Changes In Feeding Behavior Research Articles

Optimal control problems of mosquito-borne disease subject to changes in feeding behavior of Aedes mosquitoes

Dengue viruses (DENV) are transmitted to humans by the bite of Aedes mosquitoes. It is known that dengue virus infection in Aedes aegypti female mosquitoes makes a change in the feeding behavior of the infected mosquitoes. In this study, using the forces of infection, we incorporated the effect of changes in the feeding behavior of mosquitoes into the standard vector-borne SIR-SI model. It has been proved that both a single-strain model and a two-strain model exhibit forward bifurcations. Moreover, optimal implementations of control with specific prevention measures for dengue transmission are analyzed. As a result we found that more implementation of controls on the secondary infection of humans should be considered for the behavioral changes in feeding of the infected mosquitoes.

Paleolithic Diet and Exercise Improve Metabolic and Cardiovascular Risk Factors

For nearly 6 million years, the ability to store dietary energy for later times has served humans well during food scarce periods. In our current world of over‐consumption; overweight and obesity are linked to more deaths worldwide than underweight, with 1.9 billion adults classified as overweight and of these, 600 million obese (World Health Organization, 2014). This puts those individuals at an increased risk for chronic diseases, such as cardiovascular disease, metabolic syndrome, type 2 diabetes (T2D), nonalcoholic fatty liver disease, Alzheimer dementia, and some cancers. This trend has had devastating effects on the loss of health, reductions in quality of life, and health system resources. One approach to slow the pandemic of obesity and chronic disease is to look to our evolutionary past for clues of the changing behaviors contributing to the emergence of ‘diseases of civilization’. One theory is that agricultural and technological advances have introduced pressures (i.e. diet and activity changes) quicker than our genetic ability to respond, causing a mismatch between our systems and the environment. Over the past 10,000 years, we have had profound changes in feeding and activity behavior which have left an imprint on the human genome.PURPOSEThe purpose of this study was to investigate the health effects of diet and exercise patterns that more closely resemble those of our evolutionary past in individuals characterized as having Metabolic Syndrome (MetS).METHODSSubjects (N=4) were instructed to consume a diet consisting of unprocessed lean meat, fish, eggs, leafy and cruciferous vegetables, root vegetables, fruit, and nuts and devoid of cereal grains, dairy, beans, legumes, refined fats, bakery items, soft drinks, beer, extra salt and sugar. Foods such as nuts, dried fruit, potatoes (<1 medium‐sized per day) and wine (<1 glass per day) were recommended in limited amounts. Carbohydrate restriction was set at <50gCHO with emphasis on fat intake for replacement. Subjects also participated in high intensity interval training (HIIT), which included a 3‐min warm‐up, 10 × 60 s cycling intervals interspersed with 60s of active recovery, and a 3‐min cool‐down for 4 total weeks.RESULTSCompared to baseline, the intervention led to improvements in MetS markers; including mean arterial pressure (124+6.2 vs. 82+4.1), waist adiposity (110+8.9 vs. 92.1+9.0), fasting glucose (114.2+6.9 vs. 83.3+5.4), high density lipoprotein (HDL; 34.8+7.4 vs. 54.2+6.9), and triglycerides (TG; 214.8+35.5 vs. 92.9+24.2). Improvements were also observed in peak oxygen uptake (VO2max; 20.5+3.2 vs. 25.1+2.2) and low grade inflammation (hsCRP; 7.2+0.6 vs. 4.4+1.3).CONCLUSIONThe combined intervention of paleolithic diet with exercise elicits favorable metabolic and cardiovascular profiles in those that characterize with MetS. The type 2 diabetes epidemic and associated risk factors may be improved from an evolutionary approach in diet and exercise as a preventable and reversible treatment.

Developmental changes in feeding behaviors of infant chimpanzees at Mahale, Tanzania: Implications for nutritional independence long before cessation of nipple contact.

