Temporal Feeding Patterns Research Articles

Parrotfish soundscapes: implications for coral reef management

Parrotfishes are prominent members of the herbivore/detritivore feeding guild on coral reefs. Their feeding activity is important for the removal of algae and detritus, the clearing of new settlement sites for coral and other larvae, and the bioerosion and redistribution of sand across the reef. Estimates of parrotfish feeding activity are normally obtained by divers that may influence or overlook fish behaviors, and are of short duration, limited to shallow habitats, and have limited temporal resolution to associate feeding activity with ecological processes. Excavator and scraper parrotfishes have a robust beak-like jaw morphology that produces a unique sound as the teeth scrape the surface of hard coral rock. We tested the hypothesis that ambient parrotfish bite sounds can be used to estimate their temporal patterns of feeding and associations with environmental variates in the area of an acoustic recorder. Acoustic recorders were deployed on 2 Hawaiian reefs to collect ambient fish sounds for a period of 3 yr. Parrotfish bite sounds showed distinct and repetitive variations in daily, seasonal, and annual feeding patterns, and were statistically correlated with factors of day length and tide range. This study demonstrates the utility of using parrotfish bite sounds to estimate patterns of feeding at coral reef sites. We suggest that regular sampling by multiple acoustic monitors may be a cost-efficient and valuable tool for monitoring the health, degradation, and recovery of large coral reef areas.

­­Effect of multimodal cues from a predatory fish on refuge use and foraging on an amphidromous shrimp

BackgroundPrey can alter their behavior when detecting predator cues. Little is known about which sensory channel, number of channels, or the interaction among channels that shrimp species use to evaluate the threat from predators. The amphidromous shrimp Xiphocaris elongata has an induced defense, an elongated rostrum, where predatory fishes are present. We sought to test if kairomones or visual cues when presented singly from fish either eating flakes or shrimp, had more effect on altering the temporal feeding and refuge use patterns of long-rostrum (LR) X. elongata. We were also interested in elucidating potential interactions among cues when presented simultaneously in different combinations (kairomones + visual + mechanosensory, kairomones + alarm + visual, kairomones + alarm, kairomones + visual) on the same response variables. We expected that when presented alone kairomones will significantly increase refuge use and decrease foraging, particularly late at night, in comparison to visual cues alone, and that multiple cues when presented simultaneously will further increase refuge use and decrease foraging at night.MethodsWe exposed shrimp to individual or multiple cues from the predatory fish mountain mullet, Augonostomus monticola. We examined shrimp behavior with respect to refuge use and foraging activity during four time periods (after sunset, nighttime, sunrise, and sunset) in a 24-hour period.ResultsShrimp presented fish visual and chemical cues singly did not differ from one another but differed from control shrimp (no cues) with respect to refuge use or foraging. The number of shrimp using refuge in the treatment with most cues (KVM: kairomones+ visual + mechanosensory) was higher than in all the treatments with less cues. A significant decline in foraging was observed when multiple cues were presented simultaneously. The highest number of shrimp foraged one hour after sunset and at nighttime. A significant interaction was observed between cue treatments and time periods, with shrimp in the KVM treatment foraging less and using more refuge late at night and at sunrise than shrimp in other treatments or time periods.ConclusionsThe observation that fish chemical and visual cues when presented singly produced similar refuge use and foraging patterns was contrary to expectation and suggests that visual and chemical cues, when presented alone, provide redundant information to X. elongata with regards to predation threat. The significant increase in refuge use and reduction in foraging observed in the KVM treatment suggest multimodal signal enhancement in the perception of threat. This makes evolutionary sense in “noisy” environments, such as streams, where detection, localization, and intention of predators is much improved when cues are received through multiple sensory channels.

Temporal and Spatial Blood Feeding Patterns of Urban Mosquitoes in the San Juan Metropolitan Area, Puerto Rico.

