On the adaptive benefits of mammal migration

2014 ◽  
Vol 92 (6) ◽  
pp. 481-490 ◽  
Author(s):  
T. Avgar ◽  
G. Street ◽  
J.M. Fryxell
Keyword(s):  
Predation Risk ◽  
Cross Section ◽  
Mammal Species ◽  
Ecological Constraints ◽  
Energetic Costs ◽  
Mate Finding ◽  
Aquatic Mammal ◽  
Risk Of Predation ◽  
Evolution Of Migration ◽  
Combined Strategy

Migration is well developed among mammals, but there has been little attempt to date to review common ecological constraints that may guide the evolution of migration among mammals, nor to consider its prevalence across different taxa. Here we review several alternate hypotheses for the evolution of migration in mammals based on improvements in energetic gain and mate-finding contrasted with reduction in energetic costs or the risk of predation and parasitism. While there are well-documented examples of each across the order Mammalia, the available evidence to date most strongly supports the energy gain and predation risk hypotheses in the terrestrial realm, whereas a combined strategy of reducing energetic costs in one season but improving energetic gain in another season seems to characterize aquatic mammal species, as well as bats. We further discuss behavioral and physiological specialization and provide a taxonomic cross section of mammalian migration.

scholarly journals Basking and diurnal foraging in the dasyurid marsupial Pseudantechinus macdonnellensis

2008 ◽  
Vol 56 (2) ◽  
pp. 129 ◽  
Author(s):  
Chris R. Pavey ◽  
Fritz Geiser
Keyword(s):  
Predation Risk ◽  
Arid Zone ◽  
Activity Patterns ◽  
Active Phase ◽  
Temperature Sensitive ◽  
Body Temperatures ◽  
Mammal Species ◽  
Energetic Costs ◽  
Trade Offs

Several mammal species bask to passively rewarm during arousal from torpor, a strategy that can decrease energetic costs. Nothing is known about basking behaviour in these species or the trade-offs between energetic benefits of basking and potential costs associated with changes in activity patterns and increased predation risk. We assessed basking during winter in Pseudantechinus macdonnellensis, an Australian arid-zone marsupial that belongs to a family (Dasyuridae) that is typically nocturnal. Animals were implanted with temperature-sensitive transmitters to assess body temperatures and to assist in visually locating animals active during the day. Tagged animals regularly exhibited diurnal foraging. Foraging bouts occurred throughout the day; however, most bouts were observed within 3 h of sunset. By comparison, basking occurred much more frequently in the morning. Basking and a shift towards diurnal foraging in winter is associated with a decrease in richness and abundance of predators. P. macdonnellensis appears to compensate for the occurrence of torpor during the active phase (i.e. night) in winter by changing activity patterns such that foraging commences during what is usually the rest phase. These activity patterns are not expected to occur during the remainder of the year.

scholarly journals Silent katydid females are at higher risk of bat predation than acoustically signalling katydid males

2015 ◽  
Vol 282 (1798) ◽  
pp. 20142319 ◽  
Author(s):  
Hanumanthan Raghuram ◽  
Rittik Deb ◽  
Diptarup Nandi ◽  
Rohini Balakrishnan
Keyword(s):  
High Risk ◽  
Predation Risk ◽  
Acoustic Signals ◽  
Diet Analysis ◽  
Playback Experiments ◽  
Long Distance ◽  
Mate Finding ◽  
Risk Of Predation ◽  
Males And Females ◽  
Behavioural Experiments

Males that produce conspicuous mate attraction signals are often at high risk of predation from eavesdropping predators. Females of such species typically search for signalling males and their higher motility may also place them at risk. The relative predation risk faced by males and females in the context of mate-finding using long-distance signals has rarely been investigated. In this study, we show, using a combination of diet analysis and behavioural experiments, that katydid females, who do not produce acoustic signals, are at higher risk of predation from a major bat predator, Megaderma spasma , than calling males. Female katydids were represented in much higher numbers than males in the culled remains beneath roosts of M. spasma . Playback experiments using katydid calls revealed that male calls were approached in only about one-third of the trials overall, whereas tethered, flying katydids were always approached and attacked. Our results question the idea that necessary costs of mate-finding, including risk of predation, are higher in signalling males than in searching females.

Do changes in reef habitats influence relative predation risk on the juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875)?

Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs
Keyword(s):  
Predation Risk ◽  
Spatial Scales ◽  
Spiny Lobster ◽  
Habitat Type ◽  
Small Spatial Scale ◽  
Important Species ◽  
Early Juvenile ◽  
Risk Of Predation ◽  
Jasus Edwardsii ◽  
Commercially Important

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.

