Locating Nesting Sites for Critically Endangered Galápagos Pink Land Iguanas (Conolophus marthae).

Invasive alien species control is recognized worldwide as a priority action to preserve global biodiversity. However, a lack of general life history knowledge for threatened species can impede the effectiveness of conservation actions. Galápagos pink land iguanas (Conolophus marthae) are endemic to Wolf Volcano, Galápagos, Ecuador. These iguanas are threatened by invasive alien species, particularly feral cats, that may affect their small population size. To guarantee the long-term survival of C. marthae, the Galápagos National Park Directorate is considering, along with an ongoing campaign of feral cat control, the implementation of a head-start program. However, the success of this management strategy necessarily relies on the identification of pink iguana nesting grounds, which were still unknown at the onset of this study. We modeled the movement patterns of male and female iguanas during the reproductive season, using location data collected from custom-made remote tracking devices installed on adult pink iguanas in April 2021. We first calculated for each individual the vector of distances from its starting location, which was defined as net displacement. We then used net displacement as the response variable in a generalized additive mixed model with day of the year as the predictor. Based on the hypothesis that males and females may behaviorally differ after mating, we looked for female-specific migratory behavior suggesting females were moving toward nesting areas. The results obtained confirmed our hypothesis, as females exhibited a distinct migratory behavior, reaching a small plateau area inside of Wolf Volcano's caldera and ca. 400 m below the volcano's northern rim. Moreover, once inside the caldera, females displayed a more aggregated distribution pattern. The movement data obtained allowed Galápagos National Park rangers to locate individual pink iguana nests and subsequently to sight and collect the first observed hatchlings of the species. This work constitutes a necessary baseline to perform dedicated studies of pink iguana nests and emerging hatchling iguanas, which is an essential step toward the development of an effective head-start program.

Do birds select the plastics debris used for nest construction? A case study in a Mediterranean agricultural landscape.

Plastic pollution is becoming a global problem due to its ubiquitous occurrence and the impacts detected for many species. However, the research about plastics in nests of terrestrial bird species has remained relatively overlooked in comparison to those devoted to marine ecosystems. Here we study the occurrence and patterns of use of anthropogenic material in nests of two passerine birds, the Eurasian magpie (Pica pica) and the European serin (Serinus serinus), breeding in an orange tree cultivation in Mediterranean Spain. Our results show that both species use extensively plastic debris as nest material; almost 71% of the European serin nests and 96% of nests of Eurasian magpies contained plastic debris. Furthermore, by analyzing the plastic debris availability in the agricultural landscape surveyed we confirmed a selection pattern in the two species. Thus, both species preferably select plastic filaments over other plastic debris. The Eurasian magpie does not select plastic based on size or color but the European serin avoid black plastics prefer smaller fragments in comparison to the average size available. Moreover, we suggest the apparent similarity of plastic filaments with the natural materials typically used by these species, as well as how they use the plastic in their nests could influence their selection behavior. More studies focused on terrestrial birds inhabiting human modified habitats could offer a deeper approach to how plastic debris interacts with wildlife in different ways.

Dynamic shoreline alterations and their impacts on Olive Ridley Turtle (Lepidochelys olivacea) nesting sites in Gahirmatha Marine Wildlife Sanctuary, Odisha (India).

Currently, sea turtle habitats are being altered by climate change and human activities, with habitat loss posing an urgent threat to Indian sea turtles. Thus, the objective of this study is to analyze the dynamic shoreline alterations and their impacts on Olive Ridley Sea Turtle (ORT) nesting sites in Gahirmatha Marine Wildlife Sanctuary from 1990 to 2022. Landsat satellite images served as input datasets to assess dynamic shoreline changes. This study assessed shoreline alterations and their rates across 929 transects divided into four zones using the Digital Shoreline Analysis System (DSAS) software. The results revealed a significant 14-km northward shift in the nesting site due to substantial coastal erosion, threatening the turtles' Arribada. This study underscores the need for conservation efforts to preserve nesting environments amidst changing coastal landscapes, offering novel insights into the interaction between coastal processes and marine turtle nesting behaviors.

Olfaction is essential for nest recognition in solitary Hymenoptera.

