Animal Preference Research Articles

Inversion of pheromone preference optimizes foraging in C. elegans.

Foraging animals have to locate food sources that are usually patchily distributed and subject to competition. Deciding when to leave a food patch is challenging and requires the animal to integrate information about food availability with cues signaling the presence of other individuals (e.g., pheromones). To study how social information transmitted via pheromones can aid foraging decisions, we investigated the behavioral responses of the model animal Caenorhabditis elegans to food depletion and pheromone accumulation in food patches. We experimentally show that animals consuming a food patch leave it at different times and that the leaving time affects the animal preference for its pheromones. In particular, worms leaving early are attracted to their pheromones, while worms leaving later are repelled by them. We further demonstrate that the inversion from attraction to repulsion depends on associative learning and, by implementing a simple model, we highlight that it is an adaptive solution to optimize food intake during foraging.

The use of protein binders and sorghum crisps as potential ingredients in a cereal bar for dogs

AbstractThis study aimed to evaluate the inclusion of different protein binders and sorghum crisps in cereal bars for dogs and their effect on sensory properties, product texture, and dog preference. Fifteen cereal bars were developed in which three crisp sources (rice crisp, white and red sorghum crisp) and five sources of binders (corn syrup, spray dried plasma, gelatin, albumin, and egg product) were evaluated. An interaction effect between binder and crisp sources was found for textural properties (p <.05). A total of 103 volatile compounds were identified and semi‐quantified in the cereal bar samples, with aldehydes being the most represented. Unlike crisp source, protein binders played a major role on sensory properties and impacted the dog's preference. This study suggests that sorghum crisps and protein binders may be used in cereal bars for dogs; however, considerations regarding sensory attributes and dog's preference should be taken to maximize product acceptance.Practical applicationsThis is the first study to report information regarding the use of novel ingredients in a cereal bar application for dogs. The findings observed wherein provide a comprehensive understanding about product development and the impact of ingredients on final product quality, sensory properties, and animal preference. The methodologies and outcomes of our work can be directly translated to the pet food industry to aid in the development of dog treats.

Plant competition under simultaneous adaptation by herbivores and pollinators

Two plants can influence one another indirectly by affecting population dynamics of shared exploiters and/or shared mutualists, giving rise to apparent competition or apparent mutualism, respectively. Indirect interactions between plants also occur when the preferences of exploiters and mutualists adapt to changes in relative plant densities. Here we study simultaneous effects of adaptive herbivore and pollinator preferences on the dynamics of two competing plant populations. As a result of feedbacks between plant dynamics and adaptive animal preferences, plants coexist at alternative stable states. This outcome is favored at low abundances of herbivores and pollinators when consumers tend to specialize on a single plant. As herbivore and pollinator abundances increase, generalism becomes more common. This promotes plant coexistence by balancing antagonistic and mutualistic effects between plants. Plant community dynamics become also more predictable due to reduction in the number of alternative stable states. This shows that the global decline in insect populations can lead to structural changes in plant communities that are difficult to predict.

Toddlers and Preschoolers Understand That Some Preferences Are More Subjective Than Others.

Four experiments examined Canadian 2- to 3-year-old children's (N=224; 104 girls, 120 boys) thoughts about shared preferences. Children saw sets of items, and identified theirs and another person's preferences. Children expected that food preferences would be more likely to be shared than color preferences, regardless of whether the items were similar or different in appeal (Experiments 1-3). A final study replicated these findings while also exploring children's expectations about activity and animal preferences. Across all studies, children expected shared preferences at surprisingly low rates (never higher than chance). Overall, these findings suggest that young children understand that some preferences are more subjective than others, and that these expectations are driven by beliefs about domains of preferences.

Stability and individual variability of social attachment in imprinting

Filial imprinting has become a model for understanding memory, learning and social behaviour in neonate animals. This mechanism allows the youngs of precocial bird species to learn the characteristics of conspicuous visual stimuli and display affiliative response to them. Although longer exposures to an object produce stronger preferences for it afterwards, this relation is not linear. Sometimes, chicks even prefer to approach novel rather than familiar objects. To date, little is known about how filial preferences develop across time. This study aimed to investigate filial preferences for familiar and novel imprinting objects over time. After hatching, chicks were individually placed in an arena where stimuli were displayed on two opposite screens. Using an automated setup, the duration of exposure and the type of stimuli were manipulated while the time spent at the imprinting stimulus was monitored across 6 days. We showed that prolonged exposure (3 days vs 1 day) to a stimulus produced robust filial imprinting preferences. Interestingly, with a shorter exposure (1 day), animals re-evaluated their filial preferences in functions of their spontaneous preferences and past experiences. Our study suggests that predispositions influence learning when the imprinting memories are not fully consolidated, driving animal preferences toward more predisposed stimuli.

