Behav Ecol Research Articles

Brook trout use individual recognition and transitive inference to determine social rank

Transitive inference (TI) occurs when information about known relationships is used to construct novel associations, for example, when an individual infers the order of 3 conspecifics in a linear dominance hierarchy (A > B > C) by watching 2 dyads (A > B and B > C). TI has been demonstrated for several species, but never for organisms with hierarchies involving many individuals whose rank order changes often. Under these circumstances, theory predicts natural selection may favor use of explicit cues to rank conspecifics, rather than TI. Here we show that brook trout (Salvelinus fontinalis), a species that exhibits complex, shifting dominance hierarchies, can combine individual recognition and TI to rank individuals within a hierarchy without use of explicit cues. Subjects that were allowed to directly interact with rivals were able to identify the social rank of each individual. In addition, we found that a subject, whose rank was C within a 5-fish hierarchy (A > B > C > D > E), could use TI to correctly infer the ranks of A and E after first interacting with B and D and then watching dyads involving A > B and D > E. This demonstration of TI in brook trout contributes to the understanding of stream trout population dynamics as TI could lower the energetic costs associated with movement. Key wor ds: brook trout, individual recognition, social learning, transitive inference. [Behav Ecol]

Maternally chosen nest sites positively affect multiple components of offspring fitness in a lizard

Maternal nest-site choice is a behavioral phenotype with transgenerational consequences that can appear at multiple stages of offspring ontogeny. In many reptiles, the microenvironment surrounding eggs (e.g., moisture) can affect multiple aspects of offspring fitness across several life stages (e.g., embryo survival, phenotypic development, and posthatching survival). Thus, natural selection should favor maternal nesting behaviors that positively affect both embryonic and postembryonic ontogenetic trajectories. We tested this hypothesis in a 2-part laboratory experiment using the brown anole lizard (Anolis sagrei). In the first experiment, gravid lizards were given a choice of nesting substrates containing 5 levels of moisture content. By incubating eggs at the same 5 moisture levels, our second experiment tested if maternal choice of nest substrate facilitates embryonic development and enhances offspring quality and viability. Females strongly preferred nesting substrates with high moisture content, and these conditions yielded high hatching success, large offspring size, and overall increased offspring survival. These results suggest that selection has adaptively matched maternal nesting behaviors, embryonic development, and posthatching phenotypes in ways that enhance both offspring and parental fitness. In addition, our results highlight the importance of incorporating multiple life-history stages when assessing the fitness consequences of transgenerational effects. Key words: Anolis sagrei, brown anole, incubation moisture, maternal effects, nest-site choice, ontogenetic trajectory, phenotypic plasticity. [Behav Ecol]

Modeling multiple nonconsumptive effects in simple food webs: a modified Lotka-Volterra approach

Nonconsumptive effects are an important component of many ecological systems. Yet, modeling these interactions has proven challenging, with the few current models being either overly simplified or very complex. Here I build on the idea of predator interference to derive a model that is both flexible and intuitive. The model is derived using a 4-species food web that includes multiple nonconsumptive effects (NCEs) and interactions among them, though this approach may be adaptable to larger ecological communities. I apply this model to 2 example systems—a stream community and a coffee insect community—and discuss how the incorporation of NCEs changes the dynamics of each system. In the Appendix, I discuss the empirical data and statistics necessary to parameterize the model in hopes that future empirical studies will include additional experiments that can inform modeling frameworks such as the one proposed here. Empirically informed theoretical studies will help evaluate the importance of NCEs on the long-term dynamics of simple communities. Key words: coexistence, Crowley–Martin model, food web modules, functional response, nonconsumptive effects, predator interference. [Behav Ecol]

Opposing effects of sperm viability and velocity on the outcome of sperm competition

Sperm competition is often envisaged as a raffle where differences in sperm quality ‘‘load’’ the raffle in favor of the male with the higher quality sperm. Sperm quality, however, is a complex trait, and the effects of its various components on the outcome of sperm competition are likely to depend upon their role in sperm transport, storage, and fertilization. Here, I use artificial insemination to assess the relationships between sperm viability, velocity, and storage on siring success in the swordtail Xiphophorus nigrensis (Teleostei: Poeciliidae), an internally fertilized fish with alternative reproductive tactics. Males with greater sperm viability sired more offspring than their rival, as predicted if the number of fertilization-capable sperm influences sperm competition in a numerical raffle. In contrast, males with faster swimming sperm sired fewer offspring, but only when sperm were stored prior to fertilization. Faster swimming sperm were thus a liability following sperm storage, suggesting a trade-off between sperm velocity and longevity in vivo. These results provide experimental evidence that the sign and magnitude can differ among components of sperm quality depending upon the mechanisms that mediate their effects. Key words: alternative reproductive tactics, artificial insemination, Poeciliidae, sperm quality. [Behav Ecol]

