The Role of Predation in Shaping the Behavior, Morphology and Community Organization of Desert Rodents

1994 ◽  
Vol 42 (4) ◽  
pp. 449 ◽  
Author(s):  
BP Kotler ◽  
JS Brown ◽  
WA Mitchell
Keyword(s):  
Great Basin ◽  
Foraging Behaviour ◽  
Species Coexistence ◽  
Community Organization ◽  
Middle Eastern ◽  
Bipedal Locomotion ◽  
Theory Approach ◽  
Community Processes ◽  
Desert Rodents ◽  
Risk Of Predation

Predation greatly influences many aspects of the ecology of desert rodents, from foraging behaviour to mechanisms of species coexistence to the evolution of specialised morphologies. Using a foraging-theory approach, we examine consequences of predation for assemblages of desert rodents from North America and the Middle East. In particular, we review experimental evidence that examines the influence of predation on foraging costs and foraging behaviour, explore how predation can act to structure communities, and discuss the role that predation may have played in the evolution of bipedal locomotion. Finally, we compare the importance of predation for the evolution of anti-predator behaviours and morphology, for population dynamics, and for community processes, with its magnitude and heterogeneity. In regard to foraging behaviour, desert rodents treat the risk of predation as a cost of foraging. They combine assessments of food and safety to arrive at foraging decisions, exploiting resource patches less intensively in response to increased predatory risk. The cost of predation can be up to 91% of the foraging costs of desert rodents, but the proportion is greater for Middle Eastern rodents than for North American rodents. In regard to community structure, predation can provide the niche axis as well as the necessary tradeoff for species coexistence. Despite the importance of predation in shaping the foraging behaviour of desert rodents, predation may not always influence species coexistence. Predation contributes to species coexistence at sites in the Sonoran and Great Basin deserts. But in the Negev Desert, where predation costs are the greatest, predation does not provide a mechanism of species coexistence. In regard to bipedal locomotion, predation most likely confers superior ability to avoid predators by improving sprint speed and ability to take evasive action, but at the expense of foraging ability in safe microhabitats. The evolution of bipedality will be favoured by situations where the risk of predation is great: the open microhabitat is riskier than the bush, the richest patches are found in the riskiest places, and rich patches are far apart. The magnitude of predatory risk will affect the evolution of anti-predator behaviour and morphologies. However, the importance of predation in community processes is not determined by its magnitude, but by its heterogeneity in time and space relative to the abilities of potentially coexisting species.

Foraging behaviour in East Asian desert rodents and its implications on coexistence

2016 ◽  
Vol 62 (3-4) ◽  
pp. 171-177 ◽  
Author(s):  
Ling-Ying Shuai ◽  
Yan-Ling Song ◽  
Burt P. Kotler ◽  
Keren Embar ◽  
Zhi-Gao Zeng
Keyword(s):  
Foraging Behaviour ◽  
Species Coexistence ◽  
Interspecific Interactions ◽  
Interference Competition ◽  
Foraging Efficiency ◽  
Gobi Desert ◽  
Patch Use ◽  
Desert Rodents ◽  
Daily Scale

We studied the foraging behaviour of two sympatric rodents (Meriones meridianus and Dipus sagitta) in the Gobi Desert, Northwestern China. The role of the foraging behaviour in promoting species coexistence was also examined. We used giving-up densities (GUDs) in artificial food patches to measure the patch use of rodents and video trapping to directly record the foraging behaviour, vigilance, and interspecific interactions. Three potential mechanisms of coexistence were evaluated (1) microhabitat partitioning; (2) spatial heterogeneity of resource abundance with a tradeoff in foraging efficiency vs. locomotion; and (3) temporal partitioning on a daily scale. Compared to M. meridianus, D. sagitta generally possessed lower GUDs, spent more time on patches, and conducted more visits per tray per capita, regardless of microhabitat. However, M. meridianus possessed advantages in average harvesting rates and direct interference against D. sagitta. Our results only partly support the third mechanism listed above. We propose another potential mechanism of coexistence: a tradeoff between interference competition and safety, with M. meridianus better at interference competition and D. sagitta better at avoiding predation risk. This mechanism is uncommon in previously studied desert rodent systems.