Children’s sleepiness facilitates the effect of vicarious learning on the development of fear

A substantial body of research demonstrates the importance of sleep for emotional processing and learning as well as the association between sleep problems and heightened anxiety. However, there is currently no research exploring the impact of sleepiness on vicariously learned fear responses. Experiment 1 (N = 38) first demonstrated no effect of trait or state sleepiness on children’s (7–11 years of age) subjective ratings of fear. Experiment 2 (N = 42) and Experiment 3 (N = 46) used an established vicarious learning paradigm to demonstrate that trait sleepiness facilitated vicariously acquired avoidance preferences for animals paired with fearful faces (fear-paired animals), whereas state sleepiness facilitated children’s fear cognitions and attentional bias toward fear-paired animals. This study is the first to demonstrate the role of state and trait sleepiness in moderating vicarious fear learning in children.

The irrelevancy of the inter-trial interval in delay-discounting experiments on an animal model of ADHD

Delay discounting involves choosing between a small, immediate reward, and a larger but delayed one. As the delay between choice and large reward gets longer, people with ADHD tend to become impulsive faster than controls, indicated by a switch in preference from the large to the smaller reward. Choosing the smaller reward when the larger is considered reward maximizing is labeled impulsive behaviour. It is well documented that increased delays between choice and reward affects choice preference in both humans and other animals. Other variables such as the inter-trial interval or trial length are observed to have an effect on human discounting, but their effect on discounting in other animals is largely assumed rather than tested. In the current experiment, we tested this assumption. One group of rats was exposed to increasing delays between choosing the large reward and receiving it, while another group experienced longer inter-trial intervals that were equal in length to the delays in the other group. This ensured that trial length was controlled for in delay discounting, but that the delay function and inter-trial intervals could be manipulated and measured separately. Results showed that while the delay between choice and reward caused impulsive behaviour in rats, the length of the inter-trial interval (and by extension trial length) had no impact on choice behaviour. A follow-up experiment found this to be the case even if the length of the inter-trial interval was signaled with audio cues. These results suggest that rats, and possibly animals in general, are insensitive to time between trials, and therefore cannot easily represent human counterparts on the task.

RETRACTED: The imprinted lncRNA Peg13 regulates sexual preference and the sex-specific brain transcriptome in mice

Mammalian genomes include many maternally and paternally imprinted genes. Most of these are also expressed in the brain, and several have been implicated in regulating specific behavioral traits. Here, we have used a knockout approach to study the function of Peg13, a gene that codes for a fast-evolving lncRNA (long noncoding RNA) and is part of a complex of imprinted genes on chromosome 15 in mice and chromosome 8 in humans. Mice lacking the 3' half of the transcript look morphologically wild-type but show distinct behavioral differences. They lose interest in the opposite sex, instead displaying a preference for wild-type animals of the same sex. Further, they show a higher level of anxiety, lowered activity and curiosity, and a deficiency in pup retrieval behavior. Brain RNA expression analysis reveals that genes involved in the serotonergic system, formation of glutamatergic synapses, olfactory processing, and estrogen signaling-as well as more than half of the other known imprinted genes-show significant expression changes in Peg13-deficient mice. Intriguingly, these pathways are differentially affected in the sexes, resulting in male and female brains of Peg13-deficient mice differing more from each other than those of wild-type mice. We conclude that Peg13 is part of a developmental pathway that regulates the neurobiology of social and sexual interactions.

The evaluation by passes energy based on in vitro gas production digestibility and palatability

The purpose of this study was to evaluate the influence of combined treatments of the fish oil protected with different NaOH concentration and drying method as bypass energy based in vitro total gas production and palatability. Lemuru fish oil, starch and NaOH were used for capsulation and optimizing saponification, along with CaCl2 and required reagents were used for in vitro gas test. The indicators for protected fish oil palatability test were 18 female lamb, aged 7-8 months, with average weight 15.37 ± 1.09 kg. A completely randomized design was deployed for in vitro gas production with three replications in which different NaOH concentrations and drying methods were applied. Then, to see the results of the animal preference level, it was by reducing the feeding time and feeding residue in 24 hours. All data was analysed using analysis of variance (ANOVA) with Duncan test. As a results, fish oil protected with different NaOH concentration and drying method have no significant effect on total gas production. Furthemore, the results on the palatability analysis showed that there was no significant different in all treatments.