Male dimorphism of a neotropical arachnid: harem size, sneaker opportunities, and gonadal investment

Serracutisoma proximum is a harvestman with alternative male morphs. Large males use sexually dimorphic second legs in fights for the possession of territories on the vegetation, where females oviposit. Small males have short second legs and do not fight but rather sneak into the territories and copulate with egg-guarding females. We investigated the presence of male dimorphism across 10 populations of S. proximum, compared gonadal investment between male morphs, and assessed if the distribution of the sneakers is influenced by harem size. In all populations, there was male dimorphism, indicated by the bimodal distribution of the leg II length/body length. Gonadal investment did not differ between morphs and was not affected by male size, second leg length, and morph relative frequency in the populations. We found 361 territories, 90.0% containing 1 male, 9.7% containing 2 males (dyads), and 0.3% containing 3 males. The probability of encountering dyads increased with the number of females present in the territories. Moreover, the proportion of sneakers in territories containing dyads was higher than would be expected by chance. One possible reason for the ubiquity of alternative morphs in S. proximum could be the high mating opportunities experienced by sneakers in spatially structured populations with a resource defense polygyny system. Additionally, the high frequency of successful invasions by sneakers and hence the high sperm competition risk for both morphs may explain the similarity in gonadal investment between male morphs. Key words: alternative mating tactics, resource defense polygyny, sperm competition, testis mass. [Behav Ecol]

Mixing nutrients mitigates the intake constraints of a plant toxin in a generalist herbivore

The diversity and concentration of primary plant compounds, including nutrients and secondary metabolites, such as plant toxins differ spatially and temporally among food resources, creating a varied feeding environment for herbivores. Both nutrients and toxins influence foraging behavior, but their interactive effects remain poorly understood. Our aim was to determine how patterns of intake and feeding behavior are influenced by the nutritional composition of foods as modified by the presence of toxins and the capacity to choose between nutritionally different foods. We offered common brushtail possums, a generalist mammalian herbivore, a choice between 2 food mixtures, one high in protein (HP), the other high in carbohydrate (HC), or a no-choice diet formulated to reflect the mixture of protein and carbohydrate selected when animals had access to both HP and HC foods. We tested choice and no-choice dietary regimes in the presence or absence of the toxin, cineole, at a concentration known to limit intake by ;50%. We found that possums could compensate for the effect of a high concentration of cineole on food intake if they could mediate dietary concentrations of the HP and HC foods. They appeared to do this by 1) selecting an increased proportion of dietary protein and 2) by continually adjusting the proportion of protein and carbohydrate eaten throughout a feeding night. Our results demonstrate that the protective effect of cineole against herbivory by possums is not a simple function of its concentration but rather depends strongly on the nutritional context in which it occurs. Key words: behavior, carbohydrate, choice, diet mixing, feeding, food selection, herbivore, nutrient‐toxin interactions, nutrition, protein. [Behav Ecol]

Direct and indirect assessment of parasitism risk by a cuckoo host

When the risk of encountering enemies varies in space or in time, this may select for plasticity of costly defenses. Hosts are known to vary both mobbing of adult cuckoos and egg rejection with spatiotemporal variation in brood parasitism, but it is unclear what parasitism cues they use to guide their defense plasticity. There is evidence that hosts use cuckoo activity near their nests as a direct cue, but cuckoos are secretive and resemble dangerous birds of prey so hosts may use indirect environmental predictors of parasitism too, such as their nest’s proximity to potential cuckoo lookout perches. Here, we compared reed warbler Acrocephalus scirpaceus nest defense responses with models of various enemies at a parasitized site and at a site where no common cuckoos Cuculus canorus were present. Reed warblers approached model cuckoos less closely and mobbed them less at the unparasitized site. However, at both sites, the warblers reduced their mobbing in a similar manner with increasing distance to the nearest potential cuckoo perch. The variation in response was specific to cuckoos and was not shown to harmless controls. Thus, hosts use both direct (cuckoo presence) and indirect cues (perch distance) of parasitism risk for modulating their costly defenses against their secretive parasite. We suggest that reciprocal selection for detection and suppression of direct and indirect cues provides a unifying feature of cuckoo–host arms races. Key words: brood parasites, coevolution, direct cues, host defense, indirect cues, phenotypic plasticity. [Behav Ecol]

