Intraspecific Competition For Food Research Articles

Ritualized male–male combat resulting from intraspecific food competition in three Agkistrodon species

Ritualized male–male combat resulting from intraspecific food competition in three Agkistrodon species

Feeding habits of Pacific anchovy, Engraulis japonicus (Actinopterygii: Clupeiformes: Engraulidae), captured off the southern coasts of Korea

Understanding the feeding ecology of anchovies in the southern waters of Korea is crucial for improving ecosystem management. However, to date, few studies have examined seasonal changes in the diet of Pacific anchovy, Engraulis japonicus Temminck et Schlegel, 1846, in Korean waters, with the majority of these focusing on the larval and adult stages. The presently reported study provides updates on the feeding habits of E. japonicus off the southern coast of Korea. We analyzed 347 individuals. One-way analysis of similarity was performed to evaluate the differences in diet composition among size classes and seasons of E. japonicus, and correspondence analysis was conducted using the matrix of the percentage by number (%N) data for prey with occurrence of less than 10% to determine the distribution of prey across all size classes and each season. The diet of E. japonicus was investigated according to season and four size classes. The fork length of these specimens ranged from 5.4 to 14.1 cm. A total of 55 prey taxa of varying sizes between 0.33 mm (diatom Coscinodiscus spp.) and 5.8 mm (fish larvae) were recorded. Anchovies were exclusively planktivorous, and copepods were the most common prey, comprising 82.1% of the identified food items and 84.3% of anchovy stomach contents analyzed. However, their occurrence and abundance varied according to season and Pacific anchovy size class. According to the percentage of the index of relative importance (%IRI), the most important prey items were the copepods Calanus sinicus (48.0%), Paracalanus orientalis (31.7%), bivalve larvae (5.8%), Ditrichocorycaeus affinis (4.2%), and calanoid copepods (2.4%). Analysis of similarities and similarity percentage analysis indicated that a distinct diet of Pacific anchovy in the southern waters of Korea is potentially driven by differences in hydrological conditions. Correspondence analysis revealed that anchovies had the most significant impact on the differences between size classes. The results deepen our understanding of prey species diversity and intraspecific food competition off the southern coast of Korea.

Sediment reworking of intertidal sediments by the benthic foraminifera Haynesina germanica: the importance of motion behaviour and densities.

This study aimed to describe for the first time the vertical motion behaviour of the intertidal foraminifera Haynesina germanica and its contribution to bioturbation. Its infaunal behaviour leads to the creation of a one-end tube within the first centimetre of sediment. In addition, a vertical trail following behaviour was described for the first time in foraminifera, which may be linked to the sustainability of the biogenic sedimentary structures. As a consequence, H. germanica produces a vertical transport of both mud and fine sediment fractions similarly to the sediment reworking mode reported for gallery-diffusor benthic species. This finding allows us to refine the bioturbating mode of H. germanica, previously classified as surficial biodiffusor. Furthermore, sediment reworking intensity appeared to be dependent on the foraminiferal density. H. germanica would adapt its motion behaviour to deal with the intra-specific competition for food and space that may occur when density increases. Consequently, this behavioural modification would affect both the species and the individual contribution to sediment reworking processes. In fine, sediment reworking in H. germanica may further contribute to the bioirrigation of intertidal sediments, which has implications for oxygen availability in sediments and on aerobic microbial processes involved in carbon and nutrient cycling at the sediment-water interface.

Individual foraging site fidelity increases from incubation to nestling rearing in a colonial bird

Foraging specialization, whereby animals exploit only a minor fraction of the population's foraging home range or trophic niche, may arise as a response to increasing levels of intraspecific competition. This phenomenon may be particularly frequent in colonial species, when individuals breed in large aggregations and are constrained to exploit shared foraging areas surrounding the colony site where competition for access to food resources may be high. Foraging specialization may be driven by individual foraging site fidelity, occurring whenever individuals consistently target specific foraging sites, which may differ from those used by other colony members. We assessed the extent of foraging specialization in a colonial breeding raptor, the lesser kestrel, Falco naumanni , by estimating the repeatability of foraging movement patterns of 45 GPS-tracked individuals during both incubation and nestling rearing. We found that the consistency of individual movement patterns was generally higher during nestling rearing than during incubation. Nestling-rearing individuals, but not incubating ones, travelled along relatively consistent routes when targeting foraging grounds and tended to target the same foraging areas throughout the tracking period. In colonial birds, and likely in altricial species more generally, an increased individual foraging site fidelity during nestling rearing versus incubation may result from increased energy demands due to frequent nestling provisioning in addition to self-provisioning. By consistently exploiting previously visited foraging sites that are likely to be rewarding, nestling-rearing birds might indeed increase their foraging efficiency, shortening food-searching time and maximizing their foraging effort. In addition, the use of distinct foraging areas may reduce intraspecific competition for food, thus buffering an important cost of coloniality. • Nestling-rearing lesser kestrels showed high individual foraging site fidelity. • Incubating birds were less consistent in foraging movement and commuting routes. • Site fidelity likely resulted in optimized foraging effort and food-searching time. • Site fidelity may increase foraging efficiency in a high energy-demanding phase. • Using distinct foraging sites could also reduce intraspecific competition.

