skip to main content


The NSF Public Access Repository (NSF-PAR) system and access will be unavailable from 10:00 PM ET on Friday, December 8 until 2:00 AM ET on Saturday, December 9 due to maintenance. We apologize for the inconvenience.

Title: The emergence and development of behavioral individuality in clonal fish

Behavioral individuality is a ubiquitous phenomenon in animal populations, yet the origins and developmental trajectories of individuality, especially very early in life, are still a black box. Using a high-resolution tracking system, we mapped the behavioral trajectories of genetically identical fish (Poecilia formosa), separated immediately after birth into identical environments, over the first 10 weeks of their life at 3 s resolution. We find that (i) strong behavioral individuality is present at the very first day after birth, (ii) behavioral differences at day 1 of life predict behavior up to at least 10 weeks later, and (iii) patterns of individuality strengthen gradually over developmental time. Our results establish a null model for how behavioral individuality can develop in the absence of genetic and environmental variation and provide experimental evidence that later-in-life individuality can be strongly shaped by factors pre-dating birth like maternal provisioning, epigenetics and pre-birth developmental stochasticity.

more » « less
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Nature Publishing Group
Date Published:
Journal Name:
Nature Communications
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Background

    The language of the science curriculum is complex, even in the early grades. To communicate their scientific observations, children must produce complex syntax, particularly complement clauses (e.g.,I think it will float;We noticed that it vibrates). Complex syntax is often challenging for children with developmental language disorder (DLD), and thus their learning and communication of science may be compromised.


    We asked whether recast therapy delivered in the context of a science curriculum led to gains in complement clause use and scientific content knowledge. To understand the efficacy of recast therapy, we compared changes in science and language knowledge in children who received treatment for complement clauses embedded in a first‐grade science curriculum to two active control conditions (vocabulary + science, phonological awareness + science).

    Methods & Procedures

    This 2‐year single‐site three‐arm parallel randomized controlled trial was conducted in Delaware, USA. Children with DLD, not yet in first grade and with low accuracy on complement clauses, were eligible. Thirty‐three 4–7‐year‐old children participated in the summers of 2018 and 2019 (2020 was cancelled due to COVID‐19). We assigned participants to arms using 1:1:1 pseudo‐random allocation (avoiding placing siblings together). The intervention consisted of 39 small‐group sessions of recast therapy, robust vocabulary instruction or phonological awareness intervention during eight science units over 4 weeks, followed by two science units (1 week) taught without language intervention. Pre‐/post‐measures were collected 3 weeks before and after camp by unmasked assessors.

    Outcomes & Results

    Primary outcome measures were accuracy on a 20‐item probe of complement clause production and performance on ten 10‐item unit tests (eight science + language, two science only). Complete data were available for 31 children (10 grammar, 21 active control); two others were lost to follow‐up. Both groups made similar gains on science unit tests for science + language content (pre versus post,d= 2.9,p< 0.0001; group,p= 0.24). The grammar group performed significantly better at post‐test than the active control group (d= 2.5,p= 0.049) on complement clause probes and marginally better on science‐only unit tests (d= 2.5,p= 0.051).

    Conclusions & Implications

    Children with DLD can benefit from language intervention embedded in curricular content and learn both language and science targets taught simultaneously. Tentative findings suggest that treatment for grammar targets may improve academic outcomes.

    What this paper addsWhat is already known on the subject

    We know that recast therapy focused on morphology is effective but very time consuming. Treatment for complex syntax in young children has preliminary efficacy data available. Prior research provides mixed evidence as to children’s ability to learn language targets in conjunction with other information.

    What this study adds

    This study provides additional data supporting the efficacy of intensive complex syntax recast therapy for children ages 4–7 with Developmental Language Disorder. It also provides data that children can learn language targets and science curricular content simultaneously.

    What are the clinical implications of this work?

    As SLPs, we have to talk about something to deliver language therapy; we should consider talking about curricular content. Recast therapy focused on syntactic frames is effective with young children.

    more » « less
  2. Abstract

    In humans, socioeconomic status (SES) has profound outcomes on socio‐emotional development and health. However, while much is known about theconsequencesofSES, little research has examined thepredictorsofSESdue to the longitudinal nature of such studies. We sought to explore whether interindividual differences in neonatal sociality, temperament, and early social experiences predicted juvenile social status in rhesus monkeys (Macaca mulatta), as a proxy forSESin humans. We performed neonatal imitation tests in infants’ first week of life and emotional reactivity assessments at 2 and 4 weeks of age. We examined whether these traits, as well as the rearing environment in the first 8 months of life (with the mother or with same‐aged peers only) and maternal social status predicted juvenile (2–3 years old) social status following the formation of peer social groups at 8 months. We found that infants who exhibited higher rates of neonatal imitation and newborn emotional reactivity achieved higher social status as juveniles, as did infants who were reared with their mothers, compared to infants reared with peers. Maternal social status was only associated with juvenile status for infant dyads reared in the same maternal group, indicating that relative social relationships were transferred through social experience. These results suggest that neonatal imitation and emotional reactivity may reflect ingrained predispositions toward sociality that predict later outcomes, and that nonnormative social experiences can alter socio‐developmental trajectories. Our results indicate that neonatal characteristics and early social experiences predict later social outcomes in adolescence, including gradients of social stratification.

    more » « less
  3. Abstract Background

    Environmental fluctuation during embryonic and fetal development can permanently alter an organism’s morphology, physiology, and behaviour. This phenomenon, known as developmental plasticity, is particularly relevant to reptiles that develop in subterranean nests with variable oxygen tensions. Previous work has shown hypoxia permanently alters the cardiovascular system of snapping turtles and may improve cardiac anoxia tolerance later in life. The mechanisms driving this process are unknown but may involve epigenetic regulation of gene expression via DNA methylation. To test this hypothesis, we assessed in situ cardiac performance during 2 h of acute anoxia in juvenile turtles previously exposed to normoxia (21% oxygen) or hypoxia (10% oxygen) during embryogenesis. Next, we analysed DNA methylation and gene expression patterns in turtles from the same cohorts using whole genome bisulfite sequencing, which represents the first high-resolution investigation of DNA methylation patterns in any reptilian species.