Latency to flee from an immobile predator: effects of predation risk and cost of immobility for the prey

When a predator is immobile near an immobile prey, the probability that the predator will detect and attack increases over time. The prey’s cost of moving, thereby abandoning crypsis due to immobility, therefore decreases. Cost of not moving increases over time if movement is required for prey to conduct fitness-enhancing activities. We tested a cost-benefit model that predicts effects of factors that affect predation risk and cost of not moving on a prey’s latency to flee. Acting as simulated predators, we conducted experiments on the lizards Iberolacerta cyreni and Podarcis lilfordi. All predictions for 5 risk factors and a cost of moving factor were verified. Lizards fled sooner when the predator stood closer, approached rapidly rather than slowly before stopping, approached directly rather than indirectly, and gazed at the lizard rather than away from it, and after the second of 2 successive approaches. Latency to move was shorter in the presence than absence of a mealworm, suggesting the importance of opportunity cost of immobility. The effect of standing distance has 2 components, greater rate of detection by the predator and greater risk of being captured if detected at shorter distances. Escape theory has been highly successful in predicting how close a prey allows a predator to approach before fleeing. Our model extends an economic approach to study of escape decisions in response to an immobile predator that may be an ambush forager or an active forager that has stopped moving nearby. Key words: ambush, escape, latency to flee, opportunity cost, predation risk, standing distance. [Behav Ecol]

Male and female aggression: lessons from sex, rank, age, and injury in olive baboons

Aggression is ubiquitous, influencing reproduction through inter- and intraspecific effects in ways that reflect life-history strategies of species. In many social mammals, females remain in their natal group for life, whereas males emigrate and compete for rank in other social groups. Competition for rank is inherently risky. Therefore, it has long been hypothesized that risks of injury depend on an individual’s sex, rank, and age in ways that maximize an individual’s reproductive output. However, studies quantifying such risks have been lacking. We analyzed 20 years of long-term data on wounds among olive baboons (Papio anubis) in Gombe National Park, Tanzania. Males received significantly more wounds than female baboons, and both sexes received the most wounds at ages when they competed most intensely for rank. Immature females received more wounds than immature males in their natal groups, and immature females were more likely to be wounded by females than were immature males. Males in their natal group were wounded less often than immigrant males of the same age. The risk of wounding did not depend on rank in females but rose with rank in immigrant males. Lastly, females received significantly more wounds when cycling (not pregnant or lactating). This study is among the first to quantify the risk of injury for competitors of different sexes, ages, and ranks in social groups. Our results support the prediction that individuals target aggression toward present and future competitors and suggest that sexual coercion increases the risk of wounding in cycling females. Key words: competition, injury, life history, olive baboon, Papio anubis, rank. [Behav Ecol]

Socially induced tactic change in 2 types of sand goby sneaker males

Male alternative reproductive tactics, like satellite or sneaking tactics, typically parasitize reproductively on a larger resourceholding tactic. In the sand goby, Pomatoschistus minutus, 2 types of sneaker males are known. Sneaker males with melanization, a typical male breeding coloration, have small testes and large sperm-duct glands, and sneaker males without melanization have large testes and small sperm-duct glands. We tested their potential to change into the nest-holding tactic experimentally by keeping them with or without a large nest-holding male. With nest-holding males, neither sneaker male type built nests. However, without nest-holding males, a large proportion of both types of sneaker males built nests and became nest-holders, and all the nest-building nonmelanized sneaker males developed melanization. Furthermore, nest-building nonmelanized sneaker males had larger sperm-duct glands (used to produce a sperm-containing mucus) than nonnest-building nonmelanized sneaker males. However, contrary to our expectation, treatment did not affect testes size. Compared with melanized sneaker males nonmelanized sneaker males tended to have a lower proportion of nest-building males and showed significantly less reproductive activity, especially in the early experimental period. Finally, in a separate experiment, we confirmed that nonmelanized sneaker males that build nests can spawn and tend eggs normally. Taken together, our results suggest that these tactics are not genetically or ontogenetically fixed but condition dependent. However, this does not exclude an underlying genetic variation in phenotype expression. Key words: alternative reproductive strategies, bourgeois, genetic polymorphism, Gobiidae, seminal vesicles, sperm competition. [Behav Ecol]

