1
|
Tylan C, Engler HI, Villar G, Langkilde T. Consumption of fire ants, an invasive predator and prey of native lizards, may enhance immune functions needed to combat envenomation. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02939-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
2
|
MacLeod KJ, Langkilde T, Heppner JJ, Howey CAF, Sprayberry K, Tylan C, Sheriff MJ. Compensating for a stressful pregnancy? Glucocorticoid treatment during gravidity reduces metabolic rate in female fence lizards post-parturition. Horm Behav 2021; 136:105072. [PMID: 34628291 DOI: 10.1016/j.yhbeh.2021.105072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 07/26/2021] [Accepted: 09/23/2021] [Indexed: 11/23/2022]
Abstract
Reproduction is a critical part of an animal's life history, but one which incurs significant costs to survival and future reproductive potential. These physiological consequences are likely to be influenced by context - for example, if an individual is subject to environmental stressors, physiological and behavioral changes associated with reproduction may be altered. Glucocorticoids, hormones produced as part of the physiological response to stressors, may alter how reproduction affects female physiology and behavior, and therefore the outcomes of reproductive trade-offs. Glucocorticoids prioritize immediate survival over reproduction, for example through changes in immune function, metabolic rate, and foraging, which may reduce energy expenditure or increase energy gain. However, we previously found that female eastern fence lizards (Sceloporus undulatus) experiencing elevated glucocorticoid levels during gestation were nevertheless able to maintain reproductive output and body condition. Here we investigate compensatory mechanisms by which eastern fence lizard females may maintain reproduction under experimental increases in a glucocorticoid, corticosterone (CORT). We found that, although CORT-treated females had similar immune function and behavior, they had reduced metabolic rates 3-5 days post-parturition compared to control females. Given that CORT-treated females spent a similar time basking and had equal food intake compared to control females, we suggest that the reduced metabolic rate is a mechanism by which CORT-treated females maintain their energy balance and reduce the energetic costs of gestation during periods of stress. This study suggests that physiological responses to reproduction may be context-dependent and could act to minimize costs of reproduction in situations where CORT is elevated (such as during periods of environmental stress).
Collapse
Affiliation(s)
- K J MacLeod
- Department of Ecosystem Science and Management, Pennsylvania State University, Forest Resources Building, University Park, PA 16802, USA; Department of Biology, Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA; Department of Biology, Lund University, Sölvegatan 37, Lund 223 62, Sweden.
| | - T Langkilde
- Department of Biology, Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - J J Heppner
- Department of Ecosystem Science and Management, Pennsylvania State University, Forest Resources Building, University Park, PA 16802, USA; Department of Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - C A F Howey
- Department of Biology, Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA; Department of Biology, University of Scranton, Loyola Science Center, Scranton, PA 18510, USA
| | - K Sprayberry
- Department of Biology, Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - C Tylan
- Department of Biology, Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - M J Sheriff
- Department of Ecosystem Science and Management, Pennsylvania State University, Forest Resources Building, University Park, PA 16802, USA; Biology Department, University of Massachusetts Dartmouth, Dartmouth, MA 02747, USA
| |
Collapse
|
3
|
Assis BA, Avery JD, Tylan C, Engler HI, Earley RL, Langkilde T. Honest signals and sexual conflict: Female lizards carry undesirable indicators of quality. Ecol Evol 2021; 11:7647-7659. [PMID: 34188841 PMCID: PMC8216924 DOI: 10.1002/ece3.7598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/22/2022] Open
Abstract
Sex differences in animal coloration often result from sex-dependent regulatory mechanisms. Still, some species exhibit incomplete sexual dimorphism as females carry a rudimentary version of a costly male trait, leading to intralocus sexual conflict. The underlying physiology and condition dependence of these traits can inform why such conflicts remain unresolved. In eastern fence lizards (Sceloporus undulatus), blue iridophore badges are found in males and females, but melanin pigmentation underneath and surrounding badges is male-exclusive. We track color saturation and area of badges across sexual maturity, and their relationship to individual quality (body condition and immunocompetence) and relevant hormones (testosterone and corticosterone). Saturation and testosterone were positively correlated in both sexes, but hormone and trait had little overlap between males and females. Saturation was correlated with body condition and immunocompetence in males but not in females. Co-regulation by androgens may have released females from resource allocation costs of color saturation, even when in high condition. Badge area was independent of testosterone, but associated with low corticosterone in females, indicating that a nonsex hormone underlies incomplete sexual dimorphism. Given the evidence in this species for female reproductive costs associated with ornamentation, this sex-nonspecific regulation of an honest signal may underlie intralocus sexual conflict.