Flying insects are believed to rely primarily on visual cues for orientation, with chemical cues often being overlooked. In the case of solitary bees and wasps, being able to return successfully to their nests and provision their brood cells is paramount for the survival of the species. While vision has been shown to be involved in pinpointing the nest location, our results confirm that olfaction is important in nest recognition. The large diversity in nesting strategies observed among solitary Hymenoptera makes them an excellent model to comparatively study the use of olfactory cues from the nesting individual for nest recognition. We have analyzed the chemical profiles of three nesting bees (Osmia spp.) and one wasp (Sceliphron curvatum) and that of their nest entrances. A striking match in the identified chemicals was revealed between each nest and its occupant. When the chemicals were removed from the nest, a clear behavioral response could be observed for Osmia cornuta. This shows the importance of olfactory cues in complementing visual orientation for precise homing in a solitary species, thereby opening up various promising biological questions in the fields of sensory perception and complementation, or the trade-offs of nest aggregation and associated costs.

DNA Aß42 immunization via needle-less Jet injection in mice and rabbits as potential immunotherapy for Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of dementia found in the elderly and disease progression is associated with accumulation of Amyloid beta 1-42 (Aß42) in brain. An immune-mediated approach as a preventive intervention to reduce amyloid plaques without causing brain inflammation is highly desirable for future clinical use. Genetic immunization, in which the immunizing agent is DNA encoding Aß42, has great potential because the immune response to DNA delivered into the skin is generally non-inflammatory, and thus differs quantitatively and qualitatively from immune responses elicited by peptides, which are inflammatory with production of IFNγ and IL-17 cytokines by activated T cells. DNA immunization has historically been proven difficult to apply to larger mammals. A potential barrier to use DNA immunization in large mammals is the method for delivery of the DNA antigen. We tested jet injection in mice and rabbits and found good antibody production and safe immune responses (no inflammatory cytokines). We found significant reduction of amyloid plaques and Aß peptides in brains of the DNA Aß42 immunized 3xTg-AD mouse model. This study was designed to optimize DNA delivery for possible testing of the DNA Aß42 vaccine for AD prevention in a clinical trial.

Nesting Biology of the Potter Wasp Ancistrocerus flavomarginatus (Hymenoptera, Vespidae, Eumeninae) Revealed by Trap-Nest Experiments in Southern Brazil.

This paper provides the first description of the nesting biology of Ancistrocerus flavomarginatus (Brèthes) (Hymenoptera, Vespidae, Eumeninae), the only species of the genus found in Brazil. Our trap-nest experiments were conducted in two Mixed Ombrophilous Forest fragments and two adjacent matrices in Guarapuava (Paraná state, Brazil) from August 2017 to July 2018. In each area, we set 192 trap nests divided into six groups of 32 units, totalling 768 trap nests. We obtained a total of 47 nests of A. flavomarginatus, the vast majority of them (43, 91.5%) founded in the forest fragments. Most nests were built in wooden traps with a bore diameter of either 5 or 7 mm (19 nests in each type, 80.8%). Nests comprised 1-12 subcylindrical brood cells arranged linearly and separated from one another by transverse partitions of soil mastic. Larvae consumed 6-10 lepidopteran caterpillars before spinning the cocoon. Ancistrocerus flavomarginatus produced up to 6 annual generations (multivoltinism) and its immature forms were parasitized by chrysidid and ichneumonid wasps. The calculated sex ratio (1.78:1) was statistically biased towards males, but since they (21.3 ± 2.0 mg) were significantly lighter than females (50.9 ± 4.0 mg), the resulting investment ratio (1.34:1) was female biased. Males emerged from more external cells and developed significantly faster (27.2 ± 0.46 days) than females (30.1 ± 0.66 days), hence a case of protandry. We demonstrated that A. flavomarginatus is largely dependent on the Atlantic Rainforest and thus that deforestation poses a critical threat to this important species.

Embryo, Relocation and Secondary Nests of the Invasive Species Vespa velutina in Galicia (NW Spain).