The glossy black-cockatoo (Calyptorhynchus lathami halmaturinus) spends little time and energy foraging on Kangaroo Island, South Australia

2005 ◽  
Vol 53 (3) ◽  
pp. 177 ◽  
Author(s):  
Tamra F. Chapman ◽  
David C. Paton
Keyword(s):  
Food Supply ◽  
Small Proportion ◽  
Foraging Behaviour ◽  
Time Budget ◽  
South Australia ◽  
Breeding Birds ◽  
Additional Energy ◽  
Allocasuarina Verticillata ◽  
Risk Of Predation ◽  
Time And Energy

The endangered Kangaroo Island glossy black-cockatoo (Calyptorhynchus lathami halmaturinus) relies entirely on the seeds of the drooping sheoak (Allocasuarina verticillata) for food. The time budget of the glossy black-cockatoos and their foraging behaviour was recorded to provide an indication of whether their food supply was likely to be limiting. The foraging behaviour of non-breeding and breeding cockatoos was also compared to record the strategy they used to collect the additional energy needed to raise young. Glossy black-cockatoos spent a relatively small proportion of their time foraging, suggesting that the food supply was abundant in the habitats used for feeding. Non-breeding birds spent only 26% of their time feeding and breeding birds spent only 36% of their time feeding. The cockatoos spent 0.4% of their time flying, foraged in a mean of only five trees per day and harvested cones in no more than five bouts per tree. This shows that the cockatoos made few movements between drooping sheoaks and within the canopy of the sheoaks when foraging. When breeding, the cockatoos spent significantly more time per day foraging, cropped cones in significantly more bouts per tree and harvested significantly more cones per tree than non-breeding birds. This shows that breeding birds increased their energy intake without greatly increasing movement between trees. The small number of movements made by glossy black-cockatoos when foraging on Kangaroo Island reflects the abundance of food trees and may be a strategy to reduce the risk of predation.

scholarly journals Possums in the park: efficient foraging under the risk of predation or of competition?

2000 ◽  
Vol 48 (2) ◽  
pp. 155 ◽  
Author(s):  
Eve McDonald-Madden ◽  
Lian K. Akers ◽  
Deena J. Brenner ◽  
Sarah Howell ◽  
Blair W. Patullo ◽  
...  
Keyword(s):  
Urban Population ◽  
Foraging Behaviour ◽  
Field Experiments ◽  
Foraging Efficiency ◽  
Trichosurus Vulpecula ◽  
Initial Amount ◽  
Trade Off ◽  
Food Items ◽  
Risk Of Predation

Many eutherian mammals adjust their foraging behaviour according to the presence or threat of predators. Here, we examine experimentally whether an urban population of brushtail possums, Trichosurus vulpecula, similarly adjust their foraging behaviour. Our field experiments manipulated the quantity of food items in artificial feeders placed at different distances from trees. These experiments showed that the possums remained longer at feeders placed far from the trees, but their foraging behaviour did not change with the initial amount of food. The scanning behaviour of possums did not simply increase with distance from the trees, as predicted from studies of other vertebrates. Nevertheless, the number of physical conflicts between individuals increased as the amount of available food decreased. These data suggest that the changes in the foraging behaviour of the possums in this population do not reflect a simple trade-off between foraging efficiency and the risk of predation or competition.

scholarly journals Effects of Iraq’s Parliamentary Gender Quota on Women’s Political Mobilization and Legitimacy Post-2003

2018 ◽  
Vol 11 (4) ◽  
pp. 41-62
Author(s):  
Huda Al-Tamimi
Keyword(s):  
Middle Eastern ◽  
Political Legitimacy ◽  
Political Mobilization ◽  
Political Agency ◽  
Gender Quotas ◽  
Theory Approach ◽  
Political Climate ◽  
And Gender ◽  
Gender Quota ◽  
The Impact

