Synchrony Of Emergence Research Articles

Climate change affects the early‐life history of a freshwater turtle in a severely drying region

AbstractFreshwater turtles are one of the most threatened vertebrate groups. Climate change is a major threat to these species, with impacts affecting all life‐history stages. There is currently a limited understanding of how changes in climate may alter the environmental triggers for hatching and emergence from the nests of freshwater turtle hatchlings. This precludes making predictions about how climate change may impact freshwater turtle recruitment success. The southwestern snake‐necked turtle (Chelodina oblonga) is endemic to south‐western Australia, a global biodiversity hotspot that has undergone severe climatic drying. Recruitment failure is thought to be occurring in many populations of the species. However, there is little understanding as to how environmental change may be influencing recruitment. This study aimed to: (1) determine the incubation duration and hatching and hatchling emergence success of C. oblonga, (2) determine if the species exhibits hatching or emergence synchrony and/or delayed emergence and (3) quantify the effects of temperature and rainfall on hatchling emergence. Using this information, the study assesses how climatic drying and warming may be impacting C. oblonga's early life‐history. Between 2018 and 2020 nest sites were monitored around a large urban wetland with weekly assessments of egg and hatchling status. Incubation duration and hatching and hatchling emergence success were calculated, and generalized linear models were built to determine how temperature and/or rainfall predicted emergence. Hatchlings either emerged shortly after hatching or overwintered in the nest, and both hatching and emergence were asynchronous. Both emergence periods were positively associated with temperature and rainfall. This study reveals that incubation duration, hatching success, hatchling emergence and survival are all likely to be impacted by recent and projected climate change, and especially drying. Warming and drying are predicted for many temperate regions globally, and it is therefore important that their impacts on the early life history of freshwater turtles be better understood.

The effects of warm and cold periods on resource depletion and emergence synchrony in diapausing Hypena opulenta: Implications for biological control of invasive swallow‐worts in North America

AbstractTemperature plays an important role in winter diapause of temperate insects. Its effects can cause problems for biological control programs, both for the establishment of insects in novel climates and for the mass rearing of insects in the laboratory. Hypena opulenta (Christoph) (Lepidoptera: Erebidae), a biological control agent for invasive swallow‐wort species in North America, has been observed to enter diapause in mid‐summer in its introduced range. Additionally, H. opulenta has proved complicated to mass‐rear, in part because individuals sometimes enter diapause unexpectedly, meaning that diapausing pupae may need to be stored over winter for varying lengths of time. We conducted pupal storage experiments to determine the effects of high pre‐winter temperatures, like those experienced by early diapausing individuals in the field, on lipid store depletion. We conducted a second experiment to compare the effects of cold treatments of different lengths (1, 3, and 6 months), during diapause, on pupal mortality, development times, and the synchrony of adult emergence. Exposure to warm periods ranging from 25 to 75 days during early diapause did not affect pupal weight, adult emergence rates, or lipid store depletion in H. opulenta. Conversely, the length of cold exposure (between 1 and 6 months) during diapause clearly affected moth mortality, and the timing and consistency of adult emergence. Longer cold periods (3 and 6 months) resulted in earlier, more synchronous adult emergence, and lower diapause mortality, than shorter cold periods (1 month). Our results indicate that in terms of energy depletion, early diapause will not affect the fitness of emerging adults, which is important for the viability of univoltine populations in the southernmost part of the introduced range. Additionally, our results will assist with the H. opulenta mass rearing program, indicating the timing required to synchronize adult emergence.

