Influence of Resource Availability on the Foraging Strategies of the Triangle Butterflyfish Chaetodon triangulum in the Maldives

Obligate coral feeders such as many members of the Chaetodontidae family (also known as butterflyfish) often show strong preferences for particular coral species. This is thought to have evolved through natural selection as an energy-maximising strategy. Although some species remain as highly specialised feeders throughout their lifetime, many corallivores show a degree of dietary versatility when food abundance is limited; a strategy described by the optimal foraging theory. This study aimed to examine if, within-reef differences in the feeding regime and territory size of the Triangle Butterflyfish Chaetodon triangulum occurred, as a function of resource availability. Results showed that the dietary specialisation of C. triangulum was significant in both areas of low and high coral cover (χL2² = 2.52 x 102, P<0.001 and χL2² = 3.78 x 102, P<0.001 respectively). Resource selection functions (RSFs), calculated for the two main sites of contrasting coral assemblage, showed that in the resource-rich environments, only two Genera (Acropora and Pocillopora) were preferentially selected for, with the majority of other corals being actively ‘avoided’. Conversely, in territories of lower coral coverage, C. triangulum was being less selective in its prey choice and consuming corals in a more even distribution with respect to their availability. Interestingly, coral cover appeared to show no significant effect on feeding rate, however it was a primary determinant of territory size. The findings of the study agree with the predictions of the optimal foraging theory, in that where food supply is scarce, dietary specialisation is minimised and territory size increased. This results in maximising energy intake. This study represents the first scientific evidence that C. triangulum is an obligate corallivore and, as with many other butterflyfish, is therefore dependent on healthy scleractinian corals for survival.     

Feeding territoriality and the reproductive consequences in brown skuas<Emphasis Type="Italic"> Catharacta antarctica lonnbergi</Emphasis>

In the maritime Antarctic, brown skuas (Catharacta antarctica lonnbergi) show two foraging strategies: some pairs occupy feeding territories in penguin colonies, while others can only feed in unoccupied areas of a penguin colony without defending a feeding territory. One-third of the studied breeding skua population in the South Shetlands occupied territories of varying size (48 to >3,000 penguin nests) and monopolised 93% of all penguin nests in sub-colonies. Skuas without feeding territories foraged in only 7% of penguin sub-colonies and in part of the main colony. Females owning feeding territories were larger in body size than females without feeding territories; no differences in size were found in males. Territory holders permanently controlled their resources but defence power diminished towards the end of the reproductive season. Territory ownership guaranteed sufficient food supply and led to a 5.5 days earlier egg-laying and chick-hatching. Short distances between nest and foraging site allowed territorial pairs a higher nest-attendance rate such that their chicks survived better (71%) than chicks from skua pairs without feeding territories (45%). Due to lower hatching success in territorial pairs, no difference in breeding success of pairs with and without feeding territories was found in 3 years. We conclude that skuas owning feeding territories in penguin colonies benefit from the predictable and stable food resource by an earlier termination of the annual breeding cycle and higher offspring survivorship.Research licence: Umweltbundesamt Bonn 13.4-94003-1/5-7.     

Dominance hierarchies in group-living cleaning gobies: causes and foraging consequences

In species living in social groups, aggression among individuals to gain access to limiting resources can lead to the formation of stable social hierarchies. We tested whether dominance rank in social groups of sponge-dwelling cleaning gobies Elacatinus prochilos in Barbados was determined by physical attributes of individuals or by prior experience of dominance, and examined the foraging consequences of dominance rank. Intraspecific aggression within groups resulted in stable dominance hierarchies that were strongly correlated with fish length. Dominant individuals maintained exclusive territories while subordinate fish occupied broader home ranges. Larger, competitively dominant fish were able to monopolize areas inside the sponge lumen with the highest abundance of the polychaete Haplosyllis spp., a favoured prey item, and achieved the highest foraging rates. The removal of a territorial individual from large groups resulted in a domino-like effect in territory relocation of the remaining fish as individuals moved to the territory previously occupied by the individual just above them in the group hierarchy. Individuals added to existing groups generally failed to gain access to territories, despite being formerly dominant in their original groups. When given the opportunity to choose a location in the absence of larger competitors, gobies frequently preferred positions that were previously defended and that had abundant food. These results suggest that intraspecific competition for resources creates the observed dominance structures and provides support for the role of individual physical attributes in the formation and maintenance of dominance hierarchies.     