Invasive species become established in non-native areas due to their intrinsic characteristics and the ability to adapt to new environments. This work describes the characteristics of the nesting behavior of the invasive yellow-legged hornet (Vespa velutina nigrithorax) in Galicia (Northwest Spain). The first nest was detected in the area in 2012 and after that, the distribution pattern shows a species-invasion curve with slow progress at first but followed by rapid expansion. The nesting places for this hornet differ between the kinds of nests, while embryo nests are mainly found in buildings in spring, secondary nests are observed in vegetation in summer, autumn, and winter. The annual life cycle starts when the queen builds the embryo nests and starts to lay eggs. This leads to the emergence of the first workers, usually small in size, and sometimes a few males. After this stage, large nests called secondary nests are normally observed in most exposed sites. Relocation nests can also be observed; these are nests in the first stage of development presenting adults insects but without brood or meconium. The period of decline is characterized by the emergence of new queens and males, that are distinguishable even in the pupal stage, the appearance of two eggs per cell, and an irregular brood pattern.

Natural nest substrates influence squamate embryo physiology but have little effect on hatchling phenotypes.

Vertebrate embryos require access to water; however, many species nest in terrestrial habitats that vary considerably in moisture content. Oviparous, non-avian reptiles have served as models to understand how environmental factors, like moisture availability, influence development because eggs are often exposed to prevailing environments in the absence of parental care. Though much research demonstrates the importance of water absorption by eggs, many ecological factors that influence moisture availability in natural nests have received little attention. For example, the type of substrate in which nests are constructed is understudied. We experimentally incubated eggs of the brown anole lizard (Anolis sagrei) in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations. One substrate consisted of sand and crushed seashells and the other was mostly organic material (i.e. decayed plant material). Both are common nesting substrates at our field site. When controlling for water uptake by eggs, we found that egg survival and hatchling phenotypes were similar between substrates; however, embryos developed more quickly in the sand/shell substrate than the organic substrate, indicating substrate-specific effects on embryo physiology. These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable; however, some aspects of development, like developmental rate, are affected by the type of substrate, independent of water availability. Further study is required to determine how natural substrates influence embryo physiology independent of water content.

Environmental and anthropogenic effects on the nesting patterns of Nigeria-Cameroon chimpanzees in North-West Cameroon.

Environmental conditions and human activity influence the selection of nest sites by chimpanzees and may have serious conservation implications. We examined the characteristics of nesting trees preferred by chimpanzees, investigated the effect of vegetation composition and topography on nest site locations and seasonality on nesting heights of chimpanzees, and verified the effect of predator occurrence and human activity on the nesting behavior of the Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti) in Kom-Wum Forest Reserve (KWFR) and surrounding unprotected forest in Cameroon. We recorded 923 nests, 502 signs of human activity, and 646 nesting trees along line transects and recces (reconnaissance) for two seasons. We found that chimpanzees constructed more arboreal nests on tall primary trees with high lowest branch height and large diameter at breast height. Moreover, they oriented their nests within trees in the slope direction when the nesting trees were located on slopes. Additionally, the occurrence of chimpanzee nests was positively related to increasing elevation and slope and decreased with distance to primary forest. In contrast, the number of nests increased with distance to secondary forest, open land, and villages, and nesting height was not influenced by seasons. While we recorded no signs of large nocturnal chimpanzee predators at nesting trees, we found signs of hunting activity at nesting locations. Nesting high in trees is likely a way of avoiding hunting, while nest orientation within trees in slope direction shortens escape routes from human hunters. Our findings suggest that chimpanzees select safe trees (tall trees with high lowest branch height) located in nesting areas (primary forest, high elevation, and steep slopes) that are not easily accessible by humans. Therefore, conservation efforts should focus on protecting primary forests at high elevation and steep slopes and reducing human impact.

Nesting, Sex Ratio and Natural Enemies of the Giant Resin Bee in Relation to Native Species in Europe.

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with local wild bees, we set up trap nests for above-ground nesting bees on a semi-urban area of north-western Italy. We aimed to investigate the interaction in artificial traps between the exotic and native wild bees and to assess offspring traits accounting for exotic bee fitness: progeny sex ratio and incidence of natural enemies. We found that the tunnels occupied by exotic bees were already cohabited by O. cornuta, and thus the cells of later nesting alien bees may block the native bee emergence for the next year. The progeny sex ratio of M. sculpturalis was strongly unbalanced toward males, indicating a temporary adverse population trend in the local invaded area. In addition, we documented the presence of three native natural enemies affecting the brood of the exotic bee. Our results bring out new insights on how the M. sculpturalis indirectly competes with native species and on its performance in new locations.

Presence of Pathogen-killed Larvae Influences Nesting Behavior of the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae).

