Peak Feeding Activity Research Articles

Perilaku Memilih Umpan Dengan Fagostimulan Yang Berbeda Pada Kecoak Jerman Blattella germanica L. (Dictyoptera: Blattellidae)

Kecoak Jerman (Blattella germanica L.) merupakan salah satu serangga hama permukiman yang penting, karena peranannya sebagai vektor penyakit. Untuk mengurangi populasinya, dapat digunakan dengan teknik pengumpanan. Namun belakangan ini muncul perilaku glucose aversion pada kecoak Jerman terhadap umpan komersial berbasis glukosa sebagai fagostimulan. Oleh karena itu perlu dilakukan kaji ulang terhadap fagostimulan sebagai komponen umpan untuk meminimalisir kegagalan pengendalian kecoak Jerman berbasis umpan dengan menggunakan kecoak Jerman jantan strain VCRU (Vector Control Research Unit). Langkah awal untuk membuat formulasi umpan tersebut adalah mencari fagostimulan yang paling disukai oleh kecoak Jerman. Bahan yang digunakan sebagai fagostimulan adalah gula, durian, erythritol, dan pisang.
 Tujuan penelitian adalah untuk mengetahui perilaku memilih kecoak Jerman terhadap umpan dengan fagostimulan yang berbeda dan puncak aktivitas makan pada kecoak Jerman. Penelitian ini menggunakan metode eksperimental dengan Rancangan Acak Lengkap (RAL) yang terdiri dari 4 perlakuan pemberian fagostimulan dan diulang sebanyak 4 kali yang terbagi menjadi empat arena uji. Perlakuan terdiri dari umpan yang masing-masing mengandung gula, durian, erythritol, dan pisang sebagai fagostimulan. Pengamatan perilaku menggunakan metode behavior sampling yang dicatat secara continuous recording selama 24 jam menggunakan kamera Closed Circuit Television (CCTV). Parameter yang diukur berupa latensi, frekuensi, durasi, dan puncak aktivitas makan dari kecoak Jerman. Data yang diperoleh dianalisis dengan ANOVA pada p<0.05.
 Hasil penelitian yang diperoleh menunjukkan bahwa perilaku memilih kecoak jantan strain VCRU terhadap umpan tidak berbeda nyata (p>0.05) dan tertarik dengan semua umpan yang diberikan, tetapi umpan gel dengan fagostimulan gula merupakan umpan yang lebih disukai dengan melihat ketiga parameter latensi, frekuensi, dan durasi. Hasil rata-rata latensi pada strain VCRU menuju gel durian selama 17 menit, rata-rata frekuensi kunjungan terbanyak ke gel gula pada strain VCRU sebanyak 10 kali, rata-rata durasi terlama pada gel gula strain VCRU selama 1 menit 46 detik dan puncak aktivitas makan strain VCRU terjadi antara pukul 17.00 – 20.00.

Resting Dynamics and Diel Activity of the Green Turtle (Chelonia mydas) in Rapa Nui, Chile

Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) 21170169 21160168 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 3170392

Effect of water temperature on diel feeding, locomotion behaviour and digestive physiology in the sea cucumber Apostichopus japonicus.

This study used controlled laboratory conditions to directly assess the role of water temperature in controlling diel feeding and locomotion behaviours, and digestive physiology, in the sea cucumber Apostichopus japonicus The results revealed that both the proportion of feeding individuals and ingestion rate were highest at 16°C. Regardless of water temperature, sea cucumbers appeared to be nocturnal and their peak feeding activity occurred at 00:00 h to 04:00 h. Tentacle insertion rate was not significantly correlated with water temperature (<24°C). In all temperature treatments except 24°C, the proportion of moving sea cucumbers was also observed to be higher at night than during the day. The water temperature above thermal threshold (24°C) for aestivation may alter the diel locomotion rhythm. The highest lipase and amylase activities were both observed at 20°C. The highest activities of lipase and amylase at all temperature treatments were observed at 22:00 h to 02:00 h, which was slightly earlier than the feeding peak. In conclusion, even in total darkness, A. japonicus showed more active feeding and moving activities, and higher digestive enzyme activities, at night than during the day. These results demonstrated that diel feeding and locomotion behaviours, at least in the short term, were not controlled by light or low water temperature (<24°C) but by an endogenous rhythm, and A. japonicus had the ability to optimize the digestive function for the coming feeding peak. These findings should provide valuable information for the development of the aquaculture of this species.

