Reproductive Rhythm Research Articles

Reproduction Accuracy for Short Rhythms Following Melodic or Monotonic Presentation

Some researchers and study participants have expressed an intuition that novel rhythmic sequences are easier to recall and reproduce if they have a melody, implying that melodicity (the presence of musical pitch variation) fundamentally enhances perception and/or representation of rhythm. But the psychoacoustics literature suggests that pitch variation often impairs perception of temporal information. To examine the effect of melodicity on rhythm reproduction accuracy, we presented simple nine-note auditory rhythms to 100 college students, who attempted to reproduce those rhythms by tapping. Reproductions tended to be more accurate when the presented notes all had the same pitch than when the presented notes had a melody. Nonetheless, a plurality of participants judged that the melodically presented rhythms were easier to remember. We also found that sequences containing a Scotch snap (a sixteenth note at a quarter note beat position followed by a dotted eighth note) were reproduced less accurately than other sequences in general, and less accurately than other sequences containing a dotted eighth note.

Disentangling the effects of modality, interval length and task difficulty on the accuracy and precision of older adults in a rhythmic reproduction task.

Studies on the functional quality of the internal clock that governs the temporal processing of older adults have demonstrated mixed results as to whether they perceive and produce time slower, faster, or equally well as younger adults. These mixed results are due to a multitude of methodologies applied to study temporal processing: many tasks demand different levels of cognitive ability. To investigate the temporal accuracy and precision of older adults, in Experiment 1, we explored the age-related differences in rhythmic continuation task taking into consideration the effects of attentional resources required by the stimulus (auditory vs. visual; length of intervals). In Experiment 2, we added a dual task to explore the effect of attentional resources required by the task. Our findings indicate that (1) even in an inherently automatic rhythmic task, where older and younger adult's general accuracy is comparable, accuracy but not precision is altered by the stimulus properties and (2) an increase in task load can magnify age-related differences in both accuracy and precision.

Reproductive phenology of aquatic macrophytes in the Cerrado-Pantanal ecotone

Studies of plant phenology have been performed predominantly with terrestrial species and rarely so with aquatic communities. Such plants are fundamental for the aquatic ecosystems, representing a valuable source of resources when they are scarce in terrestrial environments for the fauna. Studies of phenology help to understand the reproduction rhythms of plant communities and provide fundamental support to management and conservation. This study aimed to describe the reproductive phenology of 15 species of aquatic plants and determine how it is related to climatic factors and physicochemical variables of water. Plants were collected every 15 days throughout a single year, from two ponds in the Cerrado-Pantanal ecotone, Central-West Brazil. Species were observed in flower and fruit throughout the year with varying phenophases among life forms (amphibious, emergent, rooted, floating and rooted submerged). Photoperiod stood out among climatic variables for flowering and fruiting times. Phenophases were explained by climatic factors, as well as by physicochemical variables of the water. Nitrogen and pH were the variables most related to the highest number of phenophases of different life forms. Such information is relevant to understanding how physicochemical alterations to water by pollution, eutrophication and siltation, among others, can change the phenology of aquatic macrophytes.

Genome-Scale Phylogenetic and Population Genetic Studies Provide Insight Into Introgression and Adaptive Evolution of Takifugu Species in East Asia.