Simple SummaryUnderstanding the biodiversity of urban ecosystems is critical for management of invasive and pest species, conserving native species, and disease control. Mosquitoes (Culicidae) are ubiquitous and abundant in urban ecosystems, and rely on blood meals taken from vertebrates. We used DNA from freshly blood-fed mosquitoes to characterize the diversity of vertebrate host species in the San Juan Metropolitan Area, Puerto Rico. We collected two mosquito species that fed on a variety of vertebrates. Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Aedes aegypti blood meals were from a less diverse group, with two avian taxa (11.1%) and three mammalian taxa (88.9%) identified. Domestic chickens dominated the blood meals of Cx. quinquefasciatus, both temporally and spatially, and no statistically significant shift from birds to mammals was detected. The species we detected from the mosquito blood meals provided a snapshot of the vertebrate community in the San Juan Metropolitan Area, most of which were domestic species. However, we also identified a variety of native and nonnative wild species. These results add knowledge about potential ecological factors that impact vector-borne disease management in urban habitats.Urban ecosystems are a patchwork of habitats that host a broad diversity of animal species. Insects comprise a large portion of urban biodiversity which includes many pest species, including those that transmit pathogens. Mosquitoes (Diptera: Culicidae) inhabit urban environments and rely on sympatric vertebrate species to complete their life cycles, and in this process transmit pathogens to animals and humans. Given that mosquitoes feed upon vertebrates, they can also act as efficient samplers that facilitate detection of vertebrate species that utilize urban ecosystems. In this study, we analyzed DNA extracted from mosquito blood meals collected temporally in multiple neighborhoods of the San Juan Metropolitan Area, Puerto Rico to evaluate the presence of vertebrate fauna. DNA was collected from 604 individual mosquitoes that represented two common urban species, Culex quinquefasciatus (n = 586) and Aedes aegypti (n = 18). Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Domestic chickens dominated these blood meals both temporally and spatially, and no statistically significant shift from birds to mammals was detected. Aedes aegypti blood meals were from a less diverse group, with two avian taxa (11.1%) and three mammalian taxa (88.9%) identified. The blood meals we identified provided a snapshot of the vertebrate community in the San Juan Metropolitan Area and have potential implications for vector-borne pathogen transmission.

Multi‐tissue stable isotope analyses reveal temporal changes in the feeding patterns of green turtles in the Galapagos Marine Reserve

Knowledge of feeding patterns of highly migratory species is critical for understanding their habitat use and informing the management of their populations. The Galapagos Islands are one of the most important nesting and feeding areas for green turtles (Chelonia mydas) across the tropical eastern Pacific, yet little is known about the feeding patterns of this species. The isotopic composition of different tissues has been used to gain insight into the trophic dynamics of mobile aquatic consumers whose trophic behavior is difficult to directly measure. To elucidate the temporal feeding patterns and isotopic niche sizes of Galapagos green turtles, stable isotope analyses were performed on multiple tissues (skin and carapace) collected at the two most important nesting areas in the archipelago: Bachas and Quinta Playa. The δ13 C and δ15 N signatures on the skin and carapace samples from 56 adult femalesrevealed significant differences between tissues (p = .001 and p = .021, respectively) and nesting areas (p = .011 and p = .003, respectively). These differences suggest a shift from oceanic feeding grounds to neritic habitats before nesting. The carapace isotope values indicated an offshore feeding strategy and a greater isotopic niche (SEAc = 1.91‰2 ), whereas the skin isotope values represented an inshore feeding strategy with a narrower niche (SEAc = 1.37‰2 ), likely related to the consumption of specific coastal prey. Our results suggest that Galapagos green turtles feed across different habitats, and this information can be applied to improve the management ofthis endangered species.