The alfalfa leafcutting bee (Megachile rotundata (Fabricius)), a commercial pollinator used for alfalfa seed production, is susceptible to chalkbrood disease via ingested fungal spores. Diseases of insects can elicit behavioral changes in their hosts, but there are no recorded behaviors of alfalfa leafcutting bees in response to this fungal exposure. We conducted field studies to determine whether bees in pathogen-dense environments altered their nesting patterns, specifically if bees exposed to fungal spores produced higher numbers of nest cells and whether the proportions of nest cells that failed as eggs or small larvae (a state known as 'pollen ball') were greater. We found that our control bees, nontreated bees which were not exposed to chalkbrood spores other than those in the natural environment, had the highest proportion of pollen ball cells. Bees experimentally exposed to infective spores created the lowest number of nests and the fewest cells. Bees experimentally exposed to heat killed noninfective spores produced the greatest number of nests and cells overall and the greatest number of healthy progeny. We conclude that there are underlying behaviors that are elicited in response to the presence of chalkbrood spores that reduce the proportion of failed nest cells (grooming) and increase retention of bees at nesting sites (delay of bee emergence). Through further study of these behaviors, bee managers can potentially increase the productivity of their bee populations.

Assessment of nest building and social interaction behavior in mice exposed to acute social defeat stress using a three-dimensional depth camera.

Nest building is an instinctive behavior toward protection from predators, body temperature regulation, and courtship. Previously, we discovered that acute and chronic social defeat stress suppresses the onset of nest-building behavior in male mice (C57BL/6J). Here, we analyzed nest building and other behavioral deficits induced by acute social defeat stress (ASDS). We utilized a customized cage and specifically developed observational programs for nest building, social avoidance, and other behaviors using an infrared depth camera to acquire three-dimensional (3D) data of animal behavior (Negura system). We determined the volume of nesting materials from these 3D depth images. Mice exposed to ASDS showed increased spontaneous activities, decreased rearing, and delayed nest building; however, nest-building activity was gradually recovered during the dark period of the 24 hr observation interval. At the endpoint following 24 hr, the ASDS and control groups showed no differences in nest volumes. Furthermore, we observed the time courses of both nest building and social avoidance behaviors and their relationship using the Negura system. Our data demonstrated a weak positive correlation between nest-building delay and social avoidance in ASDS mice. The Negura system can observe various behaviors that reflect the effects of social defeat stress.

Microclimate Temperatures Impact Nesting Preference in Megachile rotundata (Hymenoptera: Megachilidae).

The temperature of the nest influences fitness in cavity-nesting bees. Females may choose nest cavities that mitigate their offspring's exposure to stressful temperatures. This study aims to understand how cavity temperature impacts the nesting preference of the solitary bee Megachile rotundata (Fabricius) under field conditions. We designed and 3D printed nest boxes that measured the temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, northwest, southeast, and southwest. Nest boxes were placed along an alfalfa field in Fargo, ND and were observed daily for completed nests. Our study found that cavity temperature varied by direction the cavity faced and by the position of the cavity within the nest box. The southwest sides recorded the highest maximum temperatures while the northeast sides recorded the lowest maximum temperatures. Nesting females filled cavities on the north-facing sides faster than cavities on the south-facing sides. The bees preferred to nest in cavities with lower average temperatures during foraging hours, and cavities that faced to the north. The direction the cavity faced was associated with the number of offspring per nest. The southwest-facing cavities had fewer offspring than nests on the northeast side. Our study indicates that the nesting box acts as a microclimate, with temperature varying by position and direction of the cavity. Variation in cavity temperature affected where females chose to nest, but not their reproductive investment.

Enhanced Expression of Secreted α-Klotho in the Hippocampus Alters Nesting Behavior and Memory Formation in Mice.

The klotho gene family consists of α-, ß-, and γ-Klotho, which encode type I single-pass transmembrane proteins with large extracellular domains. α-Klotho exists as a full-length membrane-bound and as a soluble form after cleavage of the extracellular domain. Due to gene splicing, a short extracellular Klotho form can be expressed and secreted. Inactivation of α-Klotho leads to a phenotype that resembles accelerated aging, as the expression level of the α-Klotho protein in the hippocampal formation of mice decreases with age. Here, we show that intrahippocampal viral expression of secreted human α-Klotho alters social behavior and memory formation. Interestingly, overexpression of secreted human α-Klotho in the CA1 changed the nest-building behavior and improved object recognition, object location and passive avoidance memory. Moreover, α-Klotho overexpression increased hippocampal synaptic transmission in response to standardized stimulation strengths, altered paired-pulse facilitation of synaptic transmission, and enhanced activity-dependent synaptic plasticity. These results indicate that memory formation benefits from an augmented level of secreted α-Klotho.