As a typical marine adaptive radiation species, most Takifugu species are widely distributed in East Asian offshore, which have diversified morphological characteristics and different ecological habits. The phylogenetic relationship and population structure of the Takifugu species was complicated because of incomplete lineage sorting, widespread hybridization and introgression. Therefore, to systematically clarify the phylogenetic relationships of Takifugu genus, explore the introgression and natural hybridization between different Takifugu species, and detect the selective signatures in the adaptive evolution of diversified traits, whole-genome resequencing was used in 122 Takifugu samples from 10 species. Phylogenetic analysis showed solid sister-group relationships between Takifugu bimaculatus and Takifugu flavidus, Takifugu oblongus, and Takifugu niphobles, Takifugu rubripes, and Takifugu obscurus, Takifugu xanthoptreus, and Takifugu ocellatus. Further admixture analysis indicated the divergence of T. obscurus population and the bidirectional gene flow between T. bimaculatus and T. flavidus. Using species-specific homozygous genetic variance sites, we detected the asymmetric introgression between T. bimaculatus and T. flavidus at China East sea and southern Taiwan Strait. By genome-scale genetic diversity scanning, we detected two copies of syt1, zar1 and tgfbr1 related to the semilunar reproduction rhythm in T. niphobles, involved in memory formation, embryo maturation and female reproduction. Furthermore, we also found lots of T. niphobles specific mutations in CDS region of circadian rhythm related genes and endocrine hormone genes. For Takifugu species, our research provides reliable genetic resources and results for the phylogeny, introgression, hybridization and adaptive evolution, and could be used as a guide for the formulation of the protection and proliferation release policies.

Seasonal reproduction of northernmost endangered forest musk deer (Moschus berezovskii) in China and the synchronization with climatic conditions

Reproductive rhythms, as a response to environmental seasonality, may maximize the survival possibility of both newborns and parents, which is vital for ex situ conservation and sustainable management in wildlife. Forest musk deer (Moschus berezovskii) is a critically endangered ungulate of China. In order to estimate its reproduction characteristics and performance in northern China, a historical distribution area, the parturition pattern of the northernmost captive forest musk deer in Huailai Musk Deer Farm from 2017 to 2018 was analyzed. We found that the parturition of forest musk deer was highly seasonal with a peak on May 27<sup>th</sup>, and 75% of parturitions were completed within 22 days from May to June, which could be an adaptation to the seasonality of local food resources. The parturition peak was four weeks before the best hydrothermal conditions when food resources were maximally provided. The time lag between the parturition date and the peak of food availability was affected by climatic conditions during lactation as warmer temperatures in the 4<sup>th</sup> and 5<sup>th</sup> week and heavier precipitation in the 4<sup>th</sup> week of lactation shortened the time lag by five days (P < 0.05). The synchronization between parturition rhythms and seasonality of climatic conditions indicated that the forest musk deer could be farmed in Northeastern Taihang Mountains and northern China, where there is a suitable climate for the musk deer reproduction. Sustainable musk production and musk deer release into the wild where there are suitable climatic conditions has been proved to be practicable, which can benefit the ex situ conservation of endangered forest musk deer and musk resources sustainability.

Оптимизация воспроизведения заданного ритма дыхания при проведении пробы сердечно-дыхательного синхронизма

This article analyses optimization guidelines for assessment of human regulatory and adaptive capabilities (RAC) using the cardiorespiratory synchronism (CRS) method. The study participants aged 19 ± 1 were randomized into two groups: main group (n = 30) and reference group (n = 30). In the main group, before conducting the CRS tests, a number of techniques were applied to facilitate reproduction of the set breathing rhythm by the subject: relieving one hand from the ECG electrode by recording a single lead (II or III), which is sufficient to monitor heart rate, for the subjectʼs convenience (with detecting motor asymmetry of the hemispheres); viewing an instructional video showing the algorithm of the upcoming test to the subject; ideomotor training; detecting the latent period of a simple sensorimotor reaction to sound and light stimuli as a preparation for the test. The degree of correspondence between the reproduced and the set breathing rhythms in the main group was 47.0 ± 15.7 % (M ± SD), which is higher than in the reference group. The maximum number of exact respiratory cycles repeated in a row in the first test also demonstrated the advantages of the main group, where this indicator was 10.3 ± 3.4 cycles. The number of respiratory cycles from the beginning of the first test to the exact reproduction of the set rhythm decreased in the main group compared to the reference group by 76.3 %. The correlation analysis revealed no relationship between RAC and the accuracy of breathing rhythm reproduction (correlation coefficient was −0.115 at p = 0.536). Testing duration in the reference group significantly (p < 0.001 according to Mann–Whitney U-test) exceeded that in the main group (by 10.2 min). Thus, the research demonstrated the effectiveness of the proposed techniques for optimizing the CRS test, which can contribute to an even wider spread of this method.