Role of weather and other factors in the dynamics of a low-density insect population.

Insect population dynamics are the result of an interplay between intrinsic factors such as density dependence, trophic web interactions, and external forces such as weather conditions. We investigate potential mechanisms of population dynamics in a natural, low‐density insect population. Eggs and larvae of the noctuid moth, Abrostola asclepiadis, develop on its host plant during summer. The population density, and mortality, was closely monitored throughout this period during 15 years. Densities fluctuated between one and two orders of magnitude. Egg–larval developmental time varied substantially among years, with lower survival in cool summers with slower development. This was presumably due to the prolonged exposure to a large guild of polyphagous arthropod enemies. We also found a density‐dependent component during this period that could be a result of intraspecific competition for food among the last larval instars. Dynamics during the long period from pupation in late summer through winter survival in the ground to adult emergence and oviposition the next year displayed few clear patterns and more unexplained variability, thus giving a more random appearance. The population hence shows more unexplained or unpredictable variation during the long wintering period, but seems more predictable over the summer egg–larval period. Our study illustrates how weather—via a window of exposure to enemies and in combination with density‐dependent processes—can determine the course of population change through the insect life cycle.

Larval Competition Between Aedes albopictus and Aedes aegypti (Diptera: Culicidae) in Argentina: Coexistence and Implications in the Distribution of the Asian Tiger Mosquito.

Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) are worldwide vectors of dengue and yellow fever viruses. These species coexist in many countries and the biotic interactions between them can influence their abundances and distributions. In Argentina, Ae. aegypti is widely distributed in the north and center regions of the country, with temperate and subtropical climate, while both are sympatric only in the northeastern area of the subtropical region. Interspecific and intraspecific larval competition for food was evaluated to assess if their interaction influences on patterns of abundance and distribution. Finite rates of increase and survivorship for each species were estimated and the effects of mosquito density ratio and detritus availability were determined. The Lambda (λ´) index of population performance of both showed there is no competitive exclusion pattern. However, survival of Ae. albopictus was negatively affected by the presence of Ae. aegypti. These results suggest one possible explanation for the codominance pattern of both species display in rural regions of the southernmost distribution of Ae. albopictus in South America. They also show Ae. aegypti as a potential biotic barrier for the expansion of Ae. albopictus as was reported in regions of the United States.

Ant Mortality with Food Competition in Forests along a Temperature Gradient.

Simple SummaryAnts are aggressive, and many ants die from inter- or intraspecific attacks while acquiring food. Temperature influences animal behavior, including aggression and competition, but the effect of temperature on ant mortality due to food competition in the field remains unclear. We aimed to elucidate the relationship between temperature and mortality due to food competition in ant communities in forests. A field experiment was conducted using four bait types at six different oak forest sites with different mean annual temperatures along a temperature gradient. The results showed that the mortality rate due to food competition displayed a hump-shaped trend with temperature distribution being higher with intermediate temperatures and a linear trend increasing or decreasing with temperature along the temperature gradient. The mortality rate due to interspecific competition was higher than that due to intraspecific competition. The results indicated that mortality due to inter- or intraspecific competition for food was associated with temperature, density of other species, and species characteristics such as body size, dominance, feeding strategy, and aggressiveness.The authors elucidated the relationship between temperature and mortality due to food competition in ant communities in forests. A field experiment was conducted using four bait types at six different oak forest sites with different mean annual temperatures in South Korea. The mortality rate due to food competition showed a hump-shaped trend, with temperature distribution being higher at study sites with intermediate temperatures and a linear trend increasing or decreasing with temperature along the temperature gradient. In most species, the mortality rate due to interspecific competition was higher than that due to intraspecific competition, but the dominant species, which were less affected by other species, had a higher mortality rate due to intraspecific competition. In subordinate species that are highly affected by other species, the mortality rate due to intraspecific competition increased as the mortality rate due to interspecific competition decreased. The results indicated that mortality due to inter- or intraspecific competition for food was associated by temperature, density of other species, and species characteristics (body size, dominance, feeding strategy, and aggressiveness). Given the relationship between temperature and mortality due to food competition, the authors expect that changes in competition due to climate warming will affect the fitness of ant species.

