Effects of reproduction on activity and foraging behaviour of adult female Columbian ground squirrels

Macwhirter, R. Bruce

doi:10.1139/z91-308

Cited by 43 publications

(28 citation statements)

References 34 publications

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“…The present study concentrated on economic and orientation issues. Tests employing empirical manipulations with predator models and comparative analyses of rodent species with different degrees of risk of predation in the wild would provide specific information on the extent to which predation risk has shaped path following behavior (see, e.g., Cassini, 1991;MacWhirter, 1991).…”

Section: Paths and Landmarks 83mentioning

confidence: 99%

The influence of artificial paths and landmarks on the foraging behavior of Norway rats (Rattus norvegicus)

Roche

Timberlake

1998

Animal Learning & Behavior

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In two experiments, we explored how the foraging behavior of Norway rats was influenced by different arrangements of artificial paths and vertical landmarks, The rats used the paths successively less for orienting to food in treatments in which paths led to food but were crooked, in which paths led only halfway to food, and in which paths were misaligned with respect to food. The arrangement of paths influenced the rats' rate of energy intake in the beginning of the experiment, whereas the arrangement of beacons did not. With experience, the rats employed different orientation strategies in the presence of different arrangements of paths or beacons, and, by the final 4 days, all groups achieved statistically indistinguishable net rates of return. The rates of energy intake were similar because the rats in different treatments traveled similar distances per session, despite differing arrangements of paths and landmarks.

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Section: Paths and Landmarks 83mentioning

confidence: 99%

The influence of artificial paths and landmarks on the foraging behavior of Norway rats (Rattus norvegicus)

Roche

Timberlake

1998

Animal Learning & Behavior

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“…longer than those with lower energetic needs when foraging on the same type of vegetation or in similar habitats (Bunnell and Gillingham 1985;Shipley et al 1994Shipley et al , 1999. Females with young often increase forage intake by spending more time foraging than non-lactating females (Clutton-Brock et al 1982;MacWhirter 1991;Komers et al 1993;Ruckstuhl and Festa-Bianchet 1998). At a finer scale, however, nutrient intake is controlled by the consumption rate achieved while foraging as well as by digestive capacities and excretion rates.…”

Section: Introductionmentioning

confidence: 99%

Foraging decisions in a capital breeder: trade-offs between mass gain and lactation

Hamel

Côté

2009

Oecologia

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The high energetic costs of lactation can lead to fundamental trade-offs in life-history traits, particularly in young females that reproduce before completing body growth. We assessed whether lactating female mountain goats (Oreamnos americanus) used behavioural tactics at fine spatio-temporal scales to increase energy intake to compensate for the costs of lactation. Lactating females increased bite rate and chewing rate compared with non-lactating females, but selected similar foraging sites in terms of plant quality and abundance. At peak lactation, forage intake of lactating females was >40% greater than that of non-lactating females. For females that had reached asymptotic body mass (i.e. > or =6 years old), summer mass gain of lactating females was similar to that of non-lactating females. At 4 and 5 years of age, however, daily mass gain of lactating females was about 20% lower than that of non-lactating females. We conclude that increased foraging may allow fully-grown lactating females to compensate for the energetic costs of lactation, but that there is a major trade-off between mass gain and lactation for younger females.

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“…Trade-offs between predation risk and foraging have been shown to exist in Belding's ground squirrels (Spermophilus beldingi), where well-fed animals showed more vigilance than deprived individuals (Bachman 1993). Lactating female hoary marmots (Marmota caligata) and Columbian ground squirrels fed farther from escape burrows and showed less vigilance than nonlactating females, presumably because of higher energy needs (Barash 1980;MacWhirter 1991). This likely leads to higher mortality through predation as well as the lower survival rate resulting from an inferior body condition.…”

Section: Introductionmentioning

confidence: 99%

Mortality in relation to season, age, sex, and reproduction in Columbian ground squirrels (Spermophilus columbianus)

Neuhaus¹,

Pelletier²

2001

Can. J. Zool.

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Abstract:We investigated the timing of and age at mortality in Columbian ground squirrels (Spermophilus columbianus) in relation to sex and reproductive status. Life-history data were collected from 1994 to 1999 in the foothills of the Rocky Mountains, Alberta, Canada. We predicted increased mortality for males during mating and for females during lactation. Further, we expected reproductively successful females to have higher mortality than females that did not reproduce successfully. Finally we assumed that at some age reproductive success of females would decrease and mortality increase because of old age. For both sexes, survival over winter was high (ca. 90%) for adults. While there was a significant increase in mortality of adult males during the mating season, females did not have higher mortality during lactation than during the rest of the active season. Reproductive status influenced mortality in females: non-reproducing females had a higher chance of surviving than reproducing females. Females that weaned young were more likely to die after the weaning period than females that lost their litter during lactation. There was a positive correlation between maternal survival and survival of offspring to yearling age. Our results showed evidence of trade-offs between reproduction and survival of male and female Columbian ground squirrels.Résumé : Nous avons étudié la phénologie de la mortalité et déterminé l'âge au décès chez le Spermophile du Columbia (Spermophilus columbianus) en fonction du sexe et du statut reproducteur à partir de données démograph-iques recueillies de 1994 à 1999 sur les contreforts des Rocheuses en Alberta, Canada. Nous avons posé en hypothèse que la mortalité augmenterait chez les mâles au cours de la période des accouplements et chez les femelles durant l'allaitement et que les femelles qui réussiraient leur reproduction auraient une mortalité plus forte que les femelles qui la rateraient. Enfin, nous nous attendions à un déclin de la reproduction chez les femelles à partir d'un certain âge et à une augmentation de la mortalité due à la vieillesse. Chez les adultes mâles et femelles, la survie en hiver est élevée (ca. 90 %). Il se produit une augmentation significative de la mortalité des mâles pendant la saison des accouplements, mais les femelles n'ont pas un taux de mortalité plus élevé durant l'allaitement que pendant le reste de la saison d'activité. Le statut reproducteur influence la mortalité chez les femelles : en effet, les femelles non reproductrices ont de meilleures chances de survie que les femelles reproductrices. La probabilité de mourir est plus forte chez les femelles qui gardent leurs petits jusqu'au sevrage que chez celles qui perdent leur portée pendant l'allaitement. Il y a une corrélation positive entre la survie des femelles et la survie des jeunes au cours de la première année. Nos résultats indiquent qu'il s'établit des compromis entre la reproduction et la survie chez les mâles et les femelles du Spermophile du Columbia.[Traduit par la Rédaction] 470Neuha...

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Effects of reproduction on activity and foraging behaviour of adult female Columbian ground squirrels

Cited by 43 publications

References 34 publications

The influence of artificial paths and landmarks on the foraging behavior of Norway rats (Rattus norvegicus)

The influence of artificial paths and landmarks on the foraging behavior of Norway rats (Rattus norvegicus)

Foraging decisions in a capital breeder: trade-offs between mass gain and lactation

Mortality in relation to season, age, sex, and reproduction in Columbian ground squirrels (Spermophilus columbianus)

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