1
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Bodensteiner BL, Iverson JB, Lea CA, Milne-Zelman CL, Mitchell TS, Refsnider JM, Voves K, Warner DA, Janzen FJ. Mother knows best: nest-site choice homogenizes embryo thermal environments among populations in a widespread ectotherm. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220155. [PMID: 37427473 PMCID: PMC10331915 DOI: 10.1098/rstb.2022.0155] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 05/02/2023] [Indexed: 07/11/2023] Open
Abstract
Species with large geographical ranges provide an excellent model for studying how different populations respond to dissimilar local conditions, particularly with respect to variation in climate. Maternal effects, such as nest-site choice greatly affect offspring phenotypes and survival. Thus, maternal behaviour has the potential to mitigate the effects of divergent climatic conditions across a species' range. We delineated natural nesting areas of six populations of painted turtles (Chrysemys picta) that span a broad latitudinal range and quantified spatial and temporal variation in nest characteristics. To quantify microhabitats available for females to choose, we also identified sites within the nesting area of each location that were representative of available thermal microhabitats. Across the range, females nested non-randomly and targeted microhabitats that generally had less canopy cover and thus higher nest temperatures. Nest microhabitats differed among locations but did not predictably vary with latitude or historic mean air temperature during embryonic development. In conjunction with other studies of these populations, our results suggest that nest-site choice is homogenizing nest environments, which buffers embryos from thermally induced selection and could slow embryonic evolution. Thus, although effective at a macroclimatic scale, nest-site choice is unlikely to compensate for novel stressors that rapidly increase local temperatures. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.
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Affiliation(s)
- Brooke L. Bodensteiner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - John B. Iverson
- Department of Biology, Earlham College, Richmond, IN 60071, USA
| | - Carter A. Lea
- Office of Research Proposal Development, Tulane University, New Orleans, LA 70118, USA
| | | | - Timothy S. Mitchell
- College of Biological Sciences, University of Minnesota, St. Paul, MN 55108, USA
| | - Jeanine M. Refsnider
- Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA
| | | | - Daniel A. Warner
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
- Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, USA
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2
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Fargevieille A, Reedy AM, Kahrl AF, Mitchell TS, Durso AM, Delaney DM, Pearson PR, Cox RM, Warner DA. Propagule size and sex ratio influence colonisation dynamics after introduction of a non-native lizard. J Anim Ecol 2022; 91:845-857. [PMID: 35114034 DOI: 10.1111/1365-2656.13671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/23/2022] [Indexed: 11/28/2022]
Abstract
The composition of founding populations plays an important role in colonisation dynamics and can influence population growth during early stages of biological invasion. Specifically, founding populations with small propagules (i.e., low number of founders) are vulnerable to the Allee effect and have reduced likelihood of establishment compared to those with large propagules. The founding sex ratio can also impact establishment via its influence on mating success and offspring production. Our goal was to test the effects of propagule size and sex ratio on offspring production and annual population growth following introductions of a non-native lizard species (Anolis sagrei). We manipulated propagule composition on nine small islands, then examined offspring production, population growth, and survival rate of founders and their descendants encompassing three generations. By the third reproductive season, per capita offspring production was higher on islands seeded with a relatively large propagule size, but population growth was not associated with propagule size. Propagule sex ratio did not affect offspring production, but populations with a female-biased propagule had positive growth, whereas those with a male-biased propagule had negative growth in the first year. Populations were not affected by propagule sex ratio in subsequent years, possibly due to rapid shifts towards balanced (or slightly female-biased) population sex ratios. Overall, we show that different components of population fitness have different responses to propagule size and sex ratio in ways that could affect early stages of biological invasion. Despite these effects, the short lifespan and high fecundity of A. sagrei likely helped small populations to overcome Allee effects and enabled all populations to successfully establish. Our rare experimental manipulation of propagule size and sex ratio can inform predictions of colonisation dynamics in response to different compositions of founding populations, which is critical in the context of population ecology and invasion dynamics.