Microclimatic variation affects developmental phenology, synchrony and voltinism in an insect population

Abstract Temperature influences the rate of most biological processes. Nonlinearities in the thermal reaction norms of such processes complicate intuitive predictions of how ectothermic organisms respond to naturally fluctuating temperatures, and by extension, to climate warming. Additionally, organisms developing close to the ground experience a highly variable microclimate landscape that often is poorly captured by coarse standard climate data. Using a butterfly population in central Sweden as a model, we quantified the consequences of small‐scale temperature variation on phenology, emergence synchrony and number of annual reproductive cycles (voltinism). By combining empirical microclimate and thermal performance data, we project development of individual green‐veined white butterflies (Pieris napi) across 110 sites in an exceptionally high‐resolved natural microclimate landscape. We demonstrate that differences among microclimates just meters apart can have large impacts on the rate of development and emergence synchrony of neighbouring butterflies. However, when considering the full development from egg to adult, these temporal differences were reduced in some scenarios, due to negative correlations in development times among life stages. The negative correlations were caused by temperatures at some sites beginning to exceed the optimum for development as the season progressed. Indeed, which sites were optimal for fast development could change across the lifetimes of individual butterflies, that is, ‘fast’ sites could become ‘slow’ sites. Thus, from a thermal point of view, there seem to be no consistently optimal microsites. Importantly, the fast sites were not always the warmest sites. We showed that such unintuitive effects could play an important role in the regulation of phenological synchrony and voltinism in insects, as most sites consistently favoured two generations. The results were generally robust across years and three different egg‐laying dates. Using high‐resolved empirical climate data on organism‐relevant temporal and spatial scales and considering nonlinear responses to temperature, we demonstrated the large and unintuitive population‐level consequences of locally and temporarily high temperatures. We suggest to—whenever possible—incorporate species‐ and life stage‐specific nonlinear responses to temperature when studying the effects of natural microclimate variation and climate change on organisms. Read the free Plain Language Summary for this article on the Journal blog.

Resilience in Multiplex Networks by Addition of Cross-Repulsive Links

A multiplex network of identical dynamical units becomes resilient against parameter perturbation by adding selective linear diffusive cross-coupling links. A parameter drift at any instant in one or multiple network nodes can destroy synchrony, causing failure and even collapse in the network performance. We introduced [PRE 95, 062204(2017)] a recovery strategy by selective addition of cross-coupling links to save synchrony in the network from the edge of failure due to parameter mismatch (small or large) in any nodes. This concept is extended to 2-layered multiplex networks when the emergent synchrony becomes resilient against a small or large parameter drifting. In addition, the stability of the synchronous state is enhanced from local stability to global stability of synchrony. By the addition of cross-coupling, the network revives complete synchrony in all the nodes except the perturbed nodes, which emerges into a type of generalized synchrony with all the unperturbed nodes. The generalized synchrony is manifested simply by a linear amplitude response in the state variable(s) of the perturbed node(s) by a scaling factor proportional to the mismatch. A set of systematic rules has been derived from the linear flow matrix of the dynamical system representing the nodes dynamics that helps find the connectivity matrix of the cross-coupling links. Lyapunov function stability condition is used to determine the cross-coupling link strength that, in turn, establishes global stability of synchrony of the multiplex network. We verify the efficacy of our proposed coupling scheme with analytical results and numerical simulations of two examples of multiplex networks. In the first example, we use non-local connectivity in each layer, with nodal dynamics of the FitzHugh-Nagumo neuron model.

Seed Coating with Biowaste Materials and Biocides—Environment-Friendly Biostimulation or Threat?

The presented study assessed the effect of bovine (BC) and fish (FC) waste-derived collagen, poly(hexamethylenebiguanide) hydrochloride (PHMB) and waste dolomite on the emergence of seedlings, growth and development of pea (Pisum sativum L. ‘Lasso’) plants. The seed coating method was used to apply the binding agents. Some of the studied agents were showed to significantly affect the index of emergence velocity (IEV) and of emergence synchrony (IES), but not the final emergence percentage (FEP). The results showed that treatment of the pea seeds with BC, FC and PHMB had a slightly positive effect on plant growth, whereas negative effects of dolomite were observed, i.e., detrimental differences in morphological traits of stipules. Moreover, BC, FC and PHMB improved maximal efficiency of PSII (FV/FM) and did not negatively influence chlorophyll content. Analyses demonstrated positive effects of FC and PHMB and negative ones of BC and dolomite on elemental composition of roots and shoots of the studied plant species. We suggest that the FC and PHMB can be used as promising agents for improvement of plant growth, whereas usage of BC and dolomite should be limited.