Collapse
Affiliation(s)
- Braulio A. Assis
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- Intercollege Graduate Degree Program in EcologyThe Pennsylvania State UniversityUniversity ParkPAUSA
| | - Julian D. Avery
- Intercollege Graduate Degree Program in EcologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- The Department of Ecosystem Science and ManagementThe Pennsylvania State UniversityUniversity ParkPAUSA
| | - Catherine Tylan
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
| | - Heather I. Engler
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
| | - Ryan L. Earley
- Department of Biological SciencesUniversity of AlabamaTuscaloosaALUSA
| | - Tracy Langkilde
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- Intercollege Graduate Degree Program in EcologyThe Pennsylvania State UniversityUniversity ParkPAUSA
| |
Collapse
|
4
|
Tylan C, Horvat-Gordon M, Bartell PA, Langkilde T. Ecoimmune reallocation in a native lizard in response to the presence of invasive, venomous fire ants in their shared environment. J Exp Zool A Ecol Integr Physiol 2020; 333:792-804. [PMID: 33038069 DOI: 10.1002/jez.2418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 09/16/2020] [Accepted: 09/19/2020] [Indexed: 01/10/2023]
Abstract
Exposure to stressors over prolonged periods can have fitness-relevant consequences, including suppression of immune function. We tested for effects of presence of an invasive species threat on a broad panel of immune functions of a coexisting lizard. Eastern fence lizards (Sceloporus undulatus) have been exposed to invasive fire ants (Solenopsis invicta) for over 80 years. Fire ants sting and envenomate lizards, causing physiological stress, but we do not have a comprehensive understanding of the broad immune consequences of lizard exposure to fire ant presence. We conducted a suite of immune measures on fence lizards caught from areas with long histories of fire ant invasion and lizards from areas not yet invaded by fire ants. The effect of fire ant presence on immunity varied depending on the immune component measured: within fire ant invaded areas, some portions of immunity were suppressed (lymphocytic cell-mediated immunity, complement), some were unaffected (phagocytic respiratory burst, natural antibodies), and some were enhanced (anti-fire ant immunoglobulin M, basophils) compared to within uninvaded areas. Rather than fire ants being broadly immunosuppressing, as generally assumed, the immune response appears to be tailored to this specific stressor: the immune measures that were enhanced are important to the lizards' ability to handle envenomation, whereas those that were unaffected or suppressed are less critical to surviving fire ant encounters. Several immune measures were suppressed in reproductive females when actively producing follicles, which may make them more susceptible to immunosuppressive costs of stressors such as interactions with fire ants.
