scholarly journals Island tameness and the repeatability of flight initiation distance in a large herbivore

2017 ◽  
Vol 95 (10) ◽  
pp. 771-778 ◽  
Author(s):  
Doreen Cabrera ◽  
Daniel Andres ◽  
Philip D. McLoughlin ◽  
Lucie Debeffe ◽  
Sarah A. Medill ◽  
...  
Keyword(s):  
Risk Aversion ◽  
Evolutionary Dynamics ◽  
Flight Initiation Distance ◽  
Time Intervals ◽  
Large Herbivore ◽  
Feral Horses ◽  
Sex Effects ◽  
Males And Females ◽  
Temporal And Spatial ◽  
Flight Initiation

Antipredator behaviours can be lost relatively quickly in populations that are relieved of predation, as is known for several species inhabiting islands. Flight initiation distance (FID) is often studied in the context of island tameness; however, little is known about the factors that influence and maintain FID variation in predation-free populations. Here, we studied FID in foals of an isolated predator-free population of feral horses (Equus caballus L., 1758) on Sable Island, Canada, to determine if FID could be used for research on consistent individual differences in risk aversion and island tameness. In addition to testing for temporal, spatial, and sex effects on FID, we compared repeatability estimates at two temporal scales (within and among days). Similar FID for measurements obtained on the same day and for males and females indicated an absence of short-term desensitization and sex effects. In contrast, FID decreased for measurements made on subsequent days and from east to west, which could reflect habituation to human presence and (or) other temporal and spatial processes. Repeatability was high (0.42 ± 0.06), but tended to decrease with increasing time intervals. This study highlights the potential of FID for individual-based research on the ecology and evolutionary dynamics of risk aversion in predation-free populations.

scholarly journals Flight initiation distance of Urosaurus ornatus from the Sierra de Samalayuca, Mexico

2021 ◽  
Vol 16 (1) ◽  
pp. 53-57
Author(s):  
Julio A. Lemos-Espinal ◽  
Geoffrey R. Smith
Keyword(s):  
Substrate Temperature ◽  
Flight Initiation Distance ◽  
Extrinsic Factors ◽  
Urosaurus Ornatus ◽  
Tree Lizards ◽  
Study Population ◽  
Males And Females ◽  
Intrinsic And Extrinsic Factors ◽  
Flight Initiation ◽  
Prey Individual

In lizards, flight initiation distance (FID), the distance between a prey individual and a predator when escape begins, can be affected by numerous intrinsic and extrinsic factors, including sex, temperature, and level of conspicuousness. Here we report on a study of FID in a population of Ornate Tree Lizards, Urosaurus ornatus, from the Sierra de Samalyuca, Chihuahua, Mexico which are cryptic due to their dorsal coloration blending into their background. Urosaurus ornatus in our study population allowed close approaches (mean FID = 65 cm). Mean FID did not differ between males and females. We also found no effect of body, air, or substrate temperature on FID. The short FID we observed may be related to the cryptic nature of U. ornatus.

scholarly journals European birds adjust their flight initiation distance to road speed limits

2013 ◽  
Vol 9 (5) ◽  
pp. 20130417 ◽  
Author(s):  
Pierre Legagneux ◽  
Simon Ducatez
Keyword(s):  
Habitat Structure ◽  
Territory Size ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Flight Initiation Distance ◽  
Speed Limits ◽  
Behavioural Responses ◽  
Road Speed ◽  
Flight Initiation ◽  
Local Speed

Behavioural responses can help species persist in habitats modified by humans. Roads and traffic greatly affect animals' mortality not only through habitat structure modifications but also through direct mortality owing to collisions. Although species are known to differ in their sensitivity to the risk of collision, whether individuals can change their behaviour in response to this is still unknown. Here, we tested whether common European birds changed their flight initiation distances (FIDs) in response to vehicles according to road speed limit (a known factor affecting killing rates on roads) and vehicle speed. We found that FID increased with speed limit, although vehicle speed had no effect. This suggests that birds adjust their flight distance to speed limit, which may reduce collision risks and decrease mortality maximizing the time allocated to foraging behaviours. Mobility and territory size are likely to affect an individuals' ability to respond adaptively to local speed limits.