Variation in primate decision-making under uncertainty and the roots of human economic behaviour.

Uncertainty is a ubiquitous component of human economic behaviour, yet people can vary in their preferences for risk across populations, individuals and different points in time. As uncertainty also characterizes many aspects of animal decision-making, comparative research can help evaluate different potential mechanisms that generate this variation, including the role of biological differences or maturational change versus cultural learning, as well as identify human-unique components of economic decision-making. Here, we examine decision-making under risk across non-human primates, our closest relatives. We first review theoretical approaches and current methods for understanding decision-making in animals. We then assess the current evidence for variation in animal preferences between species and populations, between individuals based on personality, sex and age, and finally, between different contexts and individual states. We then use these primate data to evaluate the processes that can shape human decision-making strategies and identify the primate foundations of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Assessing Preference in a Paired-Stimulus Arrangement with Captive Vultures (Aegypius Monachus)

ABSTRACT Vultures play an important role in our ecosystem by filtering out bacteria and viruses harmful to humans (e.g., rabies, botulism). However, many vultures remain in human care due to skill deficits and behavioral excesses, which can be treated using behavior-management practices that rely on effective (often edible) reinforcers. The current study replicated the forced-choice or paired-stimulus preference assessment with five birds of prey. Across all vultures, participants displayed a preference for animal (e.g., meat) over nonanimal stimuli (e.g., fruit), and mice meat was the most preferred edible for 4 of the 5 vultures. The application of this methodology to birds of prey might allow rehabilitators, conservationists, and other caretakers to make greater gains in training vultures to both acquire new skills and decrease problem behavior using highly preferred edible items.

PSI-19 Preference grazing evaluation of new forage varieties, and the effect of animal temperament on grazing behaviour

Abstract In Canada, new forage varieties need not undergo grazing trials before registration and sale. As such, little is known about forage performance under grazing, or how animal preference and temperament affect grazing behaviour. To determine these effects, 6 cool-season forage species including meadow bromegrass (Bromus bieberseinii), orchardgrass (Dactylis glomerate L.), sainfoin (Onobrychis viciifoila ssp. Viciifolia) and three alfalfa varieties (Medicago sativa L.) were established in monoculture and grass-legume binary mixtures (14 treatments) at the Livestock and Forage Centre of Excellence (Saskatchewan, Canada). Forages were seeded in randomized adjacent 0.3 ha (21 × 125 m) strips within each of three, 5 ha paddocks. Sixty-nine Bos taurus crossbred steers (396 ± 34 kg BW) were homogenously allocated to the 3 paddocks for grazing observations. Individual steer temperament was characterized via novel object and corridor tests prior to grazing. The 9 steers showing the most bold or shy temperaments were labelled for identification while grazing. The grazing period length was 19 d, from July 27 to August 15, 2019, with observations made during the first six days. Observers determined forage preference based upon the number of animals grazing each forage type every 30 min for 2 h in the morning and 2 h in the evening. Animal preference did not differ (P > 0.05) between the forage treatments. Yield of grass and legume components did not differ (P > 0.05) between monocultures or binary mixtures (1255 kg ha-1 ± 277 kg ha-1). Steer temperament affected (P < 0.0001) animal distribution, with bold steers traveling further from the center of the paddock than shy steers or average herd animals (P < 0.05). These preliminary results indicate that differences in grazing behaviour were due to individual animal temperament rather than forage preference or performance.

17 Comparing Natural Vegetation and Food Plot Preference against Supplemental Protein Pellets in Captive White-tailed Deer (Odocoileus virginianus) and Exotic Species