A Novel Automated System Yields Reproducible Temporal Feeding Patterns in Laboratory Rodents

ABSTRACTBackgroundThe impact of temporal feeding patterns remains a major unanswered question in nutritional science. Progress has been hampered by the absence of a reliable method to impose temporal feeding in laboratory rodents, without the confounding influence of food-hoarding behavior.ObjectiveThe aim of this study was to develop and validate a reliable method for supplying crushed diets to laboratory rodents in consistent, relevant feeding patterns for prolonged periods.MethodsWe programmed our experimental feeding station to deliver a standard diet [StD; Atwater Fuel Energy (AFE) 13.9% fat] or high-fat diet (HFD; AFE 45% fat) during nocturnal grazing [providing 1/24th of the total daily food intake (tdF/I) of ad libitum–fed controls every 30 min] and meal-fed (3 × 1-h periods of ad libitum feeding) patterns in male rats (Sprague-Dawley: 4 wk old, 72–119 g) and mice [C57/Bl6J wild-type (WT): 6 mo old, 29–37 g], and ghrelin-null littermates (Ghr−/−; 27–34 g).ResultsGrazing yielded accurate, consistent feeding events in rats, with an approximately linear rise in nocturnal cumulative food intake [tdF/I (StD): 97.4 ± 1.5% accurate compared with manual measurement; R2 = 0.86; tdF/I (HFD): 99.0 ± 1.4% accurate; R2 = 0.86]. Meal-feeding produced 3 nocturnal meals of equal size and duration in StD-fed rats (tdF/I: 97.4 ± 0.9% accurate; R2 = 0.90), whereas the second meal size increased progressively in HFD-fed rats (44% higher on day 35 than on day 14; P < 0.01). Importantly, cumulative food intake in grazing and meal-fed rats was identical. Similar results were obtained in WT mice except that less restricted grazing induced hyperphagia (compared with meal-fed WT mice; P < 0.05 from day 1). This difference was abolished in Ghr−/− mice, with meal initiation delayed and meal duration enhanced. Neither pattern elevated corticosterone secretion in rats, but meal-feeding aligned ultradian pulses.ConclusionsWe have established a consistent, measurable, researcher-defined, stress-free method for imposing temporal feeding patterns in rats and mice. This approach will facilitate progress in understanding the physiologic impact of feeding patterns.

SAT-096 Later Timing of Energy Intake Associates with Higher Fat Mass in Adults with Overweight and Obesity

Background Emerging literature suggests that later timing of energy intake and sleep are related to obesity (1-3). However, few studies have assessed both meal and sleep timing in adults with obesity, and it is not clear whether eating later in the day is associated with shorter sleep duration or higher adiposity. Understanding whether temporal feeding and sleep patterns are associated with body composition will help in the design of novel weight loss and maintenance interventions aimed at altering the timing of lifestyle behaviors. Methods Thirty-two overweight and obese adults (90% female sex, age 36.4±6.4 years, and BMI=33.4±5.5 kg/m2) were recruited to participate in an ongoing weight loss trial comparing daily caloric restriction to time-restricted feeding. Participants simultaneously wore an activPAL accelerometer on the thigh and an Actiwatch on the non-dominant wrist for 7 days in a free-living environment to assess waking sedentary behavior and nighttime sleep, respectively. A cell phone application (MealLogger) was used to photograph and timestamp all caloric events during the 7-day period to determine daily feeding duration, which was verified using a continuous glucose monitor. Assessments were performed at baseline and will be repeated at 12 weeks following completion of the weight loss intervention. Correlation analyses were performed on baseline data to determine associations among the duration and timing of daily energy intake and sleep. Results are reported as mean±SD. Results On average, participants consumed energy over 11.0±1.9 hours during the day and slept for 7.2±0.7 hours at night. The clock time of the last caloric event averaged 7:54pm ± 93 min. Later meal timing (midpoint of the feeding window) was positively correlated with later sleep timing (midpoint of the sleep window, r = 0.67, P = <0.0001) but did not impact sleep duration. A later feeding midpoint correlated with higher BMI (r = 0.49, P = 0.005) and fat mass (r = 0.55, P = 0.001). Conclusions We used a novel set of methods to show that individuals with overweight and obesity may be eating later into the day. In addition, later meal timing was associated with higher BMI and fat mass. Future studies are needed to compare the timing of energy intake and sleep in normal weight versus obese individuals. These findings support ongoing studies by our group investigating whether restricting energy intake to the early part of the day lowers obesity risk. References (1) McHill et al., Am J Clin Nutr. 2017 Nov;106(5):1213-1219. (2) Baron et al., Obesity (Silver Spring). 2011 Jul;19(7):1374-81. (3) Garaulet, Gomez-Abellan, Physiol Behav. 2014 Jul;134:44-50. Sources of Research Support: This research has received funding from the NIH

Measuring Food Anticipation in Mice.