Do Covariances Between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution Under Environmental Sex Determination?

Fisherian sex-ratio theory predicts sexual species should have a balanced primary sex ratio. However, organisms with environmental sex determination (ESD) are particularly vulnerable to experiencing skewed sex ratios when environmental conditions vary. Theoretical work has modeled sex-ratio dynamics for animals with ESD with regard to 2 traits predicted to be responsive to sex-ratio selection: 1) maternal oviposition behavior and 2) sensitivity of embryonic sex determination to environmental conditions, and much research has since focused on how these traits influence offspring sex ratios. However, relatively few studies have provided estimates of univariate quantitative genetic parameters for these 2 traits, and the existence of phenotypic or genetic covariances among these traits has not been assessed. Here, we leverage studies on 3 species of reptiles (2 turtle species and a lizard) with temperature-dependent sex determination (TSD) to assess phenotypic covariances between measures of maternal oviposition behavior and thermal sensitivity of the sex-determining pathway. These studies quantified maternal behaviors that relate to nest temperature and sex ratio of offspring incubated under controlled conditions. A positive covariance between these traits would enhance the efficiency of sex-ratio selection when primary sex ratio is unbalanced. However, we detected no such covariance between measures of these categories of traits in the 3 study species. These results suggest that maternal oviposition behavior and thermal sensitivity of sex determination in embryos might evolve independently. Such information is critical to understand how animals with TSD will respond to rapidly changing environments that induce sex-ratio selection.

Differences in Pre-Laying Behavior between Floor-Laying and Nest-Laying Pekin Ducks.

Floor-laying in commercially farmed Pekin ducks is not well understood. This exploratory study aimed to determine if behavioral differences exist between floor-laying and nest-laying ducks. Retrospective analysis of video footage from a small commercial breeding flock (n = 60 birds) was used to quantify the behavior of floor-laying and nest-laying birds (n = 24 events per group) in the hour prior to oviposition site selection. The frequency, percentage of time spent, and duration of bouts were compared for nest box interactions, behaviors inside and outside of boxes and aggressive interactions. Some floor-laying birds did not enter or investigate nest boxes (FL-Out), whilst some floor-layers (FL-In) used nest boxes similarly to nest-laying birds (NL). Nest-building behavior differed only in location, with FL-Out performing the behavior on the shed floor and the other groups performing it primarily in boxes. FL-Out sat more, walked less, and engaged in less aggression (p < 0.05) than FL-In and NL. The occurrence of multiple birds in a nest box was strongly correlated with the number of aggressive interactions that occurred in the box (R = 0.81). Competition appears to contribute to floor-laying in Pekin ducks; FL-Out birds may not engage with nest boxes as a coping strategy to avoid agonistic behavior. These findings indicate that developing practical strategies to reduce nest box competition could help mitigate floor-laying. However, other factors such as nest design may also contribute to FL-Out birds' reluctance to use nest boxes and require further investigation.

Reproductive ecology of the endangered Beal's-eyed turtle, Sacalia bealei.

The Beal's-eyed turtle (Sacalia bealei) is endemic to southeastern China and endangered due to poaching and habitat loss. Knowledge of S. bealei ecology is lacking and this study provides baseline information of its reproduction in a natural environment. We studied the reproductive ecology of S. bealei using X-ray, spool-and-line tracking, and direct observation. Six nesting females were successfully tracked and their nesting behaviors are documented in detail. Females produced a mean clutch size of 2.2 eggs (range 1-3). The hard-shelled eggs were ellipsoidal with a mean length of 45.50 mm, a mean width of 23.20 mm, and mean weight of 14.8 g. The relative clutch mass was 9.47%, while the relative egg mass was 4.60%. The mean incubation period was 94.7 days with a mean nest temperature of 25.08 °C. Hatchlings had a mean weight of 9.7 g, carapace length of 40.1 mm, carapace width of 33.3 mm, carapace height of 17.4 mm, plastron length of 31.6 mm, and plastron width of 25.4 mm. The results of this study provide important information to inform conservation plans and ex-situ breeding for this endangered species.