Octopamine regulates antennal sensory neurons via daytime-dependent changes in cAMP and IP3 levels in the hawkmoth Manduca sexta.

The biogenic amine octopamine (OA) mediates reward signals in olfactory learning and memory as well as circadian rhythms of sleep and activity. In the crepuscular hawkmoth Manduca sexta, OA changed pheromone detection thresholds daytime-dependently, suggesting that OA confers circadian control of olfactory transduction. Thus, with enzyme-linked immunosorbent assays we searched hawkmoth antennae for daytime-dependent changes in the concentration of OA and its respective second messengers. Antennal stimulation with OA raised cAMP- and IP3 levels. Furthermore, antennae expressed daytime-dependent changes in the concentration of OA, with maxima at Zeitgebertime (ZT) 20 when moths were active and also maximal concentrations of cAMP occurred. Maximal IP3 levels at ZT 18 and 23 correlated with maximal flight activity of male moths, while minimal IP3 levels at dusk correlated with peaks of feeding activity. Half maximal effective concentration (EC50) for activation of the OA-receptor decreased during the moth’s activity phase suggesting daytime-dependent changes in OA receptor sensitivity. With an antiserum against tyramine, the precursor of OA, two centrifugal neurons were detected projecting out into the sensory cell layer of the antenna, possibly mediating more rapid stimulus-dependent OA actions. Indeed, in fast kinetic assays OA receptor stimulation increased cAMP concentrations within 50 msec. Thus, we hypothesize that fast, stimulus-dependent centrifugal control of OA-release in the antenna occurs. Additional slow systemic OA actions might be based upon circadian release of OA into the hemolymph mediating circadian rhythms of antennal second messenger levels. The resulting rhythms of odor sensitivity are suggested to underlie circadian rhythms in odor-mediated behavior.

Development of the circadian clockwork in the kidney.

The circadian molecular clock is an internal time-keeping system composed of centrally synchronized tissue-level pacemakers. Here, we explored the ontogeny of the clock machinery in the developing kidney. Pregnant rats were housed at 12-12 h light-dark cycles. Offsprings were killed at 4-h intervals on embryonic day 20 and at postnatal weeks 1, 4, and 12. Canonical clock gene (Clock, Bmal1, Rev-erbα, Cry1, Cry2, Per1, Per2) and kidney-specific clock-controlled gene (αENaC, SGK1, NHE3, AVPR2) expression was profiled by RT-PCR. To investigate the role of nutritional cues, the feeding pattern was modified postpartum. Clock, Rev-erbα, Per2, αENaC, SGK1, NHE3, and AVPR2 showed circadian expression at the end of intrauterine development. By 1 week, all genes oscillated with a distinct acrophase shift toward the time of peak feeding activity. Daily 4-hour withdrawal of mothers induced a 12-hour phase shift of Clock and Bmal1 expression, while disrupting oscillations of the other genes. After weaning, oscillation phases shifted back toward the adult pattern, which was fully expressed at 12 weeks. Thus, functional circadian molecular clockwork evolves in the late fetal and early postnatal kidney. During the nursing period, oscillations are entrained by nutritional cues. The coupling of the circadian expression of tubular regulators of fluid and electrolyte excretion to the feeding-entrained clockwork may be important to maintain homeostasis during this critical period.

