Energy Intake Rate Research Articles

Foraging ecology of southern sea otters at the northern range extent informs regional population dynamics

Sea otters Enhydra lutris are vital keystone predators throughout the North Pacific that were nearly extirpated during the maritime fur trade. Recovery of southern sea otters E. l. nereis has proceeded slowly, with much of their historical range remaining unoccupied, resulting in reduced ecosystem functioning. Numerous studies have used foraging metrics to assess the population status of southern sea otters throughout their current range, but little is known about the northern range extent, where a stall in expansion has limited recovery. Thus, we collected census and foraging data of sea otters at Año Nuevo State Park, California, from 2019 to 2021 to determine sea otter abundance, diet composition, diet diversity, and average energy intake rate at the northern range edge. We then assessed regional population status by comparing values from Año Nuevo with previously collected data from other locations in California, including high-density, range center sites and low-density, range periphery sites. We found that sea otter density at Año Nuevo was greater than surrounding areas at the northern range periphery, and the average (±95% CI) energy intake (9.51 ± 0.91 kcal min-1) more closely resembled values observed at high-density sites. Further, dietary diversity (using the Shannon-Wiener index, H) was intermediate between previously studied high- and low-density populations (H = 1.81), with crabs making up the largest proportion of the diet (~56%). Overall, this study highlights possible effects of occupation time and range stagnation, identifies unique aspects of the prey resource base at Año Nuevo, and provides insight into the ongoing lack of northern range expansion.

It's about time: Feeding competition costs of sociality are affected more by temporal characteristics than spatial distribution.

For most herbivorous animals, group-living appears to incur a high cost by intensifying feeding competition. These costs raise the question of how gregariousness (i.e., the tendency to aggregate) could have evolved to such an extent in taxa such as anthropoid primates and ungulates. When attempting to test the potential benefits and costs, previous foraging models demonstrated that group-living might be beneficial by lowering variance in intake, but that it reduces overall foraging success. However, these models did not fully account for the fact that gregariousness has multiple experiences and can vary in relation to ecological variables and foraging competition. Here, we present an agent-based model for testing how ecological variables impact the costs and benefits of gregariousness. In our simulations, primate-like agents forage on a variable resource landscape while maintaining spatial cohesion with conspecifics to varying degrees. The agents' energy intake rate, daily distance traveled, and variance in energy intake were recorded. Using Morris Elementary Effects sensitivity analysis, we tested the sensitivity of 10 model parameters, of which 2 controlled gregarious behavior and 8 controlled food resources, including multiple aspects of temporal and spatial heterogeneity. We found that, while gregariousness generally increased feeding competition, the costs of gregariousness were much lower when resources were less variable over time (i.e., when calorie extraction was slow and resource renewal was frequent). We also found that maintaining proximity to other agents resulted in lower variance in energy intake when resources were more variable over time. Thus, it appears that the costs and benefits of gregariousness are strongly influenced by the temporal characteristics of food resources, giving insight into the pressures that shaped the evolution of sociality and group living, including in our own lineage.

Timing of conceptions in Phayre's leaf monkeys: Energy and phytochemical intake.

Raising offspring imposes energetic costs, especially for female mammals. Consequently, seasons favoring high energy intake and sustained positive energy balance often result in a conception peak. Factors that may weaken this coordinated effect include premature offspring loss and adolescent subfertility. Furthermore, seasonal ingestion of phytochemicals may facilitate conception peaks. We examined these factors and potential benefits of a conception peak (infant survival and interbirth interval) in Phayre's leaf monkeys (Trachypithecus phayrei crepusculus). Data were collected at Phu Khieo Wildlife Sanctuary, Thailand (78 conceptions). We estimated periods of high energy intake based on fruit and young leaf feeding and via monthly energy intake rates. Phytochemical intake was based on fecal progestin. We examined seasonality (circular statistics and cox proportional hazard models) and compared consequences of timing (infant survival and interbirth intervals, t-test, and Fisher exact test). Conceptions occurred in all months but peaked from May to August. This peak coincided with high fecal progestin rather than presumed positive energy balance. Primipara conceived significantly later than multipara. Neither infant survival nor interbirth intervals were related to the timing of conception. Periods of high energy intake may not exist and would not explain the conception peak in this population. However, the presumed high intake of phytochemicals was tightly linked to the conception peak. Timing conceptions to the peak season did not provide benefits, suggesting that the clustering of conceptions may be a mere by-product of phytochemical intake. To confirm this conclusion, seasonal changes in phytochemical intake and hormone levels need to be studied more directly.

