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Papers by Ilton Santos da Silva

Revista da Biologia, 2009

Hormones and Behavior, 2014

In previous laboratory investigations, we have identified enhanced cognition and reduced stress i... more In previous laboratory investigations, we have identified enhanced cognition and reduced stress in parous rats, which are likely adaptations in mothers needing to efficiently exploit resources to maintain, protect and provision their immature offspring. Here, in a series of seven behavioral tests on rats, we examined a natural interface between cognition and resource gathering: predation. Experiment 1 compared predatory behavior (toward crickets) in age-matched nulliparous mothers (NULLs) and postpartum lactating mothers (LACTs), revealing a highly significant enhancement of predation in LACT females (mean = -65s in LACTs, vs. -270s in NULLs). Experiment 2 examined the possibility that LACTs, given their increased metabolic rate, were hungrier, and thus more motivated to hunt; doubling the length of time of food deprivation in NULLs did not decrease their predatory latencies. Experiments 3-5, which examined sensory regulation of the effect, indicated that olfaction (anosmia), audition (blockade with white noise), and somatosensation (trimming the vibrissae) appear to play little role in the behavioral enhancement observed in the LACTs; Experiment 6 examined the possibility that visual augmentations may facilitate the improvements in predation; testing LACTs in a 0-lux environment eliminated the behavioral advantage (increasing their latencies from -65s to -212s), which suggests that temporary augmentation to the visual system may be important, and with hormone-neural alterations therein a likely candidate for further study. In contrast, testing NULLS in the 0-lux environment had the opposite effect, reducing their latency to catch the cricket (from -270s to -200s). Finally, Experiment 7 examined the development of predatory behavior in Early-pregnant (PREG), Mid-PREG, and Late-PREG females. Here, we observed a significant enhancement of predation in Mid-PREG and Late-PREG females--at a time when maternity-associated bodily changes would be expected to diminish predation ability--relative to NULLs. Therefore, as with the increasing reports of enhancements to the maternal brain, it is apparent that meaningful behavioral adaptations occur that likewise promote the survival of the mother and her infants at a crucial stage of their lives.

Estudos de Biologia, 2012

Journal of Women's Health, 2012

Journal of Pharmacological and Toxicological Methods, 2012

Introduction: Numerous studies employing various animal models have found that perinatal stress, ... more Introduction: Numerous studies employing various animal models have found that perinatal stress, encountered in utero during sensitive developmental stages or shortly after birth, disrupts both sexual differentiation and sexual behavior in offspring. The biochemical, cellular, genetic and epigenetic events which are involved in the organismal response to perinatal stress are currently under investigation. Methods, Results and Discussion: In this review, the reader is introduced to perinatal stressors as a toxicological phenomenon, and several recently characterized epigenetic responses to said stressors are discussed.

The study of malacological fauna in hydric bodies is crucial to maintain the biodiversity in an e... more The study of malacological fauna in hydric bodies is crucial to maintain the biodiversity in an environmental conservation area, since these organisms can interfere with water quality being potentially used as a bioindicator of environmental quality. This study aimed at identifying the diversity and population density of both native and invasive freshwater bivalves occurring in the APA of Verde River. Two sample collections were undertaken between July 2012 and March 2013. Three sampling sites (1 m 2 each) were delimited by using a PVC square in the riverbed, with a 50 m interval among them; after this procedure, the sediment contained in the sampling area was manually removed from a 10 cm depth. Then, the screening of live organisms and articulated valves was performed. The occurrence of native bivalves species was recorded as Anodontites tenebricosus, Diplodon parodizi, and the invasive mussel Corbicula fluminea. The higher population density was registered in March 2013 with 915 individuals (A. tenebricosus 4.66 ind/m 2 , D. granosus 1.0 ind/m 2 , C. fluminea 265.6 ind/m 2). The record of invasive species and the distribution of frequency analysis by length class frequency require continuous studies about the invasive species occurrence in the hydrographic basin of Verde River, because its spreading is closely related to the decline of the native bivalves population. Resumo. Avaliação da densidade de bivalves límnicos da Área de Proteção Ambiental (APA) do rio Verde, Campo magro, Paraná, Brasil. O estudo da fauna malacológica de corpos hídricos é fundamental para o conhecimento da diversidade de uma Unidade de Conservação. O objetivo do presente estudo foi identificar a diversidade de bivalves e a variação da densidade populacional de bivalves límnicos nativos e invasores com ocorrência na APA do Rio Verde. Em duas campanhas amostrais realizadas entre julho de 2012 e março de 2013, foram demarcados três pontos amostrais de 1m 2 utilizando-se quadrado de PVC disposto no leito do rio, em intervalos de 50 m. O sedimento contido na área demarcada foi removido, até uma profundidade de 10 cm e realizada triagem de organismos vivos e valvas articuladas. Foi registrada a ocorrência dos bivalves nativos Anodontites tenebricosus e Diplodon parodizi e do bivalve invasor Corbicula fluminea. Foram coletados 915 indivíduos vivos com a maior densidade registrada para março de 2013 (A. tenebricosus 4.66 ind./m 2 , D. parodizi 1.0 ind./m 2 e C. fluminea 265.6 ind./m 2). Os resultados obtidos demonstram que a espécie invasora é predominante na área de estudo e sua densidade populacional crescente pode determinar o declínio das populações de bivalves nativos.