Factors Affecting Breeding Success of White Terns (Gygis alba; Aves: Laridae) in Urban Environments of Honolulu, Hawai‘i

The White Tern (Gygis alba) is a common seabird that nests on islands in tropical and subtropical oceans. In the southeastern Hawaiian Islands, White Terns breed only in urban and suburban areas of Honolulu. The Honolulu population has grown from a single pair in 1961 to 2,300 birds in 2016. We measured breeding success of White Terns in Honolulu and examined aspects of their breeding biology and the environment that may affect breeding. We documented 3,855 breeding events in Honolulu from 2016 to 2019. Breeding success was 68.3% and varied less than 3% among years. Breeding occurred in all months, with lowest activity in the summer and a peak in the winter and spring, but the pattern varied among years. White Terns bred in 64 tree species. Breeding success varied among tree species and was related to characteristics of the trees and their attractiveness to non-native predators. The height of breeding events was 9.26 ± 0.05 m and success was related to height, with higher success in events 5–10 m above ground. The diameter of branches on which breeding occurred was 10.2 ± 0.1 cm and success was related to branch diameter, with lower success on branches >20 cm. The high breeding success of White Terns in Honolulu is related to: the small size and isolation of the O‘ahu population, which may result in reduced intra-specific competition for food; protection from predators provided by the urban environment; and trimming of trees by arborists, which unintentionally improves the value of trees as breeding sites for terns.

Analysis of the Dynamics of Marine Structures and Species with Criterial Mathematical Models

The influence of the area of artificial substrates (collectors) on the biological parameters of populations of mussels (Mytilus galloprovincialis Lamarck) during their cultivation in the Black Sea has been investigated. For growing mollusks, four types of collectors were used, with different relative areas (ω), i.e., with different ratios of the substrate area (S) per unit length of the collector (L), which were 0.09, 0.21, 0.34, and 0.55. It was found that, during a 1.5-year cultivation, the density (N, ind./m) and biomass (B, kg/m) change and reach a certain stationary state, determined by the relative area of the substrate. It was shown that, on collectors with a higher value of ω, there was a decrease in the average length (L, mm) and weight (W, g) of the mollusk yield. The Boysen–Jensen method was used to calculate the total production of mollusks (P), elimination (E), and specific production (P/B coefficient) for each type of reservoir, and it was shown that P increased with an increase in the substrate area, while E and P/B coefficients decreased. Based on the analysis of the obtained results, it was concluded that during the cultivation of mussels these parameters are regulated by density-dependent population factors (intraspecific competition) for space (substrate) and food.

Influence of intraspecific competition for food on the bodyweight of the adult aphidophagous ladybird, Coccinella transversalis

Aggregation of conspecific predators sharing a common prey, influences their bodyweights. We investigated the influence of intraspecific competition of adult ladybirds of Coccinella transversalis Fabricius on their bodyweight feeding on rusty plum aphid, Hysteroneura setariae (Thomas). Adult males and females consumed a significantly greater number of aphids with increase in predator-density, however, the aphid-consumption per predator declined with this increase. The weight gain per predator also decreased linearly with increase in the density of both male and female predators. This indicates that the weight-gain of the predator is a function of the prey consumed. The searching efficiency decreased with increase in predator density due to mutual inference. The mutual interference constants for adult male and female ladybirds were −0.419 and −0.546, respectively. The females consumed a greater number of aphids than males. The killing power of the ladybird denoted by the k-value increased curvilinearly with increase in predator density. We conclude that prey consumption is a function of body size and that the offspring of those that aggregate at low densities in prey-rich habitats develop into large adults.

Density dependence of daily activity in three ungulate species.