Seedling Emergence Comparison of Several Romanian Tomato and Pepper Varieties

Nowadays people are turning to sustainable/ecological agriculture. Romanian local varieties with valuable traits can be used to develop novel organic varieties. Nine Romanian tomato (Solanum lycopersicum L.) and seven pepper (Capsicum annuum L.) varieties were compared during seedling emergence in growth chamber and greenhouse conditions. The aim of this study was to observe the variation of several emergence indicators among the varieties of the same species under the same growing conditions, differences that can be correlated with genotype variation in further genotyping research, with the final goal of using these results as a basis for genotype-assisted breeding programs. The present survey demonstrated significant differences in the emergence indicators among the varieties studied, both in the growth chamber and in the greenhouse growing conditions. Ștefănești 24 tomato variety stood out with the longest mean emergence time, mean emergence rate, synchrony and highest uncertainty of emergence, whereas Vladimir pepper variety had the lowest values for percentage of emergence, homogeneity and uncertainty of emergence.

All together now! Hatching synchrony in freshwater turtles

Synchronous hatching is widespread among oviparous taxa. However, the adaptive significance of this phenomenon is unclear, as are the cues mediating hatching synchrony. We took a comparative approach and experimentally tested for synchronous hatching in two freshwater turtles with different life histories (Apalone spinifera and Graptemys geographica). We also aimed to disentangle the cues and mechanisms facilitating any synchronisation and explored its potential costs. For each species, we incubated eggs of different ages and from different mothers in two conditions—in direct contact with other eggs, or physically isolated but able to receive acoustic or chemical cues. We found evidence of hatching synchrony in A. spinifera, but not in G. geographica. Apalone spinifera eggs of different ages that developed in-contact hatched together, implicating mechanical cues. Younger eggs that were incubated in isolation also synchronised with in-contact eggs, which also implicates acoustic or chemosensory cues. Hatchling yolk sac size and mass were similar among treatments. Overall, A. spinifera exhibits hatching synchrony and there was no evidence of developmental costs. The lack of hatching synchrony in G. geographica may reflect their different life-history strategy, as this species can overwinter in the nest after hatching. Clutch effects explained a large and significant proportion of variance in both hatching date and incubation duration in both turtle species. Future research on hatching synchrony should control for these potentially confounding clutch effects. Variation in hatching or emergence synchrony among freshwater turtles raises questions about the selective forces that favour evolution of this behaviour. Many freshwater turtles hatch from their eggs together—but how do they coordinate? We identified that if eggs of Spiny Softshell turtles develop in contact with each other, the eggs hatch together. But, Northern Map turtles do not synchronise hatching, possibly because of an important difference in their ecology—Northern Map turtles overwinter within their nest. Variable occurrence of hatching synchrony across turtle species may reflect different egg structures and/or overwintering behaviour. Research testing for the presence of hatching synchrony typically incubates less and more advanced siblings together. But we found that clutch effects explained a large and significant proportion of variance in both hatching date and incubation duration, which highlights the need to consider and control for these effects moving forward. Our study provides a promising experimental framework to study hatching synchrony that controls for clutch effects.