The interplay between the circadian system and metabolism may give animals an evolutionary advantage by allowing them to anticipate food availability at specific times of the day. Physiological adaptation to feeding time allows investigation of animal parameters and comparison of food anticipation between groups of animals with genetic alterations and/or post pharmacological intervention. Such an approach is vital for understanding gene function and mechanisms underlying the temporal patterns of both food anticipation and feeding. Exploring these mechanisms will allow better understanding of metabolic disorders and might reveal potential new targets for pharmacological intervention. Changes that can be easily monitored and that represent food anticipation on the level of the whole organism are a temporarily restricted increase of activity and internal body temperature.

Parental care compromises feeding in the pumpkinseed (Lepomis gibbosus)

Providing parental care is potentially costly. Costs can arise through elevated energy expenditure or from an increased risk of mortality. A cost of parental care can also occur because a parent is compromised in their ability to forage. We used pumpkinseed Lepomis gibbosus, a fish with an alternative male mating strategy, to test whether parental males differed in their feeding in comparison with females and cuckolder males. To address this question, we examined the stomach contents of female, cuckolder male, and parental male pumpkinseed during the breeding season over an entire diel cycle. We showed that parental males had a lower total weight of food in their stomachs in comparison with females, while cuckolder males did not. Parental males also had a lower weight and number of chironomids in their stomachs. The temporal pattern of feeding of parental males diverged from that of females, and they had a lower probability of pupal chironomids in their stomachs, which implies spatial segregation in foraging. Parental males had a greater probability of conspecific eggs in their stomachs than females, while the probability of egg cannibalism did not differ between cuckolder males and females. Overall, these finding meet predictions in accordance with an assumption that parental care and territoriality can compromise feeding.

Fine-Tuning Circadian Rhythms: The Importance of Bmal1 Expression in the Ventral Forebrain.

Although, the suprachiasmatic nucleus (SCN) of the hypothalamus acts as the central clock in mammals, the circadian expression of clock genes has been demonstrated not only in the SCN, but also in peripheral tissues and brain regions outside the SCN. However, the physiological roles of extra-SCN circadian clocks in the brain remain largely elusive. In response, we generated Nkx2.1-Bmal1−/− mice in which Bmal1, an essential clock component, was genetically deleted specifically in the ventral forebrain, including the preoptic area, nucleus of the diagonal band, and most of the hypothalamus except the SCN. In these mice, as expected, PER2::LUC oscillation was drastically attenuated in the explants of mediobasal hypothalamus, whereas it was maintained in those of the SCN. Although, Nkx2.1-Bmal1−/− mice were rhythmic and nocturnal, they showed altered patterns of locomotor activity during the night in a 12:12-h light:dark cycle and during subjective night in constant darkness. Control mice were more active during the first half than the second half of the dark phase or subjective night, whereas Nkx2.1-Bmal1−/− mice showed the opposite pattern of locomotor activity. Temporal patterns of sleep-wakefulness and feeding also changed accordingly. Such results suggest that along with mechanisms in the SCN, local Bmal1–dependent clocks in the ventral forebrain are critical for generating precise temporal patterns of circadian behaviors.

Long Term Feeding Patterns Highlight Preference for Sucrose in the Fruit Fly Anastrepha serpentina When Given a Choice over Other More Nutritious Food Sources