Weaning of chimpanzees is considered to occur at 4-5-years-old with complete cessation of nipple contact and timing of reconception calculated by inter-birth interval minus gestation length. This is also the basis of "early weaning" in humans (i.e., approximately 2.5-years-old). However, recent studies of the survival of orphans and the first molar (M1) eruption in wild chimpanzees have predicted that infants move toward nutritional independence at 3-years-old. Therefore, this study aimed to investigate ontogeny of feeding behavior at around 3-years-old in wild infant chimpanzees. I studied 19 infants aged 1-60 months in the M group in Mahale Mountains National Park, Tanzania. The total observation time was 518 h, 25 min. At around 3-years-old, infant chimpanzees spent more total feeding time, and time feeding on leaves, and food physically difficult to process without food transfer from other individuals. These results suggest that infant chimpanzees significantly reduced their dependence on milk for nutrition at around 3-years-old, that is, before cessation of nipple contact. This study suggests that M1 eruption in wild Eastern Chimpanzees is an index of the period when infants move toward nutritional independence with a key dietary transition. This is the first study to provide behavioral evidence of the large temporal gap between nutritional independence of infants and reconception of mothers in great apes, and clarify the unique feature of human life history whereby mothers can reconceive before an infant reaches nutritional independence.

Coexisting small fish species in lotic neotropical environments: evidence of trophic niche differentiation

Differences among species and their ecological requirements are considered fundamental in determining the outcome of species interactions as well as in coexistence. Thus, species that co-occurs tends to differ in the use of resources as a way to mitigate the effects of interspecific competition, facilitating interactions between pairs of species. So, this study used a set of seven small-sized characid species with similar morphology and feeding strategies, in order to investigate the hypothesis that the coexistence these species is facilitated by the differential use of food resources. Samplings were conducted in the rivers Verde and Sao Domingos, Upper Parana River basin, Brazil, in hydrological periods rainy and dry. The analysis of 1055 stomach contents, by the volumetric method, indicated that the species consumed mainly allochthonous items, such as seeds, terrestrial plants and insects. In addition, they showed inter- and intraspecific differences in the diet composition between hydrological periods, which allowed the identification of items that particularise each species and contribute to the trophic segregation between them. Despite the wide variety of food items used, it was not possible to observe a consistent pattern of widening or narrowing of the food spectrum between hydrological periods, as expected. The trophic niche overlap showed intermediate and low values in both periods. In this sense, resource partitioning among species of small characids, facilitated by exploitation of different preferential resources as well as the intraspecific variation in response to seasonal availability of resources, became evident. The alternation of items and proportions of items in the diet as well as changes in feeding behaviour in opportune moments was probably the key for the coexistence of these species.

Development of a threshold-based classifier for real-time recognition of cow feeding and standing behavioural activities from accelerometer data

Change in feeding behaviour is one of the indicators useful to help identifying when animals become ill. The need to analyse a large number of animals at a time due to the increase in the herd dimension in intensive farming has led to the use of automated systems. Among automated systems, inertial sensor-based systems have been utilised to distinguish behavioural patterns in livestock animals.In this study, a new approach based on statistical analyses of accelerometer data, which were collected from wearable sensors fixed at the cow’s collar, was defined and developed in order to define thresholds suitable for real-time classification of cow feeding and standing behavioural activity. The obtained classifier could be implemented within a software tool of a movement sensor-based system composed of low-cost devices. Accuracy of the classification was assessed by computing specific indicators: Misclassification Rate, Sensitivity, Precision, Specificity, Quality Percentage, Branching Factor, and Miss Factor. The results showed that the classifier produced the following values of the indicators: 5.56%, 93.33%, 95.45%, 95.56%, 89.36%, 0.05, and 0.07, respectively.The proposed threshold-based classifier allows for monitoring individual cows automatically and continuously and it is suitable for Real Time Computing Applications, since it does not require high computational time and resources.

Effects of macroalgal expansion triggered by the 2011 earthquake and tsunami on recruitment density of juvenile abalone Haliotis discus hannai at Oshika Peninsula, northeastern Japan

AbstractThe effects of the 2011 mega‐earthquake and massive tsunami on the recruitment process of juvenile abalone Haliotis discus hannai inhabiting the rocky shore ecosystem were investigated at Oshika Peninsula, northeastern Japan. Before the earthquake and tsunami, H. discus hannai of 2007–2010 yr classes were shown to undergo habitat shifts with growth from the crustose coralline algal area (CCA) to kelp beds (KB) via algal turfs (AT). These habitat shifts of abalone appear to occur because of its migration, associated with the ontogenetic changes in feeding behavior. Densities of 0‐yr‐old juvenile abalone (2010 yr class) and the sea urchin Mesocentrotus nudus inhabiting the CCA largely decreased just after the earthquake and tsunami, mainly affected by the catastrophic disturbance by this event. After that, previously unrecorded recruitments of juvenile macroalgae were observed in the CCA after the event probably because of the large‐scale removal of the primary herbivore, the sea urchin M. nudus. Subsequently, the KB and AT expanded into the previous CCA area. After the tsunami, the major factors causing the continuously low densities of the 0‐yr‐old juvenile abalone (2011–2013 yr classes) are inferred to be the limited nursery CCA habitat because of mud and silt sedimentation, the expansion of the KB and AT, and/or the decreased densities of reproductive adult abalone due to the direct disturbance of the tsunami. The results of this study imply that maintaining diverse algal communities which enable the habitat shifts of juvenile abalone H. discus hannai is one of the crucial factors to their successful recruitment.