Straw interference in the emergence of talquezal seeds from different origins

Abstract Background: Talquezal (Paspalum virgatum L.) has become one of the main pasture weeds due to its association with the Urochloa brizantha death syndrome, a disease that causes the progressive death of clumps of susceptible grasses in patches, which leads to weed colonization and pasture degradation. Understanding the weed emergence pattern is essential in decision making for management strategies. Objective: Thus, this study aimed to evaluate the emergence pattern of talquezal seedlings according to its origin and the amount of straw covering the soil. Methods: The experiment was carried out in a greenhouse in a completely randomized design, with six replications and treatments arranged in an 8 × 3 factorial scheme with eight amounts of Urochloa brizantha straw covering the seeds (0, 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 ton ha-1) and three collection sites (Rondonopolis, Redencao, and Cacoal). The effect of the origin and amount of straw was evaluated by the percentage of emergence, relative emergence frequency, mean emergence time, emergence synchrony, and emergence speed index of seedlings obtained over 35 days after sowing. Results: Talquezal seeds showed high seedling emergence vigor regardless of their origin under amounts of straw lower than 4.0 ton ha-1. Conclusions: The result suggests that the amounts of U. brizantha straw higher than 4.0 ton ha-1 on the soil surface, the lower is the percentage of Talquezal seedling emergence.

When spring ephemerals fail to meet pollinators: mechanism of phenological mismatch and its impact on plant reproduction.

The flowering phenology of early-blooming plants is largely determined by snowmelt timing in high-latitude and high-altitude ecosystems. When the synchrony of flowering and pollinator emergence is disturbed by climate change, seed production may be restricted due to insufficient pollination success. We revealed the mechanism of phenological mismatch between a spring ephemeral ( Corydalis ambigua) and its pollinator (overwintered bumblebees), and its impact on plant reproduction, based on 19 years of monitoring and a snow removal experiment in a cool-temperate forest in northern Japan. Early snowmelt increased the risk of phenological mismatch under natural conditions. Seed production was limited by pollination success over the 3 years of the pollination experiment and decreased when flowering occurred prior to bee emergence. Similar trends were detected on modification of flowering phenology through snow removal. Following snowmelt, the length of the pre-flowering period strongly depended on the ambient surface temperature, ranging from 4 days (at greater than 7°C) to 26 days (at 2.5°C). Flowering onset was explained with an accumulated surface degree-day model. Bumblebees emerged when soil temperature reached 6°C, which was predictable by an accumulated soil degree-day model, although foraging activity after emergence might depend on air temperature. These results indicate that phenological mismatch tends to occur when snow melts early but subsequent soil warming progresses slowly. Thus, modification of the snowmelt regime could be a major driver disturbing spring phenology in northern ecosystems.

Modeling mountain pine beetle (Dendroctonus ponderosae) oviposition

AbstractMountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is a significant forest disturbance agent with a widespread distribution in western North America. Population success is influenced by temperatures that drive phenology and ultimately the adult emergence synchrony required to mass attack and kill host trees during outbreaks. In addition to lifestage‐specific developmental rates and thresholds, oviposition timing can be a source of variance in adult emergence synchrony, and is a critical aspect of mountain pine beetle phenology. Adaptation to local climates has resulted in longer generation times in southern compared to northern populations in common gardens, and the role of oviposition rate in these differences is unclear. Oviposition rates and fecundity in a northern population have been described, although data are lacking for southern populations. We assessed southern mountain pine beetle oviposition rates and fecundity in a range of temperatures using a non‐destructive technique that included frequent X‐ray imaging. We found that oviposition rate and fecundity vary independently such that a female with high oviposition rate did not necessarily have high fecundity and vice versa. Observed fecundity within the 30‐day experimental period was lowest at the lowest temperature, although estimated potential fecundity did not differ among temperatures. Females at varying temperatures have the potential to lay similar numbers of eggs, although it will take longer at lower temperatures. Southern mountain pine beetle reared in Pinus strobiformis Engelm. (Pinaceae) had a higher upper threshold for oviposition, a similar lower threshold, and slightly greater potential fecundity compared to a northern population reared in Pinus contorta Douglas. A comparison of modeled oviposition rates between the two populations, which could be influenced by host tree, suggests that differences in oviposition rate do not explain observed differences in total generation time. Our oviposition model will facilitate development of a phenology model for southern mountain pine beetle populations.