Day and night feeding territoriality in Willets Catoptrophorus semipalmatus and Whimbrel Numenius phaeopus during the non-breeding season in the tropics

This study was carried out to determine whether or not, and under what conditions, Willets Catoptrophorus semipalmatus and Whimbrel Numenius phaeopus continue to defend and use their daytime feeding territories at night in a tropical environment. The study was conducted in coastal Venezuela by registering, by night and by day, the behaviour and the position of colour-marked and radio-tagged birds. Night observations were made with the use of a light intensifier.
In Willets, both territorial and non-territorial birds were observed. The use and defence of territories was observed only on sandy mud areas where Fiddler Crabs Uca cumulanta were plentiful; the soft mud sites were used only by non-territorial birds. All Whimbrel were territorial. Individuals of both species defending a given space during daytime continued to occupy and defend the same area during the night. The proportion of birds foraging at night was higher on moonlit than on moonless nights. Territorial defence involved alert postures, parallel walks, calls and the chasing of intruders. Agonistic encounters between Willets and Whimbrel and other species were rare. Willets were territorial at all states of the tide except when high tides flooded the territories. Tide had no effect on the time of feeding in Whimbrel. Moonlight was clearly the factor conditioning the occurrence of nocturnal foraging on territories by both species. Foraging strategies and the type of prey and substrata explain why the incidence of night foraging varied with moonlight in territorial Willets and Whimbrels and not in non-territorial individuals.     

Mutualistic cleaner fish initiate trait-mediated indirect interactions by influencing the behaviour of coral predators

1.?Indirect interactions resulting from changes in organismal traits such as behaviour [i.e. trait-mediated indirect interactions (TMIIs)] are widespread in biological communities, yet few studies have explored the potential for mutualisms to initiate TMIIs. 2.?This study used a combination of behavioural observations and manipulative field experiments to investigate potential TMIIs resulting from a mutualism between specialized cleaner fish and the 'clients' that visit cleaners for the removal of ectoparasites. 3.?Behavioural observations indicate that the bluestreak cleaner wrasse, Labroides dimidiatus, increases local predation pressure on corals at cleaner stations by attracting corallivorous butterflyfish to their territories. 4.?Observations of the ornate butterflyfish, Chaetodon ornatissimus, suggest a trade-off between seeking cleaning and foraging; individuals decreased their foraging rate at cleaner stations and shifted their diet to include a greater proportion of less preferred prey items. Nonetheless, predation pressure on corals was higher at cleaner stations because the spatial response of butterflyfish to cleaners more than compensated for their lower foraging rates. 5.?The results of a field experiment suggest that the greater predation pressure observed at cleaner stations may be sufficient to reduce the growth rate of the unpreferred coral Porites rus. 6.?Together, these results emphasize the need to consider mutualists as potential initiators of TMIIs and highlight the importance of integrating individual movement into conceptual analyses of TMIIs.     