Collapse
Affiliation(s)
- Catherine Tylan
- Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, Pennsylvania, USA
| | - Maria Horvat-Gordon
- Department of Animal Science, The Pennsylvania State University, Forest Resource Laboratory, University Park, Pennsylvania, USA
| | - Paul A Bartell
- Department of Animal Science, The Pennsylvania State University, Forest Resource Laboratory, University Park, Pennsylvania, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, Pennsylvania, USA
| |
Collapse
|
5
|
Tylan C, Camacho K, French S, Graham SP, Herr MW, Jones J, McCormick GL, O'Brien MA, Tennessen JB, Thawley CJ, Webb A, Langkilde T. Obtaining plasma to measure baseline corticosterone concentrations in reptiles: How quick is quick enough? Gen Comp Endocrinol 2020; 287:113324. [PMID: 31733208 DOI: 10.1016/j.ygcen.2019.113324] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 11/06/2019] [Accepted: 11/12/2019] [Indexed: 12/15/2022]
Abstract
There is growing interest in the use of glucocorticoid (GC) hormones to understand how wild animals respond to environmental challenges. Blood is the best medium for obtaining information about recent GC levels; however, obtaining blood requires restraint and can therefore be stressful and affect GC levels. There is a delay in GCs entering blood, and it is assumed that blood obtained within 3 min of first disturbing an animal reflects a baseline level of GCs, based largely on studies of birds and mammals. Here we present data on the timing of changes in the principle reptile GC, corticosterone (CORT), in four reptile species for which blood was taken within a range of times 11 min or less after first disturbance. Changes in CORT were observed in cottonmouths (Agkistrodon piscivorus; 4 min after first disturbance), rattlesnakes (Crotalus oreganus; 2 min 30 s), and rock iguanas (Cyclura cychlura; 2 min 44 s), but fence lizards (Sceloporus undulatus) did not exhibit a change within their 10-min sampling period. In both snake species, samples taken up to 3-7 min after CORT began to increase still had lower CORT concentrations than after exposure to a standard restraint stressor. The "3-min rule" appears broadly applicable as a guide for avoiding increases in plasma CORT due to handling and sampling in reptiles, but the time period in which to obtain true baseline CORT may need to be shorter in some species (rattlesnakes, rock iguanas), and may be unnecessarily limiting for others (cottonmouths, fence lizards).
Collapse
Affiliation(s)
- Catherine Tylan
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kiara Camacho
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Susannah French
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Sean P Graham
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Mark W Herr
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jermayne Jones
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Gail L McCormick
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA; Intercollege Graduate Degree Program in Ecology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, University Park, PA 16802, USA
| | - Melissa A O'Brien
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jennifer B Tennessen
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA; Intercollege Graduate Degree Program in Ecology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, University Park, PA 16802, USA
| | - Christopher J Thawley
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA; Intercollege Graduate Degree Program in Ecology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, University Park, PA 16802, USA
| | - Alison Webb
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA; Intercollege Graduate Degree Program in Ecology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, University Park, PA 16802, USA.
| |
Collapse
|
6
|
Telemeco RS, Simpson DY, Tylan C, Langkilde T, Schwartz TS. Contrasting Responses of Lizards to Divergent Ecological Stressors Across Biological Levels of Organization. Integr Comp Biol 2019; 59:292-305. [PMID: 31127305 DOI: 10.1093/icb/icz071] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
It is frequently hypothesized that animals employ a generalized "stress response," largely mediated by glucocorticoid (GC) hormones, such as corticosterone, to combat challenging environmental conditions. Under this hypothesis, diverse stressors are predicted to have concordant effects across biological levels of an organism. We tested the generalized stress response hypothesis in two complementary experiments with juvenile and adult male Eastern fence lizards (Sceloporus undulatus). In both experiments, animals were exposed to diverse, ecologically-relevant, acute stressors (high temperature or red imported fire ants, Solenopsis invicta) and we examined their responses at three biological levels: behavioral; physiological (endocrine [plasma corticosterone and blood glucose concentrations] and innate immunity [complement and natural antibodies]); and cellular responses (gene expression of a panel of five heat-shock proteins in blood and liver) at 30 or 90 min post stress initiation. In both experiments, we observed large differences in the cellular response to the two stressors, which contrasts the similar behavioral and endocrine responses. In the adult experiment for which we had innate immune data, the stressors affected immune function independently, and they were correlated with CORT in opposing directions. Taken together, these results challenge the concept of a generalized stress response. Rather, the stress response was context specific, especially at the cellular level. Such context-specificity might explain why attempts to link GC hormones with life history and fitness have proved difficult. Our results emphasize the need for indicators at multiple biological levels and whole-organism examinations of stress.
