Does Food Availability affect Growth and Survival of Males and Females Differently in a Promiscuous Small Mammal, Tamiasciurus hudsonicus?

10.2307/5367 ◽  
1993 ◽  
Vol 62 (2) ◽  
pp. 364 ◽  
Author(s):  
Stan Boutin ◽  
Karl W. Larsen
Keyword(s):  
Food Availability ◽  
Small Mammal ◽  
Tamiasciurus Hudsonicus ◽  
Growth And Survival ◽  
Males And Females

Spring and summer time budgets and feeding behaviourof the red squirrel (Tamiasciurus hudsonicus)

1986 ◽  
Vol 64 (2) ◽  
pp. 385-391 ◽  
Author(s):  
J. Ferron ◽  
J. P. Ouellet ◽  
Y. Lemay
Keyword(s):  
Ambient Temperature ◽  
Food Availability ◽  
Time Budget ◽  
Coniferous Forest ◽  
Tamiasciurus Hudsonicus ◽  
Time Budgets ◽  
Red Squirrel ◽  
The North ◽  
Males And Females ◽  
Summer Time

The purpose of the study was to attempt to understand how feeding requirements, reproductive constraints, and fluctuating environmental conditions (specifically, ambient temperature and food availability) are integrated in the time budget of the red squirrel (Tamiasciurus hudsonicus), an arboreal sciurid of the North American coniferous forest that remains active year-round. It appears that ambient temperature and food availability have important influences on the allocation of time among different activities. Reproductive constraints apparently do not affect differently the time budgets of males and females during the spring breeding season. The analysis of food habits of the red squirrel demonstrates that the species is opportunistic and takes advantage of the continuously changing food availability during the growing season. Fluctuations in diet influence whether feeding and foraging are arboreal or terrestrial, as well as affecting the relative importance of these two activities in the time budget of the red squirrel.

scholarly journals Habitat, food, and small mammal community structure in Namaqualand

Koedoe ◽  
2006 ◽  
Vol 49 (1) ◽  
Author(s):  
M. Van Deventer ◽  
J.A.J. Nel
Keyword(s):  
Species Richness ◽  
Food Availability ◽  
Small Mammal ◽  
Plant Cover ◽  
Plant Litter ◽  
Shrub Cover ◽  
Habitat Features ◽  
Habitat Differences ◽  
Elephant Shrew ◽  
Density And Biomass

The effect of habitat differences and food availability on small mammal (rodent and elephant shrew) species richness, diversity, density and biomass was investigated in Namaqualand, South Africa. Species richness in the three habitats sampled, namely Upland Succulent Karoo, Dry Riverine Shrub and North-western Mountain Renosterveld was low, with only 2–4 species per habitat. Rodents trapped were predominantly Gerbillurus paeba and Aethomys namaquensis, with fewer Mus minutoides and Petromyscus sp. The only non-rodent was the elephant shrew Elephantulus edwardii. Ten habitat features, the percentage of total plant cover, tree cover, shrub cover, grass cover, plant litter, total basal cover, sand, gravel or rock cover, and the dominant plant height were recorded at 30 randomly chosen points on five sampling grids in each habitat. Small mammal density and biomass was significantly correlated with food availability (green foliage cover, seeds, and relative density and biomass of insects). Species richness and diversity of small mammals were significantly correlated with shrub cover. Numbers and biomass of specific species correlated significantly with different habitat features in each case.

The influence of sibling gender on the growth and survival of Great-tailed Grackle nestlings

1990 ◽  
Vol 68 (9) ◽  
pp. 1925-1930 ◽  
Author(s):  
Kevin L. Teather
Keyword(s):  
Sex Ratio ◽  
Growth Rates ◽  
Egg Mass ◽  
Hatching Date ◽  
Growth And Survival ◽  
Nestling Growth ◽  
Males And Females ◽  
Predominantly Female ◽  
Sibling Gender

Growth and survival of Great-tailed Grackle (Quiscalus mexicanus) nestlings were monitored over 3 years to determine if greater food demands of sons influenced nestling success. I predicted that (i) the growth rates of nestlings would be lower in nests containing mostly males, and (ii) the chance of all nestlings in predominantly male broods fledging would be less than that in predominantly female broods. Sibling gender and the overall sex ratio of the brood had little effect on nestling growth. There was no evidence that starvation was more frequent if the oldest nestlings were males rather than females, although there was some evidence that broods of three containing two or three males were less likely to fledge all nestlings than those containing two or three females. Mass at fledging for both males and females was influenced most strongly by hatching sequence and to a lesser extent by egg mass and hatching date.

scholarly journals Can behavioural ecology unite hypotheses for fish recruitment?