THE ORIGINS OF ADAPTIVE INTERSPECIFIC TERRITORIALISM

1. In order to understand fully the evolution of a behavioural trait one must not only consider whether it is adaptive in its present environment but also whether it originated as an adaptation to existing selective forces or as a fortuitous consequence of selection for a different role in other environments (i.e., as a pre-adaptation) or of selection for different traits (e.g., as a pleiotropic effect). In this paper interspecific territorialism is examined in species of humming-birds, sun-birds, tropical reef fishes, stingless bees, stomatopods, crayfish, and limpets as a means of determining its adaptiveness and its origins. 2. Humming-birds form complex assemblages with species sorted out among the available resources. Dominant species establish feeding territories where flowers provide sufficient nectar. A few large, dominant species, usually uncommon, are marauders on others' territories. Subordinate species establish territories where flowers are more dispersed or produce less nectar, or they fly a circuit from nectar source to nectar source when flowers are even more dispersed, a foraging pattern called ‘traplining’, or they steal nectar from the territorial species by being inconspicuous while foraging. Two species, Amazilia saucerottei and Selasphorus sasin, subordinate in one-to-one encounters, are able to take over rich resources by establishing several small territories within a territory of a dominant and forcing it to forage elsewhere. 3. Among humming-birds, territorial individuals attacked not only subordinate competitors but marauding humming-birds and some insects, which stayed in the territory and foraged at will, and seemingly inappropriate targets, such as non-competitors. This suggests that the stimulus for aggression is ‘any flying organism near the food resources’, regardless of its appearance. The behaviour rather than the identity of the intruder is the stimulus. 4. Sun-birds resemble humming-birds to the extent that dominants establish territories on rich nectar sources and subordinates establish territories on less rich nectar sources or steal from the territories of dominants. The diversity of foraging patterns is not so great as in humming-birds, perhaps because so few species of sun-birds have been studied. However, the advantage of territorialism has been measured in the sun-bird Nectarinia reichenowi. Individuals with territories lose much less nectar to competitors than do those without territories. 5. Field work on three species of tropical reef fishes involved a single aggressive species whose individuals attacked a wide range of species intruding on their territories. The stimulus for aggression in Pomacentrus jenkinsi seemed to be an “object moving through [its] territory”. As suggested for humming-birds, the stimulus is the behaviour rather than the identity of the intruder. 6. The relationships found in stingless bees, stomatopods, crayfish, and limpets are simpler. The dominant and subordinate species divide the resources in their habitat, the dominants' aggression preventing the subordinates from using resources that were otherwise available to them. 7. A general pattern emerges. Mutual interspecific territorialism occurs between species that (i) have different geographic ranges, (ii) occupy different habitats, or (iii) use different resources within the same habitat. Examples of two species holding separate territories on the same resources within the same habitat are rare and occur when the dominant species is rare relative to the available resources. These observations are contrary to the usual view that interspecific territorialism is an adaptation that permits co-existence of potential competitors within the same habitat. 8. Interspecific territorialism is sometimes adaptive and sometimes maladaptive, depending upon the species and the situation. 9. The general pattern of occurrence of the behaviour and the general nature of the stimulus for aggression, i.e., the behaviour rather than the identity of the intruder, suggest that interspecific territoriality is a fortuitous consequence of selection for intraspecific territorialism, the latter being not only an adaptation to the presence of conspecific competitors but a pre-adaptation to the presence of competitors of other species, should they occur.     

Population density,resource patterning,and territoriality in the Everglades pygmy sunfish

The means by which pygmy sunfish compete for food are influenced by the density of the population and the dispersion of the prey as well as by the sex and dominance status of the individual. At all densities when the prey were predictably located in a central clump, males established territories. When prey were dispersed randomly in both the high and low density population, males abandoned territorial behaviour and, like females, swam freely about the aquaria. Only in the intermediate density populations did the males maintain territories and continue to defend resources. Development of a simple cost-benefit model shows that male territorial behaviour is governed to a large extent by economic considerations. Despite these overall patterns, differences in competitive strategies were observed within populations. Dominant individuals tended to possess territories nearest the central patch of prey, and use the most intense and physiologically exhausting displays. Only under the most stressful conditions did they acquire significantly more food than subordinates, and even then these benefits were not translated into increased growth, largely because dominant fish engaged in disproportionately more energy-consuming contests.     

Behavioural flexibility does not prevent numerical declines of harvester ants under intense livestock grazing

1. Human‐induced rapid environmental change may decrease food resources and create unfavourable conditions for native species. Organisms showing a flexible foraging behaviour can exploit novel or alternative foods and are more likely to persist, whereas less flexible organisms might suffer starvation and numerical reductions. 2. This study assessed whether declines in the quality and availability of seeds prompted by grazing provoke behavioural and numerical responses in Pogonomyrmex mendozanus ants, and aimed to test whether behavioural flexibility buffers habitat degradation and prevents numerical declines. 3. Heavy grazing caused seed reductions, especially of the highly consumed and preferred grass seeds, and triggered two kinds of ant responses. Ants expanded their diet by incorporating a greater proportion of non‐seed items, and they reduced foraging activity. As a consequence, the rate of food intake per colony lessened, particularly that of carbohydrate‐rich seeds like grass seeds. Colony density under heavy grazing also fell. 4. Habitat degradation triggered a cascade of mechanisms that starts with a decrease in the seed resources and continues with changes in ant behaviour. However, behavioural responses were insufficient to prevent ant numerical declines. The results of this study suggest that the reduction in the colony density under habitat degradation was provoked by ant nutritional deficit and starvation, and predict a deterioration in body condition, colony performance and reproduction of ants, which deserve further assessment.     