Behavioural responses of voles to simulated risk of predation by a native and an alien mustelid: an odour manipulation experiment

2010 ◽  
Vol 37 (4) ◽  
pp. 273 ◽  
Author(s):  
Karen Fey ◽  
Peter B. Banks ◽  
Hannu Ylönen ◽  
Erkki Korpimäki
Keyword(s):  
Baltic Sea ◽  
Predation Risk ◽  
Myodes Glareolus ◽  
The Baltic Sea ◽  
Short Term ◽  
Behavioural Responses ◽  
Alien Predator ◽  
Risk Of Predation ◽  
The Baltic ◽  
The Impact

Context. Potential mammalian prey commonly use the odours of their co-evolved predators to manage their risks of predation. But when the risk comes from an unknown source of predation, odours might not be perceived as dangerous, and anti-predator responses may fail, except possibly if the alien predator is of the same archetype as a native predator. Aims. In the present study we examined anti-predator behavioural responses of voles from the outer archipelagos of the Baltic Sea, south-western Finland, where they have had no resident mammalian predators in recent history. Methods. We investigated responses of field voles (Microtus agrestis) to odours of native least weasels (Mustela nivalis) and a recently invading alien predator, the American mink (Mustela vison), in laboratory. We also studied the short-term responses of free-ranging field voles and bank voles (Myodes glareolus) to simulated predation risk by alien mink on small islands in the outer archipelago of the Baltic Sea. Key results. In the laboratory, voles avoided odour cues of native weasel but not of alien mink. It is possible that the response to mink is a context dependent learned response which could not be induced in the laboratory, whereas the response to weasel is innate. In the field, however, voles reduced activity during their normal peak-activity times at night as a response to simulated alien-mink predation risk. No other shifts in space use or activity in safer microhabitats or denser vegetation were apparent. Conclusions. Voles appeared to recognise alien minks as predators from their odours in the wild. However, reduction in activity is likely to be only a short-term immediate response to mink presence, which is augmented by longer-term strategies of habitat shift. Because alien mink still strongly suppresses vole dynamics despite these anti-predator responses, we suggest that behavioural naiveté may be the primary factor in the impact of an alien predator on native prey. Implications. Prey naiveté has long been considered as the root cause of the devastating impacts of alien predators, whereby native prey simply fail to recognise and respond to the novel predation risk. Our results reveal a more complex form of naiveté whereby native prey appeared to recognise alien predators as a threat but their response is ultimately inadequate. Thus, recognition alone is unlikely to afford protection for native prey from alien-predator impacts. Thus, management strategies that, for example, train prey in recognition of novel threats must induce effective responses if they are expected to succeed.

scholarly journals Predation Risk by Gastronomic Boom - Case Peru

2018 ◽  
Vol 11 (1) ◽  
pp. 100-103
Author(s):  
Aldo Alvarez-Risco ◽  
Jaime Delgado-Zegarra ◽  
Jaime A. Yáñez ◽  
Santiago Diaz-Risco ◽  
Shyla Del-Aguila-Arcentales
Keyword(s):  
Natural Resources ◽  
Predation Risk ◽  
Environmental Sustainability ◽  
Natural Sources ◽  
Risk Of Predation ◽  
Significant Damage

Abstract The growth of tourism to Peru and the gastronomic boom with millions of people looking to taste Peruvian food is resulting in a risk of predation of natural sources necessary to make these dishes. The focus in only obtaining these ingredients can generate significant damage to the Peruvian biodiversity, so stakeholders need to develop strategies to avoid predation due to the gastronomic boom. Citizens and visitors need to play a role in protecting the natural resources and contributing to environmental sustainability.

scholarly journals Temperature alters the physiological response of spiny lobsters under predation risk

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Felipe A Briceño ◽  
Quinn P Fitzgibbon ◽  
Elias T Polymeropoulos ◽  
Iván A Hinojosa ◽  
Gretta T Pecl
Keyword(s):  
Climate Change ◽  
Predation Risk ◽  
Environmental Changes ◽  
Environmental Drivers ◽  
Climate Change Scenarios ◽  
Metabolic Rates ◽  
Energetic Costs ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Spiny Lobsters