The neuropeptide allatostatin C from clock-associated DN1p neurons generates the circadian rhythm for oogenesis

The link between the biological clock and reproduction is evident in most metazoans. The fruit fly Drosophila melanogaster, a key model organism in the field of chronobiology because of its well-defined networks of molecular clock genes and pacemaker neurons in the brain, shows a pronounced diurnal rhythmicity in oogenesis. Still, it is unclear how the circadian clock generates this reproductive rhythm. A subset of the group of neurons designated "posterior dorsal neuron 1" (DN1p), which are among the ∼150 pacemaker neurons in the fly brain, produces the neuropeptide allatostatin C (AstC-DN1p). Here, we report that six pairs of AstC-DN1p send inhibitory inputs to the brain insulin-producing cells, which express two AstC receptors, star1 and AICR2. Consistent with the roles of insulin/insulin-like signaling in oogenesis, activation of AstC-DN1p suppresses oogenesis through the insulin-producing cells. We show evidence that AstC-DN1p activity plays a role in generating an oogenesis rhythm by regulating juvenile hormone and vitellogenesis indirectly via insulin/insulin-like signaling. AstC is orthologous to the vertebrate neuropeptide somatostatin (SST). Like AstC, SST inhibits gonadotrophin secretion indirectly through gonadotropin-releasing hormone neurons in the hypothalamus. The functional and structural conservation linking the AstC and SST systems suggest an ancient origin for the neural substrates that generate reproductive rhythms.

Роль зеркальных нейронов в интерпретации действий и намерений

Роль зеркальных нейронов в интерпретации действий и намерений

Capacidad reproductiva de Nannochloropsis oculata en diferentes concentraciones de salinidad y fertilizante: Una contribución a la Bioeconomía acuícola

El estudio se centró en contribuir a la Bioeconomía Acuícola evaluando el ritmo reproductivo de Nannochloropsis oculata en dos baterías experimentales con concentraciones salinas de 33 ‰, 25 ‰, 20 ‰, 15 ‰, 10 ‰ y 5 ‰. A cada una se le aplicó dosis únicas de 0.32 ‰ y 1 ‰ de F/2 Guillard, respectivamente. Se realizaron dos experimentos en tiempos de 10 y 23 días a temperatura de 25 ºC. El primer experimento con 0.32 ‰ de F/2 Guillard, N. oculata presentó mayor número de cel/ml en salinidades de 33 ‰ y 25 ‰, a los 8 días de estudio, denotando la afinidad de N. oculata de reproducirse con mayor velocidad en ese rango de salinidad. La importancia del uso de F/2 Guillard fue observada usando 1‰ debido a que la microalga presenta similar número de cel/ml (P≤0.05) en concentraciones salinas de 33 ‰, 25 ‰, 20 ‰ y 15 ‰ y similar concentración a las microalgas cultivadas con 0.32 ‰ de F/2 Guillard en salinidades de 33 ‰ y 25 ‰. La capacidad de N. oculata fue testado en un segundo experimento donde los resultados muestran similar número de cel/ml entre los tratamientos salinos, en ambas baterías, a los 23 días de cultivo. Los resultados muestran que N. oculata puede ser cultivada con bajas concentraciones de F/2 Guillard en rangos de salinidad entre 25 ‰ y 33 ‰, implica reducción de costos.

Effect of season and pregnancy on minerals serum variations of local rabbits in Tiaret, Algeria

Abstract The present study aimed to assess the season and pregnancy influence on minerals serum of local rabbits raised in semi-arid climate type. Fifty-nine multiparous does was used in this study during 2019. The semi-intensive rhythm of reproduction was used. All pregnant does were at the late stage of pregnancy at the sampling date. Serum samples were collected in two seasons: winter and summer. In this study, biochemical parameters concentrations of pregnant rabbits were significantly higher (p<0,05) compared with non-pregnant rabbit. The value of biochemical parameters total protein, albumin, triglyceride, cholesterol, calcium, and phosphorusus changed significantly. In this study, most parameters were influenced by pregnancy.