Evolutionary correlation between male substances and female remating frequency in a seed beetle

An evolutionary correlation between the effects of male seminal substances that reduce female sexual receptivity and female remating frequency was found among strains of the adzuki bean beetle, Callosobruchus chinensis. Variation in female remating frequency had been also previously documented in this species, together with the identification in males of low- and highmolecular weight substances that exhibited quick- and slow-acting effects on female sexual receptivity. Here, we examined the differences in the effects of both substances on female sexual receptivity between strains with high and low remating frequencies. We found that the female response to the quick-acting substances differed. Moreover, not only female response to the slow-acting substances but also the male effect of these substances differed between strains. In remating experiments, a difference in female response to mating was found, but no difference was found in the effect of males between strains. Thus, male sexual receptivityinhibiting substances are one of the reasons for the difference in female remating frequency between the 2 strains. Next, the relationship between the effect of male substances on female sexual receptivity and female remating frequency was examined among multiple strains. Correlations between the effect of mating and male substances were found for both molecular weight classes of male substances. These results suggest that both female response to male substances and the effect of male receptivityinhibiting substances reflect variations in female remating frequency among strains. Key words: coevolution, female choice, female remating, receptivity-inhibiting substance, seminal fluids, sperm competition. [Behav Ecol]

Bolder, older, and selective: factors of individual-specific foraging behaviors in Steller’s jays

Several species of animals, particularly corvids, will sample from a collection of items before making a decision. There is an expected trade-off between investing effort in making better choices and increased exposure to risk. Little is known about individuals’ consistency in sampling behavior and whether it covaries with other behavior traits. Risk-taking and neophobia are documented components of behavioral syndromes; we examined whether sampling behavior is comparable. We quantified food sampling behavior (i.e., number of items sampled, visit duration, and number of items taken) of individual Steller’s jays (Cyanocitta stelleri) during experimental field trials. Sampling behavior of individual jays was moderately repeatable within and between winter field seasons and was positively correlated with birds’ willingness to approach a novel object and take food in front of a predator mount. These results suggest that food sampling is a measurable component in the suite of traits comprising the Steller’s jay behavioral syndrome. Model selection techniques indicated that sampling behavior was more common in older, neophilic, risk-prone, larger jays, whereas jays that took multiple items were more likely to be older and risk-prone. This suggests that experience and size may additionally influence individuals’ habitual foraging behaviors. Key words: behavioral syndrome, Cyanocitta stelleri, foraging, neophobia, risk-taking, sampling, Steller’s jay. [Behav Ecol]

Lack of floral constancy by bee fly pollinators: implications for ethological isolation in an African daisy

Although divergent floral preferences of pollinating species is a likely mechanism maintaining integrity of co-occurring floral ecotypes or incipient species, reproductive isolation of floral morphs could also result from temporary floral constancy of shared pollinators. Context-dependent floral preferences have been demonstrated for many pollinating insects, suggesting that this behavior might be widespread. However, it is not yet known whether 2 plant species or morphotypes that share a single pollinator could be reproductively isolated through assortative visitation. We investigated the foraging behavior of the bee fly, Megapalpus capensis, in experimental arrays of distinct floral morphotypes of Gorteria diffusa, a South African daisy which is pollinated almost exclusively by M. capensis. Flies exhibited no intrinsic or context-dependent (according to prevailing morph) preference for floral variants nor do they display floral constancy behavior during visitation bouts. Thus, pollinator isolation through assortative visitation is an unlikely explanation for the maintenance of floral integrity across the narrow contact zones encountered in Gorteria. Despite random visitation patterns on arrays, flies exhibited different behaviors on different floral morphotypes, suggesting intrinsic responses to morphotype-specific floral cues. Our findings suggest that results of previous studies demonstrating labile preferences and constancy in insects such as bees and butterflies cannot necessarily be extrapolated to other important groups of pollinators. In pollinators, such as Megapalpus, which use flowers as arenas for multiple behaviors, including mating, and feed during long stationary bouts, learning constraints on flower handling time, the most widely accepted explanation for floral constancy, is unlikely to drive constant foraging behavior. Key words: assortative mating, Bombyliidae, floral constancy, Gorteria diffusa, pollination, reproductive isolation, South Africa, species integrity. [Behav Ecol]

