| 1. |
- Bass, Nathan Charles, et al.
(author)
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Residency and movement patterns of adult Port Jackson sharks (Heterodontus portusjacksoni) at a breeding aggregation site
- 2021
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In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 99:4, s. 1455-1466
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Journal article (peer-reviewed)abstract
- Examining the movement ecology of mesopredators is fundamental to developing an understanding of their biology, ecology and behaviour, as well as the communities and ecosystems they influence. The limited research on the residency and movements of benthic marine mesopredators has primarily used visual tags, which do not allow for the efficient and accurate monitoring of individual space use. In this study, the authors investigated the residency and movement patterns of Port Jackson sharks Heterodontus portusjacksoni (Meyer 1793) at a breeding aggregation site in Jervis Bay, south-eastern Australia, using passive acoustic telemetry to further our understanding of the movement ecology of these important mesopredators. Between 2012 and 2014, individuals were tagged with acoustic transmitters, and their residency and movements within the bay were monitored for up to 4 years. H. portusjacksoni showed strong preferences for particular reefs within and between breeding seasons. Males had significantly higher residency indices at their favoured sites relative to females, suggesting that males may be engaging in territorial behaviour. Conversely, female H. portusjacksoni exhibited higher roaming indices relative to males indicating that females may move between sites to assess males. Finally, H. portusjacksoni showed temporal variation in movements between reefs with individuals typically visiting more reefs at night relative to the day, dusk and dawn corresponding with their nocturnal habits.
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| 2. |
- De Waele, Hannah, et al.
(author)
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Jumping out of trouble : evidence for a cognitive map in guppies (Poecilia reticulata)
- 2022
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In: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 33:6, s. 1161-1169
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Journal article (peer-reviewed)abstract
- Spatial cognitive abilities allow individuals to remember the location of resources such as food patches, predator hide-outs, or shelters. Animals typically incorporate learned spatial information or use external environmental cues to navigate their surroundings. A spectacular example of how some fishes move is through aerial jumping. For instance, fish that are trapped within isolated pools, cut off from the main body of water during dry periods, may jump over obstacles and direct their jumps to return to safe locations. However, what information such re-orientation behavior during jumping is based on remains enigmatic. Here we combine a lab and field experiment to test if guppies (Poecilia reticulata) incorporate learned spatial information and external environmental cues (visual and auditory) to determine where to jump. In a spatial memory assay we found that guppies were more likely to jump towards deeper areas, hence incorporating past spatial information to jump to safety. In a matched versus mismatched spatial cue experiment in the field, we found that animals only showed directed jumping when visual and auditory cues matched. We show that in unfamiliar entrapments guppies direct their jumps by combining visual and auditory cues, whereas in familiar entrapments they use a cognitive map. We hence conclude that jumping behavior is a goal-directed behavior, guided by different sources of information and involving important spatial cognitive skills.
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| 3. |
- Heinrich, Dennis D. U., et al.
(author)
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Effects of reward magnitude and training frequency on the learning rates and memory retention of the Port Jackson sharkHeterodontus portusjacksoni
- 2020
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In: Animal Cognition. - : Springer Science and Business Media LLC. - 1435-9448 .- 1435-9456. ; 23, s. 939-949
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Journal article (peer-reviewed)abstract
- The development of adaptive responses to novel situations via learning has been demonstrated in a wide variety of animal taxa. However, knowledge on the learning abilities of one of the oldest extant vertebrate groups, Chondrichthyes, remains limited. With the increasing interest in global wildlife tourism and shark feeding operations, it is important to understand the capacities of these animals to form associations between human activities and food. We used an operant conditioning regime with a simple spatial cognitive task to investigate the effects of reinforcement frequency and reward magnitude on the learning performance and memory retention of Port Jackson sharks (Heterodontus portusjacksoni). Twenty-four Port Jackson sharks were assigned one of four treatments differing in reward magnitude and reinforcement frequency (large magnitude-high frequency; large magnitude-low frequency; small magnitude-high frequency; small magnitude-low frequency). The sharks were trained over a 21-day period to compare the number of days that it took to learn to pass an assigned door to feed. Sharks trained at a high reinforcement frequency demonstrated faster learning rates and a higher number of passes through the correct door at the end of the trials, while reward magnitude had limited effects on learning rate. This suggests that a reduction in reinforcement frequency during tourism-related feeding operations is likely to be more effective in reducing the risk of sharks making associations with food than limiting the amount of food provided.
