Food Searching Research Articles

Food search and transport in red imported fire ants (Hymenoptera: Formicidae) under wet conditions

The red imported fire ant, Solenopsis invicta Buren, has invaded various wetlands such as beaches, swamps, and mangrove forests. We hypothesize that S. invicta can effectively forage food in these habitats. Here, the food searching and transport by S. invicta on each substrate (sand or soil with freshwater or artificial seawater) at different saturation levels (70%, 100%, 130%, or 160%) were evaluated. Ants walked on unsubmerged substrates (70%- and 100%-saturated) to search for food, and surprisingly, they swam and passed 130%- or 160%-saturated substrates that were submerged with thin layers of water. Saturation level may significantly affect duration of food search and/or transport, depending on substrate types. The number of foraging ants rapidly increased and decreased on the food-releasing platform located on the 70%-saturated substrate and remained stable on the platform located on the 100%-saturated substrate. However, only a few ants were found on the platform located on waterlogged substrates throughout the experiment. In addition, no food was successfully transported passing the waterlogged substrate. We also compared food search and transport among four substrates (sand or soil with freshwater or seawater) at the 70%- or 100%-saturation level. Ants spent similar time searching for food and transporting food on the platform, but minimal food was transported passing the soil with freshwater or seawater. Our results showed that S. invicta can successfully search for food but fail to transport food on waterlogged substrates. In addition, both substrate types and saturation level affected food transport under unsubmerged conditions.

Suprachiasmatic to paraventricular nuclei interaction generates normal food searching rhythms in mice.

Searching for food follows a well-organized decision process in mammals to take up food only if necessary. Moreover, scavenging is preferred during their activity phase. Various time-dependent regulatory processes have been identified originating from the suprachiasmatic nuclei (SCN), which convert external light information into synchronizing output signals. However, a direct impact of the SCN on the timing of normal food searching has not yet been found. Here, we revisited the function of the SCN to affect when mice look for food. We found that this process was independent of light but modified by the palatability of the food source. Surprisingly, reducing the output from the SCN, in particular from the vasopressin releasing neurons, reduced the amount of scavenging during the early activity phase. The SCN appeared to transmit a signal to the paraventricular nuclei (PVN) via GABA receptor A1. Finally, the interaction of SCN and PVN was verified by retrograde transport-mediated complementation. None of the genetic manipulations affected the uptake of more palatable food. The data indicate that the PVN are sufficient to produce blunted food searching rhythms and are responsive to hedonistic feeding. Nevertheless, the search for normal food during the early activity phase is significantly enhanced by the SCN.

HSWOA: An ensemble of hunger games search and whale optimization algorithm for global optimization

The search for food stimulated by hunger is a common phenomenon in the animal world. Mimicking the concept, recently, an optimization algorithm Hunger Games Search (HGS) has been proposed for global optimization. On the other side, the Whale Optimization Algorithm (WOA) is a commonly utilized nature-inspired algorithm portrayed by a straightforward construction with easy parameters imitating the hunting behavior of humpback whales. However, due to minimum exploration of the search space, WOA has a high chance of trapping into local solutions, and more exploitation leads it towards premature convergence. The concept of hunger from HGS is merged with the food searching techniques of the whale to lessen the inherent drawbacks of WOA. Two weights of HGS are adaptively designed for every whale using the respective hunger level for balancing search strategies. Performance verification of the proposed hunger search-based whale optimization algorithm (HSWOA) is done by comparing it with 10 state-of-the-art algorithms, including three very recently developed algorithms on 30 classical benchmark functions. Comparison with some basic algorithms, recently modified algorithms, and WOA variants is performed using IEEE CEC 2019 function set. Statistical performance of the proposed algorithm is verified with Friedman's test, boxplot analysis, and Nemenyi multiple comparison test. The operating speed of the algorithm is determined and tested with complexity analysis and convergence analysis. Finally, seven real-world engineering problems are solved and compared with a list of metaheuristic algorithms. Numerical and statistical performance comparison with state-of-the-art algorithms confirms the efficacy of the newly designed algorithm.

