress bouts from nest boxes centered in a laboratory room equipped with sound playback equipment to simulate far-field naturalistic sounds. Three sound treatments were compared: 1) ambient room sound, 2) temperate forest, and 3) rainstorm. Analyses indicated that the higher-altitude Sierra Valley squirrels were reliably less likely to leave the nestbox to explore the room than were low-altitude Sunol squirrels under the rain treatment. The results of both studies suggest that the enhanced low-frequency hearing of Sierra Valley squirrels is a sensory adaptation for coping with the reduced sound transmission of low frequencies at higher altitudes.
{"title":"Adaptive variation in the acoustic sensitivity of California ground squirrels (Otospermophilus beecheyi) living in higher- and lower-elevation habitats","authors":"Chris T. Tromborg, Richard G. Coss, Kenneth R. Henry","doi":"10.1016/j.beproc.2025.105323","DOIUrl":"10.1016/j.beproc.2025.105323","url":null,"abstract":"<div><div>California ground squirrels (<em>Otospermophilus becheeyi</em>) exhibit adaptive variation to their local environments based on antipredator, immunological, and social-communication evaluations. The following pair of experiments investigated the acoustic and behavioral responses of California ground squirrels from the higher-elevation Sierra Valley (alt. ∼1900 m) and from the lower-elevation Sunol region (alt. ∼270 m). Analyses of their genetic distance suggest that these populations diverged during the Late Pleistocene. The first experiment compared small groups from these populations on the basis of their auditory brainstem responses (ABR) to a range of sound frequencies. The ABR audiograms of Sierra Valley squirrels showed greater acoustic sensitivity to frequencies lower than 4 kHz than the Sunol squirrels. Both groups exhibited similar audiograms for higher frequencies. Such an adaptation would be useful for coping with dangerous circumstances possibly masked by inclement weather. The second experiment compared the squirrel groups for several 9-hr observation periods focusing on the number of egress bouts from nest boxes centered in a laboratory room equipped with sound playback equipment to simulate far-field naturalistic sounds. Three sound treatments were compared: 1) ambient room sound, 2) temperate forest, and 3) rainstorm. Analyses indicated that the higher-altitude Sierra Valley squirrels were reliably less likely to leave the nestbox to explore the room than were low-altitude Sunol squirrels under the rain treatment. The results of both studies suggest that the enhanced low-frequency hearing of Sierra Valley squirrels is a sensory adaptation for coping with the reduced sound transmission of low frequencies at higher altitudes.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105323"},"PeriodicalIF":1.5,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Captive animals are commonly used in laboratory research, however, captive and wild animals often differ, limiting the applicability of laboratory findings based on captive animals to the “real” world. A comprehensive understanding of how captive and wild animals differ is necessary to assess if captive animals are suitable substitutes for their wild counterparts, however, few studies have compared cognition between captive and wild animals. In this study, we compared aspects of cognition between captive and wild fathead minnow (Pimephales promelas) to investigate how life in captivity might impact traits essential to fitness in the wild. Specifically, we assessed aversive learning performance using an associative learning assay and a more complex reversal learning assay, and we also measured anxiety and brain mass. Performance in the associative learning task was negatively correlated with performance in the reversal learning task, suggesting a potential tradeoff. No differences were observed between captive and wild fish in associative learning performance, anxiety, or brain mass, but wild fish were three times more likely to complete the more complex reversal learning task. Aversive reversal learning, which appears to be dampened in captive fathead minnow, may be particularly relevant for appropriate antipredator responses and fitness in challenging or fluctuating environments. We advocate for further research comparing wild and captive animal cognition and urge researchers to exercise caution when generalizing results from captive animals to wild populations.
