Linking Colony Size with Foraging Behavior and Brain Investment in Odorous Ants (Formicidae: Dolichoderinae)

2019 ◽  
Vol 95 (1) ◽  
pp. 15-24 ◽  
Author(s):  
R. Keating Godfrey ◽  
Wulfila Gronenberg
Keyword(s):  
Foraging Behavior ◽  
Colony Size ◽  
Antennal Lobe ◽  
Natural Experiment ◽  
Brain Size ◽  
Biological Organization ◽  
Individual Level ◽  
Cell Diversity ◽  
Reproductive Unit ◽  
Small Colony

Superorganisms represent a unique level of biological organization in which the phenotype of the reproductive unit, the colony, results from traits expressed at the level of individual workers. Because body size scaling has important consequences for cell diversity and system complexity in solitary organisms, colony size is a trait of particular interest in superorganism evolution. In some instances, division of labor and worker polymorphism scale with colony size, but in general little is known about how colony size drives differences in individual-level behavior or neural traits. Ants represent the greatest diversity of superorganisms and provide a manner of natural experiment to test trends in trait evolution across multiple instances of colony size expansion. In this study, we control for environmental differences and worker size polymorphism to test if colony size correlates with measures of foraging behavior and brain size in dolichoderine ants. We present data from 3 species ranked by colony size. Our results suggest colony size correlates with measures of exploratory behavior and brain investment, with small-colony ants showing higher exploratory drive and faster exploration rate than the larger colony species, and greater relative investment in the primary olfactory brain region, the antennal lobe, than the larger colony species.

scholarly journals The influence of subcolony-scale nesting habitat on the reproductive success of Adélie penguins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annie E. Schmidt ◽  
Grant Ballard ◽  
Amélie Lescroël ◽  
Katie M. Dugger ◽  
Dennis Jongsomjit ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Colony Size ◽  
Nest Predation ◽  
Size Variation ◽  
Area Ratio ◽  
Slope Aspect ◽  
Nesting Habitat ◽  
Terrain Attributes ◽  
Small Colony ◽  
Adélie Penguins

AbstractGroup-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies was perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.

scholarly journals Improvements in Neighborhood Socioeconomic Conditions May Improve Resident Diet

2020 ◽  
Author(s):  
Andrea S Richardson ◽  
Rebecca L Collins ◽  
Madhumita Ghosh-Dastidar ◽  
Feifei Ye ◽  
Gerald P Hunter ◽  
...  
Keyword(s):  
Low Income ◽  
Structural Equation ◽  
Natural Experiment ◽  
Group Testing ◽  
Positive Association ◽  
Dietary Quality ◽  
Equation Modeling ◽  
Socioeconomic Conditions ◽  
Cross Sectional ◽  
Individual Level

Abstract Neighborhood socioeconomic conditions (NSEC) are associated with resident diet, but most research has been cross-sectional. We capitalize on a natural experiment where one neighborhood experienced substantial investments, compared to a sociodemographically similar neighborhood that did not, in order to examine pathways from neighborhood investments to changed NSEC and changed dietary behavior. We examine differences between renters and homeowners. Data are from a random sample of households (n=831) in each of these low-income Pittsburgh neighborhoods who were surveyed in 2011 and 2014. Structural equation modeling tested direct and indirect pathways from neighborhood to resident dietary quality, adjusting for individual-level sociodemographics, with multi-group testing by homeowners versus renters. Neighborhood investments were directly associated with improved dietary quality for both renters (β, 95% confidence interval [CI]) =0.27, CI: 0.05, 0.50) and homeowners (β=0.51, CI: 0.10, 0.92). Among renters, investments were also associated with dietary quality through a positive association with commercial prices (β= 0.34, CI: 0.15, 0.54) and a negative association with residential prices (β=-0.30, CI: -0.59, -0.004). Among homeowners, we did not observe any indirect pathways from investments to dietary quality through tested mediators. Investing in neighborhoods may support resident diet, doing so through improvements in neighborhood commercial environments for renters, but mechanisms appear to differ for homeowners.

scholarly journals Longitudinal access and exposure to green-blue spaces and individual-level mental health and well-being: protocol for a longitudinal, population-wide record-linked natural experiment

BMJ Open ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. e027289 ◽  
Author(s):  
Amy Mizen ◽  
Jiao Song ◽  
Richard Fry ◽  
Ashley Akbari ◽  
Damon Berridge ◽  
...  
Keyword(s):  
Mental Health ◽  
Natural Experiment ◽  
Research Programme ◽  
Well Being ◽  
Evidence Base ◽  
Academic Community ◽  
Subjective Well Being ◽  
Cross Sectional ◽  
Individual Level ◽  
The Impact