Dealing with host and food searching in a diurnal parasitoid: consequences of light at night at intra‐ and trans‐generational levels

Abstract Light pollution is a widespread phenomenon with major consequences on nocturnal organisms from individual to community. However, its effects on diurnal organisms are still scarcely studied. We exposed diurnal parasitoid wasps (Venturia canescens) to low (0.7 lux) or high (20 lux) artificial light for two to eight consecutive nights, and quantified its consequences on their physiology and daytime behaviour compared to a control group (0 lux). We next considered potential trans‐generational effects on offspring whose mothers were exposed to light pollution. While in the dark night the wasps showed no activity, exposure to artificial light triggered nocturnal activity and altered diurnal behaviours related to foraging. Wasps exposed to light at night had a greater propensity to choose hosts rather than food compared to controls. They also spent more time feeding when exposed to 0.7 lux of light at night. However, these behavioural modifications were not related to changes in individual energy reserves. Light pollution effects persisted at trans‐generational level: offspring development time and latency before feeding increased when mothers were exposed to 0.7 lux light at night. Even at low intensity, light pollution alters foraging behaviour of a diurnal insect. Searching for hosts or food being essential for fitness, light pollution is likely to have long‐term repercussions on insect populations. Light pollution caused behavioural modifications potentially beneficial for V. canescens in the short term. However, longer term studies (e.g. on lifetime reproductive success) are needed to fully understand its consequences on insects.

Feeding behavior and responsivity to food odors in Nile tilapia Oreochromis niloticus (Cichlidae) after chronic polisensory deprivation

The paper reports the study of the food searching behavior in the Nile tilapia Oreochromis niloticus before and after the experimental anosmia combined with visual deprivation. The threshold concentration of the water extract of the common food organisms (Chironomidae larvae) was found for the tilapia with intact olfaction to be 10–4 g/L, which allows this fish to search for food under the restriction of visual reception. The food searching behavior in response to food odors is completely lost as a result of irreversible anosmia and do not be restored after a 4.5-month period even for the high concentrations of the extract (10–1–10–2 g/L). These findings point to the absence of external taste buds on the head, body, and fins, or to their extremely low numbers. It is assumed that tactile sense also plays a significant role in the food search and prey location in the Nile tilapia.

Orientation and food search behaviour of a deep sea lobster in turbulent versus laminar odour plumes

New Zealand scampi (Metanephrops challengeri) is a commercially important deep-water lobster species that is caught by bottom trawling on areas of muddy seafloor on the continental shelf below 300 m. Efforts are being made to develop lower impact potting methods to harvest scampi, however, they can only be caught when out of their burrows and searching for food. This emergent food searching behaviour appears to be associated with periods of higher tidal flow. Such water flow will increase turbulence along the sea floor, which has been observed to improve the efficiency of chemosensory food searching in some lobster species. Consequently, this study examined the food search behaviour of scampi in response to odours from two types of bait (mackerel and mussel) in both turbulent and laminar flows. Scampi were more efficient at foraging in the turbulent flow than in the laminar flow, using shorter search paths in response to both types of bait. Scampi in the turbulent flow reached the mussel bait 44% faster and with lower mean heading angles than in laminar flow. However, there was no difference between the flow regimes for the mackerel bait. The pattern of orientation behaviour was similar under both flow regimes, suggesting that the scampi were using the same orientation strategy, but it was more accurate in turbulent flows. The results show that the foraging efficiency of scampi improves in turbulent conditions and that this may explain their increased emergent behaviour during periods of higher tidal flows.

Effect of age and severity of cognitive dysfunction on two simple tasks in pet dogs

Dogs exhibit age-dependent losses in learning and memory as well as a progressive accumulation of neuropathology that parallels that observed in normal human aging and early Alzheimer’s disease. These deficits have been extensively studied using a number of standard cognitive tasks in the laboratory; however, appropriate tools for their assessment in veterinary clinics are still lacking. The aim of this study was to evaluate the effect of age and the severity of cognitive dysfunction syndrome (CDS) on two simple tests conducted in a clinical setting. A food searching (FS) task and a problem-solving (PS) task were administered to young (1–4years, n=9), middle-aged (5–8years, n=10), cognitively unimpaired aged (⩾9years, n=31), and cognitively impaired aged (⩾9years, n=37) dogs. Cognitive status was classified using an owner-based questionnaire, and in the impaired group, dogs were categorized as having either mild or severe CDS.During the FS task, younger dogs (<9years) were able to locate the food more quickly and with more success than the aged groups (⩾9years). Dogs with severe CDS exhibited poorer performance than those with mild CDS or their healthy counterparts. In the PS task, younger dogs performed better than the aged dogs in obtaining food, but there were no differences related to CDS severity. The FS task might help to better characterize cognitively affected dogs in the clinical setting than the PS task. These and similar tasks require further investigations in the field.