Reproductive Diseases in Farmed Rabbit Does.

Simple SummaryThe domestic rabbit doe can have several reproductive diseases, including infertility. These were causes for consultations from rabbit producers. This led us to study the reproductive diseases of farmed does. To do this, we relied on visits to rabbitries, made since 1994. Low fertility, which in our case we considered less than 70% pregnancies (85.5% was the average observed on farms), plus an abortion rate equal to or greater than 2% of inseminated does, were the most frequent problems. Then, we scheduled work from 2014, through pregnancy checks with abdominal palpation. We recorded the results for each rebred lactating doe examined, along with data on her body and sanitary condition, and parity order. We found an effect of low body condition or diseases, such as mastitis, on infertility. Age also had an effect: first parity does were less fertile. Therefore, before servicing a doe, it is necessary to evaluate its condition, as well as various management practices (reproductive rhythm) or environmental factors (lighting).In this study, we determined the occurrence of reproductive diseases in does on 1373 visited farms in Spain and Portugal, between 1994 and 2019. The retrospective information obtained was entered in a database classified as follows: apparent infertility (≤70% pregnancy rate), abortions (≥2% of serviced does), high fetal death risk at parturition (≥10%) or dystocia, amongst others. Infertility was the reason for 181 visits. The median of prevalence of apparent infertility in these cases was 35% (minimum to maximum: 25–90%) and the mean, 37.4%. We performed a prospective study to determine risk factors at the individual and farm level, with a second database corresponding to 2014–2019. We carried out pregnancy checks, assessed sanitary status and body condition, and recorded the age of 17,297 rebred lactating does on 142 farms. The median size of the farms was 800 does, and the examined cohorts, 350 does. Predisposing risk factors for infertility were observed: e.g., mastitis had an effect. During the 5-year study, we made a third database with the results from 190,508 does palpated by producers in a subset of 134 farms. In this case, the median of the prevalence of apparent infertility was 14.5% (minimum to maximum: 4.1–50%), which could be considered baseline occurrence when monitoring the theriogenology of rabbit doe farms. Reproductive rhythm was an enabling risk factor: does serviced ≤25 d postpartum were less fertile than at ≥32 d. We made a database with the body condition score (BCS) on a linear scale from 1 (emaciated) to 9 (obese). The pregnancy rate (PR) of underweight and borderline does (4/9) was 73.1%. The PR of overweight and borderline does (6/9) was 82.6% and those classified with a mean BCS (5/9): PR = 79.3%. We may infer that the optimum BCS for reproduction is 6/9, rather than 5/9. Some changes in female rabbit health and husbandry to improve reproductive performance and welfare are highlighted.

Impact of music-based intervention on verbal memory: an experimental behavioral study with older adults.

Normal age-related declines have been reported in different cognitive functions, such as episodic memory. Some environmental factors have the potential to reduce cognitive decline and promote healthy aging. In this research, we employed musical improvisation as a focal music-based intervention to explore its effects as a modulator of verbal memory. We evaluated two types of verbal memory: a neutral one, employing the Rey Auditory Verbal Learning Test (Study 1), and an emotional one, implementing the Spanish version of Affective Norms for English Words (Study 2) in a volunteer group of older adults. After the acquisition of neutral (Study 1) or emotional (Study 2) verbal information, the participants were exposed to musical improvisation (experimental condition) or two control conditions (rhythmic reproduction as a musically active control condition or a rest condition as a passive control condition) for 3min. Then, memory was evaluated through two memory tasks (immediate and deferred free-recall and recognition tests). In both studies, we compared memory performance among musicians (with five or more years of music training) and non-musicians. We found a significant improvement in neutral verbal memory among participants involved in musical improvisation, who remembered more words than those in the control conditions. Differences were also found according to the musical experience of the sample, with musicians outperforming non-musicians. The current research supports the late-life cognitive benefits of music-based intervention and music training.