Bugs, guts and brains, and the regulation of food intake and body weight.

The microbiota-gut-brain axis is currently being explored in many types of rodent models, including models of behavioral, neurodegenerative and metabolic disorders. Our laboratory is interested in determining the mechanisms and consequences of activation of vagal afferent neurons that lead to activation of parasympathetic reflexes and changes in feeding behavior in the context of obesity. Obesity is associated with microbial dysbiosis, decreased intestinal barrier function, gut inflammation, metabolic endotoxemia, chronic low-grade systemic inflammation and desensitization of vagal afferent nerves. This review will present the evidence that altered gut microbiota together with decreased gut barrier function allows the passage of bacterial components or metabolites in obese individuals, leading to the disruption of vagal afferent signaling and consequently resulting in an increase in body weight. We first review the most recent descriptions of gut microbial dysbiosis due to a high fat diet and describe changes in the gut barrier and the evidence of increased intestinal permeability in obesity. We then will review the evidence to show how manipulating the gut microbiota via pre and probiotics can restore gut barrier function and prevent weight gain. Lastly, we present possible mechanisms by which the microbe-gut-brain axis may have a role in obesity. The studies mentioned in this review have provided new targets to treat and prevent obesity and have highlighted how the microbiota-gut-brain axis is involved.

Migratory behavior, metabolism, oxidative stress and mercury concentrations in marine and estuarine European glass eels (Anguilla anguilla)

The relationships between the migratory behavior, methylmercury (MeHg) concentrations, oxidative stress response and detoxification processes were investigated in glass eels collected in marine (Molliets) and estuarine (Urt) waters (Adour estuary, South West France) at the end of the fishing season (April). Glass eel migratory behavior was investigated in an experimental flume according to their response to dusk. Fish responding to the decrease in light intensity by ascending in the water column and moving with or against the flow were considered as having a high propensity to migrate (migrant). Glass eels still sheltering at the end of the 24h catching period were considered as having a low propensity to migrate and were called non-migrant. Our results provide some evidence that estuarine glass eels were bigger, presented a higher propensity to migrate and a lower oxidative stress response than marine glass eels. This might reflect a selection process, some marine glass eels progressively settling or dying before reaching Urt and/or a change in feeding behavior. In April, glass eels restart feeding in the Adour estuary which might decrease the oxidative stress possibly related to starvation, and enhance migration. MeHg concentrations was significantly higher in non-migrant than in migrant glass eels and it is suggested that non-migrant glass eels might present a higher vulnerability to stress (at least contamination and/or starvation), although the underlying mechanisms remain to be elucidated.

Mu-opioid receptor inhibition decreases voluntary wheel running in a dopamine-dependent manner in rats bred for high voluntary running

The mesolimbic dopamine and opioid systems are postulated to influence the central control of physical activity motivation. We utilized selectively bred rats for high (HVR) or low (LVR) voluntary running behavior to examine (1) inherent differences in mu-opioid receptor (Oprm1) expression and function in the nucleus accumbens (NAc), (2) if dopamine-related mRNAs, wheel-running, and food intake are differently influenced by intraperitoneal (i.p.) naltrexone injection in HVR and LVR rats, and (3) if dopamine is required for naltrexone-induced changes in running and feeding behavior in HVR rats. Oprm1 mRNA and protein expression were greater in the NAc of HVR rats, and application of the Oprm1 agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) to dissociated NAc neurons produced greater depolarizing responses in neurons from HVR versus LVR rats. Naltrexone injection dose-dependently decreased wheel running and food intake in HVR, but not LVR, rats. Naltrexone (20mg/kg) decreased tyrosine hydroxylase mRNA in the ventral tegmental area and Fos and Drd5 mRNA in NAc shell of HVR, but not LVR, rats. Additionally, lesion of dopaminergic neurons in the NAc with 6-hydroxydopamine (6-OHDA) ablated the decrease in running, but not food intake, in HVR rats following i.p. naltrexone administration. Collectively, these data suggest the higher levels of running observed in HVR rats, compared to LVR rats, are mediated, in part, by increased mesolimbic opioidergic signaling that requires downstream dopaminergic activity to influence voluntary running, but not food intake.

