scholarly journals Body condition and pregnancy in northern Yellowstone elk: Evidence for predation risk effects?

2011 ◽  
Vol 21 (1) ◽  
pp. 3-8 ◽  
Author(s):  
P. J. White ◽  
Robert A. Garrott ◽  
Kenneth L. Hamlin ◽  
Rachel C. Cook ◽  
John G. Cook ◽  
...  
Keyword(s):  
Predation Risk ◽  
Body Condition ◽  
Risk Effects

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

Food supplementation and predation risk in harsh climate: interactive effects on abundance and body condition of tit species

Oikos ◽  
2016 ◽  
Vol 126 (6) ◽  
pp. 863-873 ◽  
Author(s):  
Chiara Morosinotto ◽  
Alexandre Villers ◽  
Rauno Varjonen ◽  
Erkki Korpimäki
Keyword(s):  
Predation Risk ◽  
Body Condition ◽  
Interactive Effects ◽  
Food Supplementation ◽  
Harsh Climate

Comfort over safety: thermoregulation overshadows predation risk effects in the activity of a keystone prey

2021 ◽  
Author(s):  
M. Rocha ◽  
A. Serronha ◽  
M. Rodrigues ◽  
P. C. Alves ◽  
P. Monterroso
Keyword(s):  
Predation Risk ◽  
Risk Effects

scholarly journals Herbivore release through cascading risk effects

2009 ◽  
Vol 5 (6) ◽  
pp. 773-776 ◽  
Author(s):  
Martin H. Schmidt-Entling ◽  
Eva Siegenthaler
Keyword(s):  
Field Experiment ◽  
Predation Risk ◽  
Top Down ◽  
Wolf Spiders ◽  
Risk Effects ◽  
Mediated Effects ◽  
Top Predators ◽  
Inverse Pattern

Predators influence prey through consumption, and through trait-mediated effects such as emigration in response to predation risk (risk effects). We studied top-down effects of (sub-) adult wolf spiders (Lycosidae) on arthropods in a meadow. We compared risk effects with the overall top-down effect (including consumption) by gluing the chelicers of wolf spiders to prevent them from killing the prey. In a field experiment, we created three treatments that included either: (i) intact (‘predation’) wolf spiders; (ii) wolf spiders with glued chelicers (‘risk spiders’); or (iii) no (sub-) adult wolf spiders. Young wolf spiders were reduced by their (sub-) adult congeners. Densities of sheetweb spiders (Linyphiidae), a known intraguild prey of wolf spiders, were equally reduced by the presence of risk and predation wolf spiders. Plant- and leafhoppers (Auchenorrhyncha) showed the inverse pattern of higher densities in the presence of both risk and predation wolf spiders. We conclude that (sub-) adult wolf spiders acted as top predators, which reduced densities of intermediate predators and thereby enhanced herbivores. Complementary to earlier studies that found trait-mediated herbivore suppression, our results demonstrate that herbivores can be enhanced through cascading risk effects by top predators.

Does body condition affect fecundity in a cyclic population of snowshoe hares?

1999 ◽  
Vol 77 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Karen E Hodges ◽  
Carol I Stefan ◽  
Elizabeth A Gillis
Keyword(s):  
Predation Risk ◽  
Body Condition ◽  
Age Structure ◽  
Lepus Americanus ◽  
Decline Phase ◽  
Skeletal Size ◽  
Nutritional Deficit ◽  
Snowshoe Hares ◽  
Cyclic Changes ◽  
Cyclic Fluctuation

Snowshoe hares (Lepus americanus) undergo a 10-year cycle in abundance, with cyclic changes in reproduction occurring 3 years prior to numeric changes. Reproduction may be associated with body condition, which might change with nutrition or predation pressure. We describe hare body condition (as a mass - skeletal size relationship) through a cycle in the southern Yukon from 1989 to 1996, test the effects of food and predation risk on body condition, and examine whether changes in body condition are related to cyclic reproductive changes. Hare body condition was lowest during the decline phase but rapidly improved during the low phase. Although yearling hares were in poorer condition than adults, changes in age structure cannot explain the cyclic fluctuation in condition. Food addition and predator reduction both resulted in better body condition. Body condition did not affect reproduction. The highest natality occurred when hares were in intermediate condition, while the lowest natality occurred when hares were in the best condition. Although changes in food and predation risk affect hare body condition, we found no relationship between body condition and cyclic reproductive changes. Rather, during times of nutritional deficit, female hares may maintain mass during gestation and lactation, but at a proximate cost to their offspring. Thus, inferences based on indices of condition incorporating body mass may be misleading.

scholarly journals Predation risk effects on fitness related measures in a resident bird

Oikos ◽  
2006 ◽  
Vol 113 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Robert L. Thomson ◽  
Jukka T. Forsman ◽  
Mikko Mönkkönen ◽  
Markku Hukkanen ◽  
Kari Koivula ◽  
...  
Keyword(s):  
Predation Risk ◽  
Risk Effects ◽  
Resident Bird

Habitat deterioration affects antipredatory behavior, body condition, and parasite load of female Psammodromus algirus lizards

2007 ◽  
Vol 85 (6) ◽  
pp. 743-751 ◽  
Author(s):  
Luisa Amo ◽  
Pilar López ◽  
José Martín
Keyword(s):  
Predation Risk ◽  
Body Condition ◽  
Relative Abundance ◽  
Microhabitat Use ◽  
Health State ◽  
Habitat Deterioration ◽  
Antipredatory Behavior ◽  
Risk Of Predation ◽  
Psammodromus Algirus

Deforestation may increase predation risk for prey because it may make prey more conspicuous and limit the number of refuges suitable to avoid predators. Therefore, prey may need to increase the magnitude of escape responses. However, excessive antipredatory effort might lead to a loss of body mass and a decrease in defense against parasites, with important consequences for short- and long-term fitness. We analyzed whether Psammodromus algirus (L., 1758) lizards that inhabit patches with different levels of deterioration of the vegetation within the same oak forest differed in relative abundance numbers, microhabitat use, antipredatory strategies, and health state. Results showed lizards selected similar microhabitats regardless of the level of deterioration of the vegetation and relative abundance of lizards was similar in both areas. However, habitat deterioration seemed to increase predation risk, at least for females, because they were detected at longer distances in deteriorated areas. Females seemed to adjust their antipredatory behavior accordingly to high risk of predation by increasing approach distances allowed to predators. The costs associated with frequent antipredatory displays might explain why females in deteriorated habitats had lower body condition and greater blood parasite loads than females in natural areas. This loss of body condition and increased parasitemia might have deleterious consequences for female fitness and therefore affect the maintenance of lizard populations in the long-term.

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