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Robert L. Baker
University of Toronto
53Publications
24H-index
1,398Citations
Publications 53
Newest
#1Dorina Szuroczki (U of T: University of Toronto)H-Index: 2
#2Janet Koprivnikar (RyeU: Ryerson University)H-Index: 18
Last.Robert L. Baker (U of T: University of Toronto)H-Index: 24
view all 3 authors...
Abstract The negative effects of abiotic and biotic stressors on animal condition, physiology, behaviour, and fitness have become increasingly recognized, making it critical to understand how these may be mitigated, such as through diet. When consumed, dietary antioxidants (secondary metabolites produced by plants) provide protection from oxidative damage that can result from exposure to stressors. We examined the effects of dietary antioxidants (β-carotene and vitamin E) on the ability of Litho...
Source
#1Dorina Szuroczki (U of T: University of Toronto)H-Index: 2
#2Janet Koprivnikar (RyeU: Ryerson University)H-Index: 18
Last.Robert L. Baker (U of T: University of Toronto)H-Index: 24
view all 3 authors...
Abstract Dietary antioxidants have been shown to confer a variety of benefits through their ability to counter oxidative stress, including increased immunocompetence and reduced susceptibility to both infectious and non-infectious diseases. However, little is known about the effects of dietary antioxidants on immune function in larval amphibians, a group experiencing worldwide declines driven by factors that likely involve altered immunocompetence. We investigated the effects of dietary antioxid...
5 CitationsSource
#1Merrylee McGuffin (U of T: University of Toronto)H-Index: 6
#2Robert L. Baker (U of T: University of Toronto)H-Index: 24
Larvae of some species of damselflies respond to chemical cues of fish predators but, while larvae of many species are thought to detect prey through vision, there is little evidence that larvae respond to visual cues of predator presence. This laboratory study indicated larval Ischnura verticalis behaviours are affected by visual cues and, to a much lesser extent, chemical cues of fish; there was no significant interaction between the effects of visual and chemical cues. Responses to chemical c...
1 CitationsSource
#1Tarini Duggal (U of T: University of Toronto)
#2Robert L. Baker (U of T: University of Toronto)H-Index: 24
Last.Nicholas C. Collins (U of T: University of Toronto)H-Index: 20
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Abstract: Most experiments on effects of anti-predator behaviours use small enclosures and study behaviour and development of prey in the constant and immediate presence of predators. While useful, such studies are difficult to relate to natural situations where prey and predators are unrestricted. We describe a system designed specifically to estimate the impact of fish on foraging of larval Chironomus tentans under field levels of encounters with fish. The system involves raceways designed to ...
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#1Janet Koprivnikar (UOP: University of the Pacific (United States))H-Index: 18
#2M. R. Forbes (Carleton University)H-Index: 4
Last.Robert L. Baker (U of T: University of Toronto)H-Index: 24
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Population density and infection with parasites often are important factors affecting the growth and development of individuals. How these factors co-occur and interact in nature should have important consequences for individual fitness and higher-order phenomena, such as population dynamics of hosts and their interactions with other species. However, few studies have examined the joint effects of density and parasitism on host growth and development. We examined the co-influences of rearing den...
22 CitationsSource
#1Pamela L. Rutherford (UPR-RP: UPRRP College of Natural Sciences)H-Index: 1
#2Robert L. Baker (U of T: University of Toronto)H-Index: 24
Last.Mark R. Forbes (UPR-RP: UPRRP College of Natural Sciences)H-Index: 4
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The importance of multiple enemies from different trophic levels on investment in defence by prey has, with some exceptions, received little attention. Some defences may make the victim more susceptible to other enemies; this latter situation applies to predators and parasites of larval damselflies. Baker and Smith [Oecologia 109 (1997) 622) showed that larval damselflies were as active in the presence of both mites and fish as they were when only mites were present, an apparently maladaptive be...
7 CitationsSource
#1Janet Koprivnikar (U of T: University of Toronto)H-Index: 18
#2Robert L. Baker (U of T: University of Toronto)H-Index: 24
Last.Mark R. Forbes (U of T: University of Toronto)H-Index: 33
view all 3 authors...
Agricultural activity and landscape features have previously been associated with diversity and prevalence of trematode species in amphibian second intermediate hosts. In this study, the density, diversity, and size of snail first intermediate hosts, and the diversity and prevalence of their trematode species, were assessed in 2 types of ponds, i.e., those adjacent to cornfields and those from the same region in southwestern Ontario that were adjacent to nonagricultural settings. Species of trem...
20 CitationsSource
#1Robert L. Baker (U of T: University of Toronto)H-Index: 24
#2Merrylee McGuffin (U of T: University of Toronto)H-Index: 6
AbstractWe experimentally tested for systematic biases in techniques commonly used to study behavior of larval aquatic insects. We determined whether larval Zygoptera responded to the presence of an observer and whether live observation missed some behaviors. We found significant differences between behaviors recorded during live observations and behaviors videotaped in the absence of an observer. All behaviors, except Rotate, were exhibited less frequently in the presence of an observer. These ...
9 CitationsSource
#1Janet Koprivnikar (U of T: University of Toronto)H-Index: 18
#2Mark R. Forbes (Carleton University)H-Index: 33
Last.Robert L. Baker (U of T: University of Toronto)H-Index: 24
view all 3 authors...
41 CitationsSource
#1Janet KoprivnikarH-Index: 18
#2M. R. ForbesH-Index: 4
Last.Robert L. BakerH-Index: 24
view all 3 authors...
Many animals respond behaviourally to the infective stages of parasites, but the efficacy of such responses in reducing risk of parasitism often is not established. It was found that tadpoles of Rana clamitans Latr., 1801 (green frogs) and R. sylvatica LeConte, 1825 (wood frogs) increased their activity when exposed to live infective stages (cercariae) of the trematode Echinostoma trivolvis Rudolphi, 1809. The susceptibility to parasitism for green frog tadpoles subjected to three different trea...
51 CitationsSource
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