2013 ◽  
Vol 71 (4) ◽  
pp. 909-917 ◽  
Author(s):  
Christian Jørgensen ◽  
Anders Frugård Opdal ◽  
Øyvind Fiksen
Keyword(s):  
Predation Risk ◽  
Food Availability ◽  
Larval Fish ◽  
High Growth ◽  
Selective Predation ◽  
Growth And Survival ◽  
Larval Behaviour ◽  
Fish Recruitment ◽  
Trade Offs ◽  
Risk Of Predation

Abstract Since the classical works by Hjort linked the survival of early life stages of fish to year-class strength and recruitment, fisheries science has struggled to understand the fate of fish eggs and larvae. Here we discuss how food availability will influence growth and survival of larvae when foraging behaviour is flexible and involves predation risk. We use theory to show that small larval fish with a high risk of predation should nevertheless forage intensely and maintain high growth rates. The implication of this is that food availability is more important to recruitment success than is often assumed from studies of growth rate, since the main effect of low food availability appears as increased predation rates. As larvae develop and grow bigger, they are expected to tailor their behaviour to balance food intake and predation risk, which makes it more probable that environmental fluctuations will cause growth differences. A theoretical framework including larval behaviour thus illustrates how several existing hypotheses, i.e. “bigger is better”, “stage duration”, and “growth-selective predation”, emphasize different aspects of larval success but can be understood more generally and coherently when interpreted in the light of behavioural trade-offs. This may lead to more consistent consideration of larval behaviour in biophysical models of fish recruitment.

Reduced recruitment of Chinook salmon in a leveed bar-built estuary

2021 ◽  
Author(s):  
Emily K Chen ◽  
Mark J. Henderson
Keyword(s):  
Food Availability ◽  
Chinook Salmon ◽  
Stream Flow ◽  
Oncorhynchus Tshawytscha ◽  
Relative Proportion ◽  
Adult Survival ◽  
Growth And Survival ◽  
Estuary Circulation ◽  
Dynamics And Function ◽  
And Function

Estuaries are commonly touted as nurseries for salmonids, providing numerous advantages for smolts prior to ocean entry. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low stream flow, closing access to the ocean and preventing outmigration. We evaluated how summer residency in a leveed bar-built estuary affects the growth, survival, and recruitment of a Chinook salmon (Oncorhynchus tshawytscha) population. We performed a mark-recapture study on outmigrants to determine juvenile estuary abundance, growth, and survival. We used returning adult scales and otoliths to determine the relative proportion of summer estuary residents in spawning adults. Juveniles in the estuary grew less after mouth closure, and ultimately summer estuary residents had lower smolt-to-adult survival and contributed disproportionately less to the spawning population than juveniles that reared in the ocean their first summer. Mouth closure may lower food availability and deteriorate estuary conditions by reducing marine prey influx and estuary circulation. This research demonstrates the complexity of estuary dynamics and function as salmonid nurseries, particularly when considering the extensive modification of estuaries.

Juvenile growth and survival under dietary restriction: are males and females equal?

Oikos ◽  
2005 ◽  
Vol 111 (2) ◽  
pp. 368-376 ◽  
Author(s):  
J.-F. Le Galliard ◽  
R. Ferriere ◽  
J. Clobert
Keyword(s):  
Dietary Restriction ◽  
Juvenile Growth ◽  
Growth And Survival ◽  
Males And Females

scholarly journals Aggression is induced by resource limitation in the monarch caterpillar

2020 ◽  
Author(s):  
Joseph Collie ◽  
Odelvys Granela ◽  
Elizabeth Brown ◽  
Alex C. Keene
Keyword(s):  
Aggressive Behavior ◽  
Food Availability ◽  
Danaus Plexippus ◽  
Resource Limitation ◽  
Monarch Butterfly ◽  
Insect Larvae ◽  
Resource Defense ◽  
Growth And Survival ◽  
Developmental Progression ◽  
Limited Food

AbstractFood represents a limiting resource for the growth and developmental progression of many animal species. As a consequence, competition over food, space, or other resources can trigger territoriality and aggressive behavior. Throughout their early development stages, insect larvae eat voraciously and limited food availability can potently impact their viability through metamorphosis. In the monarch butterfly, Danaus plexippus, caterpillars feed predominantly on milkweed, raising the possibility that access to milkweed is critical for growth and survival. Here, we characterize the role of food availability on aggression in monarch caterpillars. We find that monarch caterpillars display stereotyped aggressive lunges that increase during development, peaking during the 4th and 5th instar stages. Detailed behavioral analysis reveals that aggressive actions are most likely to occur when the target is feeding and increases the probability that the target will leave the food source. To determine the relationship between food availability and the initiation of an aggressive encounter, we provided groups of caterpillars differing amounts of food availability and measured aggressive behavior. The number of lunges toward a conspecific caterpillar was significantly increased under conditions of low food availability, suggesting resource defense may trigger aggression. We find that aggression occurs independently of light, suggesting the visual system is dispensable for the induction of aggression. These findings establish monarch caterpillars as a model for investigating interactions between resource availability and aggressive behavior under ecologically relevant conditions and set the stage for future investigations into the neuroethology of aggression in this system.

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