A division between foraging range and territory related to food distribution in the red fox

Spatial organization of the red fox (Vulpes vulpes schrencki) was investigated on the basis of seasonal food distribution in the Shiretoko National Park, Hokkaido from 1992 to 1994. Four periods were recorded pertaining to the distribution of 2 kinds of food resources: human food and spawning salmonid carcasses. The home range utilizations of radio-collared foxes were compared for the periods. In the periods when food was not spatially concentrated, resident foxes were territorial, showing exclusive distribution of home ranges between families, defense against intruding foxes at the edge of home ranges, and site specific dominance over intruding foxes. In contrast, during periods when food distribution was concentrated, home ranges overlapped. In the latter periods, foxes made round trips of up to 8 km from their territories to the localized concentration of food, the distance that foxes can travel within a day. This suggests that red foxes in this area have unique foraging ranges that include some seasonally available food outside their territories, and that these ranges depend on fluctuating food distribution caused by humans.     

Monogamy in a feeding generalist, <Emphasis Type="Italic">Chaetodon trichrous</Emphasis>, the endemic Tahitian Butterflyfish

Butterflyfishes have been well studied for their feeding ecology and mating systems. In particular, studies of corallivorous butterflyfishes have supported models of monogamy based on their predictable, low quality food; a patch of coral that is economically defensible by a pair. Moreover, pairs often exhibit trade-offs in territorial defense (greater by males) and feeding (greater by females) that improve their reproductive success. However, this model has not been well tested for more generalist feeders. In addition, recent hypotheses for monogamy in fish have emphasized parental care, but butterflyfishes do not provide parental care. This study tests five hypotheses for monogamy in the endemic Tahitian butterflyfish, Chaetodon trichrous: 1) uniform distribution of limiting resources, 2) joint defense of a territory, 3) low mate availability, 4) predator detection, and 5) benefits of cooperative behavior. Chaetodon trichrous was the most abundant butterflyfish in bays. Pairs jointly patrolled feeding territories. They preferentially fed over hard substrate other than live coral, however, this substrate was available outside of territories. They also ate plankton. Pairs were sorted positively for size, and all pairs were heterosexual. Males were larger than their partners, but females fed at higher rates. These results suggest that C. trichrous is monogamous, but reject the hypotheses that pairs form for joint defense of a territory (pairs swam together), that pairs remain together because of low mate availability (frequent interactions with neighbors), or that pairs form for predator detection (no homosexual pairs). Monogamy in C. trichrous is associated with the uniform distribution of hard substrate, although this resource is not limiting. Further, the higher feeding rate of females may represent a benefit provided by their monogamous mates.     

THE ECOLOGY OF THE GREENISH WARBLER PHYLLOSCOPUS TROCHILOIDES IN ITS WINTER QUARTERS

The Greenish Warbler is an abundant entirely insectivorous Pafaearctic migrant wintering in the tropical deciduous forests of India and east Asia. A population was studied at one locality in the eastern Ghats of south India over one winter, with a short return the following winter. Individuals maintain, and annually re-occupy, territories throughout their seven or eight months stay. A general account of territorial behaviour is given.
There is much evidence that food is critically short, particularly during the months of December to February and March, which coincides with the end of the dry season. Because of the short duration of the study, there are shortcomings in data presented. Nevertheless there is evidence that territories vary severalfold in quality and individual birds' behaviour and survival probability are correlated with this. It is suggested that territorial behaviour is the best individual strategy for long-term resource management. The presence of food competitors can alter this behaviour, much as changes in food dispersion are known to. The ability to control return time to a patch as a subsidiary function for territoriality is briefly discussed.     

Toxic coral gobies reduce the feeding rate of a corallivorous butterflyfish on Acropora corals

The obligate coral-dwelling gobiid genus Gobiodon inhabits Acropora corals and has developed various physiological, morphological and ethological adaptations towards this life habit. While the advantages of this coral-fish association are well documented for Gobiodon, possible fitness-increasing factors for the host coral are unknown. This study examines the influence of coral-dwelling gobies on the feeding behaviour of obligate corallivorous butterflyfishes. In an aquarium experiment using video observation, the corallivorous butterflyfish Chaetodon austriacus fed significantly less on corals inhabited by two Gobiodon species compared to unoccupied coral colonies of similar size. The more agonistic species G. histrio, which mostly displayed directed movements towards butterflyfishes, decreased butterflyfish bite rate by 62–98 % compared to uninhabited colonies. For Gobiodon sp. 3, which mostly displayed undirected movements in response to visits by C. austriacus, bite rate reduction was 64–68 %. The scale-less skin of Gobiodon spp. is covered by mucus that is toxic and multi-functional by reducing predation as well as affecting parasite attachment. A choice flume experiment suggests that the highly diluted skin mucus of Gobiodon spp. also functions as a corallivore repellent. This study demonstrates that Gobiodon spp. exhibit resource defence against coral-feeding butterflyfishes and also that coral colonies without resident Gobiodon suffer higher predation rates. Although the genus Gobiodon is probably a facultative corallivore, this study shows that by reducing predation on inhabited colonies by other fishes, these obligate coral-dwellers either compensate for their own fitness-decreasing impact on host colonies or live in a mutualistic association with them.     