Parliamentary gender quotas have become increasingly prevalent since the 1990s, yet in-depth research illuminating their effects on women’s political agency remains scarce. Iraq’s political evolution offers a unique perspective on feminist, democratization, and gender quota scholarship as related to Middle Eastern women in politics since the US and allied invasion of Iraq in 2003. Throughout Iraq’s modern history, Iraqi women’s ability to pursue legitimate political agency has fluctuated with changes in the country’s political climate. The 2003 invasion set in motion sweeping reforms to the judicial, legislative, and executive governing powers. Women’s potential role in the emerging polity was enhanced by enactment of an electoral gender quota stipulating no less than twenty-five percent of seats in the Iraq parliament to be filled by women. This article presents research that sought to elucidate the impact of that quota on women’s political mobilization since 2003. Data collected included televised interviews, reports, and media articles that were qualitatively analyzed using a critical literary theory approach. Analysis was aided by NVivo qualitative analysis software. The findings indicate that although the gender quota has nominally increased descriptive representation, it has proven insufficient to support women’s substantive and symbolic representation. Issues of women’s socioeconomic position, lack of cooperation among female members of parliament, and ongoing security threats must be addressed for women to achieve full political legitimacy.

scholarly journals Foraging behaviour and the risk of predation in the black house spider, Badumna insignis (Desidae)

1999 ◽  
Vol 47 (1) ◽  
pp. 29 ◽  
Author(s):  
Robbie J. Henderson ◽  
Mark A. Elgar
Keyword(s):  
Foraging Behaviour ◽  
Foraging Efficiency ◽  
Foraging Success ◽  
Short Term ◽  
Risk Of Predation ◽  
House Spider ◽  
The Web ◽  
Model Predator

Many animals adjust their behaviour according to the presence or threat of predators. However, the foraging behaviour of sit-and-wait predators is typically thought to be inflexible to short-term changes in the environment. Here we investigate the foraging behaviour of the nocturnally active black house spider, Badumna insignis. Experiments in which different kinds of prey were introduced into the web during either the day or night indicated that the foraging success of Badumna is compromised by behaviours that reduce the risk of predation. During the day, spiders generally remain within the retreat and take longer to reach the prey, which may reduce their foraging success. In contrast, spiders sat exposed at the edge of the retreat at night, and from here could usually reach the prey before it escaped. The spiders were able to escape from a model predator more rapidly if they were at the edge of the retreat than if they were out on the web. These data suggest that the costs to Badumna of reduced fecundity through poor foraging efficiency may be outweighed by the benefits of reducing the risk of predation

Guilds and Community Organization: Analysis of an Oak Woodland Avifauna in Sonora, Mexico

The Auk ◽  
1980 ◽  
Vol 97 (2) ◽  
pp. 351-365 ◽  
Author(s):  
Peter B. Landres ◽  
James A. MacMahon
Keyword(s):  
Species Coexistence ◽  
Community Organization ◽  
Fold Increase ◽  
Guild Structure ◽  
Oak Woodland ◽  
Avian Community ◽  
Food Site ◽  
Organization Analysis ◽  
Over Time ◽  
Height Use

Abstract Community organization of an oak woodland breeding avifauna was studied in Sonora, Mexico. Species were classified into guilds by quantifying foraging behavior, based on investigator-defined resource classes, and subjecting these data to cluster analysis. From this analysis five guilds were recognized: foliage gleaning, wood gleaning, wood probing, air sallying, and ground sallying. Within each resource class all guilds foraged in a significantly different manner, except for air and ground salliers. Species within guilds were most often separated by food-site and perch height. Use of height classes by the avian community was significantly different from the quantity of tree vegetation per height class. Differential height utilization generally resulted from gleaning and probing guilds foraging at upper heights and sallying guilds foraging at lower heights. Ecological separation within and among guilds is discussed and related to community organization in this oak woodland avifauna. When the guild structure of this community is compared to other oak woodland avifaunas, a decrease in foliage gleaners of nearly 2.5-fold and a 6.4-fold increase in salliers occur from Oregon to Sonora, Mexico. Utility of the guild approach is discussed in relation to some prominent questions raised by results of the above comparison concerning (1) foraging plasticity in species coexistence and (2) change in community structure over time and between geographic locations.

scholarly journals Divergent Behavior Amid Convergent Evolution: A Case of Four Desert Rodents Learning to Respond to Known and Novel Vipers

2018 ◽  
Author(s):  
Sonny S. Bleicher ◽  
Burt P. Kotler ◽  
Omri Shalev ◽  
Dixon Austin ◽  
Keren Embar ◽  
...  
Keyword(s):  
Perceived Risk ◽  
Convergent Evolution ◽  
Middle Eastern ◽  
The Novel ◽  
Kangaroo Rats ◽  
Desert Rodents ◽  
Giving Up Density ◽  
Heteromyid Rodents ◽  
Divergent Behavior ◽  
Cheek Pouches