Abstract Predation risk can strongly shape prey ecological traits, with specific anti-predator responses displayed to reduce encounters with predators. Key environmental drivers, such as temperature, can profoundly modulate prey energetic costs in ectotherms, although we currently lack knowledge of how both temperature and predation risk can challenge prey physiology and ecology. Such uncertainties in predator–prey interactions are particularly relevant for marine regions experiencing rapid environmental changes due to climate change. Using the octopus (Octopus maorum)–spiny lobster (Jasus edwardsii) interaction as a predator–prey model, we examined different metabolic traits of sub adult spiny lobsters under predation risk in combination with two thermal scenarios: ‘current’ (20°C) and ‘warming’ (23°C), based on projections of sea-surface temperature under climate change. We examined lobster standard metabolic rates to define the energetic requirements at specific temperatures. Routine metabolic rates (RMRs) within a respirometer were used as a proxy of lobster activity during night and day time, and active metabolic rates, aerobic scope and excess post-exercise oxygen consumption were used to assess the energetic costs associated with escape responses (i.e. tail-flipping) in both thermal scenarios. Lobster standard metabolic rate increased at 23°C, suggesting an elevated energetic requirement (39%) compared to 20°C. Unthreatened lobsters displayed a strong circadian pattern in RMR with higher rates during the night compared with the day, which were strongly magnified at 23°C. Once exposed to predation risk, lobsters at 20°C quickly reduced their RMR by ~29%, suggesting an immobility or ‘freezing’ response to avoid predators. Conversely, lobsters acclimated to 23°C did not display such an anti-predator response. These findings suggest that warmer temperatures may induce a change to the typical immobility predation risk response of lobsters. It is hypothesized that heightened energetic maintenance requirements at higher temperatures may act to override the normal predator-risk responses under climate-change scenarios.

Follicle Microstructure and Innervation Vary between Pinniped Micro- and Macrovibrissae

2016 ◽  
Vol 88 (1) ◽  
pp. 43-58 ◽  
Author(s):  
Erin E. Mattson ◽  
Christopher D. Marshall
Keyword(s):  
Cross Section ◽  
Hair Shaft ◽  
Silver Stain ◽  
Cross Sectional ◽  
Aquatic Mammal ◽  
Pagophilus Groenlandicus ◽  
Histological Data ◽  
The Mean ◽  
Capsule Thickness ◽  
The Relationship

Histological data from terrestrial, semiaquatic, and fully aquatic mammal vibrissa (whisker) studies indicate that follicle microstructure and innervation vary across the mystacial vibrissal array (i.e. medial microvibrissae to lateral macrovibrissae). However, comparative data are lacking, and current histological studies on pinniped vibrissae only focus on the largest ventrolateral vibrissae. Consequently, we investigated the microstructure, medial-to-lateral innervation, and morphometric trends in harp seal (Pagophilus groenlandicus) vibrissal follicle-sinus complexes (F-SCs). The F-SCs were sectioned either longitudinally or in cross-section and stained with a modified Masson's trichrome stain (microstructure) or Bodian's silver stain (innervation). All F-SCs exhibited a tripartite blood organization system. The dermal capsule thickness, the distribution of major branches of the deep vibrissal nerve, and the hair shaft design were more symmetrical in medial F-SCs, but these features became more asymmetrical as the F-SCs became more lateral. Overall, the mean axon count was 1,221 ± 422.3 axons/F-SC and mean axon counts by column ranged from 550 ± 97.4 axons/F-SC (medially, column 11) to 1,632 ± 173.2 axons/F-SC (laterally, column 2). These values indicate a total of 117,216 axons innervating the entire mystacial vibrissal array. The mean axon count of lateral F-SCs was 1,533 ± 192.9 axons/ F-SC, which is similar to values reported in the literature for other pinniped F-SCs. Our data suggest that conventional studies that only examine the largest ventrolateral vibrissae may overestimate the total innervation by ∼20%. However, our study also accounts for variation in quantification methods and shows that conventional analyses likely only overestimate innervation by ∼10%. The relationship between axon count and cross-sectional F-SC surface area was nonlinear, and axon densities were consistent across the snout. Our data indicate that harp seals exhibit microstructural and innervational differences between their microvibrissae (columns 8-11) and macrovibrissae (columns 1-7). We hypothesize that this feature is conserved among pinnipeds and may result in functional compartmentalization within their mystacial vibrissal arrays.

Developmental costs of yellow colouration in fire salamanders and experiments to test the efficiency of yellow as a warning colouration

2020 ◽  
Vol 41 (3) ◽  
pp. 373-385 ◽  
Author(s):  
Barbara A. Caspers ◽  
E. Tobias Krause ◽  
Isabelle Hermanski ◽  
Christopher Wiesbrock ◽  
Friedrich-Wilhelm Kastrup ◽  
...  
Keyword(s):  
Predation Risk ◽  
Carabid Beetles ◽  
Colour Pattern ◽  
Natural Habitats ◽  
Yellow Colour ◽  
Risk Of Predation ◽  
Fire Salamander ◽  
Food Conditions ◽  
In Fire ◽  
Salamander Larvae