Tracking Change in the Illinois River using Stable Isotopes in Modern and Ancient Fishes

The Illinois River has been heavily modified by human activities. We examined the nitrogen and carbon stable isotope composition of collagen from fish bones in two Native American middens comparing them to modern fishes in the River today. We also compared ancient and modern fishes to three reference samples—(i) Illinois River phytoplankton; (ii) backwater lake sediment; and (iii) tissue from riverside trees. We found a large increase in δ15N values in modern fish bone collagen relative to ancient collagen. However, there is little change in δ13C between ancient and modern samples. Bone collagen from invasive carp species (Hypopthalmichthys and Cyprinus) are similar to modern phytoplankton. All fishes are different from riverside trees and backwater lake sediment. The large shift in δ15N values between ancient and modern fishes is probably caused by contamination of the river by Chicago treated wastewater and by denitrified fertilizer run-off. Our results indicate a major change in nitrogen biogeochemistry in the modern river. Comparisons between ancient and modern δ13C values suggest little change in feeding behaviour of fishes between ancient and modern times. However, our data for invasive carp suggest strong competition with native planktivores. © 2016 The Authors. River Research and Applications Published by John Wiley & Sons Ltd.

Starvation-Induced Depotentiation of Bitter Taste in Drosophila

Nutrient deprivation can lead to dramatic changes in feeding behavior, including acceptance of foods that are normally rejected. In flies, this behavioral shift depends in part on reciprocal sensitization and desensitization of sweet and bitter taste, respectively. However, the mechanisms for bitter taste modulation remain unclear. Here, we identify a set of octopaminergic/tyraminergic neurons, named OA-VLs, that directly modulate bitter sensory neuron output in response to starvation. OA-VLs are in close proximity to bitter sensory neuron axon terminals and show reduced tonic firing following starvation. We find that octopamine and tyramine potentiate bitter sensory neuron responses, suggesting that starvation-induced reduction in OA-VL activity depotentiates bitter taste. Consistent with this model, artificial silencing of OA-VL activity induces a starvation-like reduction in bitter sensory neuron output. These results demonstrate that OA-VLs mediate a critical step in starvation-dependent bitter taste modulation, allowing flies to dynamically balance the risks associated with bitter food consumption against the threat of severe starvation.

Nestling Growth is Impaired by Heat Stress: an Experimental Study in a Mediterranean Great Tit Population.

Samuel Rodríguez and Emilio Barba (2016) During the nestling stage, nestlings of small altricial birds face energetic limitations due to their rapid development and the need to maintain a stable body temperature once homeothermy is achieved. In Mediterranean habitats, high air temperatures reached during the breeding season could negatively affect the health and condition of the nestlings. The aim of this study was to determine the effect of an experimental increase of nest temperatures during the nestling stage on the growth and survival of Great Tit (Parus major) nestlings. Additionally, changes in parental brooding and feeding behavior as a result of the alteration of the nest microclimate were addressed. Increased nest temperatures affected nestling mass, as heated nestlings were lighter than controls on day 15 in the warmer of the two breeding seasons considered. Moreover, females from the heating treatment reduced their brooding time. Fledging success and parental feeding rates were not altered by the experimental treatment. The results of this study suggest that high nest temperatures may impair nestling development and therefore affect post-fledging survival probability. Negative effects are more likely to occur in warm habitats and/or warmer years, where juveniles are liable to suffer from thermal stress.