Abstract Supplemental feed is the most expensive input in the captive wildlife industries. This is due to operations utilizing high-energy pellets as supplemental feed. Low fence operations often utilize food plots with high quality vegetation to minimize cost and increase forage availability for wildlife. The objective of this study was to determine forage preference of animals in captivity, and determine the most cost effective method of supplemental feeding. Seven food plots covering 25 acres contained one of three treatments. The treatments were: a commercial blend of soybeans; a commercial blend of soybeans, sunflowers, and milo; native/unplanted. Three utilization cages were set up to inhibit wildlife access to samples within each food plot to act as a control. Height of vegetative samples, inside and outside of the utilization cages, was collected on days 30, 60, and 90 after planting. The 30-d sample showed a preference of native/unplanted vegetation over the commercial treatments, P < 0.05. However, samples taken on days 60 and 90 showed the preference shifted toward the commercial blends, P < 0.05. This browsing preference indicates stage of maturity had an impact on plant selection. Regardless of sample date, the commercial blends showed a difference of P < 0.01, selecting the soybean blend more frequently. With an increased selection of the forages in the food plots, there was a decrease in cost of purchasing feed pellets with a total savings of approximately $5,500.00 from April 5-July 5, 2019. These results suggest that white-tailed deer and exotic species in captivity prefer forages compared to pelleted feed. Supplemental feeding programs that include food plots could allow for natural feeding tendencies, while being more cost effective for operations in the captive wildlife industries.

16 Comparing Natural Vegetation and Food Plot Preference against Supplemental Protein Pellets in Captive White-tailed Deer (Odocoileus virginianus) and Exotic Species

Abstract Supplemental feed is the most expensive input in the captive wildlife industries. This is due to operations utilizing high-energy pellets as supplemental feed. Low fence operations often utilize food plots with high quality vegetation to minimize cost and increase forage availability for wildlife. The objective of this study was to determine forage preference of animals in captivity, and determine the most cost effective method of supplemental feeding. Seven food plots covering 25 acres contained one of three treatments. The treatments were: a commercial blend of soybeans; a commercial blend of soybeans, sunflowers, and milo; native/unplanted. Three utilization cages were set up to inhibit wildlife access to samples within each food plot to act as a control. Height of vegetative samples, inside and outside of the utilization cages, was collected on days 30, 60, and 90 after planting. The 30-day sample showed a preference of native/unplanted vegetation over the commercial treatments, P < 0.05. However, samples taken on days 60 and 90 showed the preference shifted toward the commercial blends, P < 0.05. This browsing preference indicates stage of maturity had an impact on plant selection. Regardless of sample date, the commercial blends showed a difference of P < 0.01, selecting the soybean blend more frequently. With an increased selection of the forages in the food plots, there was a decrease in cost of purchasing feed pellets with a total savings of approximately $5,500.00 from April 5-July 5, 2019. These results suggest that white-tailed deer and exotic species in captivity prefer forages compared to pelleted feed. Supplemental feeding programs that include food plots could allow for natural feeding tendencies, while being more cost effective for operations in the captive wildlife industries.

Suitable nesting sites for specialized cavity dependent wildlife are rare in woodlands

Non-excavating species that prefer rare combinations of cavity traits are limited to only a fraction of the available tree cavity resource. Understanding animal preferences and quantifying the abundance of suitable cavities is fundamental to protecting non-excavators. We aimed to identify the traits of trees and cavities selected by a vulnerable, non-excavating bird, the superb parrot Polytelis swainsonii. We also evaluated cavity abundance and the accuracy of ground-based survey techniques (where an observer estimated the number of cavities in the canopy with binoculars from the ground). We then climbed trees to accurately identify true cavities and to measure their internal dimensions. Ground-based counts of tree cavities were correlated with the true number of cavity entrances in trees. When trees had zero cavities, ground counts overestimated their abundance, but for cavity-bearing trees ground counts underestimated their abundance. We found that superb parrot nest trees contained more cavities than random trees. Superb parrots selected cavities that were deeper, with wider floors and entrance sizes than random cavities. Cavities with the combination of selected traits comprised only 0.5% of the standing cavity resource. Our results confirm that non-excavators can be very selective about the types of trees and cavities they use for nesting. Rarity of suitable cavities may be a factor limiting the population growth and recovery of superb parrots. Without accounting for the critical information gap between what is observed on the ground, and what is in fact present in trees, effective habitat management for non-excavators may be compromised by inaccurate assessments of cavity abundance and conservation status.

Cellular metabolic reprogramming controls sugar appetite in Drosophila.

