Peak Feeding Activity Research Articles

Diet and food utilization in Oreochromis esculentus (Graham) in Lake Kanyaboli, Kenya

Abstract Blue‐green algae (Cyanophyta) and green algae (Chlorophyta) were the principal food items ingested by Oreochromis esculentus (Graham) in Lake Kanyaboli. Diatoms (Bacillariophyta), euglenoids (Euglenophyta) and zooplankton were also consistently present in the diet in small quantities. O. esculentus of different sizes fed on similar food items in the lake. The species fed actively during the day, from 0700 h until 1700 h when peak feeding activity occurred. Thereafter, digestion took place steadily until 0600 h, when 90% of the fish had empty stomachs. The diet composition remained the same throughout the year, as did the composition of phytoplankton in the lake. O. esculentus tended to select and digest the diatoms and zooplankton and, to some extent, the euglenoids. Blue‐green and green algae were the least utilized food items and passed through the gut undigested.

Relationships Between Social Dominance and Feeding Behaviour in Lactating Heifers During Periods of Heavy Competition

Previous research has shown that social dominance in dairy herds can be measured using replacements of one cow by another at feed stations (Rutter et al,1987). When there is competition for feed or space, the motivation to engage in physical and non-physical agonistic interactions will be stronger than if resources are freely available. When resources are limited, social dominance becomes very important and high ranking animals have priority.This becomes especially important after cows are returned from milking and/or when fresh feed is added when the number of cows is far greater than the number of feeding spaces (Campling and Morgan, 1981). This experiment aimed to further investigate the way in which social interaction between cows affects the feeding behaviour, particularly at times of peak feeding activity.

Feeding habits of hatchery-reared barramundi Lates calcarifer (Bloch) fry

Hatchery-reared barramundi Lates calcarifer fry were studied to determine feeding behaviour, diel feeding patterns, stomach evacuation rates, daily food consumption and growth rates. At 16–18 mm total length, the feeding behaviour of the fry changed abruptly from a roving zooplanktivore habit to that of a lurking predator. A distinct change in pigmentation accompanied the change in feeding behaviour. Fry reared in hatchery ponds were obligate zooplanktivores between 10 and 17 mm. Between 17 and 50 mm the diet changed progressively from zooplankton to insect larvae and small vertebrates. The fry were visual feeders, taking food throughout the day, and showed a peak in feeding activity at dusk. Feeding continued at a reduced level under moonlit conditions, but ceased in total darkness. Stomach evacuation rates for 16-mm fry under continuous feeding and non-feeding conditions were 47 and 210 min, respectively; for 37-mm fry the rates were 73 and 108 min, respectively. The daily rations for these two size groups were 19–86% and 38–56%, respectively. Weight specific daily growth rates were 13–16% for fry reared in ponds. The significance of these results is discussed with respect to the biology and husbandry of small barramundi.

Vertical distribution of copepods and the utilization of the chlorophyll a-rich layer within Concepcion Bay, Chile

The potential factors contributing to the development of vertical distribution patterns of two copepod species, Calanus chilensis and Calanoides patagoniensis, were studied in Concepcion Bay, Chile, during three 24-h cruises in late winter, mid-spring 1984 and early winter 1986. Results show that both species tend to aggregate at the depth of maximum chlorophyll a in the water column and that neither minimum oxygen concentrations (<1 ml O 2l −1) nor strong thermoclines play a determinant role in the depth of maximum copepod aggregation. Gut contents (chlorophyll a and phaeopigments) in copepods revealed that the peak in feeding activity occurred during the night for both C. chilensis in June and for C. patagoniensis in November. The C. chilensis and C. patagoniensis populations consumed about 70% and 50% of their total daily ingestion in the chlorophyll a-rich layers in June and November, respectively. In spite of the environmental and population abundance differences between June and November, both copepod populations presented similar values of food consumption: the C. chilensis population ingested up to 8·47 mg C m 2 day −1 in June while the C. patagoniensis population consumed 6·81 mg C m −2 day −1 in November. The daily ingestion carried out by each copepod species would represent less than 1% of the total daily primary productivity in both months. Our results suggest that a great amount of phytoplankton biomass is not directly utilized by zooplankton in Concepcion Bay.