scholarly journals Increasing corvid tolerance to humans in urban ecosystems with increasing latitude

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Nadezhda Poddubnaya ◽  
Tatyana Korotkova ◽  
Polina Vanicheva
Keyword(s):  
Environmental Factors ◽  
Human Disturbance ◽  
Urban Ecosystems ◽  
Flight Initiation Distance ◽  
Protection Measures ◽  
Non Invasive ◽  
Alert Distance ◽  
Behaviour Changes ◽  
Hooded Crows ◽  
Flight Initiation

The rapid growth of cities causes behaviour changes in birds in response to urban environmental factors. The avian response to human disturbance has recently been studied by a non-invasive research tool as an alert distance (AD) and a flight initiation distance (FID) assessment. The tolerance of hooded crows (n = 395), jackdaws (n = 394) and rooks (n = 169) to humans was assessed by AD and FID. It was shown that the FID of all species is maximal during the summer, when the parents send clear “danger—fly away” signals to the young and the birds fly away. The AD and FID of the three species reliably correlates with the season. Rooks showed FID species-specificity in seven cities of Eastern Europe. Comparison of the attitude of birds to people in cities that have similarities in human culture showed that tolerance increases with increasing latitude in all species and is statistically significant only in the jackdaw. This should be taken into account in environmental protection measures.

scholarly journals Maximum likelihood estimation of fitness components in experimental evolution

2018 ◽  
Author(s):  
Jingxian Liu ◽  
Jackson Champer ◽  
Chen Liu ◽  
Joan Chung ◽  
Riona Reeves ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Experimental Evolution ◽  
Evolutionary Dynamics ◽  
Likelihood Estimation ◽  
Loss Of Function ◽  
Wild Type ◽  
Fitness Components ◽  
Linked Gene ◽  
Males And Females

AbstractEstimating fitness differences between allelic variants is a central goal of experimental evolution. Current methods for inferring selection from allele frequency time series typically assume that evolutionary dynamics at the locus of interest can be described by a fixed selection coefficient. However, fitness is an aggregate of several components including mating success, fecundity, and viability, and distinguishing between these components could be critical in many scenarios. Here we develop a flexible maximum likelihood framework that can disentangle different components of fitness and estimate them individually in males and females from genotype frequency data. As a proof-of-principle, we apply our method to experimentally-evolved cage populations of Drosophila melanogaster, in which we tracked the relative frequencies of a loss-of-function and wild-type allele of yellow. This X-linked gene produces a recessive yellow phenotype when disrupted and is involved in male courtship ability. We find that the fitness costs of the yellow phenotype take the form of substantially reduced mating preference of wild-type females for yellow males, together with a modest reduction in the viability of yellow males and females. Our framework should be generally applicable to situations where it is important to quantify fitness components of specific genetic variants, including quantitative characterization of the population dynamics of CRISPR gene drives.

Take only pictures, leave only… Cameras influence marmot vigilance but not perceptions of risk

2021 ◽  
Author(s):  
Kenta Uchida ◽  
Albert A. Burkle ◽  
Daniel T. Blumstein
Keyword(s):  
Risk Assessment ◽  
Predation Risk ◽  
Visual Stimulus ◽  
Zoom Lens ◽  
Flight Initiation Distance ◽  
Vulnerable Species ◽  
Species Ranges ◽  
Perceptions Of Risk ◽  
Flight Initiation ◽  
Subsequent Risk

Ecotourism promotes conservation efforts while also allowing for low impact observation of wildlife. Many ecotourists photograph wildlife and photography plays an important role in focusing the public’s attention on nature. Although photography is commonly believed to be a low impact activity, how the visual stimulus of a camera influences wildlife remains unknown. Since animals are known to fear eyes pointed towards them, we predicted that a camera with a large zoom lens would increase animal’s vigilance levels. Using yellow-bellied marmots (Marmota flaviventer) as a mammalian model, and adopting a behavioural approach to identify how marmots responded to cameras, we experimentally quantified vigilance and flight initiation distance towards humans when marmots were approached with and without a camera. While a camera was pointed at an individual, marmots allocated less time to searching predators and increased time to looking at the observer than they did without a camera. However, whether a camera was pointed at a marmot or not had no effect on the distance the marmot flushed. Our results indicated that cameras distracted marmots but did not influence subsequent risk assessment (i.e., flight initiation distance); marmots may be curious about cameras but were not threatened by them. Capturing animals’ attentions reduces searching for predators and may increase the vulnerability to predation. Therefore, regulating photography in locations where predation risk is high or vulnerable species ranges’ overlap with humans may be required to reduce photography’s impact on wildlife.