Emergence of Holling type III zooplankton functional response: Bringing together field evidence and mathematical modelling

Food-web population models are rather sensitive to parameterization of functional response in predation terms. Theoretical studies predict enhancing of ecosystems’ stability for a functional response of sigmoid type (Holling type III). The choice of a correct type of response is especially important for modelling outcome of grazing control of algal blooms by zooplankton in nutrient-rich ecosystems. Extensive experiments on zooplankton feeding in laboratories show non-sigmoid nature of response for most herbivorous zooplankton species. As a consequence, there is a strong opinion in literature that the implementation of Holling III type grazing in plankton models is biologically meaningless. I argue, however, that such an ‘evident’ claim might be wrong and sigmoid functional responses in real plankton communities would emerge more often than was suggested earlier. Especially, this concerns plankton models without vertical resolution, which ignore heterogeneity in vertical distribution of species. Having conducted extensive literature search of data on zooplankton feeding in situ, I show that vertical heterogeneity in food distribution as well as active food searching behaviour of zooplankton can modify the type of functional response. In particular, the rate of food intake by the whole zooplankton population in the column, as a function of total amount of food, often exhibits a sigmoid behaviour, instead of a non-sigmoid one postulated previously based on laboratory experiments. This conceptual discrepancy is due to the ability of zooplankton to feed mostly in layers with high algal density. I propose a generic model explaining the observed alteration of type between overall and local functional responses. I show that emergence of Holling type III in plankton systems is due to mechanisms different from those well known in the ecological literature (e.g. food search learning, existence of alternative food, refuge for prey).

Olfactory memory established during trophallaxis affects food search behaviour in ants

Camponotus mus ants can associate sucrose and odour at the source during successive foraging cycles and use this memory to locate the nectar in the absence of other cues. These ants perform conspicuous trophallactic behaviour during recruitment while foraging for nectar. In this work, we studied whether Camponotus mus ants are able to establish this odour-sucrose association in the social context of trophallaxis and we evaluated this memory in another context previously experienced by the ant, as a nectar source. After a single trophallaxis of a scented solution, the receiver ant was tested in a Y-maze without any reward, where two scents were presented: in one arm, the solution scent and in the other, a new scent. Ants consistently chose the arm with the solution scent and stayed longer therein. Trophallaxis duration had no effect on the arm choice or with the time spent in each arm. Workers are able to associate an odour (conditioned stimulus) with the sucrose (unconditioned stimulus) they receive through a social interaction and use this memory as choice criteria during food searching.

Food Searching Strategy of Amoeboid Cells by Starvation Induced Run Length Extension

Food searching strategies of animals are key to their success in heterogeneous environments. The optimal search strategy may include specialized random walks such as Levy walks with heavy power-law tail distributions, or persistent walks with preferred movement in a similar direction. We have investigated the movement of the soil amoebae Dictyostelium searching for food. Dictyostelium cells move by extending pseudopodia, either in the direction of the previous pseudopod (persistent step) or in a different direction (turn). The analysis of ∼4000 pseudopodia reveals that step and turn pseudopodia are drawn from a probability distribution that is determined by cGMP/PLA2 signaling pathways. Starvation activates these pathways thereby suppressing turns and inducing steps. As a consequence, starved cells make very long nearly straight runs and disperse over ∼30-fold larger areas, without extending more or larger pseudopodia than vegetative cells. This ‘win-stay/lose-shift’ strategy for food searching is called Starvation Induced Run-length Extension. The SIRE walk explains very well the observed differences in search behavior between fed and starving organisms such as bumble-bees, flower bug, hoverfly and zooplankton.