Insects are known to be able to regulate food ingestion according to its nutrient composition rather than its energetic content. Several studies have found that individuals can feed selectively when given the opportunity, and balance the intake of different nutrients so as to optimize fitness. However, there are cases in which individuals do not strictly adopt this pattern of optimal nutrient balancing. This study examined the periodicity of feeding on different food substrates and also water by adult individuals of Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) over a 38-day observation period analyzing daily feeding patterns, feeding time, and sequences of feeding events. Two artificial food substrates, one rich in protein (hydrolyzed yeast) and one rich in carbohydrates (sucrose), and one natural diet (open sapodilla fruit) were offered alone or paired (sucrose vs. open fruit or sucrose vs. yeast) to newly emerged individuals during 38 days or until death. Water was also provided in all cases. Our results provide new and interesting insights on long-term individual dietary preferences and feeding periodicity in a tropical fruit fly, including water consumption. In general, flies exhibited different feeding patterns according to the diet, but preferred to feed on sucrose when offered a choice of sucrose and yeast. This preference was evident from the outset of the trial. When sucrose was offered together with an open fruit, the latter was preferred. However, there were conspicuous individual differences in temporal feeding patterns among flies fed the same diet, including variability in the number of consecutive days some individuals did not consume any food or water (up to five days in some cases). Individuals fed with sucrose only exhibited the lowest survival and those fed with sucrose-open fruit the highest. We discuss these feeding choices and their possible causes, including individual differences in the gut microbiota and nutritional reserves of newly emerged flies.

Incorporating toxicokinetics into an individual-based model for more realistic pesticide exposure estimates: A case study of the wood mouse

The potential risk of agricultural pesticides to mammals typically depends on internal concentrations within individuals, and these are determined by the amount ingested and by absorption, distribution, metabolism, and excretion (ADME). Pesticide residues ingested depend, amongst other things, on individual spatial choices which determine how much and when feeding sites and areas of pesticide application overlap, and can be calculated using individual-based models (IBMs). Internal concentrations can be calculated using toxicokinetic (TK) models, which are quantitative representations of ADME processes. Here we provide a population model for the wood mouse (Apodemus sylvaticus) in which TK submodels were incorporated into an IBM representation of individuals making choices about where to feed. This allows us to estimate the contribution of individual spatial choice and TK processes to risk. We compared the risk predicted by four IBMs: (i) “AllExposed-NonTK”: assuming no spatial choice so all mice have 100% exposure, no TK, (ii) “AllExposed-TK”: identical to (i) except that the TK processes are included where individuals vary because they have different temporal patterns of ingestion in the IBM, (iii) “Spatial-NonTK”: individual spatial choice, no TK, and (iv) “Spatial-TK”: individual spatial choice and with TK. The TK parameters for hypothetical pesticides used in this study were selected such that a conventional risk assessment would fail. Exposures were standardised using risk quotients (RQ; exposure divided by LD50 or LC50). We found that for the exposed sub-population including either spatial choice or TK reduced the RQ by 37–85%, and for the total population the reduction was 37–94%. However spatial choice and TK together had little further effect in reducing RQ. The reasons for this are that when the proportion of time spent in treated crop (PT) approaches 1, TK processes dominate and spatial choice has very little effect, and conversely if PT is small spatial choice dominates and TK makes little contribution to exposure reduction. The latter situation means that a short time spent in the pesticide-treated field mimics exposure from a small gavage dose, but TK only makes a substantial difference when the dose was consumed over a longer period. We concluded that a combined TK-IBM is most likely to bring added value to the risk assessment process when the temporal pattern of feeding, time spent in exposed area and TK parameters are at an intermediate level; for instance wood mice in foliar spray scenarios spending more time in crop fields because of better plant cover.

Disrupted circadian rhythmicity of the intestinal glucose transporter SGLT1 in Zucker diabetic fatty rats.