Onchocerca raillieti: Release from skin snips, maintenance in vitro and periodicity of microfilariae

Several media were tested for the release of Onchocerca raillieti microfilariae from skin snips and for their subsequent in vitro maintenance. Tyrode's solution containing 20% equine serum and antibiotics was the best medium tested, followed by phosphate buffered saline. Tyrode's solution alone or distilled water were poor media. A temperature 7-12 degrees C lower than the host's body temperature favoured release of the microfilariae from skin snips. The microfilariae were best maintained at 4-10 degrees C, when they remained alive for up to 5 days. O. raillieti microfilariae had an evening periodicity which could be related to a possible vector's peak of feeding activity.

Influence of temperature and light on feeding behaviour of pigs

Feeding behaviour and feed consumption of growing pigs (36 kg) were observed over a 6-day period while they were in two chambers, each housing four pigs. The temperature in one chamber was held constant at 33°C while the other cycled between a minimum of 26°C at 0530 h and a maximum of 40°C at 1400 h. The light schedule was 16 h light (0500–2100 h) and 8 h dark. Water and feed were provided ad libitum. Each chamber had one feeder capable of accommodating three pigs. Feeding behaviour was monitored continuously on a video recorder while feed consumption was determined every 4 min from an electronic output from a feeder scale. Feed consumption and feeder usage in both treatments were primarily a response to the light: dark pattern with two peaks in food intake; one at about the time the lights were turned on and the other shortly before the lights were turned off. Cyclic temperatures resulted in similar daily feed intakes and feeder usage, but shifted the diurnal feeding pattern. Feed consumption shifted to the coolest part of the thermal cycle, and the period of highest feed intake occurred earlier in the morning and later at night than those in the constant temperature treatment. The feeder was occupied for only 22 and 23% of the time in the constant and cyclic temperature treatment, respectively. During peak feeding activity, feeders were utilized by only one pig ∼50% of the time. Social facilitation did not appear to influence feeder usage. Only 25% of total feeding time occurred with two or three pigs at the feeder. During the remaining time, feeder usage was on an individual animal basis. During periods of peak feeder usage, 30% of the feeder usage was by two or three pigs at one time in the constant temperature treatment, while 40% of the feeder usage was by two or three pigs in the cyclic temperature treatment. Rate of ingestion (defined as feed consumed in g min −1 a pig was at the feeder) indicated that for 74% of the time the pigs in both temperature treatments consumed feed at a rate <25 g min −1 per pig. Mean ingestion rates for both thermal treatments were similar (15 g min −1 per pig).

Ecological correlates of foraging periodicity in herbivorous reef fishes of the Coral Sea

Diurnal feeding activity patterns of five herbivorous reef fishes were studied at two sites in the Coral Sea, Motupore Island and Davies Reef. A marked peak in feeding activity in the afternoon was found for the damselfishes Pomacentrus flavicauda Whitley, Stegastes apicalis (De Vis) and Plectroglyphidodon lacrymatus (Quoy et Gaimard), and the surgeonfishes Acanthurus lineatus (L.) and Ctenochaetus striatus (Quoy et Gaimard). Pomacentrus flavicauda and Ctenochaetus striatus exhibited weak territorial aggression, but afternoon foraging was as marked in them as in the other species. Pomacentus flavicauda, Stegastes apicalis, Plectroglyphidodon lacrymatus and Acanthurus lineatus fed on the algal turfs within their territories. Although some Ctenochaetus striatus on the outer reef flat foraged on algal turfs, most individuals fed over crustose-coralline-algal surfaces and rocks with diatom and sparse filamentous-algal coverage; afternoon peaks of feeding were found in both cases. Afternoon foraging was not found to be a metabolic response to diurnal temperature increase, and did not correlate directly with average tidal, wind (water movement), or light-intensity patterns. Although ambient dissolved-oxygen maxima did correspond with afternoon foraging, there was no evidence that oxygen was limiting to fish metabolism and no sign was found of an intrinsic respiratory rhythm in one species, Plectroglyphidodon lacrymatus. Assuming negligible exudation of soluble organics, measurements of community net oxygen flux by turf algae indicate that photosynthetic carbon accumulated through the daytime at both sites in the Coral Sea. At Motupore Island, organic matter tended to rise and crude-fibre levels fell diurnally in turf algae collected from the reef, demonstrating a measurable increase in more-assimilable carbon later in the day. Afternoon foraging may be an adaptation by herbivorous reef fishes to the diurnal build-up of photosynthate in productive microalgal communities, particularly turfs.