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| 4. |
- Vega-Trejo, Regina, et al.
(author)
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Predation impacts brain allometry in female guppies (Poecilia reticulata)
- 2022
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In: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 36:6, s. 1045-1059
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Journal article (peer-reviewed)abstract
- Cognitive and sensory abilities are vital in affecting survival under predation risk, leading to selection on brain anatomy. However, how exactly predation and brain evolution are linked has not yet been resolved, as current empirical evidence is inconclusive. This may be due to predation pressure having different effects across life stages and/or due to confounding factors in ecological comparisons of predation pressure. Here, we used adult guppies (Poecilia reticulata) to experimentally test how direct predation during adulthood would impact the relative brain size and brain anatomy of surviving individuals to examine if predators selectively remove individuals with specific brain morphology. To this end, we compared fish surviving predation to control fish, which were exposed to visual and olfactory predator cues but could not be predated on. We found that predation impacted the relative size of female brains. However, this effect was dependent on body size, as larger female survivors showed relatively larger brains, while smaller survivors showed relatively smaller brains when compared to control females. We found no differences in male relative brain size between survivors and controls, nor for any specific relative brain region sizes for either sex. Our results corroborate the important, yet complex, role of predation as an important driver of variation in brain size.
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| 5. |
- Vila Pouca, Catarina, et al.
(author)
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Early predation risk shapes adult learning and cognitive flexibility
- 2021
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 130:9, s. 1477-1486
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Journal article (peer-reviewed)abstract
- Predation risk during early ontogeny can impact developmental trajectories and permanently alter adult phenotypes. Such phenotypic plasticity often leads to adaptive changes in traits involved in anti-predator responses. While plastic changes in cognition may increase survival, it remains unclear whether early predation experience shapes cognitive investment and drives developmental plasticity in cognitive abilities. Here, we show that predation risk during early ontogeny induces developmental plasticity in two cognitive domains. We reared female guppies Poecilia reticulata with and without predator cues and tested their adult cognitive abilities. We found that females reared under simulated predation took longer to learn a simple association task, yet outperformed animals reared without predation threat in a reversal learning task testing cognitive flexibility. These results show that predation pressure during ontogeny shapes adult cognitive abilities, which we argue is likely to be adaptive. Our study highlights the important role of predator-mediated developmental plasticity on cognitive investment in natural populations and the general role of plasticity in cognitive performance.
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| 6. |
- Vila Pouca, Catarina, et al.
(author)
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Hybridization May Promote Variation in Cognitive Phenotypes in Experimental Guppy Hybrids
- 2022
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In: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 200:4, s. 607-619
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Journal article (peer-reviewed)abstract
- Hybridization is an important mechanism of evolution. While hybrids often express inferior traits and are selected against, hybridization can promote phenotypic variation and produce trait combinations distinct from the parentals, generating novel adaptive potential. Among other traits, hybridization can impact behavior and cognition and may reinforce species boundaries when hybrids show decreased cognitive abilities. However, the hypothesized role of hybridization in the diversification of cognitive phenotypes re-mains enigmatic. To test this idea, we compare the performance of female guppies (Poecilia reticulata), Endler’s guppies (Poecilia wingei), and their experimental hybrids in color association and reversal learning. In addition, we introduce a new approach to compare mul-tidimensional cognitive phenotypes. We found that hybrids showed intermediate learning abilities in both tasks compared with the pa-rentals. Moreover, hybrids had slightly higher phenotypic dispersion, new trait combinations occurred in some hybrid individuals, and the mean phenotype of one hybrid group deviated away from the axis of variation of the parentals. Our method should hence be useful in further exploring how hybridization and other evolutionary processes impact behavioral and cognitive traits. Our results suggest that hy-bridization may promote cognitive variation and generate new trait combinations, even when learning performance at the group level is intermediate between parentals.
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