Intestinal absorptive capacity shows a circadian rhythm synchronized with eating patterns. Disrupting these coordinated rhythms, e.g., with shift work, may contribute to metabolic disease. Circadian expression of nutrient transporters has not been studied in metabolic disease. We studied the circadian rhythm of intestinal transporter sodium glucose co-transporter type 1 (SGLT1) in an obese diabetic rat. We compared obese Zucker diabetic fatty (ZDF) rats to lean ZDF littermates. Temporal feeding patterns were assessed, then rats were harvested at Zeitgeber (ZT, ZT0 = 7:00 a.m.) 3, 9, or 15 to measure insulin resistance, SGLT1 expression and intestinal glucose absorption capacity. Regulators of SGLT1 (sweet taste receptor T1R2/3; clock genes) were measured to elucidate underlying mechanisms. Both groups exhibited altered circadian food intake. Obese ZDF rats lost circadian rhythmicity of SGLT1 mRNA expression and functional activity. Lean ZDF rats maintained rhythmicity of SGLT1 mRNA expression but that of functional glucose absorption was blunted. Circadian rhythms of intestinal clock genes were maintained in both groups. Neither group had discernible rhythms of intestinal GLUT2 (glucose transporter) or T1R2 (sweet taste receptor component) mRNA expression. In summary, lean and obese ZDF rats exhibited similar disruptions in circadian feeding. Glucose intolerance was evident in lean rats, but only obese rats further developed diabetes and exhibited disrupted circadian rhythmicity of both SGLT1 mRNA expression and function. Our findings suggest that disrupted circadian feeding rhythms contribute to glucose intolerance, but additional factors (genetics, changes in nutrient sensing/transport) are needed to lead to full diabetes.

Relationships between residual feed intake, average daily gain, and feeding behavior in growing dairy heifers

Residual feed intake (RFI) is a measure of an individual’s efficiency in utilizing feed for maintenance and production during growth or lactation, and is defined as the difference between the actual and predicted feed intake of that individual. The objective of this study was to relate RFI to feeding behavior and to identify behavioral differences between animals with divergent RFI. The intakes and body weight (BW) of 1,049 growing dairy heifers (aged 5–9mo; 195±25.8kg of BW) in 5 cohorts were measured for 42 to 49d to ascertain individual RFI. Animals were housed in an outdoor feeding facility comprising 28 pens, each with 8 animals and 1 feeder per pen, and were fed a dried, cubed alfalfa diet. This forage diet was chosen because most dairy cows in New Zealand are grazed on ryegrass-dominant pastures, without grain or concentrates. An electronic feed monitoring system measured the intake and feeding behavior of individuals. Feeding behavior was summarized as daily intake, daily feeding duration, meal frequency, feeding rate, meal size, meal duration, and temporal feeding patterns. The RFI was moderately to strongly correlated with intake in all cohorts (r=0.54–0.74), indicating that efficient animals ate less than inefficient animals, but relationships with feeding behavior traits (meal frequency, feeding duration, and feeding rate) were weak (r=0.14–0.26), indicating that feeding behavior cannot reliably predict RFI in growing dairy heifers. Comparison of the extremes of RFI (10% most and 10% least efficient) demonstrated similar BW and average daily gain for both groups, but efficient animals ate less; had fewer, longer meals; shorter daily feeding duration; and ate more slowly than the least-efficient animals. These groups also differed in their feeding patterns over 24h, with the most efficient animals eating less and having fewer meals during daylight (0600 to 2100h), especially during the afternoon (1200 to 1800h), but ate for a longer time during the night (0000–0600h) than the least-efficient animals. In summary, correlations between RFI and feeding behavior were weak. Small differences in feeding behavior were observed between the most- and least-efficient animals but adverse behavioral effects associated with such selection in growing dairy heifers are unlikely.

Spatial and temporal patterns in the feeding behavior of a fiddler crab

Fiddler crabs consume the surficial microphytobenthos around their burrows during low tide. We studied the spatial and temporal feeding patterns in the species Uca uruguayensis by using sequences of digital pictures of feeding pellets accumulation. Data from 61 crabs, feeding without the interference of neighbors, were fitted to different models using Maximum Likelihood and Bayesian approaches. Initial feeding location was independent from the emergence location, and then, crabs continued holding a main feeding direction (clockwise or counterclockwise), suggesting a systematic mechanism that may avoid feeding over already processed sediment. Crabs used at least half of their potential feeding area, but these areas were heterogeneous. Both sexes developed similar feeding areas; however, females were faster and needed less time to feed than males, suggesting that males are time restricted. Our work also highlights the importance of incorporating other underlying mechanisms of the behavior of species into the study of feeding strategies.