Influence of Reproductive Rhythm and Weaning Age on Fertility and Body Condition of Local Breed Does in the District of Abidjan

The objective of this study is to evaluate the reproductive performance of locally bred rabbits by comparing the production of females mated 11 days postpartum (semi-intensive R42) with those mated 25 days postpartum (extensive rhythm R56). Females are naturally protruding.120 rabbits selected from a private farm in Bingerville in the district of Abidjan were followed during the experiment. Receptivity and gestation rates were not significantly influenced (p>0.05) by the reproductive rhythm in the breeding females. Fertility in multiparous females showed a higher rate in the extensive rhythm (89-100%). The semi-intensive rhythm had the highest stillbirth rate (5.6%) and pre-weaning morbidity (14.03%). However, after weaning, morbidity was higher in bunnies in the extensive rhythm (13.6%). In the extensive rhythm, the highest values were observed for the number of weaned bunnies and the survival rate of breeding females. The extensive rhythm significantly increases the longevity of does with a high mortality rate of bunny rabbits. These results could be indicators for further investigation in the search for an optimum rate of rabbit reproduction.

Rhythm Reproduction in English Translation of Chinese Poetry: A Contrastive Analysis of Li Bai's “GUAN SHAN YUE”（关山月）and its English Version

This paper contrasts the rhythm of Li Bai's “GUAN SHAN YUE”（关山月）and that of Fletcher's English version “The MOON OVER The PASS” and finds out the functional equivalence between the Ping (平) and Ze (仄) (level and oblique tones) of Chinese poetry and the lightly stressed and heavily stressed syllables of English poetry, the number of Yan (言) (the number of characters) and the number of feet, and the rhymes. To promote the realization of musical beauty, formal beauty and emotional expression in the translation of Chinese poetry and reproduce the rhythm of ancient Chinese poetry, five-character and seven-character poem with regular line can be translated into iambic pentameter; pre-Tang poem and Song Ci with irregular line can be translated according to the analogy of character and syllable, and the feet of the translated poem can mainly be iambs; the rhyme of the translated poem can be couplet rhyme, cross rhyme or alternate rhyme. Based on this strategy, the author translates her self-created poem “MAN JIANG HONG ZHAN YI”（满江红·战疫）into English to prove the feasibility of the rhythm reproduction strategy of the English translation of ancient Chinese poetry.

Cerebral Substrates for Controlling Rhythmic Movements.

Our daily lives are filled with rhythmic movements, such as walking, sports, and dancing, but the mechanisms by which the brain controls rhythmic movements are poorly understood. In this review, we examine the literature on neuropsychological studies of patients with focal brain lesions, and functional brain imaging studies primarily using finger-tapping tasks. These studies suggest a close connection between sensory and motor processing of rhythm, with no apparent distinction between the two functions. Thus, we conducted two functional brain imaging studies to survey the rhythm representations relatively independent of sensory and motor functions. First, we determined brain activations related to rhythm processing in a sensory modality-independent manner. Second, we examined body part-independent brain activation related to rhythm reproduction. Based on previous literature, we discuss how brain areas contribute rhythmic motor control. Furthermore, we also discuss the mechanisms by which the brain controls rhythmic movements.

Effects of photoperiod on morphology and function in testis and epididymis of Cricetulus barabensis.