Collapse
Affiliation(s)
- Rory S Telemeco
- Department of Biology, California State University, Fresno, CA 93740, USA.,Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Dasia Y Simpson
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Catherine Tylan
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Tracy Langkilde
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.,Intercollege Graduate Degree Program in Ecology, Pennsylvania State University, University Park, PA 16802, USA
| | - Tonia S Schwartz
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| |
Collapse
|
7
|
Sprayberry K, Tylan C, Owen DAS, Macleod KJ, Sheriff MJ, Langkilde T. History of predator exposure affects cell-mediated immunity in female eastern fence lizards, Sceloporus undulatus (Squamata: Phrynosomatidae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abstract
On exposure to stressors, energy is diverted from non-urgent functions towards those important for immediate survival. The degree and nature of reallocation may be affected by the evolutionary history of the animal. The eastern fence lizard (Sceloporus undulatus) coexists in parts of its range with invasive fire ants (Solenopsis invicta), which attack and wound lizards and elevate stress-relevant hormones (corticosterone), whereas other populations have never been exposed to fire ants. We examined how a history of fire ant invasion affected the immune response in female lizards after exposure to exogenous corticosterone (mimicking exposure to a stressor) during gestation (dosing regimens differed among corticosterone-exposed lizards owing to the constraints of the original studies, but we found no evidence that this affected the outcome of the present study). A history of exposure to predatory stressors (fire ants) and corticosterone treatment affected cell-mediated immunity. Lizards from fire ant-invaded sites had a reduced immune response compared with those from uninvaded sites. Corticosterone treatment had no effect on the immune response of lizards from invaded sites but reduced the immune response of lizards from uninvaded sites. This suggests that an evolutionary history of exposure to wounding alters the immune response to corticosterone. Future work on how the immune system responds to environmental threats will be informative for the prediction and management of these threats.
Collapse
Affiliation(s)
- Kristen Sprayberry
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, USA
| | - Catherine Tylan
- Department of Biology, The Pennsylvania State University, University Park, USA
| | - Dustin A S Owen
- Department of Biology, The Pennsylvania State University, University Park, USA
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, USA
| | - Kirsty J Macleod
- Department of Biology, The Pennsylvania State University, University Park, USA
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, USA
| | - Michael J Sheriff
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, University Park, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, USA
| |
Collapse
|
8
|
Tylan C, Langkilde T. Local and systemic immune responses to different types of phytohemagglutinin in the green anole: Lessons for field ecoimmunologists. J Exp Zool A Ecol Integr Physiol 2017; 327:322-332. [PMID: 29356446 DOI: 10.1002/jez.2108] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/13/2017] [Accepted: 08/21/2017] [Indexed: 01/15/2023]
Abstract
The phytohemagglutinin (PHA) skin test is commonly used by ecologists to assess cell-mediated immune function of wild animals. It can be performed quickly and easily in the field, involving injection of PHA and measurement of the resultant swelling. There are multiple formulations of PHA used in ecological studies, with potentially differing outcomes that could produce inconsistent results. We tested two common types of PHA in the green anole (Anolis carolinensis) to identify local and systemic immune responses underlying the resultant swelling at 6, 18, 24, and 48 hr post injection. There were differences in both local (injection site) and systemic (blood) leukocyte responses to PHA-L versus PHA-P. PHA-P injection produced a greater overall increase in local heterophil count at the injection site compared with PHA-L, and this response was greatest at 6 and 24 hr post injection. Systemically, heterophil percentage was higher in the blood of PHA-P- versus PHA-L-injected anoles at 24 hr post injection; the time point at which heterophil percentage peaked in PHA-P-injected anoles. These results indicate that although both PHA types are effective tests of immune function in green anoles, the PHA-P swelling response invokes a much stronger heterophilic response. PHA-L is a more specific test of lymphocyte function, particularly at 24 hr post injection, making it preferable for ecoimmunology studies.
Collapse
Affiliation(s)
- Catherine Tylan
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Tracy Langkilde
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.,Intercollege Graduate Degree Program in Ecology, The Center for Brain, Behavior and Cognition, The Pennsylvania State University, University Park, Pennsylvania, USA
| |
Collapse
|