Emergence of Razor Grass on the Basis of Origin and Seed Depth in the Soil Profile

ABSTRACT: Razor grass (Paspalum virgatum L) is one weed that has gain importance because of its high seed production capability, mainly when pasture fields need to be renewed. Understanding seedling emergence behavior is crucial to devise strategies to manage this weed. This trial was carried out to evaluate the emergence pattern of razor grass seedlings on the basis of seed depth in the soil profile. The experiment was conducted in a green-house in a completely randomized design, with six replications. The treatments performed in a 11 x 3 factorial arrangement: eleven seeding depths (surface, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 and 10.0 cm) by three ecotypes (Rondonópolis, Redenção and Cacoal, Brazil). The effect of origin and seed depth was measured by number of emerged seedlings, emergence speed index, relative emergence frequency, mean emergence time and emergence synchrony of seedlings at 35 days after planting. The seeds of ecotype Rondonópolis had higher vigor than those of ecotype Redenção, which had higher vigor that the ones of ecotype Cacoal. The highest seedling emergence percentage, uniformity and speed were found when the seeds were located at the soil surface, regardless of seed origin. There was no seedling emergence when the seeds of ecotypes Rondonópolis and Cacoal were located at a depth equal to or higher than 8.0 cm; and of ecotype Redenção when they were at a depth equal or higher than 7.0 cm.

Climate-mediated population dynamics enhance distribution range expansion in a rice pest insect

Environmental fluctuations can influence invertebrate population dynamics over large spatial scales, and effects of climate change are of particular importance in understanding phenology. In this study, we tested whether changing climate patterns could increase voltinism and emergence synchrony in Stenotus rubrovittatus and drive the mirid bug’s expansion into currently uninhabited areas of Japan. This expansion could have potentially serious economic consequences for the rice industry. We modelled development of S. rubrovittatus in the field applying the effective accumulated temperature model to calculate the theoretical number of generations and the egg hatching dates from 2003 to 2012 based on a high-resolution, daily weather database. We then performed a regional analysis to assess the relationship between population dynamics and range expansion across the study region and also included a local analysis to evaluate how population parameters affect the presence of S. rubrovittatus at local sites in each year. Results showed that distribution expanded with a relative increase in voltinism and with synchrony of egg hatching date. Moreover, we showed that increased voltinism in the previous year positively influenced local population occurrence. This positive effect suggests that the species’ distribution range expands through increased reproduction at both the regional and local scale. Climate-mediated population dynamics play a significant role in range expansion of the mirid bug.

Temperature affects phenological synchrony in a tree-killing bark beetle.

Phenological synchrony can promote population growth in species with positive density dependence. Variation among life stages in the thermal thresholds for development can foster phenological synchrony under thermal regimes that include frequent occurrence of temperatures between developmental thresholds. The southern pine beetle is an insect with positive density dependence that has recently undergone important shifts in population abundance at the northern extremes of their distribution. We evaluated the hypothesis that cooler winter temperatures in their northern range cause a convergence of the population life stage structure that leads to synchrony in spring flight phenology. We used a combination of approaches. First, in situ laboratory experiments demonstrated a threshold temperature for pupation that was greater than was required for larval development; rearing larvae at lower temperatures increased the pooling of individuals at the end stage of larval development and synchrony in adult emergence. Second, a development rate model showed a similar convergence of the majority of the population at the end stage of larval development when brood experienced the cooler temperatures of the northern region, but not with temperatures from the southern region, or as a null model. Finally, field trapping of wild beetles showed greater synchrony in the pine forests of New Jersey than in the warmer, historically occupied forests of Georgia and Mississippi. Given these results, pine-dominated forests in the northern edge of the southern pine beetle's range may experience more frequent occurrence of outbreaks, due to the positive feedbacks associated with a synchronous spring emergence of this insect.