Horizontal prey distribution determines the foraging performance of short‐ and long‐billed waders in virtual resource landscapes

When waders gather in mixed‐species flocks to feed on benthic prey, differences in morphological traits, foraging strategies and prey selection may allow different species to optimize their energy intake while reducing competition. As the effect of the fine‐scale spatial distribution of resources on energy intake is unknown, we simulated the foraging performance of two types of waders with contrasting body plans and foraging strategies in a variety of virtual mudflats with different horizontal and vertical prey distribution patterns. Although larger, longer‐billed individuals had higher energy intake rates, smaller individuals with shorter bills maintained higher prey capture rates by relocating if prey was insufficiently available. Shorter‐billed individuals struggled more to meet their energetic demands because they selected smaller prey items and had a more limited capacity to metabolize energy from food. Being able to catch larger, high‐quality prey offered a competitive advantage for longer‐billed individuals, which could be a driving force for the evolutionary lengthening of bills in waders. Interestingly, their performance was more affected by the horizontal than by the vertical prey distribution. Quantifying prey distributions may help explain how some wader species can co‐occur in the field and why some wetland areas are unattractive as foraging areas. The work confirms that the foraging performance of larger, longer‐billed birds is not limited by bill size per se, but by the energetic trade‐offs associated with the ability to catch larger prey items more efficiently, increased handling times and higher absolute energy costs. These trade‐offs may become particularly important in landscapes where prey is scarce and spatially patchy.

Neurobiology of eating behavior, nutrition, and health.

Eating behavior and food-related decision making are among the most complex of the motivated behaviors, and understanding the neurobiology of eating behavior, and its developmental dynamics, is critical to advancing the nutritional sciences and public health. Recent advances from both human and animal studies are revealing that individual capacity to make health-promoting food decisions varies based on biological and physiological variation in the signaling pathways that regulate the homeostatic, hedonic, and executive functions; past developmental exposures and current life-stage; the food environment; and complications of chronic disease that reinforce the obese state. Eating rate drives increased calorie intake and represents an important opportunity to lower rates of food consumption and energy intake through product reformulation. Understanding human eating behaviors and nutrition in the context of neuroscience can strengthen the evidence base from which dietary guidelines are derived and can inform policies, practices, and educational programs in a way that increases the likelihood they are adopted and effective for reducing rates of obesity and other diet-related chronic disease.

Speed limits: the effects of industrial food processing and food texture on daily energy intake and eating behaviour in healthy adults