Feeding Territoriality in Female Northern Bats,Eptesicus nilssoni

A nursing colony of 26 Northern bats was studied in South-Central Sweden. The foraging behaviour is described with emphasis on social interactions on feeding grounds. The bats foraged in small feeding territories used night after night. The reproducing females defended feeding territories against other colony members as well as non-members by means of aggressive chases and vocalizations. A linear dominance order occurred among the females that regularly visited a feeding site. Intrusions into already occupied feeding sites resulted in territorial conflicts (47 %), passive departure by one or both opponents (43%) or mutual acceptance (11%). Conflicts occurred throughout the summer, but became less frequent in July when insect abundance increased.     

Temporal shifts in the pair-bond dynamics of New Zealand robins (

Winter is a challenging time for temperate insectivorous songbirds, due to colder temperatures, reduced prey activity and shorter diurnal foraging times. For species that are non-migratory, territorial and monogamous, winter conditions may result in within-pair competition. However, little is known about how monogamous pairs coexist on their winter territories. We investigated temporal patterns in male?female interactions of the New Zealand robin (Petroica australis to better understand mechanisms of coexistence during winter. Previous work has shown that male robins are physically dominant over females and maintain priority access to food year-round. We quantified female behaviour throughout the 2008 non-breeding season to better understand how females coexist with physically dominant males on winter territories. Results showed that pairs rarely forage in close proximity in autumn and winter, suggesting females avoid males at this time of year. Males and females begin to spend more time foraging together as winter turns to spring. During this winter?spring transitional period, females steal large amounts of food hoarded by males. These results indicate that male and female New Zealand robins use different behavioural mechanisms to coexist on their winter territories. While males are dominant physically, females show a seasonally variable strategy where they avoid males in autumn and winter, and then steal male-made caches from early spring until the onset of inter-pair cooperation and the breeding season.     

Territory defense by the ant Azteca trigona: maintenance of an arboreal ant mosaic

Mosaics of exclusive foraging territories, produced by intra-and interspecific competition, are commonly reported from arboreal ant communities throughout the tropics and appear to represent a recurring feature of community organization. This paper documents an ant mosaic within mangrove forests of Panama and examines the behavioral mechanisms by which one of the common species, Azteca trigona, maintains its territories. Most of the mangrove canopy is occupied by mutually exclusive territories of the ants A. trigona, A. velox, A. instabilis, and Crematogaster brevispinosa. When foraging workers of A. trigona detect workers of these territorial species, they organize an alarm recruitment response using pheromonal and tactile displays. Nestmates are attracted over short distances by an alarm pheromone originating in the pygidial gland and over longer distances by a trail pheromone produced by the Pavan's gland. Recruits are simultaneously alerted by a tactile display. No evidence was found for chemical marking of the territory. Major workers are proportionally more abundant at territory borders than on foraging trails in the interior of the colony. The mechanisms of territory defense in A. trigona are remarkably similar to those of ecologically analogous ants in the Old World tropics.     

Adult male chimpanzees inherit maternal ranging patterns

Space use often correlates with reproductive success [1, 2]. Individual site fidelity is ubiquitous across a variety of taxa, including birds, mammals, insects, and reptiles [3-9]. Individuals can benefit from using the same area because doing so affords access to known resources, including food and/or breeding sites. The majority of studies on site fidelity have focused upon strictly territorial species in which individuals range in well-defined, exclusive areas (e.g., [4, 9]). By comparison, the transient groups that define fission-fusion species allow for considerable flexibility in individual space use. Although there is evidence that individual space use can influence reproductive success [2], relatively little is known about individual ranging patterns in fission-fusion species. Here, we investigate three potential correlates of male site fidelity (age, habitat quality, and maternal space use) in wild chimpanzees (Pan troglodytes). We found that when alone, each male preferentially concentrated his space use near the area where his mother ranged when he was dependent. We suggest that solitary ranging allows males to avoid direct competition with conspecifics and that foraging in familiar areas maximizes foraging efficiency. These results highlight the importance of male foraging strategies in a species in which male ranging is typically explained in terms of mating access to females.     