Paddlefish Polyodon spathula juveniles food searching behaviour evoked by natural food odour

Summary Using the behavioural bioassay, food search behaviour was investigated in paddlefish Polyodon spathula juveniles (2.3, 3.0, 5.0, 15.0 and 35.0 cm TL; and 16, 23, 35, 50 and 130 days post-hatch respectively) evoked by Daphnia water extracts. Main characteristics of this behaviour were increased swimming speed, sinking to the lower water layer, short and straight trajectories in the odour cloud and opening of the mouth. These responses were seldom clearly pronounced and had a fairly short time-pattern. Biting and snapping, common in food search by many other species, were never observed. Ability to respond to food odour developed at the beginning of exogenous feeding. Olfactory sensitivity of P. spathula to natural food extract was relatively low, 10 )1 –10 )2 gL )1 , 2–3 orders of magnitude lower than in some sturgeons. It was concluded that olfaction plays a minor role in the food search behaviour of paddlefish.

Host and food searching in a parasitic wasp Venturia canescens: a trade-off between current and future reproduction?

Whether to invest in current or future reproduction is an important trade-off in life history evolution. For insect parasitoids, this trade-off is determined, among other factors, by the decision whether to search for hosts (immediate gain of fitness) or food (delayed fitness gains). Although host searching has been well studied, food sources, cues that parasitoids use to search for food and how insects modify their feeding behaviour have not. To address these questions, we investigated the food- and host-searching decisions made by the parasitoid Venturia canescens in both laboratory (olfactometer experiments) and field conditions (choice experiments). The wasps detected chemical cues associated with food, as well as those associated with hosts, and moved towards one or the other according to their nutritional state. Females used as food sources the same fruits that harboured hosts and detected the olfactory cues that would direct them to these fruits. Field results were consistent with those obtained in the laboratory. By integrating responses to infochemicals related to host and food, V. canescens might reduce the costs associated with food searching, so that more time and energy can be allocated to foraging for hosts. This behaviour should result in an adaptive advantage over parasitoids that incur additional costs by searching for hosts and food in different locations.

Tonkean Macaques Orient Their Food Search From Olfactory Cues Conveyed by Conspecifics

AbstractWe investigated the ability of monkeys to use referential information about environmental resources from cues passively transmitted by conspecifics. The subjects and their companions were four young males belonging to a group of semifree‐ranging Tonkean macaques (Macaca tonkeana) raised in a 2‐acre wooded park. In a first experiment, a subject had to orient its search strategy from the information obtained from a conspecific. It first had to smell the mouth of a companion having just eaten a food item, and then search for same quality food in the field. The results showed that subjects adjusted their foraging speed according to the value of the reward to be found. They were able to recognize the food resource on the basis of the item previously eaten by their companion. In a second experiment, we asked whether the subjects could anticipate a given food quantity from smelling a companion associated with that given food quantity. When testing whether subjects oriented their search strategy on the basis of companion's identity, they did not appear to use it as a referential cue to food quantity. They nonetheless adapted their foraging speed according to food value. Both experiments indicated that macaques are liable to assess and select food from information extracted from conspecifics, and hence avoid some costs associated with individual food searching.

Leaf-Mold Trap Attractiveness to the Larvae Cupreous Chafer, Anomala cuprea (Coleoptera: Scarabaeidae), and the Role of the Antenna for Food Searching Behavior

Leaf-Mold Trap Attractiveness to the Larvae Cupreous Chafer, <I>Anomala cuprea</I> (Coleoptera: Scarabaeidae), and the Role of the Antenna for Food Searching Behavior

Feeding behaviour of cod,Gadus morhua: activity rhythm and chemically mediated food search

I studied the feeding behaviour of cod in late spring in a fjord in northern Norway by means of a stationary positioning system. The activity rhythm of eight cod tagged with acoustic transmitters was observed continuously for 3–8 days in terms of swimming speed and size of area occupied. I studied responses to food odour by setting a line with mackerel baits in the experimental area. The cod had a diurnal rhythm of swimming activity with a slightly lower swimming speed during a 5-h period at night, indicating that they searched more actively for food during the day. A shift towards a larger proportion of active prey taken in the day, accompanied by a change in hunting strategy where vision became more important, may explain this rhythmicity in feeding behaviour. The diurnal rhythm in the range of area occupied varied more than the swimming activity rhythm and there was no significant difference in range between day and night indicating that factors other than the diel light cycle also influenced periodicity in activity. A higher proportion of fish encountered by the bait odour plume located baits than that of fish that were out of range of the odour plume, indicating the importance of chemically mediated food searching in this species. The cod detected a food odour source from a distance of several hundred metres, and responded immediately to the odour plume by carrying out a rheotactic search at a moderately higher swimming speed.