Cellular metabolic reprogramming is an important mechanism by which cells rewire their metabolism to promote proliferation and cell growth. This process has been mostly studied in the context of tumorigenesis, but less is known about its relevance for nonpathological processes and how it affects whole-animal physiology. Here, we show that metabolic reprogramming in Drosophila female germline cells affects nutrient preferences of animals. Egg production depends on the upregulation of the activity of the pentose phosphate pathway in the germline, which also specifically increases the animal's appetite for sugar, the key nutrient fuelling this metabolic pathway. We provide functional evidence that the germline alters sugar appetite by regulating the expression of the fat-body-secreted satiety factor Fit. Our findings demonstrate that the cellular metabolic program of a small set of cells is able to increase the animal's preference for specific nutrients through inter-organ communication to promote specific metabolic and cellular outcomes.

Simultaneous estimation of seasonal population density, habitat preference and catchability of wild boars based on camera data and harvest records.

Analyses of life history and population dynamics are essential for effective population control of wild mammals. We developed a model for the simultaneous estimation of seasonal changes in three parameters—population density, habitat preference and trap catchability of target animals—based on camera-trapping data and harvest records. The random encounter and staying time model, with no need for individual recognition, is the core component of the model—by combining this model with the catch-effort model, we estimated density at broad spatial scales and catchability by traps. Here, the wild boar population in central Japan was evaluated as a target population. We found that the estimated population density increased after the birth period and then decreased until the next birth period, mainly due to harvesting. Habitat preference changed seasonally, but forests having abandoned fields nearby were generally preferred throughout the season. These patterns can be explained by patterns of food availability and resting or nesting sites. Catchability by traps also changed seasonally, with relatively high values in the winter, which probably reflected changes in the attractiveness of the trap bait due to activity changes in response to food scarcity. Based on these results, we proposed an effective trapping strategy for wild boars, and discussed the applicability of our model to more general conservation and management issues.

Preference study of four alternative silage fodders from the Mediterranean region in Murciano-Granadina goats

Abstract In Mediterranean countries, large quantities of by-products are generated from artichoke and broccoli crops, as well as large masses of common reed due to the cleaning of riverbeds. They have traditionally been applied directly in animal feed, especially for small ruminants, without undergoing any preservation process. Their inclusion in diets would allow three benefits: feeding animals with materials containing high nutrient contents all year round (not only in the crop season) in a well-balanced ration, lowering the feeding costs and reducing the amount of residues and their elimination cost for producers. Through the silage process, these feedstuffs can be preserved to ensure year-round availability. The aim of this short-term preference trial was to evaluate the goats' preference among four different ensiled feedstuffs and to study the relationship between animal preference and the silage composition. The four alternative silage-feedstuffs were offered to four nulliparous Murciano-Granadina goats (34.9 ± 1.9 kg) in a multiple square or cafeteria design. The feedstuffs tested were artichoke bracts (Cynara scolymus), artichoke plant, a 50:50 mixture of broccoli by-product (Brassica oleracea, var. Italica) and artichoke bracts, and common reed (Phragmites australis). To determine preference, data were collected on feed intake and the time each animal spent eating each feedstuff for four hours each day. Macrocomposition and some functional and chemical characteristic silages were analysed. The relation between DM intake and chemical composition of the tested feedstuffs was determined using correlation and regression analyses. The artichoke bracts silage presented the highest cumulative intake at 4 hours (3.26 g DM/kg BW); being different from artichoke plant silage (2.17 g DM/kg BW), the second most consumed. Broccoli + artichoke and common reed silage intake was significantly lower than those of the other two feeds (0.36 and 0.67 g DM/kg BW, respectively). The strongest correlations between DM intake after 4 hours (g of DM) and the nutritional and chemical characteristics of the silages were found with digestible energy (r = 0.60, P

Animal preferences vs regulatory standards of care.

Animal preferences vs regulatory standards of care.

How Do Visitors from Different Cultural Backgrounds Perceive the Messages Conveyed to Them by Their Local Zoo?

As educational institutions, zoos provide an informal, free-choice learning environment. To understand the complex processes of learning in the zoo we must therefore take into account the visiting family’s culture. The study presented here, conducted in the Tisch Family Zoological Gardens in Jerusalem, investigates how visitors from different cultural backgrounds experience the zoo and interpret its intended messages. We found that, ultimately, the zoo is perceived similarly by the Arab and Jewish visitors as an educational institution, although what they come there to learn is different. Moreover, with regards to the message of conservation, neither population sees it as a major, prominent message. Despite the overall similarity in our participants’ response to the zoo as an enjoyable, cultural educational institute, there were some differences in the experiences of Jewish vs. the Arab visitors, reflected primarily in their animal preferences, and also in the types of messages that they suggest the zoo is conveying to them.