{"title":"Cognition in captivity: Investigating learning, anxiety, and brain mass differences between captive and wild fathead minnow","authors":"Megan Dorothy Cyr , Jacqueline Bikker , Adrienne Yau , Sigal Balshine","doi":"10.1016/j.beproc.2025.105322","DOIUrl":"10.1016/j.beproc.2025.105322","url":null,"abstract":"<div><div>Captive animals are commonly used in laboratory research, however, captive and wild animals often differ, limiting the applicability of laboratory findings based on captive animals to the “real” world. A comprehensive understanding of how captive and wild animals differ is necessary to assess if captive animals are suitable substitutes for their wild counterparts, however, few studies have compared cognition between captive and wild animals. In this study, we compared aspects of cognition between captive and wild fathead minnow (<em>Pimephales promelas)</em> to investigate how life in captivity might impact traits essential to fitness in the wild. Specifically, we assessed aversive learning performance using an associative learning assay and a more complex reversal learning assay, and we also measured anxiety and brain mass. Performance in the associative learning task was negatively correlated with performance in the reversal learning task, suggesting a potential tradeoff. No differences were observed between captive and wild fish in associative learning performance, anxiety, or brain mass, but wild fish were three times more likely to complete the more complex reversal learning task. Aversive reversal learning, which appears to be dampened in captive fathead minnow, may be particularly relevant for appropriate antipredator responses and fitness in challenging or fluctuating environments. We advocate for further research comparing wild and captive animal cognition and urge researchers to exercise caution when generalizing results from captive animals to wild populations.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105322"},"PeriodicalIF":1.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145761982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.beproc.2025.105321
Fionnghuala L.J. James , Sayed K. Ahamed , Cheng Yang , Jigme Thinley , Carmelo M. Vicario , Juan J. Canales , Sukhwinder S. Sohal , Richard Wilson , Luke R. Johnson , Vanni Caruso
The processes of memory consolidation and reconsolidation are important in understanding the dynamics of memory storage and modification. Models to condition aversive memory have been characterised in rodents yet have been less explored in invertebrates such as planaria. Planaria are a potentially important animal model for the study of threat learning and memory as they can learn conditioned responses and may show conserved neural mechanisms underpinning these responses compared to mammals. However, no model for the study of memory in classical threat conditioning exists for planaria. The aim of this study is to replicate a standardised cued threat conditioning model for memory acquisition and reconsolidation in mice, in brown planaria (Girardia dorotocephala), using shock as the unconditioned stimulus (US) and light as the conditioned stimulus (CS). Defensive behaviours (C-shaped movements and scrunching) were assessed to evaluate learning. Planaria underwent memory acquisition training for a total of 18 learning trials. In the consolidation model, memory retention was tested 24 h after the final training session with a CS exposure. In the reconsolidation model, memory stability was assessed using a recall test 24 h after a reactivation session. In both tests, the paired shock-light group exhibited a significant increase in defensive behaviours, compared to all control groups, suggesting that the pairing of both shock and light was essential for forming a lasting memory. Furthermore, planaria exhibited a gradual extinction of defensive responses to the CS. These findings highlight the utility of planaria for studying associative learning and memory, including memory reconsolidation.
{"title":"Adapting rodent cued threat conditioning to planarians: Memory acquisition, consolidation, and reconsolidation","authors":"Fionnghuala L.J. James , Sayed K. Ahamed , Cheng Yang , Jigme Thinley , Carmelo M. Vicario , Juan J. Canales , Sukhwinder S. Sohal , Richard Wilson , Luke R. Johnson , Vanni Caruso","doi":"10.1016/j.beproc.2025.105321","DOIUrl":"10.1016/j.beproc.2025.105321","url":null,"abstract":"<div><div>The processes of memory consolidation and reconsolidation are important in understanding the dynamics of memory storage and modification. Models to condition aversive memory have been characterised in rodents yet have been less explored in invertebrates such as planaria. Planaria are a potentially important animal model for the study of threat learning and memory as they can learn conditioned responses and may show