Methylene Blue Ameliorates Olfactory Dysfunction and Motor Deficits in a Chronic MPTP/Probenecid Mouse Model of Parkinson's Disease.

Mitochondrial dysfunction and oxidative stress are very prominent and early features in Parkinson's disease (PD) and in animal models of PD. Thus, antioxidant therapy for PD has been proposed, but in clinical trials such strategies have met with very limited success. Methylene blue (MB), a small-molecule synthetic heterocyclic organic compound that acts as a renewable electron cycler in the mitochondrial electron transport chain, manifesting robust antioxidant and cell energetics-enhancing properties, has recently been shown to have significant beneficial effects in reducing nigrostriatal dopaminergic loss and motor impairment in acute toxin models of PD. However, no studies have investigated the impact of this promising agent in chronic models or for olfactory dysfunction, an early non-motor feature of PD. To test the efficacy of low-dose MB for olfactory dysfunction, motor symptoms, and dopaminergic neurodegeneration, mice were injected with ten subcutaneous doses of 25 mg/kg MPTP, plus 250 mg/kg intraperitoneal probenecid or saline/probenecid at 3.5-day intervals. Following the onset of olfactory dysfunction, MPTP/probenecid (MPTP/p) and saline/probenecid mice were provided drinking water with or without 1 mg/kg/day MB. Oral delivery of low-dose MB significantly ameliorated MPTP/p-induced deficits in motor coordination, as well as degeneration of tyrosine hydroxylase (TH)-positive neurons of the substantia nigra and TH-positive terminals in the striatum. Importantly, olfactory dysfunction was ameliorated by MB treatment, whereas this benefit is not observed with currently available anti-Parkinsonian medications. These results indicate that low-dose MB is a promising neuroprotective intervention for both motor and non-motor features of PD.

Nesting materials for does: Effect on nest building and performance at first parturition / Materiales de nido para conejas: Efecto sobre la construcción del nido y desempeño al primer parto / Materiais de ninho para coelhas: Efeito sobre a construção do ninho e desempenho na primeira parição

Abstract Background: The material placed into the nest should provide comfort to both does and their kits. Objective: To evaluate the effect of different nesting materials on rabbit doe performance and nest building. Methods: Thirty primiparous rabbit does were randomized allotted in a block design with three treatments and ten replicates each. The treatments consisted of nest bedding with wood shavings (280 g, control), Tifton hay (220 g), and thin strips of newspaper (200 g). The state of the nest was assessed to evaluate mixing of the material with doe's hair and preservation of the original material. Kit body weight, daily weight gain, and survival rate were evaluated from birth to weaning. Results: The nesting material did not affect the mixing level of material and hair, amount of hair in the nest, body weight, daily weight gain, or survival rate of rabbits from birth to 35 d of age (p>0.05). However, preservation of original material in the nest was lower when Tifton hay was used (p<0.05). Correlations between material type and total number of born alive and the amount of hair, mixture level between hair and material, and material preservation in the nest were not significant (p>0.05). No correlation (p>0.05) was observed between material preservation and hair presence or mixture level between both. Positive correlation between hair presence and mixture level (p<0.001) was observed. Conclusion: Tifton hay and cut newspaper can be used as nest bedding for pregnant does in replacement of wood shavings, with no negative effects on nest building behavior or kit performance.