Photoperiod regulates the seasonal reproductive rhythms of mammals by influencing the development and function of sexual organs; however, the underlying mechanism remains unclear. We examined the morphology and functioning of the main sex organs of striped dwarf hamsters (Cricetulus barabensis) under different photoperiods (short daylight [SD], moderate daylight [MD], and long daylight [LD]) and further investigated the underlying molecular mechanisms. There was an inverse correlation between blood melatonin levels and photoperiod in the order SD > MD > LD. Decreases in body and tissue weights were observed under SD, whereas testis and epididymis weights between MD and LD were comparable. The diameters of the spermatogenic tubules, thickness of the spermatogenic epithelium, and the number of spermatogonia and Sertoli cells decreased under SD, whereas the serum-luteinizing hormone, follicle-stimulating hormone, and fecal testosterone concentrations decreased under LD. In SD, bax/bcl2 protein expression increased in the testes and decreased in the epididymides, whereas LC3II/LC3I remained unchanged in the testes and increased in the epididymides compared with the MD group. In LD, bax/bcl2 and LC3II/LC3I protein expression levels were unchanged in the testes but were decreased in the epididymides. In SD and LD, adenosine triphosphate synthase and citrate synthase protein expression levels were unchanged in the testes but were decreased in the epididymides. Drp1 and Mff protein expression increased in the testes and decreased in the epididymides. Overall, different regulatory mechanisms in the testis and epididymis led to degeneration under SD and maintenance under LD, preferentially protecting mitochondrial function in the testis by regulating mitochondrial fission.

Action de la photopériode sur la reproduction des équidés

Juments et étalons présentent une phase de reproduction pendant les jours croissants ou longs, au printemps et en été. La majorité des juments n’ont pas d’ovulation en hiver. Ce rythme annuel de reproduction est synchronisé par les variations annuelles de la longueur du jour. Un éclairement artificiel de 14,5 h, débuté en hiver, avance la première ovulation annuelle des juments.
 Certaines des étapes de la transmission de l’information lumineuse ont été vérifiées chez les équidés. Le message lumineux est transformé en influx nerveux par des cellules spécialisées de la rétine. Cet influx, via le noyau supra-chiasmatique puis le ganglion cervical supérieur, agit sur la glande pinéale. Les pinéalocytes répondent à une stimulation noradrénergique en libérant la mélatonine. Cette hormone, sécrétée pendant la phase obscure, agit sur des récepteurs membranaires spécifiques. L’administration de mélatonine exogène sous forme d’implants sous-cutanés ou, dans certaines conditions, sous forme orale, supprime l’effet photostimulant d’un jour long. L’utilisation d’implants est actuellement à l’étude pour mettre au point un traitement de désaisonnement.
 La sécrétion des neurones à GnRH est ensuite régulée par des neuromédiateurs. La naloxone, antagoniste des opiacées endogènes, induit une décharge de GnRH suivie d’une libération de LH et de FSH chez la jument en inactivité. Les hormones thyroïdiennes ont probablement une action à ce niveau.
 L’alternance d’un mois de jours courts et d’un mois de jours longs qui permet, chez les petits ruminants mâles, d’abolir les variations saisonnières est, dans l’état actuel des travaux, inefficace chez l’étalon ou la jument.
 Pour avancer la date de la première ovulation annuelle, les éleveurs ne disposent actuellement que d’un traitement comportant 14,5 h d’éclairement par jour, commencé vers le solstice d’hiver et appliqué pendant 35 jours.

Sex Differences and the Neuroendocrine Regulation of Seasonal Reproduction by Supplementary Environmental Cues.

Seasonal rhythms in reproduction are conserved across nature and optimize the timing of breeding to environmental conditions favorable for offspring and parent survival. The primary predictive cue for timing seasonal breeding is photoperiod. Supplementary cues, such as food availability, social signals, and temperature, fine-tune the timing of reproduction. Male and female animals show differences in the sensory detection, neural integration, and physiological responses to the same supplementary cue. The neuroendocrine regulation of sex-specific integration of predictive and supplementary cues is not well characterized. Recent findings indicate that epigenetic modifications underlie the organization of sex differences in the brain. It has also become apparent that deoxyribonucleic acid methylation and chromatin modifications play an important role in the regulation and timing of seasonal rhythms. This article will highlight evidence for sex-specific responses to supplementary cues using data collected from birds and mammals. We will then emphasize that supplementary cues are integrated in a sex-dependent manner due to the neuroendocrine differences established and maintained by the organizational and activational effects of reproductive sex hormones. We will then discuss how epigenetic processes involved in reproduction provide a novel link between early-life organizational effects in the brain and sex differences in the response to supplementary cues.