PurposeFrequent consumption of industrially processed foods has been associated with obesity. However, it is unknown what drives this association. Food textures of industrially processed foods that stimulate energy overconsumption may be an important driver of this association. Therefore, this study aimed to determine the independent and combined effects of food texture and level of industrial food processing (based on the NOVA classification) on daily energy intake and eating behaviour.MethodsEighteen healthy adults (F/M: 11/7, 23 ± 3 y, 22.1 ± 2.0 kg/m2) participated in a 2 × 2 randomized crossover dietary intervention with four conditions (total of 288 meals): hard unprocessed, hard (ultra-)processed, soft unprocessed and soft (ultra-)processed. Daily diets were offered ad libitum and were equal in energy density (1 kcal/g). Food Intake (g) was measured by pre- and post-consumption weighing of the plates. Eating behaviour parameters were derived from video annotations.ResultsDaily energy intake and food intake were, respectively, 33% (571 ± 135 kcal) and 14% (247 ± 146 g) lower in the hard compared to the soft conditions (main texture p < 0.001). Energy intake was lower in both hard conditions compared to the (ultra)processed soft condition (Tukey p < 0.04). Eating rate (g/min) was on average 85% slower (P < 0.001) in the hard compared to the soft conditions (p < 0.001). Level of processing did not affect food intake.ConclusionConsumption of hard-textured foods reduces daily energy intake of (ultra-) processed foods. This preliminary investigation shows that there is great variability in food properties that affect energy and food intake beyond industrial food processing. However, findings should be interpreted with precaution considering the limited sample size of this trial. Future classification systems for public health messaging should include energy intake rate to help reduce overconsumption.Clinical trial registryNCT04280146, https://www.clinicaltrials.gov, February 21st 2020.

The scale-dependent role of submerged macrophytes as drift-feeding lotic fish habitat

Although submerged macrophyte (hereafter, “macrophyte”) communities are globally prevalent in low-gradient rivers, the net reach-scale effect of macrophytes on drift-feeding fish microhabitat preference is poorly understood. We used snorkeling and bioenergetics to study fish habitat selection for rainbow trout ( Oncorhynchus mykiss) in the Henrys Fork, ID, USA, investigating microhabitat preference across a reach-scale gradient of macrophyte growth. Fish preferred microhabitats with deep water, low velocity, and low macrophyte coverage. Preferences for microhabitats with higher net rate of energy intake (NREI) were modulated by reach-scale macrophyte coverage, higher coverage increasing preferences for higher NREI. Macrophyte coverage was a weak positive predictor for depth and NREI, and a weak negative predictor for water velocity and median substrate. Our results suggest trade-offs between fish predation risk and bioenergetic food intake, with macrophytes modulating these trade-offs across scales by affecting reach-scale geomorphology, bioenergetics, and predation risk. As such, this study highlights the important and dynamic role that macrophytes can play in fish population dynamics in rivers, with important implications for management decisions.

RAPID CONSUMPTION OF KELP CRAB: IMPLICATIONS FOR SEA OTTERS IN WASHINGTON STATE

As animal populations approach environmental carrying capacity, competition for food increases, generally leading to decreased individual energy intake rate. Energy-intake rate can therefore be used as one metric of population status relative to carrying capacity. Focal observations of Sea Otter (Enhydra lutris) foraging behavior have been used throughout their range to estimate energy-intake rates and infer population status. In Washington State, previous research has demonstrated that handling times for Kelp Crabs (Pugettia spp.) by Sea Otters are 1.5 to 2 times faster than those observed in California and British Columbia, resulting in higher energy-intake rate estimates for Sea Otters in Washington. We investigated potential causes for the difference in handling time by: (1) comparing Sea Otter handling times of Kelp Crab and non-Kelp Crab prey items in Washington, California, and British Columbia; (2) comparing the handling times of Kelp Crabs by a subset of Sea Otters in California, which are Kelp Crab specialists (2003–2012, n = 244 Kelp Crab captures) to those of Sea Otters in Washington (2015–2018, n = 541 captures) and British Columbia (2013–2017, n = 359 captures); and (3) comparing the biomass-to-width ratios of Kelp Crabs from Washington and California. We did not observe consistent differences between regions in Sea Otter handling times of non-Kelp Crab prey. Mean Sea Otter handling time of small Kelp Crabs (carapace ≤1 Sea Otter paw width) in Washington (32.7 s) was significantly faster than in British Columbia (52.0 s, P < 0.0001) and all of California (40.6 s, P < 0.0001), but was not significantly different from that of Kelp Crab-specialist Sea Otters in California (31.7 s, P = 0.313). Mean Sea Otter handling time of large Kelp Crabs (≥1 Sea Otter paw) in Washington (64.7 s) was significantly faster than in British Columbia (87.7 s, P= 0.003), in all of California (104 s, P < 0.0001), and in the subset of Kelp Crab-specialist Sea Otters in California (91.6 s, P = 0.007). Kelp Crabs in Washington had a larger biomass-to-width ratio than Kelp Crabs in California: in Washington, a Kelp Crab with a 20-mm maximum carapace width had a 3.8% greater predicted biomass than a Kelp Crab in California of the same width, and a 27.1% greater biomass for a 60-mm carapace. Our results suggest that Sea Otters in Washington are Kelp Crab specialists with behavioral differences allowing them to consume Kelp Crabs faster, a difference that may affect the inference of Sea Otter population status from energy-intake rates in Washington.