Diet, food resource partitioning and feeding periodicity of two riffle-dwelling fish species in a New Zealand river

The diets and feeding periodicities of two small, riffle-dwelling fish, the torrentfish, Cheimarrichthys fosteri, and the bluegilled bully, Gobiomorphus hubbsi, were investigated in an unstable, braided New Zealand river from May 1985 to April 1986. Aquatic insect larvae dominated diets of all fish and dietary overlap between species was high in 10 of 12 months. Nevertheless, the relative importance of prey items, as assessed by the index of relative importance (IRI), differed between species. Gobiomorphus hubbsi fed almost exclusively on larval Deleatidium (Ephemeroptera), whereas C. fosteri consumed a greater variety of prey items, with Deleatidium and trichopteran, elmid and chironomid larvae numerically dominant. A dietary switch from Deleatidium to chironomid larvae occurred in both species during December 1985, when total and relative abundances of mayfly and other benthic macroinvertebrate larvae were severely reduced by two consecutive floods. A diel sampling programme indicated that the feeding periodicity of the two species differed: C. fosteri was a nocturnal feeder, whereas G. hubbsi exhibited a strong crepuscular peak in feeding activity. Overall, the two fish partition their food resource weakly by consuming prey items in different proportions and sizes and more strongly by utilizing the food resource at different times.

Diet, food resource partitioning and feeding periodicity of two riffle‐dwelling fish species in a New Zealand river

The diets and feeding periodicities of two small, riffle‐dwelling fish, the torrentfish, Cheimarrichthys fosteri, and the bluegilled bully, Gobiomorphus hubbsi, were investigated in an unstable, braided New Zealand river from May 1985 to April 1986. Aquatic insect larvae dominated diets of all fish and dietary overlap between species was high in 10 of 12 months. Nevertheless, the relative importance of prey items, as assessed by the index of relative importance (IRI), differed between species. Gobiomorphus hubbsi fed almost exclusively on larval Deleatidium (Ephemeroptera), whereas C. fosteri consumed a greater variety of prey items, with Deleatidium and trichopteran, elmid and chironomid larvae numerically dominant. A dietary switch from Deleatidium to chironomid larvae occurred in both species during December 1985, when total and relative abundances of mayfly and other benthic macroinvertebrate larvae were severely reduced by two consecutive floods. A diel sampling programme indicated that the feeding periodicity of the two species differed: C. fosteri was a nocturnal feeder, whereas G. hubbsi exhibited a strong crepuscular peak in feeding activity. Overall, the two fish partition their food resource weakly by consuming prey items in different proportions and sizes and more strongly by utilizing the food resource at different times.

An in situ estimate of daily food consumption and alimentary canal evacuation rates of common carp, Cyprinus carpio L.

Daily food consumption and alimentary canal evacuation rates for common carp, Cyprinus carpio L., were estimated at 4‐week intervals from April to October 1979. Both the rate of food evacuation and its relationship to temperature were described by an exponential function. Gut evacuation rates ranged from 6.0% of gut contents per hour at 9°C to 32.7% h−1 at 26.5°C. Temperature accounted for 72–91% of the variation in gut evacuation rate among months. Daily food consumption varied from a low of 3.87 mg g−1 of fish wet wt per day in April at 14°C (0.39% of wet body wt) to a high of 40.75 mg g−1 (4.08%) in August at 26.5°C. Although a greater quantity of food appeared to be consumed during the morning in spring and early summer and a greater amount in the evening after July, there was not a statistically significant time of day for peak feeding activity. The field method described here seemed to provide reasonable estimates of food consumption compared with other field and laboratory studies.