Resumen Antecedentes: El material ubicado en el nido debe proporcionar confort a la coneja y a su camada. Objetivo: Evaluar el efecto de nidos forrados con diferentes materiales sobre el desempeño de la coneja y sobre la construcción del nido. Métodos: Treinta conejas primíparas fueron usadas en un diseño en bloques al azar con tres tratamientos y 10 repeticiones cada uno. Los tratamientos consistieron en forrar el nido con viruta (280 g), heno de Tifton (220 g) y periódico cortado en tiras (200 g). El estado del nido fue determinado para evaluar la mezcla del material y los vellos de la coneja, la preservación del material original, y el peso corporal, la ganancia de peso diaria y la tasa de supervivencia fueron evaluados desde el nacimiento hasta el destete. Resultados: El tipo de material no afectó el nivel de mezcla entre el material y los vellos, cantidad de vello en el nido, peso corporal, ganancia de peso diaria, o tasa de supervivencia de las crías desde el nacimiento hasta el d 35 de edad (p>0,05); sin embargo, la preservación del material original en el nido fue menor cuando el heno de Tifton fue usado (p<0,05). Las correlaciones del tipo de material y número total de nacidos vivos, y la cantidad de vello, nivel de mezcla entre vello y material, y preservación de material en el nido no fueron significativas (p>0,05). No hubo correlación (p>0,05) entre preservación del material en el nido con presencia de vello o nivel de mezcla en los nidos. Hubo una correlación positive entre la presencia de vello en el nido y el nivel de mezcla (p<0,001). Conclusión: El heno de Tifton y el periódico cortado en tiras puede ser usado como revestimiento de nidos para conejas gestantes, sustituyendo la viruta de madera sin efectos negativos sobre el comportamiento de construcción del nido de la coneja ni sobre el desempeño de las crías desde el nacimiento hasta el destete, considerando el primer parto.

Resumo Antecedentes: O material colocado no ninho deve proporcionar conforto à coelha e sua ninhada. Objetivo: Avaliar o efeito de ninhos forrados com diferentes materiais sobre o desempenho da coelha e sobre a construção do ninho. Métodos: Trinta coelhas primíparas foram usadas em delineamento em blocos ao acaso com três tratamentos e dez repetições cada. Foram avaliados três tipos de material para forrar o piso do ninho com maravalha (280 g), feno de Tifton (220 g) e jornal cortado em tiras (200 g). O estado do ninho foi determinado para avaliar a mistura do material com os pelos da coelha, a preservação do material original. Peso corporal, ganho de peso diário e a taxa de sobrevivência foram avaliados desde o nascimento até o desmame. Resultados: Nenhum efeito foi observado do tipo de material sobre o nível de mistura do material e pelos, quantidade de pelos no ninho, peso corporal, ganho de peso diário ou taxa de sobrevivência dos láparos do nascimento até 35 d de idade (p>0,05), entretanto, a preservação do material original no ninho foi menor quando o feno de Tifton foi usado (p<0,05). As correlacões de tipo de material e número total de nascidos vivos com a presença de pelo, nível de mistura entre pelo e material, e preservação de material no ninho não foram significativas (p>0,05). Não houve correlação (p>0,05) entre preservação do material no ninho com presença de pelo ou nível de mistura nos ninhos. Houve correlação positiva entre a presença de pelo no ninho com nível de mistura (p<0,001). Conclusão: Feno de Tifton e jornal cortado em tiras podem ser usados como revestimento de ninhos para coelhas gestantes, substituindo a maravalha sem efeitos negativos sobre o comportamento de construção do ninho da coelha nem sobre o desempenho dos láparos do nascimento até o desmame, considerando-se o primeiro parto.

Sex difference in thermal preference of adult mice does not depend on presence of the gonads.

BACKGROUND: The thermoneutral zone (TNZ) is a species-specific range of ambient temperature (T a), at which mammals can maintain a constant body temperature with the lowest metabolic rate. The TNZ for an adult mouse is between 26 and 34 °C. Interestingly, female mice prefer a higher T a than male mice although the underlying mechanism for this sex difference is unknown. Here, we tested whether gonadal hormones are dominant factors controlling temperature preference in male and female mice. METHODS: We performed a temperature preference test in which 10-week-old gonadectomized and sham-operated male and female C57BL/6J mice were allowed to choose to reside at the thermoneutral cage of 29 °C or an experimental cage of 26, 29, or 32 °C. RESULTS: All mice preferred a T a higher than 26 °C, especially in the inactive phase. Choosing between 29 and 32 °C, female mice resided more at 32 °C while male mice had no preference between the temperatures. Hence, the preferred T a for female mice was significantly higher (0.9 ± 0.2 °C) than that for male mice. However, gonadectomy did not influence the T a preference. CONCLUSIONS: Female mice prefer a warmer environment than male mice, a difference not affected by gonadectomy. This suggests that thermal-sensing mechanisms may be influenced by sex-specific pathways other than gonadal factors or that the thermoregulatory set point has already been determined prior to puberty.