conserved neural mechanisms underpinning these responses compared to mammals. However, no model for the study of memory in classical threat conditioning exists for planaria. The aim of this study is to replicate a standardised cued threat conditioning model for memory acquisition and reconsolidation in mice, in brown planaria (<em>Girardia dorotocephala</em>), using shock as the unconditioned stimulus (US) and light as the conditioned stimulus (CS). Defensive behaviours (C-shaped movements and scrunching) were assessed to evaluate learning. Planaria underwent memory acquisition training for a total of 18 learning trials. In the consolidation model, memory retention was tested 24 h after the final training session with a CS exposure. In the reconsolidation model, memory stability was assessed using a recall test 24 h after a reactivation session. In both tests, the paired shock-light group exhibited a significant increase in defensive behaviours, compared to all control groups, suggesting that the pairing of both shock and light was essential for forming a lasting memory. Furthermore, planaria exhibited a gradual extinction of defensive responses to the CS. These findings highlight the utility of planaria for studying associative learning and memory, including memory reconsolidation.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"235 ","pages":"Article 105321"},"PeriodicalIF":1.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145751461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.beproc.2025.105320
Marilia Pinheiro de Carvalho , Ana Paula Rocha , Soraya Tavares , Armando Machado , Marco Vasconcelos
Given a choice between a simple option offering a preferred-food item (e.g., a grape, G) and a combo option offering the same preferred-food item plus a less-preferred food item (e.g., a grape + a slice of cucumber, GC), animals often behave suboptimally by either being indifferent between the two options or by preferring the simple option—the “less-is-better” effect. To explain indifference, the selective-value hypothesis assumes that, in the choice context, the subjective value (V) of the less-preferred food is zero (i.e., VGC = VG + 0 = VG). To explain the less-is-better effect, the average-quality hypothesis assumes that the value of the combo equals the average of its components’ values [i.e., VGC = Average(VG,VC) < VG]. No unified account explains both sets of experimental findings. To test these hypotheses further, we presented six capuchin monkeys (Sapajus sp.) with a variety of choice tests, some simple (GC vs. G) and some complex (2G1C vs. 3G1C; or 2C1G vs. 3C1G), with a final sample of four individuals per test. The results confirm that capuchin monkeys also behave suboptimally, revealing either indifference or the less-is-better effect. Crucially, our findings suggest that the value of the less-preferred food, C, may become negative through a contrast-like effect. By expanding the selective-value hypothesis to accommodate situations where the less-preferred item’s value may be reduced to zero or become negative, we suggest a unified, process-based account of the two sets of research findings.
如果让动物在提供偏好食物的简单选项（如葡萄，G）和提供相同偏好食物加上不太偏好食物的组合选项（如葡萄+一片黄瓜，GC）之间做出选择，它们的行为通常不是最优的，要么对这两种选项漠不关心，要么更喜欢简单的选项——即“越少越好”的效果。为了解释无差异，选择价值假设假设，在选择情境中，不太受欢迎的食物的主观价值(V)为零（即VGC = VG + 0 = VG）。为了解释“越少越好”的效应，平均质量假设假设组合的值等于其组成部分值的平均值[即VGC = average (VG，VC) < VG]。没有统一的解释可以解释这两组实验结果。为了进一步验证这些假设，我们对6只卷尾猴（Sapajus sp.）进行了各种选择测试，有些是简单的（GC vs. G），有些是复杂的（2G1C vs. 3G1C；或2C1G vs. 3C1G），每次测试的最终样本为4个人。结果证实，卷尾猴的行为也不是最优的，要么表现出冷漠，要么表现出越少越好的效果。至关重要的是，我们的研究结果表明，不太受欢迎的食物C的价值可能会通过一种类似对比的效应变成负值。通过扩展选择价值假设，以适应不太受欢迎的项目的价值可能减少到零或变为负值的情况，我们建议对两组研究结果进行统一的，基于过程的说明。
{"title":"The ‘less-is-better’ effect in capuchin monkeys (Sapajus sp.): Some data and a contrast-like hypothesis","authors":"Marilia Pinheiro de Carvalho , Ana Paula Rocha , Soraya Tavares , Armando Machado , Marco Vasconcelos","doi":"10.1016/j.beproc.2025.105320","DOIUrl":"10.1016/j.beproc.2025.105320","url":null,"abstract":"<div><div>Given a choice between a simple option offering a preferred-food item (e.g., a grape, G) and a combo option offering the same preferred-food item <em>plus</em> a less-preferred food item (e.g., a grape + a slice of cucumber, GC), animals often behave suboptimally by either being indifferent between the two options or by preferring the simple option—the “less-is-better” effect. To explain indifference, the selective-value hypothesis assumes that, in the choice context, the subjective value (V) of the less-preferred food is zero (i.e., V<sub>GC</sub> = V<sub>G</sub> + 0 = V<sub>G</sub>). To explain the less-is-better effect, the average-quality hypothesis assumes that the value of the combo equals the average of its components’ values [i.e., V<sub>GC</sub> = Average(V<sub>G</sub>,V<sub>C</sub>) < V<sub>G</sub>]. No unified account