IntroductionStudies suggest that access and exposure to green-blue spaces (GBS) have beneficial impacts on mental health. However, the evidence base is limited with respect to longitudinal studies. The main aim of this longitudinal, population-wide, record-linked natural experiment, is to model the daily lived experience by linking GBS accessibility indices, residential GBS exposure and health data; to enable quantification of the impact of GBS on well-being and common mental health disorders, for a national population.Methods and analysisThis research will estimate the impact of neighbourhood GBS access, GBS exposure and visits to GBS on the risk of common mental health conditions and the opportunity for promoting subjective well-being (SWB); both key priorities for public health. We will use a Geographic Information System (GIS) to create quarterly household GBS accessibility indices and GBS exposure using digital map and satellite data for 1.4 million homes in Wales, UK (2008–2018). We will link the GBS accessibility indices and GBS exposures to individual-level mental health outcomes for 1.7 million people with general practitioner (GP) data and data from the National Survey for Wales (n=~12 000) on well-being in the Secure Anonymised Information Linkage (SAIL) Databank. We will examine if these associations are modified by multiple sociophysical variables, migration and socioeconomic disadvantage. Subgroup analyses will examine associations by different types of GBS. This longitudinal study will be augmented by cross-sectional research using survey data on self-reported visits to GBS and SWB.Ethics and disseminationAll data will be anonymised and linked within the privacy protecting SAIL Databank. We will be using anonymised data and therefore we are exempt from National Research Ethics Committee (NREC). An Information Governance Review Panel (IGRP) application (Project ID: 0562) to link these data has been approved.The research programme will be undertaken in close collaboration with public/patient involvement groups. A multistrategy programme of dissemination is planned with the academic community, policy-makers, practitioners and the public.

Gamifying with badges: A big data natural experiment on Stack Exchange

First Monday ◽  
2017 ◽  
Author(s):  
Benny Bornfeld ◽  
Sheizaf Rafaeli
Keyword(s):  
Big Data ◽  
Effect Size ◽  
Natural Experiment ◽  
User Behavior ◽  
Online Systems ◽  
Individual Level ◽  
The Individual

Badges are a common gamification mechanism used by many crowd-sourced online systems. This study provides evidence to their effectiveness and measures their effect size using a big data natural experiment in three large Stack Exchange online Q&A sites. We analyze the introduction of 22 different badge-launch events and the resulting changes in user behavior. Consistent with earlier studies, we report that most badge introductions have the desired effect. Going beyond traditional findings on the individual level, this study measures overall badge effect size on the service.

scholarly journals FISSION IN THE ZOANTHARIA PALYTHOA CARIBAEORUM (Duchassaing and Michelotii, 1860) POPULATIONS: A LATITUDINAL COMPARISON

2016 ◽  
Vol 36 ◽  
Author(s):  
Alberto Acosta ◽  
Ana M. González
Keyword(s):  
Colony Size ◽  
Reproductive Output ◽  
Abiotic Factors ◽  
Regional Studies ◽  
Fission Process ◽  
Palythoa Caribaeorum ◽  
Large Numbers ◽  
Small Colony ◽  
The Relationship ◽  
Brazilian Populations

There are few regional studies attempting to compare the asexual reproductive output of marine populations, particularly when they are exposed to different environmental conditions. In this study we compared Caribbean and Southwestern Atlantic Palythoa caribaeorum populations in terms of ramet production, the minimum colony size for fission, and the relationship between fission frequency and colony size. Fission process was quantified in Ponta Recife and Praia Portinho, Sao Paulo, Brazil, and in Punta de Betín, Colombia, during the summer (December-January) of 1997 and 1998, respectively. Fission started at small colony size in both populations studied (> 4 cm2). The number of ramets produced per colony increased with colony size in Brazil and Colombia. Colombian zoanthids produced more ramets by fission than Brazilian populations. The populations shared early reproduction characteristics, and production of large numbers of ramets, which increased with colony size, even though they differed in fission frequency. Fission seems to be a conservative trait in P. caribaeorum, although its expression could vary depending on habitat conditions related to biotic and / or abiotic factors.

scholarly journals Asymmetry in genitalia is in sync with lateralized mating behavior but not with the lateralization of other behaviors