Feeding biology of Aplocheilichthys normani, Ahl, a small Cyprinodontidae from West Africa

Aplocheilichthys normani is a small Cyprinodontidae endemic in tropical Africa from Senegal to central Sudan. Analysis of the gut content of two populations from Guinea reveals that it feeds mainly on small crustaceans and chironomid larvae. Experimental investigations into its predatory capacity vis‐á‐vis the larvae of Aedes aegypti show that there is a significant difference between the daily feeding rates in adult versus subadult specimens. Moreover, significant 24 h variations were also observed. The feeding rate is also related to the stage of the larvae, i.e. the predatory capacity is greater for smaller prey. The 24h feeding rate variations show that A. normani feeds both during the daylight hours and at night, with a slightly higher predatory activity during the daylight hours. The peak in feeding activity occurs during the two hours before dark. Tests on feeding preferences show that the fish prefers, in descending order, Aedes, Anopheles and Culex larvae. Its larvivorous activity against mosquito larvae was corroborated by small‐scale field studies. We propose that this species be considered for possible use in the biological control of mosquito larvae in West Africa.

Recorded sounds associated with feeding did not affect feeding behavior of lambs

This study was designed to determine whether periodic exposure to pre-recorded sound associated with feed delivery and consumption would alter feed intake or feeding pattern of lambs provided with fresh feed once daily. Thirty cross-bred lambs were randomly assigned to 6 pens. The trial lasted 44 days (30 July to 11 September 1982) and consisted of a 4-day acclimation to test facilities, and then cycles of 4 days without sound stimulation followed by 4 days with sound stimulation. Sound stimulation consisted of 6-min broadcasts, every 3 h, of sounds associated with feed delivery and eating. Lambs were observed continuously for 24 h on 3 days when lambs were subjected to sound stimulation and 3 days when they were not. The recorded sound stimulation affected neither feed intake nor feeding behavior. Lambs largely ignored the recorded sounds, and total feed intakes during 20 sound-stimulated vs. 20 non-sound-stimulated days were 1234 vs. 1240 kg, respectively. There was a rhythmic feeding pattern at 1–2-h intervals, synchronously throughout the barn, and this was not affected by the 6 min of sound stimulation at 3-h intervals. There were no major peaks in feeding activity except after the offering of fresh feed in the morning. Feeding activity did not change with sunrise or sunset, and peaks of eating activity were distributed at even time-intervals throughout the 24 h. The overall means per lamb for the total time spent eating, the number of eating bouts (separate eating incidents), the average time eating per bout and the number of drinking episodes across the 6 observation days were 118.8 min, 22.6 times, 5.5 min and 9.6 times, respectively.

志々き湾におけるチダイ当歳魚の摂じ日周期性と日摂食量

A starvation experiment and diet successive sampling were carried out to quantify the diet feeding rhythm and the daily ration of O-group crimson sea bream Evynnis japonica in Shijiki Bay, northwest Kyushu, from June to July in 1981 and 1983. Changes of stomach-contents weight in the starvation study were well applied to both exponential and square root models, with no significant difference in fitness. Evacuation rate of smaller fishes was found greater than that of larger fishes.The diel feeding rhythm was determined by MORISHITA's (ELLIOTT and PERSSON's) method to estimate food consumption using the gastric evacuation rate gained from the starvation experiment. There were three peaks in feeding activity: morning, noon and evening, with the largest peak occurring at noon time. The daily rations were 5.6 and 5.5% of body weight per day in 1981 and 1983 respectively.Clear differences were found in main food organisms and the diel feeding rhythm between the present species and the red sea bream, Pagrus major, a closely related species. The main food of the former was Polychaeta, whereas that of the latter was Gammaridea. The feeding time of day when fishes feed most actively was observed at noon for the former, while at dawn and dusk for the latter. We presumed that these differences would serve to reduce the interspecific competition for limited food resources between two related species cohabiting the same nursery ground.

