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Immune response varies with rate of dispersal in invasive cane toads (Rhinella marina).

Brown GP, Shine R - PLoS ONE (2014)

Bottom Line: Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin.Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another.The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
What level of immunocompetence should an animal maintain while undertaking long-distance dispersal? Immune function (surveillance and response) might be down-regulated during prolonged physical exertion due to energy depletion, and/or to avoid autoimmune reactions arising from damaged tissue. On the other hand, heightened immune vigilance might be favored if the organism encounters novel pathogens as it enters novel environments. We assessed the links between immune defense and long-distance movement in a population of invasive cane toads (Rhinella marina) in Australia. Toads were radio-tracked for seven days to measure their activity levels and were then captured and subjected to a suite of immune assays. Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin. Baseline and post-stress corticosterone levels were unrelated to distance moved. Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another. This pattern suggests that sustained activity is accompanied by trade-offs among immune components rather than an overall down or up-regulation. The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

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Related in: MedlinePlus

Toad in motion.Female cane toad (Rhinella marina) bearing a 3g radio-transmitter on a bead chain belt.
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pone-0099734-g001: Toad in motion.Female cane toad (Rhinella marina) bearing a 3g radio-transmitter on a bead chain belt.

Mentions: The area experiences a wet-dry tropical climate. Maximum daily air temperatures are high (>32°C) year round but rainfall is largely restricted to the November–April wet season [42]. The present study took place between 3 January and 14 March 2013, the height of the wet season, when environmental conditions are optimal for toad activity and movement [43]. On three nights during this period, we collected toads along a 1.5-km section of dirt road. Toads were returned to the lab and on the following day were weighed, measured for body size (SUL) and sexed (based on skin rugosity and coloration and the presence of nuptial pads and a release call in males). On each of the three capture occasions, 10 toads (5 males and 5 females) were matched for body size as closely as possible, and selected for radio-tracking. The male toads ranged in body size from 89–122 mm SUL and from 92–234 g in mass. Female toads ranged in size from 93–128 mm SUL and from 93–270 g in mass. Each toad was fitted with a 3-g radio-transmitter (model PD2; Holohil Systems, Ottawa, Canada) attached to a bead chain belt (Fig. 1). Toads were released at their capture point during the evening. Over the following week, toads were located each day and their position mapped using a handheld GPS. Toads in tropical Australia are nocturnal and all movements occur at night. Radio-tracking was done during daylight hours and the toads’ locations represent their daytime refugia.


Immune response varies with rate of dispersal in invasive cane toads (Rhinella marina).

Brown GP, Shine R - PLoS ONE (2014)

Toad in motion.Female cane toad (Rhinella marina) bearing a 3g radio-transmitter on a bead chain belt.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061023&req=5

pone-0099734-g001: Toad in motion.Female cane toad (Rhinella marina) bearing a 3g radio-transmitter on a bead chain belt.
Mentions: The area experiences a wet-dry tropical climate. Maximum daily air temperatures are high (>32°C) year round but rainfall is largely restricted to the November–April wet season [42]. The present study took place between 3 January and 14 March 2013, the height of the wet season, when environmental conditions are optimal for toad activity and movement [43]. On three nights during this period, we collected toads along a 1.5-km section of dirt road. Toads were returned to the lab and on the following day were weighed, measured for body size (SUL) and sexed (based on skin rugosity and coloration and the presence of nuptial pads and a release call in males). On each of the three capture occasions, 10 toads (5 males and 5 females) were matched for body size as closely as possible, and selected for radio-tracking. The male toads ranged in body size from 89–122 mm SUL and from 92–234 g in mass. Female toads ranged in size from 93–128 mm SUL and from 93–270 g in mass. Each toad was fitted with a 3-g radio-transmitter (model PD2; Holohil Systems, Ottawa, Canada) attached to a bead chain belt (Fig. 1). Toads were released at their capture point during the evening. Over the following week, toads were located each day and their position mapped using a handheld GPS. Toads in tropical Australia are nocturnal and all movements occur at night. Radio-tracking was done during daylight hours and the toads’ locations represent their daytime refugia.

Bottom Line: Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin.Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another.The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
What level of immunocompetence should an animal maintain while undertaking long-distance dispersal? Immune function (surveillance and response) might be down-regulated during prolonged physical exertion due to energy depletion, and/or to avoid autoimmune reactions arising from damaged tissue. On the other hand, heightened immune vigilance might be favored if the organism encounters novel pathogens as it enters novel environments. We assessed the links between immune defense and long-distance movement in a population of invasive cane toads (Rhinella marina) in Australia. Toads were radio-tracked for seven days to measure their activity levels and were then captured and subjected to a suite of immune assays. Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin. Baseline and post-stress corticosterone levels were unrelated to distance moved. Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another. This pattern suggests that sustained activity is accompanied by trade-offs among immune components rather than an overall down or up-regulation. The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

Show MeSH
Related in: MedlinePlus