Predatory behaviour of Langona tatarica (Charitonov, 1946) in controlled condition in district Swabi, Pakistan

The growth and reproduction of spiders are directly related to the energy intake rate. Availability of prey, capture ability, feeding and digesting time, silk and energy required to control prey are affected by this rate. The predatory behaviour of Langona tartarica (Charitonov, 1946) in controlled conditions was observed at the laboratory of the Department of Zoology, Women University, Swabi, Khyber Pakhtunkhwa, Pakistan. Live specimens of L. tartarica in a controlled environment were kept in an experimental display box covered with cover provided varied temperatures of 26 to 38 Celsius. It is first described that L. tartarica is an active predator like other Salticids species reported; it attacks prey and grasps with its four legs. It is also firstly observed that Musca domestica, Papilio casi, Psychoda spp., and Reticulitermes flavipes are their first preference over others like Coleoptera, Hoppers, and Crane fly if provided and avoid attacking or feeding on Oecobius and Oxyopes, (Araneae) in a controlled environment. Furthermore, L. tartarica builds a cocoon web in a controlled environment or, if displaced from its wild condition for rest and protection, mostly remains inside and frequently reconstructs the old web with a changed position.

MALNUTRITION IN PEDIATRIC PATIENTS WITH LOW RESPIRATORY TRACT INFECTIONS AT NATIONAL LUNG HOSPITAL, VIETNAM

Aims: To determine the nutritional status and the dietary intake of inpatient children with lower respiratory infections. Methods: This cross-sectional study was conducted in 106 children aged under 5 years admitted to the Pediatric Department of the National Lung Hospital in Hanoi, Vietnam, from August to December 2018. Body weight, height/length were measured; nutritional status was evaluated by using World Health Organization criteria and Subjective Global Assessment (SGA). Dietary intake was daily recorded during the first week of hospitalization. Results: The prevalence of malnutrition was 30.1%, 25.7%, and 17.8% respectively for underweight, stunting and wasting. According to the SGA, 20% of the patients were at risk for malnutrition. From the first day to seventh day of hospitalization, the rate of chidlren given 100% of requirement had a fluctuating upward trend from 30% to 40% in energy intake and from 66% to 84% in protein intake; the rates of energy intake under 80% of requirement were from 31% to 54% in patients, while the rates of protein intake over 1.5-fold requirement were from 37% to 50% in patients. Conclusions: The study indicated the alarmingly high prevalence of malnutrition in children aged under 5 years and the contrast between under energy intake and over protein intake in the hospitalized children.

Abstracts from the NIH Office of Research on Women's Health 2022 Annual BIRCWH Meeting:Building Interdisciplinary Research Careers in Women's Health November 2, 2022

Abstracts from the NIH Office of Research on Women's Health 2022 Annual BIRCWH Meeting:Building Interdisciplinary Research Careers in Women's Health November 2, 2022

Periconceptional diet quality is associated with gestational diabetes risk and glucose concentrations among nulliparous gravidas.