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Affiliation(s)
- Amélie Fargevieille
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.,Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Aaron M Reedy
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.,Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Ariel F Kahrl
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA.,Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg, 18B SE-10691, Stockholm, Sweden
| | - Timothy S Mitchell
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.,Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Andrew M Durso
- Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, FL, 33965, USA
| | - David M Delaney
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Department of Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, 80302, USA
| | - Phillip R Pearson
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.,Department of Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.,Centre for Conservation, Ecology and Genomics, University of Canberra, Bruce, ACT, 2617, Australia
| | - Robert M Cox
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.,Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Department of Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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3
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Shephard AM, Mitchell TS, Snell-Rood EC. Monarch caterpillars are robust to combined exposure to the roadside micronutrients sodium and zinc. Conserv Physiol 2021; 9:coab061. [PMID: 34386239 PMCID: PMC8354372 DOI: 10.1093/conphys/coab061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/08/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Human activities are increasing the environmental availability of micronutrients, including sodium and some essential metals. Micronutrients are often limiting in animal diets but may have negative effects when consumed in excess. Though prior research has documented how elevated exposure to individual micronutrients can impact organismal development and fitness, we know less about combined effects of multiple micronutrients. In the wild, monarch butterfly larvae (Danaus plexippus) commonly consume plants in roadside habitats that contain elevated levels of sodium (from road salt) and zinc (from vehicle wear-and-tear). We reared monarch caterpillars to adulthood to test individual and combined effects of dietary sodium and zinc on components of fitness, sodium-linked phenotypes (proxies for neural and flight muscle development) and concentrations of sodium and zinc in adult butterflies. Monarch survival was not impacted by elevated sodium or zinc individually or in combination. Yet, monarchs feeding on sodium-treated milkweed developed relatively larger eyes, consistent with a positive effect of sodium on neural development. Measurements of element concentrations in butterfly and plant tissue indicated that monarchs had higher zinc levels than those present in zinc-treated milkweed but lower sodium levels than those present in sodium-treated milkweed. Monarchs developing on sodium-treated milkweed also had prolonged development time, which might be a cost associated with developing extra neural tissue or investing in mechanisms to excrete excess dietary sodium during the larval stage. Our results indicate that sodium, more than zinc, is likely influencing phenotypic development and performance of insect pollinators in roadside habitats. Yet, in contrast to previous work, our experiment suggests that the highest levels of sodium found along roads are not always harmful for developing monarchs. Future work could consider how potentially stressful effects of micronutrients could be mitigated by increased macronutrient availability or how developmental factors such as migratory status might increase micronutrient requirements.
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Affiliation(s)
- Alexander M Shephard
- Corresponding author: Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, Saint Paul, MN 55108, USA.
| | - Timothy S Mitchell
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, Saint Paul, MN 55108, USA
| | - Emilie C Snell-Rood
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Twin Cities, Saint Paul, MN 55108, USA
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4
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Mitchell TS, Agnew L, Meyer R, Sikkink KL, Oberhauser KS, Borer ET, Snell-Rood EC. Traffic influences nutritional quality of roadside plants for monarch caterpillars. Sci Total Environ 2020; 724:138045. [PMID: 32408428 DOI: 10.1016/j.scitotenv.2020.138045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 02/14/2020] [Revised: 03/17/2020] [Accepted: 03/17/2020] [Indexed: 06/11/2023]
Abstract
Roadside habitats are increasingly being targeted for restoration and conservation. Roadside habitats often exhibit altered soil and plant chemistry due to pollution from maintenance (e.g. de-icing salt), car deterioration, and exhaust. Roadside plants may attract animals due to elevated levels of sodium or nitrogen, but high concentrations of heavy metals and sodium can be toxic, potentially setting an ecological trap. In this study, we determine how roads influence the chemistry of common milkweed (Asclepias syriaca) as it is the primary roadside host plant for the declining monarch butterfly (Danaus plexippus) in the eastern United States. Even though road salt is applied during the winter, we detect enhanced sodium along roads the following growing season. Road salts increase soil sodium, which in turn elevates host-plant foliar sodium (occasionally to toxic levels in <10% of plants) and sodium content in monarch caterpillars feeding on these plants. Sodium levels of milkweed leaves are highest close to the edge of busy roads. Some heavy metals (lead, zinc) are also elevated in roadside soils or plants. Nitrogen content was affected by adjacent agricultural use, but not traffic volume or proximity to a road. Other potential road pollutants (e.g. nickel) were not elevated in soil or plants. Despite a clear signature of road pollution in the chemistry of milkweed, most plants are likely still suitable for developing monarchs. Nonetheless, restoration investments in snowy regions should prioritize sites with lower-traffic density that are further from the road edge to minimize toxic impacts of high sodium. To extend this research to other insects of conservation concern, future work should characterize the nutritional quality of nectar, pollen, and other species of host-plants in roadside habitats.
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Affiliation(s)
- Timothy S Mitchell
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America.