Spatial Memory and Food Searching Mechanisms of Cattle

Uneven distribution of grazing negatively impacts rangelands through over- and under utilization of resources. The goal of this study was to quantify the role of experience on search pattern and foraging efficiency of cattle. Steers (Bos taurus x B. indicus) were exposed once daily during 15-20 min. sessions to 3 food-distribution treatments: VR (variable-random, food locations were changed randomly and daily), CR (constant-random, food locations were randomly set at the beginning and remained the same throughout the experiment), and CC (constant-clumped, food locations were constant and clumped in groups of 5). Pelleted feed was available in 20 out of 64 feeders arranged in 8 rows and 8 columns, with neighboring locations 5 m apart. Encounter rate of food locations was partitioned into search speed, total number of visits per unit distance walked, ratio of different (not previously visited within the session) locations to total visits (including revisits), and ratio of food locations to different locations visited. Intake rate increased (P < 0.01) as animals gained experience, but more slowly in variable-random than constant-clumped and constant-random. Residence time at food locations declined (P < 0.01) with increasing experience. Intake rate was negatively affected (P < 0.01) by search time per food location, which in turn was determined by the steers' ability to remember food locations. Steers in constant random and constant clumped used long-term spatial memory to return to food locations, and ignored areas where no food was found (P < 0.01). Conversely, steers in variable random used a strategy based on avoidance of locations already visited within sessions. Thus, in constant random and constant clumped food search was more efficient (P < 0.01) and concentrated in certain areas, whereas in variable random it was less efficient and more evenly distributed over the whole area. The results of this study suggest that impeding spatial memory could improve grazing patterns.

Searching for Food or Hosts: The Influence of Parasitoids Behavior on Host–Parasitoid Dynamics

A host–parasitoid system with overlapping generations is considered. The dynamics of the system is described by differential equations with a control parameter describing the behavior of the parasitoids. The control parameter models how the parasitoids split their time between searching for hosts and searching for non-host food. The choice of the control parameter is based on the assumption that each parasitoid maximizes the instantaneous growth rate of the number of copies of its genotype. It is shown that optimal individual behavior of parasitoids, with respect to time sharing between hosts and food searching, may have a stabilizing effect on the host–parasitoid dynamics.

Food searching and superparasitism in solitary parasitoids

Optimality theory predicts that, provided that a larva resulting from superparasitism has some chance of winning the competition with the other larvae present in the host, under certain conditions, solitatry parasitoids should resort to superparasitism. Both theoretical and experimental studies have shown that the life expectancy of the parasitoid has a strong influence on the decision to reject or to accept superparasitism. In many species, life expectancy on its turn depends on the feeding behaviour of the parasitoids, which have to forage for non-host food (mainly plant materials), for the maintenance of their energy reseves. As many solitary parasitoids do not find non-host food in their host patches, they have to choose at each instant whether to search for food or to search for hosts. In this paper, we develop a stochastic dynamic programming model to study the behavioural choice between host and food searching, and its consequences for the acceptance and rejection of superparasitism. We study the influence of habitat quality and parasitoid physiological state on the optimal choice. The model predicts that the crucial point determining the optimal strategy is the balance between egg-and time-limitation.

Comparative performances of non-visual food search in the hypogean cyprinidPhreatichthys andruzziiand in the epigean relativeBarbus filamentosus

The anophthalmic hypogean cyprinid Phreatichthys andruzzii Vinciguerra shows a more efficient food searching behaviour than blinded specimens of the epigean species Barbus filamentosus Cuvier and Valenciennes. This difference seems to be related to a tendency to swim near the bottom of the aquarium and the behavioural stereotypes in food localization and intake. Both in P. andruzzii and in the blinded B. filamentosus food search is guided by chemical stimulation. Other data indicate that mechanical stimulation could play an important role in the feeding behaviour of the hypogean form. The behavioural analogies in food localization between P. andruzzii and the cave forms of the characid Astyanax fasciatus Cuvier are briefly discussed.

Food Searching and Exploitation by a Primary Consumer (Ancylus fluviatilis) in a Stochastic Environment: Nonrandom Movement Patterns

Food Searching and Exploitation by a Primary Consumer (Ancylus fluviatilis) in a Stochastic Environment: Nonrandom Movement Patterns