Innate immunity and environmental correlates of<i>Haemoproteus</i>prevalence and intensity in an opportunistic breeder

Schultz, Elizabeth; Cornelius, Jamie M.; Reichard, Dustin G.; Klasing, Kirk C.; Hahn, Thomas P.

doi:10.1017/s0031182018000161

Cited by 5 publications

(7 citation statements)

References 68 publications

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“…Previous studies have found that elevated nest temperatures can have a negative or a positive effect on parasite fitness (Castano-Vazquez et al, 2021, Dube et al, 2018). Variation in parasite intensity across years and in response to environmental factors has also been recorded in other studies (Musgrave et al, 2019, Merino & Potti, 1996, Schultz et al, 2018). In our study, heat treatment increased nest temperatures by about 10°C, creating an environment of 35-45°C in heated nests.…”

Section: Discussionsupporting

confidence: 76%

Elevated nest temperature has opposing effects on host species infested with parasitic nest flies

Albert

Rumschlag

Parker

et al. 2021

Preprint

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Hosts have developed or evolved defense strategies, including tolerance and resistance, to reduce damage caused by parasites. Environmental factors, such as elevated temperature, can influence the effectiveness of these different host defenses but also can directly affect parasite fitness. Therefore, the net effect of elevated temperature on host-parasite relationships are determined by its direct effects on the host and the parasite. Furthermore, because host species can defend themselves differently against their parasites, the net effect of temperature might differ across each hosts interaction with the same parasite. Few studies have determined the net effects of temperature on both host defenses and parasites in a multi-host system. To address this gap, we experimentally manipulated temperature and parasite presence in the nests of two host species who defend themselves differently to the same parasitic nest fly (Protocalliphora sialia). Specifically, we conducted a factorial experiment by increasing temperature (or not) and removing all parasitic nest flies (or not) in the nests of tolerant eastern bluebirds (Sialia sialis) and resistant tree swallows (Tachycineta bicolor). We then quantified parasite load in nests and measured nestling body size metrics, blood loss, and survival. If temperature predominately affected parasite fitness, then elevated temperature would cause similar directional effects on parasite abundance across species. If temperature has different effects on hosts, then parasite abundance would differ in response to elevated temperature across host species. In contrast to previous years, we found that bluebird nests had half as many parasites as compared to swallow nests. Elevated temperature affected parasite abundance differently in each host species. Swallows from heated nests had fewer parasites compared to non-heated nests, suggesting that they were more resistant to the parasites. Interestingly, swallows from heated nests were also more tolerant to the effects of parasites than controls. In contrast, bluebirds from heated nests had more parasites and lower body mass compared to controls, suggesting that they lost tolerance, and resistance, to the parasites. Our results suggest that a changing climate could have complex net effects on host-parasite interactions, including on host defenses, with implications for host health and parasite survival.

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Section: Discussionsupporting

confidence: 76%

Elevated nest temperature has opposing effects on host species infested with parasitic nest flies

Albert

Rumschlag

Parker

et al. 2021

Preprint

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“…Alternatively, this overall increase in immune investment could be linked to a higher probability of disease and infection during the summer months, when Tdiff was overall higher. For example, red crossbills have higher Haemoproteus infections in the late spring and summer than other times of year [43, 71], and this was significantly related to total leukocyte counts [43].…”

Section: Discussionmentioning

confidence: 99%

“…Sample sizes per year and season appear in Table S1. A “cone year” coincides with the cone development occurring between approximately June 1st of one year until the following spring when old cones are depleted or new cones start developing [43] (See below).…”

Section: Methodsmentioning

confidence: 99%

Patterns of annual and seasonal immune investment in a temporal reproductive opportunist

Schultz

Gunning

Cornelius

et al. 2019

Preprint

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20Historically, investigations of how organisms' investments in immunity fluctuate in 21 response to environmental and physiological changes have focused on seasonally breeding 22 organisms that confine reproduction to seasons with mild environmental conditions and abundant 23 resources. Consequently, knowledge of how harsh environmental conditions and reproductive 24 effort may interact to shape investment in immunity remains limited. The red crossbill, Loxia 25 curvirostra, is a songbird that can breed on both short, cold and long, warm days if conifer seeds 26 are abundant. This species provides an ideal system to investigate the influence of environmental 27 fluctuations, reproductive investment, and their potential interactions on patterns of immune 28 investment. In this study, we measured inter-and intra-annual immune variation in crossbills 29 across four consecutive summers (2010)(2011)(2012)(2013) and multiple seasons within one year (summer 30 2011-spring 2012) to explore how physiological and environmental factors impact this immune 31 variation. Overall, the data suggest that immunity varies seasonally, among years, and in 32 response to environmental fluctuations in food resources, precipitation, and temperature, but less 33 in response to physiological measures such as reproduction. Collectively, this system 34 demonstrates that a reproductively flexible organism may breed when conditions allow 35 simultaneous investment in survival-related processes rather than at the expense of them. 36

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“…This relationship between temperature and leucocytes may be owing to a higher probability of disease and infection during the summer months. For example, red crossbills have higher Haemoproteus infections in the late spring and early summer than other times of year [45,72], and this was significantly related to leucocyte counts [45]. While PIT54 also did not exhibit significant seasonal patterns, precipitation was a significant, positive predictor.…”

Section: Discussionmentioning

confidence: 88%

Patterns of annual and seasonal immune investment in a temporal reproductive opportunist

et al. 2020

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Historically, investigations of how organismal investments in immunity fluctuate in response to environmental and physiological changes have focused on seasonally breeding organisms that confine reproduction to seasons with relatively unchallenging environmental conditions and abundant resources. The red crossbill, Loxia curvirostra , is a songbird that can breed opportunistically if conifer seeds are abundant, on both short, cold, and long, warm days, providing an ideal system to investigate environmental and reproductive effects on immunity. In this study, we measured inter- and intra-annual variation in complement, natural antibodies, PIT54 and leucocytes in crossbills across four summers (2010–2013) and multiple seasons within 1 year (summer 2011–spring 2012). Overall, we observed substantial changes in crossbill immune investment among summers, with interannual variation driven largely by food resources, while variation across multiple seasons within a single cone year was less pronounced and lacked a dominant predictor of immune investment. However, we found weak evidence that physiological processes (e.g. reproductive condition, moult) or abiotic factors (e.g. temperature, precipitation) affect immune investment. Collectively, this study suggests that a reproductively flexible organism may be able to invest in both reproduction and survival-related processes, potentially by exploiting rich patches with abundant resources. More broadly, these results emphasize the need for more longitudinal studies of trade-offs associated with immune investment.

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Innate immunity and environmental correlates ofHaemoproteusprevalence and intensity in an opportunistic breeder

Cited by 5 publications

References 68 publications

Elevated nest temperature has opposing effects on host species infested with parasitic nest flies

Elevated nest temperature has opposing effects on host species infested with parasitic nest flies

Patterns of annual and seasonal immune investment in a temporal reproductive opportunist

Patterns of annual and seasonal immune investment in a temporal reproductive opportunist

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