Groups clapping in unison undergo size-dependent error-induced frequency increase

Humans clapping together in unison is a familiar and robust example of emergent synchrony. We find that in experiments, such groups (from two to a few hundred) always increase clapping frequency, and larger groups increase more quickly. Based on single-person experiments and modeling, an individual tendency to rush is ruled out as an explanation. Instead, an asymmetric sensitivity in aural interactions explains the frequency increase, whereby individuals correct more strongly to match neighbour claps that precede their own clap, than those that follow it. A simple conceptual coupled oscillator model based on this interaction recovers the main features observed in experiments, and shows that the collective frequency increase is driven by the small timing errors in individuals, and the resulting inter-individual interactions that occur to maintain unison.

The anti-predator role of within-nest emergence synchrony in sea turtle hatchlings.

Group formation is a common behaviour among prey species. In egg-laying animals, despite the various factors that promote intra-clutch variation leading to asynchronous hatching and emergence from nests, synchronous hatching and emergence occurs in many taxa. This synchrony may be adaptive by reducing predation risk, but few data are available in any natural system, even for iconic examples of the anti-predator function of group formation. Here, we show for the first time that increased group size (number of hatchlings emerging together from a nest) reduces green turtle (Chelonia mydas) hatchling predation. This effect was only observed earlier in the night when predation pressure was greatest, indicated by the greatest predator abundance and a small proportion of predators preoccupied with consuming captured prey. Further analysis revealed that the effect of time of day was due to the number of hatchlings already killed in an evening; this, along with the apparent lack of other anti-predatory mechanisms for grouping, suggests that synchronous emergence from a nest appears to swamp predators, resulting in an attack abatement effect. Using a system with relatively pristine conditions for turtle hatchlings and their predators provides a more realistic environmental context within which intra-nest synchronous emergence has evolved.

Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines.

The effect of spring temperature on spring phenology is well understood in a wide range of taxa. However, studies on how winter conditions may affect spring phenology are underrepresented. Previous work on Anthocharis cardamines (orange tip butterfly) has shown population‐specific reaction norms of spring development in relation to spring temperature and a speeding up of post‐winter development with longer winter durations. In this experiment, we examined the effects of a greater and ecologically relevant range of winter durations on post‐winter pupal development of A. cardamines of two populations from the United Kingdom and two from Sweden. By analyzing pupal weight loss and metabolic rate, we were able to separate the overall post‐winter pupal development into diapause duration and post‐diapause development. We found differences in the duration of cold needed to break diapause among populations, with the southern UK population requiring a shorter duration than the other populations. We also found that the overall post‐winter pupal development time, following removal from winter cold, was negatively related to cold duration, through a combined effect of cold duration on diapause duration and on post‐diapause development time. Longer cold durations also lead to higher population synchrony in hatching. For current winter durations in the field, the A. cardamines population of southern UK could have a reduced development rate and lower synchrony in emergence because of short winters. With future climate change, this might become an issue also for other populations. Differences in winter conditions in the field among these four populations are large enough to have driven local adaptation of characteristics controlling spring phenology in response to winter duration. The observed phenology of these populations depends on a combination of winter and spring temperatures; thus, both must be taken into account for accurate predictions of phenology.

Egg-hatching synchrony and larval cannibalism in the dock leaf beetle Gastrophysa viridula (Coleoptera: Chrysomelidae)

Females of leaf beetles and many other herbivorous insects lay eggs in coherent batches. Hatchlings emerge more or less simultaneously and often prey on their late-hatching clutchmates. It is not certain, however, whether this synchrony of hatching is a mere by-product of cannibalism or whether an additional synchronizing factor exists. The following simple experiment was aimed at determining the causal relationship between cannibalism and simultaneous larval emergence. Egg clutches of the dock leaf beetle Gastrophysa viridula were split into two halves. These halves were either kept as coherent groups in two separate dishes or, alternatively, only one half remained whole, whereas the other one was divided into single eggs, each of which was incubated in a separate dish. Halving of a clutch into coherent groups only slightly disrupted the synchrony of emergence. The consequence of individual isolation was more dramatic. Half-clutches consisting of disconnected solitary eggs required almost twice as much time for complete emergence of all larvae, which was significantly more than cannibalism as a sole synchronizing factor might explain. Moreover, survival rates were the same in coherent half-clutches (in the presence of cannibalism) and among isolated individuals. This group effect and the small contribution of cannibalism suggest the existence of an additional synchronizing factor. Possible mechanisms underpinning this phenomenon are discussed.