Crypsis influences escape decisions in the Round-tailed Horned Lizard (Phrynosoma modestum)

2010 ◽  
Vol 88 (10) ◽  
pp. 1003-1010 ◽  
Author(s):  
William E. Cooper, ◽  
Wade C. Sherbrooke
Keyword(s):  
Body Temperature ◽  
Predation Risk ◽  
Upright Posture ◽  
Flight Initiation Distance ◽  
Lower Body ◽  
Running Speed ◽  
Predator Prey ◽  
Sandy Area ◽  
Lower Body Temperature ◽  
Flight Initiation

Flight initiation distance (predator–prey distance when escape begins) increases as predation risk increases. Prey should have longer flight initiation distance when their background, movement, or current posture reduces crypsis. Flight initiation distance of ectotherms may increase at lower body temperature to compensate for slower running speed. However, for cryptic prey, fleeing might increase the probability of being detected. The Round-tailed Horned Lizard ( Phrynosoma modestum Girard, 1852) is eucryptic and resembles small stones. We predicted that flight initiation distance by P. modestum is shorter among stones than on uniform sand. Because movement and upright posture disrupt crypsis, we predicted that flight initiation distance is greater after movement and when standing than when still and lying on the ground. As predicted, flight initiation distances were shorter on a rocky than sandy area, when lying flat than standing, and while immobile than after moving. We measured running speed and flight initiation distance to determine relationships among body temperature, speed, and escape decisions. Running speed and flight initiation distance were reduced at lower body temperature, suggesting that crypsis reinforced by immobility is more advantageous than longer flight initiation distance for cool, slow lizards. The lizards adjusted escape decisions to current effectiveness of crypsis and escape ability.

scholarly journals Variable Rates of Simple Satellite Gains across the Drosophila Phylogeny

2018 ◽  
Vol 35 (4) ◽  
pp. 925-941 ◽  
Author(s):  
Kevin H -C Wei ◽  
Sarah E Lower ◽  
Ian V Caldas ◽  
Trevor J S Sless ◽  
Daniel A Barbash ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Rapid Evolution ◽  
Single Mutation ◽  
Closely Related Species ◽  
Interspecific Differences ◽  
Limited Sampling ◽  
Drosophila Phylogeny ◽  
Males And Females ◽  
Species Specific ◽  
Turn Over

Abstract Simple satellites are tandemly repeating short DNA motifs that can span megabases in eukaryotic genomes. Because they can cause genomic instability through nonallelic homologous exchange, they are primarily found in the repressive heterochromatin near centromeres and telomeres where recombination is minimal, and on the Y chromosome, where they accumulate as the chromosome degenerates. Interestingly, the types and abundances of simple satellites often vary dramatically between closely related species, suggesting that they turn over rapidly. However, limited sampling has prevented detailed understanding of their evolutionary dynamics. Here, we characterize simple satellites from whole-genome sequences generated from males and females of nine Drosophila species, spanning 40 Ma of evolution. We show that PCR-free library preparation and postsequencing GC-correction better capture satellite quantities than conventional methods. We find that over half of the 207 simple satellites identified are species-specific, consistent with previous descriptions of their rapid evolution. Based on a maximum parsimony framework, we determined that most interspecific differences are due to lineage-specific gains. Simple satellites gained within a species are typically a single mutation away from abundant existing satellites, suggesting that they likely emerge from existing satellites, especially in the genomes of satellite-rich species. Interestingly, unlike most of the other lineages which experience various degrees of gains, the lineage leading up to the satellite-poor D. pseudoobscura and D. persimilis appears to be recalcitrant to gains, providing a counterpoint to the notion that simple satellites are universally rapidly evolving.

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