Effect of feed presentation on feeding patterns of dairy calves

The objectives of this study were to determine the effect of feed presentation on meal frequency and duration, as well as diurnal feeding patterns of dairy calves, and to assess any longer-term differences in feeding patterns resulting from previous experience. Twenty Holstein bull calves were exposed from wk 1 to 8 of life to 1 of 2 feed presentation treatments: concentrate and chopped grass hay (<2.5cm) offered at a ratio of 7:3 as a mixture (MIX), or as separate components (COM). Feed was provided ad libitum. Calves received 8L/d of milk replacer (1.2kg of dry matter), with the amount progressively reduced after 5wk to facilitate weaning by the end of wk 7. At the beginning of wk 9, all calves received the MIX diet and remained on trial for an additional 3wk. Feeding behavior was recorded from video for 4d during wk 6, 8, 9, and 11. In wk 6, calves fed MIX spent more time feeding than calves fed COM (56.7 vs. 46.8min/d). In wk 8, calves fed MIX spent more time feeding (174.0 vs. 139.1min/d) and had a lower rate of intake (11.5 vs. 14.7g/min) compared with calves fed COM. Meal frequency was similar between treatments (12.2 meals/d). Diurnal feeding patterns in wk 8 were also affected by feed presentation, with calves fed MIX spending less time feeding at time of feed delivery and more time feeding throughout the rest of the daylight hours than calves fed COM. Diurnal feeding patterns of hay and concentrate in wk 8 differed for calves fed COM, with more time spent consuming hay at time of feed delivery and less time spent consuming hay throughout the rest of the day. Once calves previously fed COM were transitioned to the MIX diet in wk 9, meal frequency, meal duration, and diurnal feeding patterns were similar between treatments: both treatments spent similar amounts of time feeding (173.9min/d) and had similar peaks in feeding activity at time of feed delivery, sunrise, and sunset. Provision of hay and concentrate to young calves as a mixed ration, compared with separate components, increases time spent feeding and results in more evenly distributed diurnal feeding patterns. However, differences in feeding patterns resulting from feed presentation did not persist after 8wk of age, when all calves were fed a mixed ration.

Competition for feed affects the feeding behavior of growing dairy heifers

The objective of this study was to determine how competition for feed influences the feeding behavior of young, growing dairy heifers. Thirty-six prepubertal Holstein heifers (231.5±12.1 d old, weighing 234.7±24.0kg), consuming a total mixed ration ad libitum, were assigned to 1 of 2 treatments: noncompetitive (1 heifer/feed bin), or competitive (2 heifers/feed bin). After 7 d of treatment adaptation, dry matter intake and feeding behavior were monitored for 7 d for each animal. Fresh feed and orts were sampled on the last 3 d of the treatment period from each bin and were subjected to particle size analysis. The particle size separator consisted of 3 screens (18, 9, and 1.18mm) and a bottom pan resulting in 4 fractions (long, medium, short, and fine). Sorting activity for each fraction was calculated as the actual intake expressed as a percentage of the predicted intake. There was no difference in sorting behavior or dry matter intake between the treatments. Overall, the heifers sorted against long particles (94%), and sorted for medium (102%) and short (103%) particles. The competitively fed heifers tended to have 10% shorter feeding times, particularly at peak feeding periods. The competitively fed heifers also consumed 9% fewer meals per day, although the duration of these meals were 10% longer, and tended to be 13% larger. Competition for feed also tended to increase the day-to-day variation in feeding time, meal duration, and meal size. It can be concluded that competition for feed for growing dairy heifers alters feeding patterns, reduces access to feed, particularly during periods of peak feeding activity, and tends to increase day-to-day variation in feeding behavior.

Studies on the food and feeding habits of Gaur Bos gaurus H. Smith (Mammalia: Artiodactyla: Bovidae) in two protected areas of Goa

Feeding habits and diet composition of gaur were studied at Bhagvan Mahaveer Wildlife Sanctuary and Mollem National Park, Goa. Altogether, 32 species of plants belonging to 17 families constitute the gaur diet. The fruits, leaves, young shoots, bark and flowers are consumed, with a preference for leaves (87%). In summer gaur also consumed the bark of cashew (Anacardium occidentale) and teak (Tectona grandis) trees. Strong association was observed between food preference and season (chi-square=12.94; p=0.001). Peak feeding activity was observed early in the morning (0630 to 0830 hr) and in the evening (1730 to 1845 hr). During hot hours of the day (1330 to 1530 hr), animals were found resting in the shade of large trees.