BackgroundGestational diabetes mellitus (GDM) and elevated glucose concentrations below the threshold for GDM diagnosis have been associated with adverse pregnancy and offspring outcomes. Dietary interventions initiated during pregnancy have demonstrated inconsistent beneficial effects. Limited data exist regarding the effects of periconceptional diet on gestational glycemia.ObjectiveTo evaluate independent associations between periconceptional diet quality with GDM frequency and glucose concentrations from GDM screening and diagnostic tests among nulliparous gravidas.DesignThis is a secondary analysis of N=7997 participants from the NuMoM2b multicenter, prospective, observational cohort study of first pregnancies. The Alternative Healthy Eating Index (AHEI)-2010 was computed from food frequency questionnaires completed in early pregnancy (6-13 weeks), reporting usual dietary intake over the preceding 3 months. GDM screening was performed either by non-fasting 1-hour 50g glucose load (N=6845), followed by 3-hour 100g glucose tolerance test (GTT) for those with raised glucose concentrations (N=1116; at risk for GDM), or by a single 2-hour 75g GTT (N=569; all GDM risk levels). Logistic and linear regression were used to estimate the associations between the AHEI-2010 score with odds of GDM, having raised blood glucose on the 1-hour screening test, and continuous glucose concentrations on screening and diagnostic tests. All models were adjusted for a priori covariates: maternal age, race/ethnicity, early-pregnancy body mass index, smoking habits, rate of gestational weight gain, energy intake, nausea and vomiting in early pregnancy, study site.ResultsPoorer periconceptional diet quality was observed among participants who were younger, with higher BMI, lower income levels, and of non-Hispanic Black or Hispanic ethnicity. The GDM rate was 4%. Each 1-point increase in AHEI-2010 score was associated with a 1% decrease in the odds of being diagnosed with GDM (beta=-0.015, p=0.022, OR=0.986, 95% CI 0.973 to 0.998). Diet quality was inversely associated with each post glucose load concentration on the non-fasting screening test and the 2-hour and 3-hour GTT.ConclusionPoor periconceptional diet quality is independently associated with an increased risk of GDM and with minor elevations in serum glucose concentrations on GDM screening and diagnostic tests, in a diverse cohort of nulliparas. Periconception intervention studies targeting diet quality are warranted.

Feeding behavior innovation increases foraging efficiency in the Amur falcon but may be a threat to Asian particolored bats.

Behavioral innovations are rare and infrequent in the natural world, but they are pivotal for animals to respond to environmental changes. The ecological benefits of these innovations remain unknown, especially in wild populations. Here, two foraging strategies and three eating behaviors of the Amur falcon (Falco amurensis) were observed during predation on Asian particolored bats (Vespertilio sinensis) across 3 years. We demonstrated that an eating behavioral innovation in F. amurensis increased the foraging efficiency of V. sinensis more than twofold during 3 consecutive years. This showed that changes in feeding behavior by a bird strongly influenced the rate of energy intake. Since predation on bats by falcons mainly occurred during the lactation and post‐lactation of bats, this may have a certain level of negative effect on the bat population.

우리나라 영유아의 삶의 질

Background/Objectives: The purpose of study is to develop well-being index for infants and toddlers, and analyze the main indicators to find their implications and suggest to develop future development plan . Methods: The methods of this study include literature review, secondary data analysis and indicator reporting, 2-time Delfi-survey and running indicator review committee, and holding seminars and a policy forum. Results: The main areas of infants and toddlers index are nutrition and health, development and learning, safety and protection, material situation and housing environment, play, relationships and care, and finally subjective well-being. In this study, as the main indicators according to the social framework of infants and toddlers: the energy intake rate, the low birth weight rate, overall cognition, the level of language development, the death toll in child safety accidents, the number of cases by type of child abuse, and household material deficit, number of rooms used, number of games with friends, TV watching by smartphone, primary caregiver status, and time spent with parents were analyzed. Conclusion/Implications: Increasing the validity and practicality of existing indicators, we continuously produce additional indices related to infants and toddlers, and focus on data production that infants and toddlers can respond to rather than related questions such as institutions or teachers. To this end, it is necessary to develop measurement methods or technical methods for infants and toddlers.