How dancing honey bees keep track of changes: the role of inspector bees

How do honey bees track changes in their foraging environment? Previously, 2 complementary mechanisms have been identified by which bees can effectively switch between food sources when their relative quality changes. First, an increase in profitability of a food source elicits an increase in waggle dances (the bees’ recruitment mechanism) for that source. Second, bees that have retired from foraging at a food source make occasional inspection visits to that food source and resume foraging if its quality improves. Here, we investigate, using both field experiments and a mathematical model, the relative importance of these 2 mechanisms. By manipulating dance information available to the bees, we find that when food sources change quality frequently, inspector bees provide a rapid response to changes, whereas the waggle dance contributes to a response over a longer time period. The bees’ ability to switch feeders without dance language information was found to be robust with respect to the spatial configuration of the feeders. Our results show that individual memory, in the form of inspector bees, and collective communication can interact to allow an insect colony to adapt to changes on both short and long timescales. Key words: Apis mellifera, collective memory, dynamic environment, foraging, honey bee, mathematical modeling. [Behav Ecol]

Mate loss affects survival but not breeding in black brant geese

For birds maintaining long-term monogamous relationships, mate loss might be expected to reduce fitness, either through reduced survival or reduced future reproductive investment. We used harvest of male brant during regular sport hunting seasons as an experimental removal to examine effects of mate loss on fitness of female black brant (Branta bernicla nigricans; hereafter brant). We used the Barker model in program MARK to examine effects of mate loss on annual survival, reporting rate, and permanent emigration. Survival rates decreased from 0.847 6 0.004 for females who did not lose their mates to 0.690 6 0.072 for birds who lost mates. Seber ring reporting rate for females that lost their mates were 2 times higher than those that did not lose mates, 0.12 6 0.086 and 0.06 6 0.006, respectively, indicating that mate loss increased vulnerability to harvest and possibly other forms of predation. We found little support for effects of mate loss on fidelity to breeding site and consequently on breeding. Our results indicate substantial fitness costs to females associated with mate loss, but that females who survived and were able to form new pair bonds may have been higher quality than the average female in the population. Key words: black brant, breeding propensity, clutch size, mate loss, nest initiation date. [Behav Ecol]

Energetically optimal foraging strategy is emergent property of time-keeping behavior in honey bees

Forager honey bees exhibit a robust time memory, based on an endogenous circadian clock, enabling them to schedule their flights to coincide with the nectar presentation of known food sources. They retain this time memory for several consecutive days even in the absence of nectar rewards. Recent work has identified 2 classes of forager: ‘‘persistent’’ foragers that reconnoiter a known food source to ascertain its status and ‘‘reticent’’ foragers that apparently wait in the hive for a waggle dance confirming source availability. Surprisingly, a foraging group contains 40‐90% persistent foragers, depending on experience at the source. What is the benefit in sending so many foragers to investigate a source when only a few foragers are required to reactivate the entire group? We used an agent-based software model to test the energetics underlying several different ratios of persistent and reticent individuals in the foraging group while varying 6 ecological factors: forager group size, source distance, source sucrose concentration, source availability in hours, number of days the source is known to the colony, and the rate at which new unemployed foragers appear on the dance floor. Our model demonstrates 2 primary explanations. First, a large number of persistent foragers are needed to ensure that at least some foragers will reconnoiter their source early in its availability, thus enabling the group to effectively exploit the source. Second, the cost of a reconnaissance flight is negligible compared with even a single successful foraging trip. Key words: agent-based model, circadian rhythms, food-anticipatory activity, foraging, honey bees, time memory. [Behav Ecol]

Tonic immobility is a measure of boldness toward predators: an application of Bayesian structural equation modeling