How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

Seasonal breeding of tropical freshwater fish may be synchronized with periods of high food consumption. We explored this hypothesis by studying the relationship between diet and reproductive activity of Creagrutus guanes (Teleostei, Characidae). Our results showed that C. guanes had a generalist and omnivorous diet dominated by aquatic insects (mainly Diptera larvae) and seeds. Creagrutus guanes did not show intersexual or ontogenetic variation in diet. Peaks of feeding activity during rainy months were not synchronized with breeding in dry months. Our results do not support the hypothesis that the reproductive season has to be synchronized with high food consumption. We discussed the hypothesis fat reserves may be an important factor for the desynchronization of peaks of feeding and reproduction as explanation of seasonal breeding of this species.

Feeding interactions and foraging of juvenile fish and shrimp in the estuaries of Peter the Great Bay in the summer-fall period

The feeding interrelations and foraging of juvenile fish and shrimp were investigated in estuaries of Peter the Great Bay in summer and fall 2006 and 2007. In total 3483 specimens were analyzed. The trophic spectra of 34 fish species and 3 shrimp species were described for the first time. Three trophic groups were singled out depending on differences in diet compositions: (i) detritophages (3 species of bitterlings—Acanthorhodeus sp., A. chankaensis and Rhodeus sericeus, redlip mullet Liza haematocheila and two species of shrimp-Palaemon macrodactylus and Crangon cf. septemspinosa); (ii) predators (lookup Culter alburnus and Amur catfish Silurus asotus); (iii) euryphages (28 fish species and the shrimp Palaemon paucidens). The detritus food chain was found to be the primary one in estuaries of Peter the Great Bay. Most of the species had two peaks of feeding activity each day. Values of daily feeding rations were determined for 21 fish species; these varied from 1.6% to 8.0% of body weight. Similarity in diet composition was significant only for 10% of the species, which shows a low level of competition for food in the community.

Diel variation in food intake and diet composition of three native fish species in floodplain lagoons of the Macintyre River, Australia

The feeding periodicity of three species of fishes in floodplain lagoons of the Macintyre River varied during 24 h cycles, however, peak feeding activity (around midday and late afternoon) was similar among the species studied, despite differences in their trophic position. In contrast, sampling season and site seemed to have a stronger effect on the composition of the diet than time of day. These findings have implications for studies of trophic dynamics and food web structure in floodplain lagoons.

A note on the diet and foraging behavior of Artibeus lituratus (Chiroptera, Phyllostomidae) in an urban park in southeastern Brazil

Bats of the genus Artibeus are among the most important seed dispersers in early successional forests. We report observations on the foraging behavior of Artibeus lituratus in Pedra da Cebola Municipal Park, an urban park in the city of Vitória, Espírito Santo, southeastern Brazil. Observations were made during six consecutive days (April 1st to April 6th, 2006). Three mist-nets were opened each night close to a Maclura tinctoria tree (Moraceae), remaining open from 18:00 to 22:00, totaling four hours per night, and 24 hours of sampling effort. We observed two peaks of feeding activity at the tree, one between 18:20 and 19:30, and a second one at 21:00. This is the first observation of Artibeus lituratus feeding on M. tinctoria fruits, therefore adding a new item to the known diet of the species. M. tinctoria fruits have large seeds that are not swallowed by bats, they consume the fruit pulp and discard the seeds. A diet of fruits with large seeds may indicate an important resource not detected in dietary studies based on fecal samples, but better detected by direct observation or by studying feeding roosts. It is important to use different sampling techniques in dietary studies since they complement each other and, together, provide a better knowledge on the diet of bats.