Comportamento ingestivo de bovinos em capim-piatã sob lotação intermitente em resposta a distintas alturas de entrada

RESUMO O conhecimento da interface planta/animal no ecossistema pastagem é de fundamental importância quando se busca maximizar o desempenho produtivo do sistema. Nesse sentido, objetivou-se verificar se a altura de entrada em capim-piatã (30, 40 e 50cm) interfere na qualidade da forragem, comportamento ingestivo, padrões de deslocamento e uso de estações alimentares de bovinos em duas condições de tempo, o pré-pastejo (zero dias de pastejo) e o pós-pastejo (sete dias de pastejo). As avaliações foram realizadas no período de 06h:30m as 18h:20m, no segundo e quarto ciclos de pastejo com animais que apresentavam 16 meses de idade e 239,8±25,7kg de PV. As alturas de entrada não alteraram o comportamento ingestivo, mas houve efeito para a condição do pasto (pré e pós-pastejo). O número de intervalo de refeições foi maior aos 30cm e menor no pré-pastejo. A maior taxa de bocados foi aos 30cm e a menor aos 40cm, enquanto que, a redução da TB aos 50cm em relação aos 30cm reflete à dificuldade de manipular bocados. No pré-pastejo, maior número de estações por minuto foi verificada aos 40cm, enquanto no pós-pastejo foi aos 50cm. No pré-pastejo houve redução do tempo por refeição em relação ao pós-pastejo, refletindo a melhor estrutura do pasto nessa condição. A altura de entrada não alterou o comportamento ingestivo, entretanto, o tempo de pastejo modifica o comportamento ingestivo o padrão de deslocamento, busca e apreensão de forragem pelos animais, principalmente na condição pós-pastejo aos 50cm.

Fatores associados às fases de comportamento alimentar de usuários dos restaurantes populares em Belo Horizonte/MG‐Brasil

Phases of change in feeding behavior of users of popular restaurants were associated to: sociodemographic aspects, nutritional status and dietary habits. An analytical descriptive study was conducted with 1656 users of popular restaurants in Belo Horizonte‐MG. Sociodemographic data, stages and phases of dietary change were assessed through structured questionnaires. The associated action phase factors were: women, economic classes A and B, higher education, overweight and good eating habits. To the pre‐action phase the association was: men, economic classes D and E, elementary education, not overweight, and regular eating habits. An association between the studied variables was observed.

Eat or be eaten? Modifications of Aplysia californica feeding behaviour in response to natural aversive stimuli

Prey often modify their behaviours to diminish predation risk, but the persistence of such behavioural changes are not well understood. We investigated the effects of predation risk in the aquatic mollusc Aplysia californica to determine whether various natural aversive stimuli alter the expression of feeding behaviour (i.e. bites) over short-term (15 min), intermediate-term (2 h) and long-term (24 h) periods. Aplysia were presented with a variety of natural aversive stimuli that are indicative of predation risk, including exposure to the spiny lobster Panulirus interruptus (a natural predator), the blue crab Callinectes sapidus (a novel predator), and the defensive secretions ink and opaline that are normally released by Aplysia when attacked. Feeding was significantly suppressed immediately after Aplysia were exposed to ink but not to opaline. Additionally, several stimuli, including exposure to lobsters, ink, opaline and attacks from crabs, suppressed feeding, but only for a short time (i.e. 15 min) after the end of the stimulus. No single-exposure treatment elicited intermediate (2 h) or long-term (24 h) changes in feeding, and multiple exposures to ink did not induce long-term feeding suppression. Thus, changes in feeding behaviour in response to predation risk cues appear short-lived in Aplysia, unlike feeding suppression after electric shocks that suppress biting behaviour over longer periods. Since Aplysia possess chemical defences to defend against consumers, it is perhaps unnecessary or too costly to maintain feeding suppression after risk subsides.

Crassostrea gigas exposure to the dinoflagellate Prorocentrum lima: Histological and gene expression effects on the digestive gland

Bivalve mollusks bioaccumulate toxins via ingestion of toxic dinoflagellates. In this study, Crassostrea gigas was used to investigate the effects related to Prorocentrum lima exposure. Oysters were fed with three diets Isochrysis galbana (2 × 106 cell mL−1) control treatment; algal mix of I. galbana (2 × 106) and P. lima (3 × 103 cell mL−1); and P. lima alone (3 × 103 cell mL−1). Feeding behavior changes, histopathological alterations, and expression patterns changes of genes involved in cell cycle (p21, cafp55, p53), cytoskeleton (tub, act), and inflammatory process (casp1) were evaluated. Results indicated that the presence of diarrheic shellfish poisoning by P. lima cells decreased the clearance rate (p < 0.05), induced structural loss, significantly decreased tubule area of the digestive gland (p < 0.05), and up-regulated in expression all gene (p < 0.05), suggesting that toxic cells might trigger inflammatory tissue process, disturb cell cycle and cytoskeleton representing a risk to oysters integrity.