Animals attacked by predators often enter a state of tonic immobility (TI) in which individuals appear to simulate death. Despite the fact that TI is often used as a proxy of fear in domesticated animals, quantitative data on individual variation is very scarce for wild vertebrates. As a consequence, we lack ecological interpretations for the variability in TI that may exist in wild populations. Here, we tested whether there are consistent differences among individuals in 2 components of TI within wild populations of 2 avian species, the Yellow-crowned bishop (Euplectes afer) and the Tree sparrow (Passer montanus). We next tested whether this variation reflects variation in boldness toward predators (measured as the response to 2 predator models) or is simply related to variation in general activity/restlessness (measured as baseline activity) in the bishop. We analyzed our data by means of Bayesian structural equation modeling (SEM), which has several general advantages and, moreover, allowed us to analyze censored (truncated) data. We found good support for relatively high repeatability within individuals of both components of TI. Measures of TI appeared to be uncorrelated with baseline activity. In contrast, our results suggest that individual variation in TI in a wild vertebrate can be interpreted in a context of boldness toward predators, making TI a meaningful and practical behavioral trait for studies involving personality and antipredation behavior in wild populations. In addition, we show that the Bayesian structural equation modeling approach to analyze censored data had greater statistical power than other approaches. Hence, this rarely implemented technique deserves to be more widely used. Key words: activity, animal personality, antipredation behavior, Bayesian structural equation modeling, boldness, fear, repeatability, tonic immobility. [Behav Ecol]

Resource limitation moderates the adaptive suppression of subordinate breeding in a cooperatively breeding mongoose

Social animal species show considerable variation in the way in which reproduction is distributed among group members. Recent attempts to explain this variation have proposed that differences in reproductive skew are attributable to differences in the net benefits group members receive from suppressing each other’s breeding attempts. Despite receiving relatively little theoretical and empirical attention, the availability of resources required for successful breeding may have an important influence in determining the costs and benefits of suppressing reproduction and thus influence reproductive skew within social groups. Here, we test this possibility using a long-term study of female reproductive success in the banded mongoose Mungos mungo .W e find that females experience greater costs of co-breeding when resources are in short supply and that older, more dominant females respond to this cost by suppressing subordinate breeding. This results in differing patterns of reproductive success for females of different competitive abilities, with the oldest, most dominant females breeding regardless of resource availability and younger, subordinate females breeding only when resources are abundant. Our findings highlight the role of resource limitation in determining the distribution of reproductive opportunities within social groups. Key words: cooperative breeding, dominance, rainfall, reproductive conflict, resource availability, suppression. [Behav Ecol]

Male greater sac-winged bats gain direct fitness benefits when roosting in multimale colonies

Social groups that are characterized by the presence of male kin are rare in mammals. Theory predicts that males reproducing in such groups need to overcome the costs of local mate competition, which are supposedly severe in polygynous or promiscuous mating systems. Here, we studied in a polygynous mammal with male philopatry whether male group size renders direct fitness benefits for males that could outweigh the costs of competing with related males for access to territories and mates. We used long-term behavioral observations and genetic data of the greater sac-winged bat to investigate the factors affecting lifetime breeding success (LBS) of harem males living in colonies that contain varying numbers of male residents. We show that tenure of harem males increased with the number of male coresidents and that harem male tenure explained a large proportion of variation in their LBS. Thus, our results provide evidence that males gain direct fitness benefits from a social organization in colonies that include additional harem territories and nonharem males. Immigration of males into colonies was significantly lower when nonharem males (young males that are often related to harem males) were permanently present in colonies, suggesting that larger male groups may be better able to maintain a patriline in a colony and thus also ensure future indirect fitness benefits. Key words: female-biased dispersal, lifetime breeding success, male tenure, Saccopteryx bilineata, social organization. [Behav Ecol]

Foraging guild influences dependence on heterospecific alarm calls in Amazonian bird flocks

Interspecific eavesdropping on alarm calling has been considered evidence that species participating in mixed-species groups benefit from reduced risk of predation. Few studies, however, have examined interspecific variation in dependence on and ability to evaluate alarm signals in mixed-species groups. We conducted a playback experiment to evaluate how species in different foraging guilds varied in their response to alarm calls of birds that lead Amazonian mixed-species flocks in both upland and inundated forests. We predicted that species that search nearby substrates myopically would react more strongly to alarm calls (i.e., take longer to resume foraging) than flycatching species that search for insects at a greater distance from a perch. We used likelihood functions to model the latency response to resume foraging for both upland and inundated forests samples, and we were able to detect significant differences among different foraging guilds. Our results indicate that flycatching birds respond weakest in both forest types, but contrary to our predictions, live-leaf gleaners showed a stronger response to alarms than deadleaf‐gleaning insectivores in inundated forest and no difference in upland forest. These results suggest that foraging guild may underlie different levels of dependence on public versus private information and, thus, the dependence of different species on heterospecific informants. These different levels of dependence on alarm calls provide a potential mechanistic basis for understanding assembly rules of flocks. Key words: alarm calls, communities, foraging ecology, mixed-species flocks, public information, threat evaluation. [Behav Ecol]