Short Communication: Effect of Feed Barrier Design on the Behavior of Loose-Housed Lactating Dairy Cows

The objective of this study was to evaluate the effects of 2 feed barrier systems on feeding and social behavior of dairy cows. Forty-eight lactating Holstein cows were subjected to each of 2 treatments in a cross-over design. The treatments were 2 types of feed-line barriers: 1) post-and-rail, and 2) headlock. Time-lapse video was used to quantify the feeding behavior and incidence of aggressive displacements of the cows at the feed bunk. Average daily feeding time did not differ when cows used the headlock barrier compared with the post-and-rail barrier. However, there were certain changes in feeding time during periods of peak feeding activity: cows that had lower feeding times relative to group mates when using the post-and-rail barrier showed more similar feeding times to group mates when using the headlock barrier. There were 21% fewer displacements at the feed bunk when cows accessed feed by the headlock barrier compared with the post-and-rail barrier. These results suggest that using a headlock barrier reduces aggression at the feed bunk and improves access to feed for socially subordinate cows during peak feeding periods.

Predation impact of juvenile Gilchristella aestuaria (Clupeidae) and Atherina breviceps (Atherinidae) on the zooplankton in the temperate Kariega estuary, South Africa

Seasonal changes in the predation impact of juvenile (SL 18–25mm) Atherina breviceps and Gilchristella aestuaria on zooplankton was investigated at three stations in the middle reaches of the permanently open Kariega estuary during 1999 and 2000. Daily rations were estimated using the gut fullness index approach. Variations in zooplankton biomass demonstrated a seasonal pattern with maximum values (generally >40mg dwt m−3) recorded in summer and minimum values during winter (generally <25mg dwt m−3). Total biomass of G. aestuaria during the study ranged between 0.04g dwt m−2 and 0.2g dwt m−2 and between 0.01g dwt m−2 and 0.04g dwt m−2 for A. breviceps. There were no seasonal patterns in biomass for either species. Results of the gut content analysis indicated that both species consume mainly copepods, amphipods and mysids. There were no seasonal patterns in the dominant prey in the guts of the juveniles. Peaks in feeding activity for G. aestuaria were recorded during daylight hours while maximum feeding activity of A. breviceps occurred at night. Gut evacuation rates (k, h−1) of G. aestuaria and A. breviceps during summer were estimated at 0.41h−1 and 0.68h−1 respectively. During winter, evacuation rates were lower and were estimated at 0.37h−1 for A. breviceps and 0.28h−1 for G. aestuaria. Daily rations of A. breviceps during summer and winter were equivalent to 8.3% and 4% body dwt d−1, while for G. aestuaria daily ration was estimated at 7.9% body dwt during summer and 4.3% body dwt d−1 during winter. Results indicate that the predation impact of G. aestuaria ranged between 2.5% and 33.6% of the zooplankton secondary production while A. breviceps impact was equivalent to between 3.3% and 11.1% of the zooplankton secondary production.

Self-feeding behavior of yellowtail, Seriola quinqueradiata, in net cages: diel and seasonal patterns and influences of environmental factors

Abstract The self-feeding pattern of yellowtail, Seriola quinqueradiata , maintained in floating net cages was examined throughout a year, and the influence of seasonal changes of the photoperiod and water temperature on the feeding pattern was investigated. Two groups of 50 yellowtail (initial mean body weight about 50 and 80 g, respectively) were kept in two experimental net cages (2×3×4 m deep), with a self-feeding device installed on each. It was possible to maintain yellowtail in net cages using a self-feeder throughout almost a year. The number of daily food demands was greatly affected by the seasonal changes in water temperature. Yellowtail showed high self-feeding activity, above 18 °C; depressing water temperatures did not influence the activity when the water temperature was over 18 °C. However, the activity decreased when the water temperature fell below 18 °C. The feeding pattern in a 24-h period was greatly affected by the temporal changes in light intensity. Annual observations revealed that yellowtail showed generally crepuscular plus nocturnal feeding behavior and had two peaks of feeding activity a day. These peaks appeared at dawn and dusk; moreover, a clear association between the most active time of self-feeding and the period of the greatest change in light intensity was observed. The results suggest that a change in light intensity might stimulate the appetite of yellowtail or that there is a light level at which yellowtail prefer to eat.