A multifactorial evaluation of different reproductive rhythms and housing systems for improving welfare in rabbit does

The most widespread reproductive rhythm practiced in rabbit farming is based on artificial insemination (AI) performed at around 11 days pospartum. This approach results in high production rates, but requires high yearly replacement of animals that cannot sustain the enormous energy demand. Rabbit does that are in energy deficit have relatively short reproductive careers. Moreover, current housing systems do not allow animals to express the typical behavioural pattern of the species, with presence of abnormal behaviours that contribute to reduce welfare. Thus, the present study aimed to evaluate the best combination of housing systems and reproductive rhythms through multiple indicators (performance, behaviour, corticosterone assessments) to improve does’ welfare. A total of 110 nulliparous rabbit does of the Grimaud hybrid maternal line were randomly allocated to 2 different housing systems, an innovative type of cage, Combi cage (C), vs. the conventional cage currently used in intensive farming, Standard cage (S), within which 3 reproductive rhythms: Intensive (I), with AI 11 days postpartum; Alternating (A), with AI alternated between 11 and 30 days postpartum; or Extensive (E), with AI 30 days postpartum, were applied. All rabbits underwent 6 consecutive reproductive cycles, according to a multifactorial balanced experimental plan (2 × 3), as follows: CI (20 does) vs. CA (20 does) vs. CE (20 does) vs. SI (5 does) vs. SA (5 does) vs. SE (5 does). At the main critical phases (AI, kindling, and peak lactation), we conducted reproductive, behavioural, and hormone assessments (salivary corticosterone). CE group showed higher motor activity, lower feeding rates, and increases in number of live kits and weaned kits, which resulted in better reproductive performance in the C cages. The SA group displayed the highest number of live-born kits/litter (P < 0.02), the highest total weight of the weaned litter (P < 0.01), and the lowest pre-weaning mortality (P < 0.04) among S cages. The housing system also influenced behaviour: S does displayed the highest frequencies of self-grooming (P < 0.01), feeding (P < 0.001), and stereotypical behaviours (sniffing and biting bars, P < 0.01), which indicated frustration from a lack of stimuli and consequent boredom. Based on our results, we concluded that AI after kit weaning (E) was the best reproductive rhythm for does in C cages, and the A rhythm was best for does in S cages. However, from an ethological point of view, in the S cages, stereotypes related to the small size of the housing system still remain.

Histological evidence of the lunar reproductive rhythm of Atlantic sea urchin Arbacia punctulata in the Gulf of Mexico

ABSTRACT Natural phenomena act as external cues that stimulate the reproductive activity of many marine organisms. In this study, we report the gonadal maturation in relation to the lunar cycle of wild-caught Atlantic sea urchin, Arbacia punctulata (Echinodermata: Arbaciidae, an edible marine invertebrate), in the Gulf of Mexico. Weekly changes in gonadal development were observed histologically according to the lunar cycle during the summer months from May to July. Histological observations revealed that testes were developed synchronously around the new moon in June and July. Several testes collected in the same moon phase contained residual sperm (~7%) or testicular lobules/acini fully occupied by mature sperm (~46%). Cyclic ovarian development was also observed during the summer months, some ovaries collected around the new moon in June and July contained oocytes at maturation stage (ova: ~39-71%) or empty follicles, suggesting that the Atlantic sea urchin spawns according to the lunar cycle in the Gulf of Mexico. To the best of our knowledge, this is the first report on the lunar reproductive rhythm of Arbacia species in the Gulf of Mexico.