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Ajie, B. C., Pintor, L. M., Watters, J., Kerby, J. L., Hammond, J. I., & Sih, A. (2007). A framework for determining the fitness consequences of antipredator behavior. Behav. Ecol., 18(1), 267–270.
Abstract: Behavioral ecologists have long been interested in understanding the adaptive value of antipredator behavior (Sih 1987Go; Lima and Dill 1990Go; Lima 1998Go). A recent review by Lind and Cresswell (2005)Go, however, noted some important difficulties with quantifying the fitness consequences of antipredator behaviors. In essence, Lind and Cresswell suggest that most studies do not provide strong evidence on the adaptive value of antipredator behavior because they do not consider 1) trade-offs between antipredator and reproductive performance, 2) the abilities of organisms to avoid fitness losses associated with constraints on focal traits by employing behavioral alternatives (behavioral compensation), and 3) the effects of behavioral defenses at different stages of the predation sequence. The authors rightfully assert that an understanding of these issues can only be accomplished by measuring multiple traits and fitness components (i.e., survival and reproduction). Nevertheless, the question of how to integrate such data into
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Fischhoff, I. R., Sundaresan, S. R., Cordingley, J., & Rubenstein, D. I. (2007). Habitat use and movements of plains zebra (Equus burchelli) in response to predation danger from lions. Behav. Ecol., 18(4), 725–729.
Abstract: Prey species must adapt their behavior to avoid predation. As a key prey item for lions (Panthera leo), plains zebras (Equus burchelli) were expected to respond to immediate threats posed by lions in their area. In addition, zebras were predicted to exhibit behavior tuned to reduce the potential for encounters with lions, by modifying their movement patterns in the times of day and habitats of greatest lion danger. We studied a population of approximately 600 plains zebra living in Ol Pejeta Conservancy, Kenya. We found that zebra abundance on or near a grassland patch was lower if lions had also been observed on that patch during the same day. Predation danger was highest in grassland habitat during the night, when lions were more active. Zebra sightings and global positioning system radio collar data indicated that zebras also reduced their use of grassland at night, instead using more woodland habitat. Zebras moved faster and took sharper turns in grassland at night. It is hypothesized that these more erratic movements assist zebras in avoiding detection or capture by lions.
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Smith, B. R., & Blumstein, D. T. (2008). Fitness consequences of personality: a meta-analysis. Behav. Ecol., 19(2), 448–455.
Abstract: The study of nonhuman personality capitalizes on the fact that individuals of many species behave in predictable, variable, and quantifiable ways. Although a few empirical studies have examined the ultimate consequences of personality differences, there has been no synthesis of results. We conducted a formal meta-analysis of published studies reporting fitness consequences of single personality dimensions to identify general trends across species. We found bolder individuals had increased reproductive success, particularly in males, but incurred a survival cost, thus, supporting the hypothesis that variation in boldness was maintained due to a “trade-off” in fitness consequences across contexts. Potential mechanisms maintaining variation in exploration and aggression are not as clear. Exploration had a positive effect only on survival, whereas aggression had a positive effect on both reproductive success and, not significantly, on survival. Such results would suggest that selection is driving populations to become more explorative and aggressive. However, limitations in meta-analytic techniques preclude us from testing for the effects of fluctuating environmental conditions or other forms of selection on these dimensions. Results do, however, provide evidence for general relationships between personality and fitness, and we provide a framework for future studies to follow in the hopes of spurring more in-depth, long-term research into the evolutionary mechanisms maintaining variation in personality dimensions and overall behavioral syndromes. We conclude with a discussion on how understanding and managing personality traits may play a key role in the captive breeding and recovery programs of endangered species.
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Smith, J. E., Van Horn, R. C., Powning, K. S., Cole, A. R., Graham, K. E., Memenis, S. K., et al. (2010). Evolutionary forces favoring intragroup coalitions among spotted hyenas and other animals. Behav. Ecol., 21(2), 284–303.