Daily food intakes and feeding strategies of sows given food ad libitum and allocated to two different space allowances in a communal farrowing system over parturition and during lactation

AbstractA total of 16 multiparous (range 2nd to 9th parity) Camborough sows were housed over parturition and during lactation in a group farrowing system. Two replicates of four sows were studied in the large pen (L) and two further replicates studied in the small pen (S) configuration, providing 13•4 m2 and 8•6 m2 per sow, respectively. A lactation diet providing 14 MJ/kg digestible energy (DE) and 180 g/kg crude protein was supplied ad libitum via a sow-operated feeder, adapted to facilitate the calculation of individual food intakes. The influence of environmental, physical, and production factors upon food intakes and feeding strategies was investigated. Daily food intakes of 7•69 (s.e. 0•31) kg and 7•72 (s.e. 0•35) kg were achieved during lactation by sows in the L and S pen configurations, respectively, accomplished by sows taking a series of small meals throughout the day. Sows in the S pen area made fewer visits to the feeder and spent less time per day feeding than sows in the L pen area. However, more food was consumed per visit by the S sows, resulting in similar daily food intakes in both treatment groups. There was a depression in lactation food intakes of sows housed at a mean daily ambient temperature of 17•5ºC compared with the other sow groups. The majority of sows consumed energy well in excess of their predicted requirements during lactation, whilst one sow in the L and two in the S pen areas had intakes within ±3•4 MJ DE of predictions. Only two of the L sows had food intakes that produced an energy deficit. In the L pen area, two distinct peaks of feeding activity occurred from 09:00 to 13:00 h and from 15:00 to 23:00 h that accounted for 0•77 of the total feeding time. In contrast, in the S pen configuration, one prolonged period of feeding occurred from 09:00 to 22:00 h accounting for 0•88 of total feeding time. The results show that S sows adapted their feeding patterns to maintain similar daily intakes to those of L sows, thus demonstrating that an ad libitum food supply enabled sows to obtain individual nutritional requirements in a communal farrowing system.

Trophic importance of the hyperiid amphipod, Themisto gaudichaudi , in the Prince Edward Archipelago (Southern Ocean) ecosystem

The feeding dynamics and predation impact of the hyperiid amphipod, Themisto gaudichaudi, on the zooplankton community in the waters surrounding the Prince Edward Archipelago were investigated at 30 stations in late austral summer (April/May) 1998. Ingestion rates of T. gaudichaudi were estimated using two approaches, the gut fullness index and in vitro incubations. Throughout the investigation mesozooplankton, comprising copepods, pteropods and chaetognaths, numerically and by biomass dominated Bongo samples. Zooplankton abundances and biomass ranged from 8 to 271 ind. m−3 and between 1.01 and 7.47 mg dwt m−3, respectively. Densities of T. gaudichaudi during the study were low, never exceeding 0.4 ind. m−3. Gut content analysis (n=61) indicates that T. gaudichaudi is a non-selective, opportunistic carnivore generally feeding on the most abundant copepod and chaetognath species. Peaks in feeding activity were recorded at sunrise and sunset, corresponding to their diel vertical migration patterns. Daily rations estimated from in vitro incubations and gut fullness index were equivalent to 1.2–8.7% and between 11.5 and 19.8% of body dry weight, respectively. The predation impact of T. gaudichaudi averaged over the upper 300 m of the water column was low, accounting for <0.4% of the mesozooplankton biomass or <3% of the mesozooplankton secondary production. Indeed, the predation impact is likely to be lower as the contribution of the smaller copepods (e.g. Oithona spp.) to total zooplankton was underestimated due to the sampling gear employed. The low predation impact recorded during this study can be related to low abundances of T. gaudichaudi. It is likely that the importance of T. gaudichaudi as a secondary production consumer in the waters surrounding the Prince Edward Archipelago demonstrates a high degree of spatio-temporal variability.