Synchronization of fishes’ temporal feeding patterns with weather in mid-Missouri

Daily food consumption was estimated over 30 successive days in summer for bluegill (Lepomis macrochirus) in a 13 ha impoundment, and simultaneously for green sunfish (Lepomis cyanellus) in a second-order mid-Missouri stream from the same watershed. Using temperature data from the Sanborn Field Station for the same period, a relationship between daily food consumption rate of the two fish species and synoptic-scale weather patterns or cycles was established using cross spectral analysis which is not found in the previous literature. Previous analyses of the two species in their respective aquatic environments showed that their daily consumption rates over 30-day periods were rhythmic and peaked on a time scale of 2 and 14 days. A spectral analysis of the temperature data from that period showed that there were statistically significant temperature variations on the time scale of 2, 6, and 15 days. The latter two periods are related to well-known synoptic meteorological rhythms (the passage of cyclones and large-scale vacillation in the jet stream). This same technique, method of cycles, when applied to the fishes’ consumption rate data showed that the spectral peaks occurred similar to those in the temperature analysis. Then, a similar analysis was performed on data taken from a 6-month feed study in another part of the world (Finland), in order to determine whether our results were robust. This result was positive as well. Thus, it is hypothesized here that the food consumption patterns of these two fishes are linked to variations in the local synoptic and large-scale weather conditions.

Maintaining fish diversity in Thailand: variations in foraging behavior

We examined foraging adaptations and diet among dominant fishes within two species-rich riffle habitats in Thailand headwater rivers during the early and late portions of the dry season. All species exhibited diel temporal variations in feeding activity. Some species fed principally during daylight, while others fed mainly during darkness. Feeding patterns within species were generally spatially and temporally consistent. All seven fishes exploited the same benthic prey, but their foraging activities were related to spatially distinct water velocities. Diets overlapped with Ephemeroptera and Trichoptera the quantitatively most important prey. Ostracods, while not a large contributor to diet biomass, were numerically important in the diet of Homaloptera smithi. Trophic diversification through diel temporal feeding patterns and microhabitat separation by water velocity are major tactics in maintaining high diversity in riffle assemblages in Thai headwater rivers.

The use of food resources by 0+ snapper, Chrysophrys auratus, from northern Spencer Gulf, South Australia

Food availability is an important factor in survival and growth of juvenile fish and has been proposed as a major factor shaping the patterns of distribution and abundance of 0+ snapper, Chrysophrys auratus, in New Zealand and Japan. Thus, we tested the hypothesis that diet of 0+ snapper would exhibit spatial variation related to their abundance within a major nursery region. Therefore, we described the stomach contents of 0+ snapper collected from within a nursery region in areas of low and high abundance of 0+ snapper. The data also provided the opportunity to consider sized based differences in diet and temporal feeding patterns. 0+ snapper were generalist carnivores that preyed on a wide range of invertebrates and fish. No evidence of sized based dietary variation was identified but feeding either ceased or was much reduced during the hours of darkness. The major finding was that more polychaetes were present in the stomachs of 0+ snapper in the area of high 0+ snapper abundance than in the areas of low 0+ snapper abundance. The spatial differences in diet observed supports the hypothesis that prey availability is important as a driver of habitat selection by 0+ fish.

Temporal pattern of feeding and drinking behaviour of gestating sows

Abstract. The aim of the present study was to investigate the temporal pattern of feed and water intake behaviour of gestating sows housed in a dynamic group. The dataset included 90 sows (parity 1 to 7). Feed and water intake were recorded by electronic feeding and drinking stations. To describe the feed and water intake behaviour single visits were combined into meals and drinking bouts. A log survivorship function identified the characteristic interval length to differentiate between two bouts. Interval lengths larger than 12 min separated two meals (29 min two drinking bouts). The meal and drinking bout criteria were used to derive the following traits: feeding and drinking duration per day (FD, DD), interval duration within feeding (pauseF) or drinking (pauseW) meal, feeding and drinking meal duration per day (FMD, DMD) and feeding and drinking visits per day (FV, DV). Additionally, an eating rank was calculated according to the order of the sows at the feeding station. The results showed that nulliparous and primiparous sows had higher FD, pauseF, FMD and FV in contrast to biparous and multiparous sows (P&lt;0.05). The DD of primiparous sows was significantly lower than that of older sows. The eating rank increased over time while nulliparous sows increased their rank more slowly than older sows. Low to moderate repeatabilities were found for feed intake traits (0.23 to 0.41); higher repeatabilities for drinking traits (0.45 to 0.55) and eating rank (0.71) indicating high variation between sows, which could be used for the identification of diseases.