Daily activity in herbivores reflects a balance between finding food and safety. The safety‐in‐numbers theory predicts that living in higher population densities increases safety, which should affect this balance. High‐density populations are thus expected to show a more even distribution of activity—that is, spread—and higher activity levels across the day. We tested these predictions for three ungulate species; red deer (Cervus elaphus), roe deer (Capreolus capreolus), and wild boar (Sus scrofa). We used camera traps to measure the level and spread of activity across ten forest sites at the Veluwe, the Netherlands, that widely range in ungulate density. Food availability and hunting levels were included as covariates. Daily activity was more evenly distributed when population density was higher for all three species. Both deer species showed relatively more feeding activity in broad daylight and wild boar during dusk. Activity level increased with population density only for wild boar. Food availability and hunting showed no correlation with activity patterns. These findings indicate that ungulate activity is to some degree density dependent. However, while these patterns might result from larger populations feeling safer as the safety‐in‐numbers theory states, we cannot rule out that they are the outcome of greater intraspecific competition for food, forcing animals to forage during suboptimal times of the day. Overall, this study demonstrates that wild ungulates adjust their activity spread and level based on their population size.

Effects of light and nutrients on intraspecific competition among midges from a shallow eutrophic lake

1. Intraspecific competition for food may affect the development, survival, and fecundity of organisms. However, environmental variation in abiotic conditions can influence resource quality and/or quantity, thereby modifying the strength of intraspecific competition.2. This study focuses on intraspecific competition among Tanytarsus gracilentus (Chironomidae: Diptera) larvae. In Lake Mývatn, Iceland, T. gracilentus undergoes large population fluctuations, and evidence suggests that these fluctuations are governed by consumer‐resource interactions between the larvae and benthic diatoms. In two experiments, we studied (i) the effects of larval density on individual development and survival, and (ii) how light and nutrients (nitrogen and phosphorus) mediate the strength of intraspecific competition across a density gradient.3. Survival declined with increasing larval density in both experiments, although not significantly in the first experiment in which we manipulated only density. In the second experiment, enhancement of either light or phosphorus mitigated the negative effect of larval density on survival. In both experiments, density had a negative effect on individual development. In the first experiment, fewer larvae progressed to the final fourth instar at higher densities. In the second experiment, larvae were smaller in high density treatments, and this effect was most pronounced in the treatments without light or phosphorus supplementation.4. These results highlight the potential for environmental factors to influence the strength of density‐dependent competition. Environmental variation that affects resource quantity or quality may influence the overall dynamics of our study organism and other populations whose dynamics are controlled by consumer‐resource relationships.

Behaviour of the oyster Rhynchostreon suborbiculatum assemblages in a Cenomanian-Turonian river dominated marginal-marine environment: multidisciplinary study from the Pieniny Klippen Belt (Western Carpathians, Slovakia)

ABSTRACT The tens of metres thick shell accumulations within the Cenomanian-Turonian strata of Western Carpathians enabled a complex study of ecological and geochemical proxies in relation to behavioural patterns of oyster Rhynchostreon suborbiculatum. Integration of geological and palaeobiological approaches enabled comparisons between one of the most famous fossil oyster species and several Recent bivalves. The analysis of grain size (Qz) and major oxides, together with taphonomic and population analysis, reveals a high-energy marginal-marine environment in the sedimentation area of the Orlové Sandstone. The life conditions of the association of bivalves, gastropods and polychaetes were influenced by the fluctuating influx of freshwater due to climatic changes that occurred during a dynamic period of the Late Cretaceous. A shift in the prominent control of biological production caused a massive increase in α-diversity, in conjunction with a change in the trophic structure of the studied system. The ecological responses of organismal association were also analogous to Recent representatives inhabiting marginal-marine environments. Size and allometric analyses of oysters forming monospecific assemblages show that their high density correlates with smaller shell sizes, indicating that intraspecific competition for food and space most intensified at times of the lowest salinity.