Gastric evacuation, feeding periodicity and daily ration of sardine Sardinops sagax in the southern Benguela upwelling ecosystem

Laboratory and field experiments were conducted to determine gastric evacuation rates of sardine Sardinops sagax, and stomach content analyses were undertaken to assess feeding periodicity and estimate the daily ration of this species in the southern Benguela. Gastric evacuation followed an exponential pattern and was influenced by food type; phytoplankton was evacuated at a much faster rate than zooplankton. Estimated gastric evacuation rates ranged between 0.05 and 0.29·h−1, with mean values of 0.09 and 0.27·h−1 for fish fed zooplankton and phytoplankton respectively. Despite this large range, no significant relationships were found between gastric evacuation rate and fish size, temperature, food particle size or meal size. Feeding periodicity was size-dependent; small fish had a peak in feeding activity at or around sunset, whereas larger fish appeared to feed continuously. This suggests that fish of different size exhibit different foraging behaviours, possibly reflecting differences in their diets. E...

Resistance to Low Temperature in Steelhead Trout and Beluga Cultivated in the Black Sea Water

Critical and lethal water temperatures were determined for the yearling steel-head trout and beluga cultivated in the Black Sea in winter. The winter period of cultivation was characterized by two peaks of feeding activity and specific growth rate in steelhead trout and one such peak in beluga.

Diets and food consumption rates of pelagic fish in Lake Malawi, Africa

SUMMARY Studies of diel feeding periodicity, rates of food consumption and diet composition of pelagic fish were undertaken to resolve the dispute regarding the existence of a vacant niche for a pelagic zooplanktivore in Lake Malawi. Six species of zooplanktivore were abundant in the offshore pelagic zone, these were: Diplotaxodon limnothrissa, D.‘bigeye’, Rhamphochromis longiceps and Copadichromis quadrimaculatus (all haplochromine cichlids), Synodontis njassae (Mochokidae) and Engraulicypris sardella (Cyprinidae). The main piscivores were cichlids of the genus Rhamphochromis. All cichlids were daytime feeders; some showed peaks in feeding activity at dawn and dusk that were related to vertical migration patterns of their prey. Synodontis njassae was able to feed throughout the day, but fed most actively at night. Food consumption: biomass ratios (Q/B yr‐1) calculated from diel stomach contents data were 5.87–7.13 for D. limnothrissa, 12.79 for D.‘bigeye’, 4.20–24.7 for R. longiceps and 6.45 for S. njassae. Annual Q/B ratios for other species, which ranged from 4.74 to 9.28, were obtained from an empirical model relating food consumption to fish morphology. Published estimates were used for E. sardella and Opsaridium microcephalum (Cyprinidae). An estimate of total prey consumption by the pelagic fish population was obtained from Q/B ratios and fish biomass estimates from acoustic surveys covering the entire offshore pelagic zone of the lake (24 000 km2). Diplotaxodon limnothrissa, R. longiceps and C. quadrimaculatus had a broad range of diets, with the ability to switch from crustacean zooplankton to larvae and pupae of Chaoborus edulis (Diptera) or larval and juvenile E. sardella. Diplotaxodon‘bigeye’ and S. njassae fed almost exclusively on fourth‐instar larvae and pupae of C. edulis. Engraulicypris sardella fed mainly on crustacean zooplankton. The main prey of the large piscivorous Rhamphochromis species were Diplotaxodon spp. and E. sardella. The fish community consumed only 3% of estimated crustacean zooplankton production directly. Predation pressure was intense (&gt; 80% of estimated production consumed by predators) on late instars of the zooplanktivorous C. edulis larvae and on E. sardella larvae. Rhamphochomis spp. consumed 22–43% of estimated production of the zooplankton‐eating fishes. Although many members of the fish community do not feed directly on crustacean zooplankton, so that the food‐chain supporting fish production involves an extra trophic level, it is considered that the endemic fish community is well adapted to feeding on the low‐density prey in the pelagic zone, and that there is no vacant feeding niche.