Altered nutrient intake by baculovirus-challenged insects: Self-medication or compensatory feeding?

Infection by parasites can alter the feeding behaviour of hosts. Some animals seek out substances that can therapeutically clear infections (self-medication), some may seek out resources to recoup resources lost while fighting off infection (compensatory feeding) and others may be manipulated to ingest substances that benefit parasite fitness (parasite manipulation of host). Recent studies have indicated that pathogen-challenged insects can self-medicate by increasing their protein intake relative to carbohydrate, which is thought to act by boosting the insect’s immune response. However, increased protein intake could also be due to compensatory feeding or pathogen manipulation of the host, and a rigorous examination of all four of the testable predictions, which is necessary for verifying self-medication behaviour, has not been conducted. The therapeutic behaviour must (1) only be employed by infected individuals and (2) alleviate the potential fitness loss of the infected individual. (3) If an uninfected individual engages in the behaviour, they suffer a decrease in fitness, and lastly, (4) the parasite cannot benefit from the behaviour. In response to baculovirus-challenge (AcMNPV) at 24°C, the cabbage looper, Trichoplusia ni, increased proportional protein intake, by increasing protein intake rather than decreasing carbohydrate intake. Increased protein intake did not benefit virus fitness, but it also did not increase the probability of host survival. Increased proportional protein intake did not occur in response to TnSNPV-challenge at 24°C or in response to AcMNPV-challenge at a higher temperature (32°C), indicating that the virus-induced change in nutrient intake depends on virus identity and temperature. Since virus-challenged T. ni did not show the typical costs associated with infection, the altered nutrient intake is likely to be a compensatory response. Understanding the motivation behind pathogen-induced changes in feeding behaviour could have significant implications for determining its importance for species interactions at multiple trophic levels.

Atypical antipsychotics and effects on feeding: from mice to men.

So-called atypical antipsychotics (AAPs) are associated with varying levels of weight gain and associated metabolic disturbances, which in patients with serious mental illness (SMI) have been linked to non-compliance and poor functional outcomes. Mechanisms underlying AAP-induced metabolic abnormalities are only partially understood. Antipsychotic-induced weight gain may occur as a result of increases in food intake and/or changes in feeding. In this review, we examine the available human and preclinical literature addressing AAP-related changes in feeding behavior, to determine whether changes in appetite and perturbations in regulation of food intake could be contributing factors to antipsychotic-induced weight gain. In general, human studies point to disruption by AAPs of feeding behaviors and food consumption. In rodents, increases in cumulative food intake are mainly observed in females; however, changes in feeding microstructure or motivational aspects of food intake appear to occur independent of sex. The findings from this review indicate that the varying levels of AAP-related weight gain reflect changes in both appetite and feeding behaviors, which differ by type of AAP. However, inconsistencies exist among the studies (both human and rodent) that may reflect considerable differences in study design and methodology. Future studies examining underlying mechanisms of antipsychotic-induced weight gain are recommended in order to develop strategies addressing the serious metabolic side effect of AAPs.

Animal or Algal Materials: Food Toughness, Food Concentration, and Competitor Density Influence Food Choice in an Omnivorous Tadpole

Abstract: Little is known about behavioral aspects of tadpole feeding ecology. Resource protein is by far the most studied factor assumed to govern food choice in tadpoles, whereas other factors such as resource toughness and competition have received less attention. Here, we tested the food choice of an omnivorous pond-dwelling tadpole when exposed to animal and algal materials at different toughnesses and concentrations (1× and 2× amount of food per volume), used as a proxy indicator of energy gain per bite. We subsequently tested how tadpole feeding behavior and food choice change with competitor density (when alone, in pairs, or in a group). We found that type, toughness, and concentration of the food influenced choice by the tadpoles; however, a three-way interaction among these variables was absent. The tadpoles did not feed randomly and preferred the algal materials when these were softer than, or as tough as, the animal materials. The tadpoles discriminated among foods of different concentrations...

Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A.bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H.axyridis significantly decreased. This suggests that despite significant declines in the UK, A.bipunctata is a superior competitor to the intraguild predator H.axyridis. In contrast, the behaviour of non-declining C.septempunctata was unaltered by the presence of H.axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A.bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A.bipunctata and H.axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We demonstrate how empirical and theoretical techniques can be combined to understand better the processes and consequences of alien species invasions for native biodiversity.