Sulfur in lucinid bivalves inhibits intake rates of a molluscivore shorebird.

A forager's energy intake rate is usually constrained by a combination of handling time, encounter rate and digestion rate. On top of that, food intake may be constrained when a forager can only process a maximum amount of certain toxic compounds. The latter constraint is well described for herbivores with a limited tolerance to plant secondary metabolites. In sulfidic marine ecosystems, many animals host chemoautotrophic endosymbionts, which store sulfur compounds as an energy resource, potentially making their hosts toxic to predators. The red knot Calidris canutus canutus is a molluscivore shorebird that winters on the mudflats of Banc d'Arguin, where the most abundant bivalve prey Loripes orbiculatus hosts sulfide-oxidizing bacteria. In this system, we studied the potential effect of sulfur on the red knots' intake rates, by offering Loripes with various sulfur content to captive birds. To manipulate toxicity, we starved Loripes for 10days by removing them from their symbiont's energy source sulfide. As predicted, we found lower sulfur concentrations in starved Loripes. We also included natural variation in sulfur concentrations by offering Loripes collected at two different locations. In both cases lower sulfur levels in Loripes resulted in higher consumption rates in red knots. Over time the red knots increased their intake rates on Loripes, showing their ability to adjust to a higher intake of sulfur.

Uncertainty in foraging success and its consequences on fitness

Optimal foraging models are commonly used to determine the strategy maximizing the proxies for fitness, such as foraging success. The strategies maximizing the proxy for fitness and fitness are assumed to be the same. However, this study shows that this assumption can be invalid when the relationship between the proxy for fitness and fitness is nonlinear and the foraging success is uncertain. A well-known prey choice model that uses long-term energy intake rate as the proxy for fitness was used as an example. This model considers a situation where predators predate on two types of prey that differ in quality, that is, one (primary prey) has higher quality than the other (alternative prey). A strategy can be represented by the probability of attacking alternative prey upon encounter while always attacking primary prey. The probability of attacking alternative prey that maximizes the expected rate of energy intake is either 0 or 1 depending on the density of primary prey (known as the zero–one rule). Meanwhile, the density of alternative prey has no influence on the optimal strategy. A simulation model was used to characterize the stochastic outcomes in the rate of energy intake in a finite foraging duration. The results revealed that foraging strategy influences the expected rate of energy intake and the uncertainty around the expectation. Consequently, the strategies maximizing the rate of energy intake and fitness may not be the same when the relationship between the rate of energy intake and fitness is nonlinear due to Jensen’s inequality. Previous results such as the zero–one rule and the independence of the optimal strategy on the availability of alternative prey are no longer valid when fitness, rather than the proxy for fitness, is explicitly considered in a finite foraging duration.

Influence of Sensory Properties in Moderating Eating Behaviors and Food Intake.

Sensory properties inform likes and dislikes, but also play an important functional role in guiding food choice and intake behavior. Odors direct food choice and stimulate sensory-specific appetites and taste helps to anticipate calorie and nutrient content of food. Food textures moderate eating rate and the energy consumed to satiation and post-ingestive metabolism. We summarize how sensory cues moderate intake, and highlight opportunities to apply sensory approaches to improve dietary behavior. Salt, sweet and savory taste influence liking, but also influence energy intake to fullness, with higher taste intensity and duration linked to lower intake. Psycho-physical studies show it is relatively easy to rank taste intensities at different concentrations but more challenging to discriminate fat contents, and fat discrimination declines further when combined with high-taste intensity. Fat has low impact on sensory intensity, but makes significant contributions to energy content. Combinations of high taste and fat-content can promote passive energy over-consumption, and adding fat also increases energy intake rate (kcals/min), reducing opportunities to orally meter consumption. Consumers adapt their oral processing behaviors to a foods texture, which can influence the rate and extent of energy intake. Understanding how texture influences eating behaviors and bolus formation, affords new opportunities to impact eating rate, energy intake and metabolic response to food. Food formulation has traditionally focused on composition and sensory appeal. Future research needs to consider the role of sensory properties in moderating consumer interaction with their food environment, and how they influence calorie selection, and shape our eating behaviors and intake.