Social calls influence the foraging behavior in wild big-footed myotis

BackgroundWhy a variety of social animals emit foraging-associated calls during group foraging remains an open question. These vocalizations may be used to recruit conspecifics to food patches (i.e. food advertisement hypothesis) or defend food resources against competitors (food defence hypothesis), presumably depending on food availability. Insectivorous bats rely heavily on vocalizations for navigation, foraging, and social interactions. In this study, we used free-ranging big-footed myotis (Myotis macrodactylus Temminck, 1840) to test whether social calls produced in a foraging context serve to advertise food patches or to ward off food competitors. Using a combination of acoustic recordings, playback experiments with adult females and dietary monitoring (light trapping and DNA metabarcoding techniques), we investigated the relationship between insect availability and social vocalizations in foraging bats.ResultsThe big-footed myotis uttered low-frequency social calls composed of 7 syllable types during foraging interactions. Although the dietary composition of bats varied across different sampling periods, Diptera, Lepidoptera, and Trichoptera were the most common prey consumed. The number of social vocalizations was primarily predicted by insect abundance, insect species composition, and echolocation vocalizations from conspecifics. The number of conspecific echolocation pulses tended to decrease following the emission of most social calls. Feeding bats consistently decreased foraging attempts and food consumption during playbacks of social calls with distinctive structures compared to control trials. The duration of flight decreased 1.29–1.96 fold in the presence of social calls versus controls.ConclusionsThese results support the food defence hypothesis, suggesting that foraging bats employ social calls to engage in intraspecific food competition. This study provides correlative evidence for the role of insect abundance and diversity in influencing the emission of social calls in insectivorous bats. Our findings add to the current knowledge of the function of social calls in echolocating bats.

Intraspecific dental variations in the deep-sea shark Etmopterus spinax and their significance in the fossil record

An important character on several taxonomic levels for shark identification is the tooth morphology. Sharks show a variety of highly specialized dentitions reflecting adaptations to their feeding habits. Intraspecific variation of tooth morphology such as sexual or ontogenetic dimorphism is poorly known in many species, even though tooth morphology plays a decisive role in the characterization of the fossil record of sharks, which comprises mostly fossil teeth. Here we analyzed the dentition of 40 jaws of the Velvet Belly Lantern Shark Etmopterus spinax and identified ontogenetic and sexual dimorphic characters such as total number of teeth, number of upper teeth, cusplet numbers in upper jaw teeth and width of lower jaw teeth. Dimorphic characters may reduce intraspecific competition for food, as E. spinax segregates by sex and size and may allow for identifying the male sex. The lower jaw tooth height, a sexually non-dimorphic character, was used to re-calculate the total length of specimens, which represents the first such approach for a squaliform shark. Results derived from the extant E. spinax are subsequently applied to fossil Etmopterus sp. teeth (Miocene) to gain individual information such as sex or size, but also characterize the extinct population from the excavation site by a size distribution profile in comparison to data from extant populations. This approach indicates the presence of multiple ontogenetic stages in the extinct population.

Diet segregation in Adélie penguins: some individuals attempt to overcome colony-induced and annual foraging challenges

Intraspecific competition for food can be especially high in colonial breeding seabirds. To minimize colony-induced or annual foraging challenges, diet may vary among individuals, but few studies have simultaneously investigated the effects of both extrinsic conditions (e.g. colony or year effects) and parameters of an individual (e.g. sex, age or individual quality) on diet in seabirds. Using stable isotope analyses, we studied the diet of 214 Adélie penguins Pygoscelis adeliae of known sex, age and breeding quality, nesting in 2 colonies on Ross Island, Antarctica, over 3 breeding seasons. During the study, δ15N and δ13C isotope values were lower in penguins breeding at Cape Crozier compared to those at Cape Bird, revealing a difference in prey proportions. Cape Bird penguins were estimated to consistently consume more energy-rich silverfish Pleuragramma antarctica, while birds at Cape Crozier ate more crystal krill Euphausia crystallorophias. We also found inter-annual differences in diet, with a higher dietary fish proportion in both colonies during 2011. Males had significantly higher δ15N values, indicating a higher fish consumption than females. This sexual segregation in diet was particularly pronounced at Cape Bird, where the overall isotopic niche was wider than at Cape Crozier. Differences in diet among adults of varying ages only existed at Cape Bird, where middle-aged penguins consumed more fish than old and young penguins. This study provides evidence that Adélie penguin diet is largely driven by annual, seasonal and local abundances of prey, with only some individuals selectively foraging for more nutritional prey if prey choices are present.

Diurnal activity in cane toads (Rhinella marina) is geographically widespread

Although adult cane toads (Rhinella marina) are generally active only at night, a recent study reported that individuals of this species switched to diurnal activity in response to encountering a novel habitat type (deeply shaded gorges) in the course of their Australian invasion. Our sampling over a broader geographic scale challenges the idea that this behaviour is novel; we documented diurnal behaviour both in the species’ native range and in several sites within the invaded range, in multiple habitat types. Diurnal activity was most common in the tropics and in areas where toads attain high population densities and are in poor body condition, suggesting that the expansion of activity times may be induced by intraspecific competition for food.

Habitat partitioning in Antarctic krill: Spawning hotspots and nursery areas.