Estimation of feeding patterns for piscivorous fish using individual prey data from stomach contents

The problem of estimating temporal feeding patterns using stomach data is considered, where the time of ingestion for each prey item can be predicted through a gastric evacuation model. The arrival of prey is modelled as a nonhomogeneous Poisson process with known periodic intensity. A maximum likelihood approach is used to estimate the intensity, which is assumed to be the same for all predators, incorporating different uncertainties for the arrival time of each prey item. The method is applied to a case where a population of whiting ( Merlangius merlangus ) is feeding on sandeel ( Ammodytes marinus ), and peak feeding periods around dusk and dawn are identified.

Aggregations and temporal changes in the activity and bioturbation contribution of the sea cucumber Holothuria whitmaei (Echinodermata: Holothuroidea)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 415:127-139 (2010) - DOI: https://doi.org/10.3354/meps08685 Aggregations and temporal changes in the activity and bioturbation contribution of the sea cucumber Holothuria whitmaei (Echinodermata: Holothuroidea) Glenn R. Shiell1,2,*, Brenton Knott1 1Animal Biology (MO92), The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia 2Present address: Oceanica Consulting Pty. Ltd., PO Box 3172, Broadway, Nedlands, Perth, WA 6009, Australia *Email: glenn.shiell@oceanica.com.au ABSTRACT: The population density, activity and bioturbation contribution of the sea cucumber Holothuria whitmaei was investigated on Ningaloo Reef, Western Australia. Two methods, stratified manta tows and blanket manta tows, recorded population densities between 11.4 and >100 individuals (ind.) ha–1. Further analysis revealed a heterogeneous pattern of distribution, with individuals tending to aggregate (Moran’s I; 0.039; p < 0.05) on the outer reef lagoon and particularly in areas of high flow. Densities within aggregations were up to 7.2 times greater than those obtained after blanket manta tows (17.1 ind. ha–1), and 4.5 to 6.3 times greater than those obtained after traditional stratified manta tows (19.3 to 27.1 ind. ha–1). Behavioural studies, including investigations of activity and bioturbation, were conducted over a 2 yr time frame (2002–2003) incorporating 3 monitoring periods within each year: January, April and August. Rates of activity varied diurnally, increasing between morning and afternoon, and seasonally, increasing in April, relative to January and August. Temporal patterns of feeding were more difficult to characterise; although rates of sediment egestion were in many cases higher in the morning, no conclusive diurnal or seasonal patterns could be established. Subsequent regression analysis, however, did find a significant positive correlation between the distance travelled and the volume of sediment egested. The volume of sediment bioturbated by H. whitmaei at a population level was found to represent only a small fraction of the sediments available (ca. 2 to 14% per annum), even though the contribution per individual was greater than that of smaller sea cucumber species. However, at maximum densities and typical rates of activity, H. whitmeai makes physical contact with approximately 2 times the available coral reef sediments per annum per hectare, simply by crawling. This may represent an important ecological contribution, particularly in light of previously documented links between sea cucumber activity, nutrient recycling and the enhancement of benthic microalgal communities. KEY WORDS: Aggregation · Behavioural activity · Bioturbation · Coral reef lagoon · Densitydependent effects Full text in pdf format PreviousNextCite this article as: Shiell GR, Knott B (2010) Aggregations and temporal changes in the activity and bioturbation contribution of the sea cucumber Holothuria whitmaei (Echinodermata: Holothuroidea). Mar Ecol Prog Ser 415:127-139. https://doi.org/10.3354/meps08685Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 415. Online publication date: September 29, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.