Nutrition research challenges for processed food and health.

Existing highly processed food (HPF) classification systems show large differences in the impact of these foods on biochemical risk factors for disease. If public health nutrition is to consider the degree of food processing as an important element of the link between food and health, certain gaps in research must be acknowledged. Quantifying the food additive exposure derived from HPFs is a task made challenging by the lack of data available on the occurrence and concentration of additives in food and the degree to which the natural occurrence of additives in unprocessed foods confounds exposure estimates. The proposed role of HPFs in health outcomes could also be associated with altered nutrient profiles. Differences exist within and between HPF classification systems in this regard and there are conflicting data on the impact of controlling for nutrient intake. Furthermore, research is needed on how the sensory aspects of HPFs contribute to energy intake. Current data suggest that high energy intake rate may be the mechanism linking HPFs and increased energy intake. A high priority now is to clarify the basis of definitions used to categorize foods as highly processed and, in a constructive sense, to distinguish between the contributions of nutrients, additives and sensory properties to health.

Optimal kinematics of the bee tongue for viscous fluid transport.

Honey bees can forage nectar from a large spectrum of nectariferous flowers using their rhythmically erectable tongue hairs in a viscous dipping fashion that involves a faster protraction stroke toward the nectar pool and a slower retraction stroke backward. Since honey bees are capable of using their hairy tongues to adapt to various feeding environments, the kinematic characteristics of the bee tongue, especially the retraction time, would likely represent evolutionary optimization. However, the phenomenon and mechanism remain elusive. In this combined experimental and theoretical study, we established a mathematical model to analyze the effects of tongue retraction time on the energy intake rate considering the unfolding dynamics of tongue hairs in the retraction phase. The theoretical optimal retraction time at which the energy intake rate reached the maximum was governed by the dimensions of tongue hairs, which matched well with the in vivo tests. This study may not only bridge the connection between the kinematics and geometry of the bee tongue but also shed light on a control strategy for micropumps equipped with dynamic surfaces.

Neonicotinoids and Optimal Foraging Theory

Determination of how neonicotinoid ingestion affects the foraging behaviour of flower-visiting animals, and using Optimal Foraging Theory to assess the nature and extent of consequent changes to foraging efficiency, provide a novel approach for understanding how neonic ingestion affects the cognitive abilities of these animals, and their ultimate reproductive success. Neonicotinoids (neonics for short) are used worldwide as insecticides to protect agricultural crops, but may be ingested by non-target flower-visiting animals, such as bees, with negative impacts on their cognitive abilities and consequent adverse effects on their foraging behaviour, reproduction and pollination services. Optimal Foraging Theory may help to understand such effects as it hypothesises that nectar-feeding animals, including bees, will adopt foraging behaviour that maximises net rate of energy intake. Simple models of foraging movements exist but require further development to be useful in this regard. Observed movement patterns could then be compared with predicted patterns, derived from such models, and compared between neonicotinoid-affected and control individuals, with the expectation that control individuals will forage optimally, while neonicotinoid-affected individuals will not exhibit such behaviour and will exhibit reduced foraging success. However, there has been little attempt to develop and test predictions for cognitive foragers, like bees, that are moving between flowers or flower clusters, potentially limiting our ability to manage neonic-use to control agricultural pests. Addressing this gap should lead to enhanced knowledge and understanding of the impacts of neonics on non-target animals, along with other possible flow-on environmental impacts, including possible reductions in pollinator abundance and hence the harvest yields of crops requiring pollination, and could lead to refinements in policy and procedure for future use of neonics to control agricultural pests. The same issues apply to other insecticides and to interactions amongst insecticides.