Abstract: Coalitionary support in agonistic interactions represents cooperation because intervening in a fight is potentially costly to the donor of support but benefits the recipient. Here, we first review the characteristics of, and evolutionary forces favoring, intragroup coalitions in 49 species and find that patterns of intragroup coalition formation are remarkably similar between primates and nonprimates. We then test hypotheses suggesting kin selection, reciprocal altruism, and direct benefits as adaptive explanations for coalitionary interventions among adult female spotted hyenas (Crocuta crocuta) belonging to a large social group in Kenya. As predicted by kin selection theory, females supported close kin most often, and the density (connectedness) of cooperation networks increased with genetic relatedness. Nevertheless, kinship failed to protect females from coalitionary attacks. We found no evidence of enduring alliances based on reciprocal support among unrelated adult females. Instead, donors generally minimized costs to themselves, intervening most often during low-intensity fights and when feeding opportunities were unavailable. Females also gained direct benefits from directing coalitionary attacks toward subordinates. Finally, females monitored the number of dominant bystanders in the “audience” at fights and modified their level of cooperation based on this knowledge. Overall, hyenas made flexible decisions regarding whether or not to intervene in fights, modifying their tendency to cooperate based on multiple types of information about their immediate social and ecological environments. Taken together, these findings indicate that the combined evolutionary forces of kin selection and direct benefits derived from reinforcing the status quo drive coalitionary interventions among adult female spotted hyenas.
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Shultz, S., & Finlayson, L. V. (2010). Large body and small brain and group sizes are associated with predator preferences for mammalian prey. Behav. Ecol., 21(5), 1073–1079.
Abstract: Predation is a major force in shaping biological communities, both over ecological and evolutionary timescales. In response to predation pressure, prey have evolved characteristics designed to mitigate predation pressure. We evaluated predator foraging biases in relation to prey characteristics across 16 vertebrate communities. We show that although predator biases vary, some prey traits are consistently associated with predator diet composition. Within their acceptable prey size range, predators show positive bias toward larger bodied prey, small-brained prey (controlling for body size), small group size, and terrestriality. Thus, whether predator foraging decisions are passive or active, predator choice exerts differential pressure on prey species according to prey characteristics. Predator biases also were positively associated with early age at maturity, supporting the role of mortality in driving life-history characteristics. These results support several theoretical models of predation including its role as a selective force driving evolutionary changes in life history, brain size and sociality, optimal diet theory, and antiapostatic predation.
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Linklater, W. L., Cameron, E. Z., Stafford, K. J., & Veltman, C. J. (2000). Social and spatial structure and range use by Kaimanawa wild horses (Equus caballus: Equidae). New Zealand J. Ecol., 24(2), 139–152.
Abstract: We measured horse density, social structure, habitat use, home ranges and altitudinal micro-climates in the south-western Kaimanawa ranges east of Waiouru, New Zealand. Horse density in the Auahitotara ecological sector averaged 3.6 horses.km-2 and ranged from 0.9 to 5.2 horses.km-2 within different zones. The population's social structure was like that of other feral horse populations with an even adult sex ratio, year round breeding groups (bands) with stable adult membership consisting of 1 to 11 mares, 1 to 4 stallions, and their predispersal offspring, and bachelor groups with unstable membership. Bands and bachelor males were loyal to undefended home ranges with central core use areas. Band home range sizes varied positively with adult band size. Home ranges overlapped entirely with other home ranges. Horses were more likely to occupy north facing aspects, short tussock vegetation and flush zones and avoid high altitudes, southern aspects, steeper slopes, bare ground and forest remnants. Horses were more likely to be on north facing aspects, steeper slopes, in exotic and red tussock grasslands and flush zones during winter and at lower altitudes and on gentler slopes in spring and summer. Seasonal shifts by bands to river basin and stream valley floors in spring and higher altitudes in autumn and winter are attributed to the beginning of foaling and mating in spring and formation of frost inversion layers in winter. Given horse habitat selectivity and the presence of other ungulate herbivores, results from present exclosures are likely to exaggerate the size of horse impacts on range vegetation. Proposals to manage the population by relocation and confinement are likely to modify current social structure and range use behaviour and may lead to the need for more intensive management in the longer term.
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Ferrari, M. C. O., Capitania-Kwok, T., & Chivers, D. P. (2006). The role of learning in the acquisition of threat-sensitive responses to predator odours. Behav. Ecol. Sociobiol., 60(4), 522–527.