Antarctic krill, Euphausia superba, have a circumpolar distribution but are concentrated within the south-west Atlantic sector, where they support a unique food web and a commercial fishery. Within this sector, our first goal was to produce quantitative distribution maps of all six ontogenetic life stages of krill (eggs, nauplii plus metanauplii, calyptopes, furcilia, juveniles, and adults), based on a compilation of all available post 1970s data. Using these maps, we then examined firstly whether “hotspots” of egg production and early stage nursery occurred, and secondly whether the available habitat was partitioned between the successive life stages during the austral summer and autumn, when krill densities can be high. To address these questions, we compiled larval krill density records and extracted data spanning 41 years (1976–2016) from the existing KRILLBASE-abundance and KRILLBASE-length-frequency databases. Although adult males and females of spawning age were widely distributed, the distribution of eggs, nauplii and metanauplii indicates that spawning is most intense over the shelf and shelf slope. This contrasts with the distributions of calyptope and furcilia larvae, which were concentrated further offshore, mainly in the Southern Scotia Sea. Juveniles, however, were strongly concentrated over shelves along the Scotia Arc. Simple environmental analyses based on water depth and mean water temperature suggest that krill associate with different habitats over the course of their life cycle. From the early to late part of the austral season, juvenile distribution moves from ocean to shelf, opposite in direction to that for adults. Such habitat partitioning may reduce intraspecific competition for food, which has been suggested to occur when densities are exceptionally high during years of strong recruitment. It also prevents any potential cannibalism by adults on younger stages. Understanding the location of krill spawning and juvenile development in relation to potentially overlapping fishing activities is needed to protect the health of the south-west Atlantic sector ecosystem.

Ontogenetic Dietary Shifts and Food Resource Partitioning in a Stream-Dwelling Urodela Community: Mechanisms to Allow Coexistence Across Seasons

Trophic interactions are important factors structuring animal communities. Although food resource partitioning among salamanders living in syntopy has often been explored in freshwater systems, the potential influence of ontogenetic shifts and seasonal patterns on resource partitioning is little known. The aim of this study was to explore the seasonal patterns in food resource partitioning among developmental stages of two Urodela species ( Calotriton asper and Salamandra salamandra ) in a fishless stream. We tested the hypothesis that seasonal patterns in intra- and interspecific food resource partitioning may occur at two different levels: (i) diet composition and (ii) prey size. For the purpose of this study, food resource partitioning was approached at three scales: (i) ontogenetic (larva, immature and adult), (ii) seasonal (winter, spring, summer and autumn) and (iii) species. Inter- and intraspecific competition for food was measured as dietary overlap according to Schoener’s index. The overlap in diet among developmental stages and species was high. However, prey size and the contribution of terrestrial invertebrates to the diets changed among developmental stages of species. This suggests that competition for food may be alleviated by ontogenetic dietary shifts in prey size and terrestrial invertebrates use.

Boldness at the nest predicts foraging and diving behaviour of female but not male African penguins

Optimal foraging theory suggests that the environment (e.g. distribution of resource patches) will shape an individual's decision to exploit the resource available or explore other locations. Together with the environment and the social context, individual characteristics such as personality have been recently discovered to affect behaviour, offering new insights in the field of behavioural ecology. In many species, personality types differ in breeding success, and foraging behaviour could potentially mediate the influence of personality on reproductive output. A recent study conducted on African penguins, Spheniscus demersus, revealed that bold and shy individuals raised chicks with different growth rates. Here we investigated whether strategies of resource acquisition vary with personality, that is, boldness degree, which may explain the differences in breeding success previously observed in this endangered species. Over 3 years, we deployed GPS loggers, sometimes in conjunction with time–depth recorders, on chick-rearing penguins on Bird Island, Algoa Bay, South Africa, and recorded their boldness degree using a standard human approach protocol. Bolder females, but not males, foraged following a more sinuous path than shyer ones. Similarly, wiggle frequency and the total vertical distance travelled underwater increased with female boldness degree. These results suggest different resource acquisition strategies between personality types in female African penguins. However, none of the foraging or diving behaviour characteristics influenced breeding success. These findings suggest that personality may influence breeding success through other mechanisms (e.g. chick provisioning). Our study indicates that, in this species, some nest behaviours (i.e. proxy of personality) may link with foraging and diving behaviours more than others. Nevertheless, the sex-specific adaptation observed in foraging and diving behaviour may result from a differential investment in the breeding season and reduce intraspecific competition for food in this species.