ABSTRACTDesert communities word-wide are used as natural laboratories for the study of convergent evolution, yet inferences drawn from such studies are necessarily indirect. Here, we brought desert organisms together (rodents and vipers) from two deserts (Mojave and Negev). Both predators and prey in the Mojave have adaptations that give them competitive advantage compared to their middle-eastern counterparts. Heteromyid rodents, kangaroo rats and pocket mice, have fur-lined cheek pouches that allow the rodents to carry larger loads under predation risk compared to gerbilline rodents. Sidewinder rattlesnakes have heat-sensing pits, allowing them to hunt better on moonless nights when their Negev sidewinding counterpart, the Saharan horned vipers, are visually impaired. In behavioral-assays, we used giving-up density (GUD) to gage how each species of rodent perceived risk posed by known and novel snakes. We repeated this for the same set of rodents at first encounter and again two months later following intensive “natural” exposure to both snake species. Pre-exposure, all rodents identified their evolutionarily familiar snake as a greater risk than the novel one. However, post-exposure all identified the heat-sensing sidewinder rattlesnake as a greater risk. The heteromyids were more likely to avoid encounters with, and discern the behavioral difference among, snakes than their gerbilline counterparts.

Comparison of Niche-Packing and Community Organization in Desert Rodents in Asia and North-America

1994 ◽  
Vol 42 (4) ◽  
pp. 479 ◽  
Author(s):  
GI Shenbrot ◽  
KA Rogovin ◽  
EJ Heske
Keyword(s):  
Species Diversity ◽  
North American ◽  
Chihuahuan Desert ◽  
Community Organization ◽  
Alpha Diversity ◽  
Mean Annual Precipitation ◽  
Spatial Organisation ◽  
Feeding Modes ◽  
Desert Rodents ◽  
Desert Rodent

We compared patterns of species diversity, locomotory morphology, feeding modes, and spatial organisation for rodent communities in four Asian deserts (Kyzylkum, Gobi, ?Thar, Negev) and one North American (Chihuahuan) desert. Deserts were similar in gamma and alpha diversity. A positive relationship between regional species diversity (and biomass) and mean annual precipitation was found. The Asian deserts showed a greater degree of divergence and specialisation between bipedal and quadrupedal forms. The range of feeding modes was similar in deserts on both continents, but the Negev was the only Asian desert in which granivory was as important as in the Chihuahuan. Temperate Asian desert rodents were organised into spatial guilds, separated primarily by characteristics of the soil and perennial vegetation. North American desert rodent species overlapped more extensively in habitat use. The similarities and differences between these deserts can be explained by their biogeographic histories.

scholarly journals Individual willingness to leave a safe refuge and the trade-off between food and safety: a test with social fish

2019 ◽  
Vol 286 (1907) ◽  
pp. 20190826 ◽  
Author(s):  
Jesse Balaban-Feld ◽  
William A. Mitchell ◽  
Burt P. Kotler ◽  
Sundararaj Vijayan ◽  
Lotan T. Tov Elem ◽  
...  
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Foraging Success ◽  
Group Foraging ◽  
Refuge Use ◽  
Trade Off ◽  
Individual Fish ◽  
Risk Of Predation ◽  
Group Members ◽  
The Individual

Refuges offer prey animals protection from predation, but increased time spent hiding can reduce foraging opportunities. Within social groups, individuals vary in their refuge use and willingness to forage in the presence of a predator. Here, we examine the relative foraging benefits and mortality costs associated with individual refuge use and foraging behaviour within groups of goldfish ( Carassius auratus ) under predation risk from an avian predator (little egret— Egretta garzetta ). We assessed individual order of emergence from the refuge and participation over 15 group foraging outings, and assigned each fish a daily outing index score. The individual fish that emerged from the refuge earlier than the other group members and that participated in more outings received high outing index scores and consumed more food compared with fish that tended to emerge in posterior positions and participate in fewer outings. However, individual fish that attained high outing index scores suffered a higher risk of predation. Furthermore, the amount of time the egret spent at the pool affected group foraging behaviour: as predation risk increased, groups of fish consumed significantly less food. Our results exemplify the trade-off between foraging success and safety from predation that prey species regularly experience.

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