Abstract: The supposition that prey animals respond to a predator with an intensity that matches the risk posed by the predator is known as the threat-sensitive predator avoidance hypothesis. Many studies have provided support for this hypothesis; yet, few studies have attempted to determine how such abilities are acquired by prey species. In this study, we investigated whether fathead minnows (Pimephales promelas) could learn to recognize an unknown predator (northern pike, Esox lucius) in such a way that they could match the intensity of their antipredator response with the threat posed by the predator. We exposed pike-naive minnows to conspecific alarm cues paired with either a high or low concentration of pike odor. The following day, both groups were tested for a response to either high or low concentration of pike odor alone. We found that minnows conditioned with alarm cues paired with a given concentration of pike odor subsequently responded with a higher intensity to higher concentrations of pike odor, and with a lower intensity to lower concentrations of pike odor. These results demonstrate that during a single conditioning trial, minnows learn the identity of the predator in a threat-sensitive manner. Minnows use predator odor concentrations that they experience in subsequent interactions to adjust the intensity of their antipredator behavior. © Springer-Verlag 2006.
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Hofmeester, T. R., Cromsigt, J. P. G. M., Odden, J., Andrén, H., Kindberg, J., & Linnell, J. D. C. (2019). Framing pictures: A conceptual framework to identify and correct for biases in detection probability of camera traps enabling multi-species comparison. Ecol Evol, .
Abstract: Abstract Obtaining reliable species observations is of great importance in animal ecology and wildlife conservation. An increasing number of studies use camera traps (CTs) to study wildlife communities, and an increasing effort is made to make better use and reuse of the large amounts of data that are produced. It is in these circumstances that it becomes paramount to correct for the species- and study-specific variation in imperfect detection within CTs. We reviewed the literature and used our own experience to compile a list of factors that affect CT detection of animals. We did this within a conceptual framework of six distinct scales separating out the influences of (a) animal characteristics, (b) CT specifications, (c) CT set-up protocols, and (d) environmental variables. We identified 40 factors that can potentially influence the detection of animals by CTs at these six scales. Many of these factors were related to only a few overarching parameters. Most of the animal characteristics scale with body mass and diet type, and most environmental characteristics differ with season or latitude such that remote sensing products like NDVI could be used as a proxy index to capture this variation. Factors that influence detection at the microsite and camera scales are probably the most important in determining CT detection of animals. The type of study and specific research question will determine which factors should be corrected. Corrections can be done by directly adjusting the CT metric of interest or by using covariates in a statistical framework. Our conceptual framework can be used to design better CT studies and help when analyzing CT data. Furthermore, it provides an overview of which factors should be reported in CT studies to make them repeatable, comparable, and their data reusable. This should greatly improve the possibilities for global scale analyses of (reused) CT data.
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Amodio, P., Boeckle, M., Schnell, A. K., Ostojic, L., Fiorito, G., & Clayton, N. S. (2018). Grow Smart and Die Young: Why Did Cephalopods Evolve Intelligence? Trends. Ecol. Evol., .
Abstract: Intelligence in large-brained vertebrates might have evolved through independent, yet similar processes based on comparable socioecological pressures and slow life histories. This convergent evolutionary route, however, cannot explain why cephalopods developed large brains and flexible behavioural repertoires: cephalopods have fast life histories and live in simple social environments. Here, we suggest that the loss of the external shell in cephalopods (i) caused a dramatic increase in predatory pressure, which in turn prevented the emergence of slow life histories, and (ii) allowed the exploitation of novel challenging niches, thus favouring the emergence of intelligence. By highlighting convergent and divergent aspects between cephalopods and large-brained vertebrates we illustrate how the evolution of intelligence might not be constrained to a single evolutionary route.
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Baragli, P., Paoletti, E., Vitale, V., & Sighieri, C. (2011). Looking in the correct location for a hidden object: brief note about the memory of donkeys (Equus asinus). Ethology Ecology & Evolution, 23(2), 187–192.
Abstract: In recent years, considerable literature has been published on cognition in horses; however, much less is known about the cognitive abilities of domestic donkey (Equus asinus). This study aimed to expand our knowledge of donkey cognition by assessing their short-term memory capacity. We employed a detour problem combined with the classic delayed-response task, which has been extensively used to compare working memory duration in a variety of different species. A two-point choice apparatus was used to investigate location recall and search behaviour for a food target, after a short delay following its disappearance. Four donkeys completed the task with a 10 sec delay, while four others were tested with a 30 sec delay. Overall, each group performed above chance level on the test, showing that subjects had successfully encoded, maintained, and retrieved the existence and location of the target despite the loss of visual contact.
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