Defence, intrusion and the evolutionary stability of territoriality

Territorial behaviour can only be adaptive if its costs are outweighed by its benefits. Territorial individuals incur costs by defending their territories against intruders. Usually these intruders are assumed to be non-territorial floaters attempting to take over the whole territory or neighbours trying to extend the borders of their own territory. We instead investigate how costs and benefits of territorial behaviour are affected by neighbours which invade to steal resources on a territory.We show analytically that in the absence of defence intrusion into neighbouring territories always pays and that even if territories are defended intrusion levels can still be high. Using a more detailed simulation model we find that territory defence usually disappears from the population even if owners have a strong advantage over intruders in terms of fighting costs or foraging efficiency. Defence and thus territoriality can only be evolutionarily stable if fighting costs for the intruder relative to the productivity of the territory are very high or if crossing the borders between territories carries additional costs.Our results show that stealing of resources by neighbours can have a considerable effect on the evolutionary stability of territory defence and thus territoriality itself. A more mechanistic model of territorial behaviour is needed to incorporate these kinds of mechanisms into a general theory on the evolution of territoriality.     

Food selection of a corallivorous butterflyfish Chaetodon austriacus in the Red Sea, with particular emphasis on size and fish symbionts of corals

The exquisite butterflyfish Chaetodon austriacus feeds mainly on Acropora , Pocillopora , Montipora and Stylophora in the northern Red Sea. Large colonies of Acropora are preferred over smaller colonies and other coral genera, whereas avoidance is indicated for corals that are occupied by certain coral-associated gobiid fishes of the genus Gobiodon . It is suggested that, apart from coral identity, colony size and potential repellent effects of particular coral symbionts are both important sources of variation in the food selectivity of corallivorous chaetodotids.     

Territoriality of the omnivorous butterflyfish, Chaetodon auriga (Chaetodontidae)

Butterflyfish research has focused on corallivorous species, with little attention paid to the other, equally abundant, omnivorous and planktivorous species. This study sought to explore the nature of ranging behaviour of the omnivorous butterflyfish, Chaetodon auriga, across two geographic regions. Pairs of C. auriga defended non-overlapping territories, ranging in area from 97.44 m² to 2281.64 m². Mean territory area varied among study sites while remaining consistent between geographic regions. Most of the variation in territory area was explained by variation in butterflyfish density, while damselfish density, total fish density, and percent sand cover inside territories were also correlated with territory area. Benthic assemblages of territories did not mirror study sites, suggesting that territory establishment is non-random. At all study sites, Chaetodon auriga exhibited significant selection in its patterns of habitat resource use. These results highlight the importance of research on generalist butterflyfishes as damage to coral reef ecosystems continues to threaten their specialist counterparts.     

Foraging plasticity in obligate corallivorous Melon butterflyfish across three recently bleached reefs

Because obligate corallivorous butterflyfish feed exclusively on coral polyps, they are particularly sensitive to changes in coral cover and its spatial distribution. To understand how such differences in coral cover influence obligate corallivores, we examined the densities and foraging behavior of Melon butterflyfish Chaetodon trifasciatus across three reefs in the Lakshadweep archipelago. These reefs suffered differential bleaching mortality after the 2010 El Niño Southern Oscillation, resulting in wide variation in coral cover and community composition. Despite these differences, C. trifasciatus were able to persist at similar densities across reefs. However, our analysis of high‐resolution video recordings of multiple focal fish revealed that time budgets, bite rates, and diet selectivity differed significantly. Fish in resource‐poor reefs spent more time moving between coral patches and less time foraging than ones in relatively resource‐rich reefs. We also found that fish in resource‐poor reefs had higher bite rates and were less selective in their foraging. Our results provide novel insights into how obligate corallivores cope with even large differences in resource availability. At a time when we are rapidly losing corals to repeated climate‐induced bleaching events, this flexibility may represent a critical mechanism that enables persistence of obligate corallivores in resource‐poor reefs, even if it does not guarantee longer‐term survival.