explains both sets of experimental findings. To test these hypotheses further, we presented six capuchin monkeys (<em>Sapajus</em> sp.) with a variety of choice tests, some simple (GC vs. G) and some complex (2G1C vs. 3G1C; or 2C1G vs. 3C1G), with a final sample of four individuals per test. The results confirm that capuchin monkeys also behave suboptimally, revealing either indifference or the less-is-better effect. Crucially, our findings suggest that the value of the less-preferred food, C, may become negative through a contrast-like effect. By expanding the selective-value hypothesis to accommodate situations where the less-preferred item’s value may be reduced to zero or become negative, we suggest a unified, process-based account of the two sets of research findings.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"234 ","pages":"Article 105320"},"PeriodicalIF":1.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145699622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.beproc.2025.105312
Sergei A. Fedotov , Anna A. Goncharova , Natalia G. Besedina , Larisa V. Danilenkova , Elena A. Kamysheva , Ulyana N. Solodukhina , Aleksandr A. Rubel , Julia V. Bragina
The courtship ritual of Drosophila males toward females has been extensively studied to elucidate the mechanisms of behavioral plasticity in insects. Courtship is an innate, fixed sequence of behaviors that results in mating. The implementation of this instinct involves adjusting specific parameters of the courtship behaviors, such as sound production, to increase the likelihood of successful copulation. Moreover, courtship can be temporarily suppressed following an unsuccessful attempt with a previously mated female. While the neural mechanisms underlying courtship learning are well described, the interaction between male behavioral sequencing and known female-derived determinants of suppression (e.g., cVA from mated females and active rejection behaviors) remains unclear. In our study, we characterized the structure of male courtship towards virgin, mated, and immature females. We found that changes in the frequencies of transitions between courtship behaviors provide adaptive restructuring in the implementation of this ritual. Courtship towards mated females causes males to reinitiate the ritual more frequently, and we hypothesize that repeated unsuccessful initiations may ultimately result in courtship suppression. When courting immature females, males neither attempt copulation nor restart the ritual, which may explain the absence of courtship suppression with this type of female and raises the question of the evolutionary significance of courtship towards immature females.
{"title":"The structure of courtship behavior in Drosophila males: Boundaries of plasticity","authors":"Sergei A. Fedotov , Anna A. Goncharova , Natalia G. Besedina , Larisa V. Danilenkova , Elena A. Kamysheva , Ulyana N. Solodukhina , Aleksandr A. Rubel , Julia V. Bragina","doi":"10.1016/j.beproc.2025.105312","DOIUrl":"10.1016/j.beproc.2025.105312","url":null,"abstract":"<div><div>The courtship ritual of Drosophila males toward females has been extensively studied to elucidate the mechanisms of behavioral plasticity in insects. Courtship is an innate, fixed sequence of behaviors that results in mating. The implementation of this instinct involves adjusting specific parameters of the courtship behaviors, such as sound production, to increase the likelihood of successful copulation. Moreover, courtship can be temporarily suppressed following an unsuccessful attempt with a previously mated female. While the neural mechanisms underlying courtship learning are well described, the interaction between male behavioral sequencing and known female-derived determinants of suppression (e.g., cVA from mated females and active rejection behaviors) remains unclear. In our study, we characterized the structure of male courtship towards virgin, mated, and immature females. We found that changes in the frequencies of transitions between courtship behaviors provide adaptive restructuring in the implementation of this ritual. Courtship towards mated females causes males to reinitiate the ritual more frequently, and we hypothesize that repeated unsuccessful initiations may ultimately result in courtship suppression. When courting immature females, males neither attempt copulation nor restart the ritual, which may explain the absence of courtship suppression with this type of female and raises the question of the evolutionary significance of courtship towards immature females.</div></div>","PeriodicalId":8746,"journal":{"name":"Behavioural Processes","volume":"234 ","pages":"Article 105312"},"PeriodicalIF":1.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145653330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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