Abstract Warning colouration reduces predation risk by signalling or mimicking the unpleasantness of prey and therefore increases survival. We tested in two experiments the evolutionary costs and benefits of the yellow colour pattern in fire salamanders (Salamandra salamandra), which display a yellow/black colour pattern usually associated with toxic alkaloids. Our first experiment aimed to test whether the development of colouration is condition dependent and thus related to developmental costs, i.e. influenced by resource availability during the developmental process. Therefore, we reared fire salamander larvae under different nutritional conditions and compared the relative amount of yellow they developed after metamorphosis. Fire salamander larvae reared under limited food conditions had a lower proportion of yellow following metamorphosis than control larvae reared under superior food conditions. In a second experiment we tested whether the proportion of yellow has an impact on the risk of being attacked using artificial models. We tested, in salamander-free and salamander-occupied natural habitats, whether artificial clay models with different proportions of yellow and black receive different attack rates from potential predators (birds, mammals, insects). In clay models the proportion of yellow and the site had a significant effect on predation risk. Models with larger amounts of yellow had fewer bite marks from predators such as carabid beetles and birds, but only in sympatry with salamanders. In conclusion, the early expression of conspicuous colouration seems to be condition dependent and therefore potentially costly. Furthermore, the yellow colouration of fire salamanders act as a signal that potentially reduces their risk of being attacked by predators. Thus, the yellow colouration of fire salamanders seems to represent an adaptive trait that reduces the risk of predation, which can be expressed in higher quantity by individuals of a certain condition.

SCREAMING AS A STRATEGY TO REDUCE THE PREDATION RISK INCURRED BY BEGGING?

Behaviour ◽  
2001 ◽  
Vol 138 (5) ◽  
pp. 615-627 ◽  
Author(s):  
Keyword(s):  
Predation Risk ◽  
Feeding Rate ◽  
Honest Signal ◽  
Apparent Paradox ◽  
Signalling System ◽  
Comparative Analyses ◽  
Risk Of Predation ◽  
Food Requirement ◽  
Per Se ◽  
High Degree

AbstractFollowing the theory of parent-offspring conflict parents request from their offspring an honest signal of food requirement to optimally adjust feeding rate. For this purpose, offspring display a highly informative signalling system, begging vocalisation, for which the conspicuousness to predators maintains honesty, since only hungry offspring are willing to take this risk. The risk of predation incurred by begging activities challenges our understanding of how begging vocalisation could evolve towards a high degree of noisiness. A solution to this apparent paradox resides in the possibility that alongside the evolution of begging, birds also evolved strategies that reduce the risk of being depredated. Following the ornithological literature nestlings scream in the presence of a predator to frighten it, induce parents to rescue them and siblings to flee from the nest and hide in the vegetation. I therefore propose the hypothesis that nestling screaming behaviour evolved as a means of reducing the risk of predation incurred by conspicuous begging. Comparative analyses supported the prediction postulating that species in which nestlings scream in the presence of a predator produce begging calls that are more conspicuous to predators than calls of non-screaming species. This suggests that the predation cost of begging lies not only in terms of predation per se but also in the requirement of anti-predator strategies.

scholarly journals Flirting with danger: predation risk interacts with male condition to influence sexual display

2019 ◽  
Vol 30 (5) ◽  
pp. 1265-1272
Author(s):  
Pedro Z de Moraes ◽  
Pedro Diniz ◽  
Esteban Fernandez-Juricic ◽  
Regina H Macedo
Keyword(s):  
High Risk ◽  
Predation Risk ◽  
Video Recording ◽  
Reproductive Value ◽  
Male Response ◽  
Residual Reproductive Value ◽  
Display Behavior ◽  
Sexual Display ◽  
Male Condition ◽  
Risk Of Predation

AbstractSexual signaling coevolves with the sensory systems of intended receivers; however, predators may be unintended receivers of sexual signals. Conspicuous aerial displays in some species may place males at high risk of predation from eavesdropping predators. There are three different hypotheses to explain how signaling males can deal with increased predation risk: (1) males invest in survival by decreasing signal conspicuousness; (2) males invest in reproduction by increasing signal conspicuousness; and (3) male response is condition-dependent according to his residual reproductive value. Here, we used blue-black grassquits (Volatinia jacarina) to test these hypotheses, asking whether males modify leap displays under different levels of predation risk. Grassquit males develop an iridescent nuptial plumage and spend considerable time emitting a multimodal signal: while leaping from a perch, males clap their wings above their heads and emit a high-pitched short song. We exposed males to predator and nonpredator playbacks while video recording their displays. We found interactions between predation risk and 2 male condition variables (ectoparasite infestation and proportion of nuptial plumage coverage) that influenced display behavior. Less parasitized males and those with higher proportion of nuptial plumage showed no change in display behavior, while more parasitized males and those with lower proportion of nuptial plumage increased the vigor of displays under predation risk. In other words, males with low residual reproductive value increased reproductive effort when there was a high risk of extrinsic death. Our study provides some empirical support for the terminal investment hypothesis.

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