Consumption of Alfalfa by Adult Alfalfa Weevils (Coleoptera: Curculionidae)

Adult alfalfa weevils, Hypera postica (Gyllenhal), had two primary feeding periods. Newly matured weevils fed during midsummer, and old, overwintered weevils fed after returning to the fields the following spring. During each feeding period, weevil adults ate more, started feeding sooner, and reached feeding peaks sooner with each increase in temperature between 16.7 and 27.8°C. At 27.8°C, old weevils completed their feeding in about half as many days as at 22.2°C. At 27.8°C, each old adult ate an average total of 12.7 mg (dry weight) of alfalfa, and each new adult ate 22.6 mg (dry weight) of alfalfa. When data from old and new adults from the same generation were combined, each adult weevil ate ca. 4.5 times as much as each larva, or ca. 35.3 mg (dry weight). In field cages, new adults during their peak feeding activity consumed new growth of alfalfa plants after harvesting and reduced the length of the old stems. Five new adults per plant prevented most new growth, whereas 20 adults per plant killed the plants.

Feeding activity and food habits of the shad, Ethmalosa fimbriata (Bowdich), in the coastal waters of Cape Coast, Ghana

The monthly feeding activity and food habits of populations of Ethmalosa fimbriata occurring in the sea and an estuary in Cape Coast, Ghana district were investigated during a 14‐month period. The juvenile fish, whose total length (T.L.) ranged from 5.3 to 14.7 cm, occur in the estuary and appeared to be more active feeders than the marine samples which measured 15.0–30.4 cm. The peak feeding activity in the marine population coincided with the onset of‘upwelling’ in the sea, which period is characterized by high salinities, decreasing temperatures and high zooplankton production. The species is primarily a plankton feeder. The stomachs of the marine samples contained mainly protozoa, crustacea, molluscan larvae and a considerable amount of detritus while the stomachs of the estuarine fish contained mainly phytoplankton, protozoa, sand grains and organic detritus. These observations have been discussed in relation to other reports on populations occurring along the West African coast.

Daily feeding periodicity of the intertidal gobyCaffrogobius caffer

The daily feeding periodicity of Caffrogobius caffer was investigated at three sites in the eastern Cape. Two 24-h collections were taken at each collection site. Three methods were used to examine stomach contents. Relative stomach fullness was assessed for all six collections, while back-calculated time of ingestion and dry mass of the stomach contents as a percentage of dry somatic mass were applied to two collections each. The results from the three methods were similar. Feeding activity of C. caffer was not influenced by tide phase; peaks of feeding occurred during both high and low tide. Feeding occurred throughout the day with a tendency for slight crepuscular peaks of feeding activity.

Agonistic behavior in a transplanted troop of Japanese macaques: Arashiyama west

Arashiyama A troop was transplanted from Japan to Texas, U.S.A. in February 1972 and released into a large outdoor enclosure (42 ha) in a semi-free ranging condition. Agonistic behavior was quantified during the first six months after the release. Agonistic interactions occurred at about one incident per 100 monkeys every 2 to 9 minutes. In general, peaks in frequency of agonistic interactions coincided with peaks in feeding activity. 97.5% of all incidents were of a “mild” type, and 85.7% were simple one-to-one, unidirectional interactions. “Severe” forms of agonistic behavior occurred only during the first month and then only rarely. Adult females and juveniles were initiators in about 93% of all cases. In general, the more severe the form of attack, the more pronounced was the form of submission.