Revista da Biologia, 2009

Hormones and Behavior, 2014

In previous laboratory investigations, we have identified enhanced cognition and reduced stress i... more In previous laboratory investigations, we have identified enhanced cognition and reduced stress in parous rats, which are likely adaptations in mothers needing to efficiently exploit resources to maintain, protect and provision their immature offspring. Here, in a series of seven behavioral tests on rats, we examined a natural interface between cognition and resource gathering: predation. Experiment 1 compared predatory behavior (toward crickets) in age-matched nulliparous mothers (NULLs) and postpartum lactating mothers (LACTs), revealing a highly significant enhancement of predation in LACT females (mean = -65s in LACTs, vs. -270s in NULLs). Experiment 2 examined the possibility that LACTs, given their increased metabolic rate, were hungrier, and thus more motivated to hunt; doubling the length of time of food deprivation in NULLs did not decrease their predatory latencies. Experiments 3-5, which examined sensory regulation of the effect, indicated that olfaction (anosmia), audition (blockade with white noise), and somatosensation (trimming the vibrissae) appear to play little role in the behavioral enhancement observed in the LACTs; Experiment 6 examined the possibility that visual augmentations may facilitate the improvements in predation; testing LACTs in a 0-lux environment eliminated the behavioral advantage (increasing their latencies from -65s to -212s), which suggests that temporary augmentation to the visual system may be important, and with hormone-neural alterations therein a likely candidate for further study. In contrast, testing NULLS in the 0-lux environment had the opposite effect, reducing their latency to catch the cricket (from -270s to -200s). Finally, Experiment 7 examined the development of predatory behavior in Early-pregnant (PREG), Mid-PREG, and Late-PREG females. Here, we observed a significant enhancement of predation in Mid-PREG and Late-PREG females--at a time when maternity-associated bodily changes would be expected to diminish predation ability--relative to NULLs. Therefore, as with the increasing reports of enhancements to the maternal brain, it is apparent that meaningful behavioral adaptations occur that likewise promote the survival of the mother and her infants at a crucial stage of their lives.

Estudos de Biologia, 2012

Journal of Women's Health, 2012

Journal of Pharmacological and Toxicological Methods, 2012

Introduction: Numerous studies employing various animal models have found that perinatal stress, ... more Introduction: Numerous studies employing various animal models have found that perinatal stress, encountered in utero during sensitive developmental stages or shortly after birth, disrupts both sexual differentiation and sexual behavior in offspring. The biochemical, cellular, genetic and epigenetic events which are involved in the organismal response to perinatal stress are currently under investigation. Methods, Results and Discussion: In this review, the reader is introduced to perinatal stressors as a toxicological phenomenon, and several recently characterized epigenetic responses to said stressors are discussed.

The study of malacological fauna in hydric bodies is crucial to maintain the biodiversity in an e... more The study of malacological fauna in hydric bodies is crucial to maintain the biodiversity in an environmental conservation area, since these organisms can interfere with water quality being potentially used as a bioindicator of environmental quality. This study aimed at identifying the diversity and population density of both native and invasive freshwater bivalves occurring in the APA of Verde River. Two sample collections were undertaken between July 2012 and March 2013. Three sampling sites (1 m 2 each) were delimited by using a PVC square in the riverbed, with a 50 m interval among them; after this procedure, the sediment contained in the sampling area was manually removed from a 10 cm depth. Then, the screening of live organisms and articulated valves was performed. The occurrence of native bivalves species was recorded as Anodontites tenebricosus, Diplodon parodizi, and the invasive mussel Corbicula fluminea. The higher population density was registered in March 2013 with 915 individuals (A. tenebricosus 4.66 ind/m 2 , D. granosus 1.0 ind/m 2 , C. fluminea 265.6 ind/m 2). The record of invasive species and the distribution of frequency analysis by length class frequency require continuous studies about the invasive species occurrence in the hydrographic basin of Verde River, because its spreading is closely related to the decline of the native bivalves population. Resumo. Avaliação da densidade de bivalves límnicos da Área de Proteção Ambiental (APA) do rio Verde, Campo magro, Paraná, Brasil. O estudo da fauna malacológica de corpos hídricos é fundamental para o conhecimento da diversidade de uma Unidade de Conservação. O objetivo do presente estudo foi identificar a diversidade de bivalves e a variação da densidade populacional de bivalves límnicos nativos e invasores com ocorrência na APA do Rio Verde. Em duas campanhas amostrais realizadas entre julho de 2012 e março de 2013, foram demarcados três pontos amostrais de 1m 2 utilizando-se quadrado de PVC disposto no leito do rio, em intervalos de 50 m. O sedimento contido na área demarcada foi removido, até uma profundidade de 10 cm e realizada triagem de organismos vivos e valvas articuladas. Foi registrada a ocorrência dos bivalves nativos Anodontites tenebricosus e Diplodon parodizi e do bivalve invasor Corbicula fluminea. Foram coletados 915 indivíduos vivos com a maior densidade registrada para março de 2013 (A. tenebricosus 4.66 ind./m 2 , D. parodizi 1.0 ind./m 2 e C. fluminea 265.6 ind./m 2). Os resultados obtidos demonstram que a espécie invasora é predominante na área de estudo e sua densidade populacional crescente pode determinar o declínio das populações de bivalves nativos.