Comparative efficacy of E-17β and GnRH administration on day 0 of a controlled internal drug release (CIDR) based protocol on synchrony of wave emergence, ovulation and conception rates in Murrah buffalos (Bubalus bubalis).

The study was undertaken to compare the efficacy of an estradiol-17β + CIDR based protocol with the conventional ovsynch + CIDR based protocol for synchrony of wave emergence and ovulation in Murrah buffalos. In group I (n=25), on day 0 (beginning of experiment), buffaloes were administered a CIDR device (1.38 g P4) and concurrently received 1.5 mg E-17β. On day 9, the CIDR was removed and a prostaglandin (PG) F2α analogue (500 µg) was administered. On day 11, buffaloes were administered a gonadotropin releasing hormone (GnRH) analogue (20 µg) and inseminated twice at 12 h and 24 h following GnRH injections. Group II (n=25) protocol was based on an ovsynch regimen plus CIDR for 7 days followed by double insemination at induced estrus. Group III (n=10) served as control and was not given any hormone on day 0 of the protocol. In groups I, II and III, the duration of new follicular wave emergences were observed on days 4.22 ± 0.12, 3.12 ± 0.33 and 5.14 ± 0.42, respectively. In group I, synchrony of wave emergence was more and the diameter of pre-ovulatory follicles was larger (P<0.05) compared to groups II and III. The first service conception rate (FSCR) was higher (P<0.05) in group I while ovulation rates were not different between groups I and II. In conclusion, more synchrony of wave emergence, larger diameter of dominant follicles and higher first service conception rate was observed following the E-17β + CIDR based protocol in buffalos.

Dynamics on networks: the role of local dynamics and global networks on the emergence of hypersynchronous neural activity.

Graph theory has evolved into a useful tool for studying complex brain networks inferred from a variety of measures of neural activity, including fMRI, DTI, MEG and EEG. In the study of neurological disorders, recent work has discovered differences in the structure of graphs inferred from patient and control cohorts. However, most of these studies pursue a purely observational approach; identifying correlations between properties of graphs and the cohort which they describe, without consideration of the underlying mechanisms. To move beyond this necessitates the development of computational modeling approaches to appropriately interpret network interactions and the alterations in brain dynamics they permit, which in the field of complexity sciences is known as dynamics on networks. In this study we describe the development and application of this framework using modular networks of Kuramoto oscillators. We use this framework to understand functional networks inferred from resting state EEG recordings of a cohort of 35 adults with heterogeneous idiopathic generalized epilepsies and 40 healthy adult controls. Taking emergent synchrony across the global network as a proxy for seizures, our study finds that the critical strength of coupling required to synchronize the global network is significantly decreased for the epilepsy cohort for functional networks inferred from both theta (3–6 Hz) and low-alpha (6–9 Hz) bands. We further identify left frontal regions as a potential driver of seizure activity within these networks. We also explore the ability of our method to identify individuals with epilepsy, observing up to 80 predictive power through use of receiver operating characteristic analysis. Collectively these findings demonstrate that a computer model based analysis of routine clinical EEG provides significant additional information beyond standard clinical interpretation, which should ultimately enable a more appropriate mechanistic stratification of people with epilepsy leading to improved diagnostics and therapeutics.

Approximate emergent synchrony in spatially coupled spiking neurons with discrete interaction.

Models for perceptual grouping and contour integration are presented. Connection weights depend on distances and angle differences, while neurons evolve following a spiking dynamics (Izhikevich's model in most of the considered cases). Although the studied synapses depend on discrete three-valued functions, simulations display the emergence of approximate synchrony, making these cognitive tasks possible. Noise effects are examined, and the possibility of achieving similar results with a different neuron model is discussed.