2019 ◽  
Vol 66 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Julián Torres-Dowdall ◽  
Sina J Rometsch ◽  
Gastón Aguilera ◽  
Guillermo Goyenola ◽  
Axel Meyer
Keyword(s):  
Natural Populations ◽  
Laboratory Population ◽  
Genital Morphology ◽  
Wild Populations ◽  
Biological Organization ◽  
Individual Level ◽  
Series Of Experiments ◽  
The Right ◽  
Different Levels ◽  
Study Species

Abstract Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm. They allow the investigation of the integration at different levels of biological organization. Here we study whether and how behavioral and asymmetrical anatomical traits co-evolved and work together. We ask if asymmetry is determined locally for each trait or at a whole individual level in a species bearing conspicuous asymmetrical genitalia. Asymmetric genitalia evolved in many species; however, in most cases the direction of asymmetry is fixed. Therefore, it has been rarely determined if there is an association between the direction of asymmetry in genitalia and other traits. In onesided livebearer fish of the genus Jenynsia (Cyprinodontiformes, Anablepidae), the anal fin of males is modified into a gonopodium, an intromittent organ that serves to inseminate females. The gonopodium shows a conspicuous asymmetry, with its tip bending either to the left or the right. By surveying 13 natural populations of Jenynsia lineata, we found that both genital morphs are equally common in wild populations. In a series of experiments in a laboratory population, we discovered asymmetry and lateralization for multiple other traits; yet, the degree of integration varied highly among them. Lateralization in exploratory behavior in response to different stimuli was not associated with genital morphology. Interestingly, the direction of genital asymmetry was positively correlated with sidedness of mating preference and the number of neuromasts in the lateral line. This suggests integration of functionally linked asymmetric traits; however, there is no evidence that asymmetry is determined at the whole individual level in our study species.

The effect of the National Birth Defects Intervention Project on the prevention of congenital disabilities among children in China: a natural experiment

2020 ◽  
Vol 124 (7) ◽  
pp. 709-714
Author(s):  
Chao Guo ◽  
Xiaoying Zheng
Keyword(s):  
Birth Defects ◽  
Natural Experiment ◽  
National Sample ◽  
Nutrition Intervention ◽  
Sample Survey ◽  
Birth Cohorts ◽  
Individual Level ◽  
Level Data ◽  
Nationally Representative ◽  
Congenital Disability

AbstractMost childhood disabilities are caused by congenital factors such as birth defects. The present study aims to evaluate the effect of periconceptional nutrition intervention on the prevention of congenital disability among Chinese children using the National Birth Defects Intervention Project as a natural experiment. We obtained individual-level data from the Second National Sample Survey on Disability, a nationally representative survey, and 110 365 children born between September 1999 and August 2003 were included for analysis. Difference-in-differences estimates of the project effects on congenital disability were captured by exploiting temporal variation in the timing of project exposure across four birth cohorts along with geographical variation in project category at the province level. The findings contribute to an emerging body of evidence showing that prenatal micronutrient intervention before and during early pregnancy could substantially reduce the risk of congenital disability in childhood (OR 0·73; 95 % CI 0·57, 0·94). The National Birth Defects Intervention Project improved the awareness of reproductive health and disability prevention in the population. It highlights the need for a potential policy change focusing on early-life health investment in China.

scholarly journals Modularity and connectivity of nest structure scale with colony size

2021 ◽  
Author(s):  
Julie Serena Miller ◽  
Emma Wan ◽  
Noa Pinter-Wollman
Keyword(s):  
Colony Size ◽  
Large Body ◽  
Nest Structure ◽  
Biological Organization ◽  
Ant Colonies ◽  
Body Sizes ◽  
Meta Analyses ◽  
Alternative Routes ◽  
Structural Solutions ◽  
Travel Distances

Large body sizes have evolved structures to facilitate resource transport. Like unitary organisms, social insect colonies must transport information and resources, and colonies with more individuals may experience transport challenges similar to large-bodied organisms. In ant colonies, transport occurs in the nest, which may consist of structures that facilitate movement. We examine three attributes of nest structures that could mitigate transport challenges related to colony size: (1) subdivision: nests of species with large colonies are more subdivided to reduce viscosity of large crowds; (2) branching: nest tunnels increase branching in species with large colonies to reduce travel distances; and (3) short-cuts: nests of species with large colonies have cross-linking tunnels to connect distant parts of the nest and create alternative routes. We test these hypotheses by comparing nest structures of species with different colony sizes in phylogenetically controlled meta-analyses. Our findings support the subdivision and branching hypotheses. The nests of species with large colonies contain more, but not larger, chambers and reduce travel distances by increasing branching frequency. The similarity in how ant nests and the bodies of unitary organisms respond to increasing size suggests structural solutions that are common across levels of biological organization.

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