Studies on the biology of young grey mullet, Mugil cephalus L. II. Food and Feeding

This is the second of a series of investigations into the biology of young grey mullet, Mugil cephalus L., and the feasibility of its culture in the coastal, estuarine waters of Sri Lanka. The food and feeding habits of mullet, 20–55 mm in length, from the coastal Negombo Lagoon (7° 10′ N; 79° 50′ E) were studied from November 1974 to October 1975. The feeding intensity, estimated as the number of food organisms found in stomachs per feeding individual, followed a seasonal pattern with the intensity increasing from April onward and reaching a peak during June–August. Over 80% of the individuals were found to feed throughout the year. The diet consisted of 18 genera of diatoms, eight genera of green algae, some desmids, six genera of blue-green algae and eight other food groups. No sand or detritus was found to occur in fish smaller than 25 mm in length, and the percentage occurrence of detritus and/or sand particles increased with increase in body length. Quantitatively and qualitatively, diatoms were the most predominant food items, accounting for more than 50% of the total diet. Although only one genus of Xanthophyceae was found to occur in the diet, its contribution was significant. M. cephalus was found to show diurnal periodicity in feeding activity; peaks of activity occurred at dawn and around midday and were unrelated to the state of the tide. The significance of the nature of the diet and the occurrence of two peaks of feeding activity within a 24-h period is evaluated in the light of present knowledge of the food and feeding behaviour of M. cephalus at various stages of growth, and the possibilities of polyculture with other herbivorous species is discussed briefly.

Diel Periodicity of Feeding, Mating, and Oviposition of Adult Chrysopa cornea1,2

The diel periodicity of feeding, mating, and ovipositional activity of field and laboratory-reared populations of adult Chrysopa carnea Stephens was studied from June 2 to Aug. 15, 1975. Between 9 AM and 6 PM, the adults were mostly inactive and were found primarily in shady areas, usually on the undersides of leaves. Most of the feeding occurred between 6 and 10 PM and between 2 and 9 AM; peak feeding activity occurred between 7 and 8 AM. Mating took place primarily between 7 PM and 2 AM; major activity occurred between 8 and 10 PM, and another small peak occurred between 8 and 9 AM. Most ovipositional activity took place between 8 PM and 1 AM; peak activity was be- tween 9 and 10 PM, and a lesser peak took place between 2 and 3 AM. Most males did not mate until they were 3-4 days old. Males remated readily after a 2-4 day resting period. Some females mated when they were 3 days old, but most were 4 days old at the time of their 1st mating. Only 3 of 15 ♀-remated during a 30-day test period, and they were all confined with more than 1 ♂. Other behavioral activities such as grooming, aggression, and trophallaxis were common preceding copulation. However, these activities were also associated with other types of behavior.

Mosquito Nectar Feeding in Wisconsin in Relation to Twilight and Microclimate1

Twenty-three mosquito species were collected feeding on floral nectar at 3 study sites. Each of the 9 most abundant species exhibited specific peak feeding periods with respect to twilight. Twilight times were expressed in crep-units. Aedes stimulans peak feeding occurred around 0.5 creps or mid-civil twilight. Aedes canadensis, Aedes communis, Aedes sticticus, Aedes vexans, Coquillettidia perturbans , and Culex restuans exhibited peak feeding activity around 1.0 to 1.5 creps or early nautical twilight, while Anopheles earlei and Anopheles walkeri fed later in nautical twilight. These 2 anophelines are known to be more active late at night, especially in search of a blood meal. Aedes stimulans fed on nectar for some time before sunset; this species is known for its aggressive daytime feeding activities, suggesting that nectar-feeding and blood-feeding activities with respect to photoperiod may be similar. Males and females of some species, such as C. perturbans , exhibited different peak feeding times, while for other species, such as A. vexans, A. canadensis, C. restuans , and A. earlei , both sexes fed at almost identical times, the correlation coefficient (r) of feeding being generally greater than 0.900. Microclimatic factors greatly influenced feeding, reducing it when they existed as extremes. Wind above 10 km/hr acted as an inhibitor to feeding, as did temperature below 10.0/C and relative humidity below 48%. The data suggest that the time of peak feeding activity is controlled by a circadian or photoperiodic rhythm, but that the level of illumination affects the initiation, cessation, and duration of feeding on a given night.