    Genome-wide correlations between CpG and CpG island methylation and gene expression patterns in the snapping turtle were consistent with patterns observed in mammals. As hypothesized, developmental hypoxia increased juvenile turtle cardiac anoxia tolerance and programmed DNA methylation and gene expression patterns. Programmed differences in expression of genes such asSCN5Amay account for differences in heart rate, while genes such asTNNT2andTPM3may underlie differences in calcium sensitivity and contractility of cardiomyocytes and cardiac inotropy. Finally, we identified putative transcription factor-binding sites in promoters and in differentially methylated CpG islands that suggest a model linking programming of DNA methylation during embryogenesis to differential gene expression and cardiovascular physiology later in life. Binding sites for hypoxia inducible factors (HIF1A, ARNT, and EPAS1) and key transcription factors activated by MAPK and BMP signaling (RREB1 and SMAD4) are implicated.


    Our data strongly suggests that DNA methylation plays a conserved role in the regulation of gene expression in reptiles. We also show that embryonic hypoxia programs DNA methylation and gene expression patterns and that these changes are associated with enhanced cardiac anoxia tolerance later in life. Programming of cardiac anoxia tolerance has major ecological implications for snapping turtles, because these animals regularly exploit anoxic environments throughout their lifespan.

    more » « less
  4. Abstract

    Modifications of Amazonian forests by pre‐Columbian peoples are thought to have left ecological legacies that have persisted to the modern day. Most Amazonian palaeoecological records do not, however, provide the required temporal resolution to document the nuanced changes of pre‐Columbian disturbance or post‐disturbance succession and recovery, making it difficult to detect any direct, or indirect, ecological legacies on tree species.

    Here, we investigate the fossil pollen, phytolith and charcoal history of Lake Kumpaka, Ecuador, during the last 2,415 years inc. 3–50 year time intervals to assess ecological legacies resulting from pre‐Columbian forest modification, disturbance, cultivation and fire usage.

    Two cycles of pre‐Columbian cultivation (one including slash‐and‐burn cultivation, the other including slash‐and‐mulch cultivation) were documented in the record around 2150–1430 cal. year BP and 1250–680 cal. year BP, with following post‐disturbance succession dynamics. Modern disturbance was documented afterc. 10 cal. year BP. The modern disturbance produced a plant composition unlike those of the two past disturbances, as fire frequencies reached their peak in the 2,415‐year record. The disturbance periods varied in intensity and duration, while the overturn of taxa following a disturbance lasted for hundreds of years. The recovery periods following pre‐Columbian disturbance shared some similar patterns of early succession, but the longer‐term recovery patterns differed.

    Synthesis. The trajectories of change after a cessation of cultivation can be anticipated to differ depending on the intensity, scale, duration and manner of the past disturbance. In the Kumpakarecord, no evidence of persistent enrichment or depletion of intentionally altered taxa (i.e. direct legacy effects) was found but indirect legacy effects, however, were documented and have persisted to the modern day. These findings highlight the strengths of using empirical data to reconstruct past change rather than relying solely on modern plant populations to infer past human management and ecological legacies, and challenge some of the current hypotheses involving the persistence of pre‐Columbian legacies on modern plant populations.

    more » « less
  5. Abstract Objectives

    Lactational programming, through which milk‐borne bioactives influence both neonatal and long‐term biological development, is well established. However, almost no research has investigated how developmental stimuli during a mother's early life may influence her milk bioactives in adulthood. Here, we investigated the association between maternal birth weight and milk epidermal growth factor (EGF) and epidermal growth factor receptor (EGF‐R) in later life. We predicted there would be a decrease in both milk EGF and EGF‐R in the milk produced by mothers who were themselves born low birth weight.


    Study participants are from the Cebu Longitudinal Health and Nutrition Survey. Mothers (n= 69) were followed longitudinally since birth with prospective data collection. Anthropometrics, health, and dietary recalls were collected with early morning milk samples when mothers were 24 to 25 years of age. Milk samples were analyzed for EGF and its receptor (EGF‐R). Analysis of variance was used to test for differences in milk EGF and EGF‐R between low and average birthweight mothers after adjustment for parity, age, and maternal dietary energy intake.


    Mothers who were low birth weight produced milk with significantly less EGF and more EGF‐R which resulted in a lower ratio of EGF to EGF‐R. These associations persisted after adjustment for infant age, maternal adiposity, and dietary energy.


    While this is a small sample size, these preliminary findings suggest that maternal early life characteristics, such as birth weight, may be important contributors to variation in milk bioactives. Future work is necessary to understand how variation in maternal early life may influence milk composition in adulthood.

    more » « less