| | - Lauren Agnew
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
| | - Rebecca Meyer
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
| | - Kristin L Sikkink
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
| | - Karen S Oberhauser
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
| | - Elizabeth T Borer
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
| | - Emilie C Snell-Rood
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, United States of America
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5
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Hall JM, Mitchell TS, Thawley CJ, Stroud JT, Warner DA. Adaptive seasonal shift towards investment in fewer, larger offspring: Evidence from field and laboratory studies. J Anim Ecol 2020; 89:1242-1253. [DOI: 10.1111/1365-2656.13182] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 01/09/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Joshua M. Hall
- Department of Biological Sciences Auburn University Auburn AL USA
| | - Timothy S. Mitchell
- Department of Biological Sciences Auburn University Auburn AL USA
- Department of Ecology, Evolution and Behavior University of Minnesota St. Paul MN USA
| | - Christopher J. Thawley
- Department of Biological Sciences University of Rhode Island Kingston RI USA
- Department of Biology Davidson College Davidson NC USA
| | - James T. Stroud
- Department of Biology Washington University St. Louis MO USA
| | - Daniel A. Warner
- Department of Biological Sciences Auburn University Auburn AL USA
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6
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7
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Warner DA, Mitchell TS, Bodensteiner BL, Janzen FJ. Sex and Incubation Temperature Independently Affect Embryonic Development and Offspring Size in a Turtle with Temperature-Dependent Sex Determination. Physiol Biochem Zool 2020; 93:62-74. [DOI: 10.1086/706786] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Carter AL, Bodensteiner BL, Iverson JB, Milne‐Zelman CL, Mitchell TS, Refsnider JM, Warner DA, Janzen FJ. Breadth of the thermal response captures individual and geographic variation in temperature‐dependent sex determination. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13410] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Anna L. Carter
- Department of Ecology, Evolution & Organismal Biology Iowa State University Ames IA USA
| | | | | | | | - Timothy S. Mitchell
- Department of Ecology, Evolution & Behavior University of Minnesota Minneapolis MN USA
| | | | - Daniel A. Warner
- Department of Biological Sciences Auburn University Auburn AL USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution & Organismal Biology Iowa State University Ames IA USA
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9
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Janzen FJ, Delaney DM, Mitchell TS, Warner DA. Do Covariances Between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution Under Environmental Sex Determination? J Hered 2019; 110:411-421. [PMID: 30982894 DOI: 10.1093/jhered/esz021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 04/11/2019] [Indexed: 11/12/2022] Open
Abstract
Fisherian sex-ratio theory predicts sexual species should have a balanced primary sex ratio. However, organisms with environmental sex determination (ESD) are particularly vulnerable to experiencing skewed sex ratios when environmental conditions vary. Theoretical work has modeled sex-ratio dynamics for animals with ESD with regard to 2 traits predicted to be responsive to sex-ratio selection: 1) maternal oviposition behavior and 2) sensitivity of embryonic sex determination to environmental conditions, and much research has since focused on how these traits influence offspring sex ratios. However, relatively few studies have provided estimates of univariate quantitative genetic parameters for these 2 traits, and the existence of phenotypic or genetic covariances among these traits has not been assessed. Here, we leverage studies on 3 species of reptiles (2 turtle species and a lizard) with temperature-dependent sex determination (TSD) to assess phenotypic covariances between measures of maternal oviposition behavior and thermal sensitivity of the sex-determining pathway. These studies quantified maternal behaviors that relate to nest temperature and sex ratio of offspring incubated under controlled conditions. A positive covariance between these traits would enhance the efficiency of sex-ratio selection when primary sex ratio is unbalanced. However, we detected no such covariance between measures of these categories of traits in the 3 study species. These results suggest that maternal oviposition behavior and thermal sensitivity of sex determination in embryos might evolve independently. Such information is critical to understand how animals with TSD will respond to rapidly changing environments that induce sex-ratio selection.
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Affiliation(s)
- Fredric J Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
| | - David M Delaney
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA
| | - Timothy S Mitchell
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN
| | - Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, AL
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10
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Affiliation(s)
- Timothy S. Mitchell
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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11
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Janzen FJ, Mitchell TS. Substrate Influences Turtle Nest Temperature, Incubation Period, and Offspring Sex Ratio in the Field. HERPETOLOGICA 2019. [DOI: 10.1655/0018-0831-75.1.57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Fredric J. Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Timothy S. Mitchell
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
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12
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Bodensteiner BL, Warner DA, Iverson JB, Milne‐Zelman CL, Mitchell TS, Refsnider JM, Janzen FJ. Geographic variation in thermal sensitivity of early life traits in a widespread reptile. Ecol Evol 2019; 9:2791-2802. [PMID: 30891217 PMCID: PMC6405489 DOI: 10.1002/ece3.4956] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/13/2018] [Accepted: 11/25/2018] [Indexed: 01/19/2023] Open
Abstract
Taxa with large geographic distributions generally encompass diverse macroclimatic conditions, potentially requiring local adaptation and/or phenotypic plasticity to match their phenotypes to differing environments. These eco-evolutionary processes are of particular interest in organisms with traits that are directly affected by temperature, such as embryonic development in oviparous ectotherms. Here we examine the spatial distribution of fitness-related early life phenotypes across the range of a widespread vertebrate, the painted turtle (Chrysemys picta). We quantified embryonic and hatchling traits from seven locations (in Idaho, Minnesota, Oregon, Illinois, Nebraska, Kansas, and New Mexico) after incubating eggs under constant conditions across a series of environmentally relevant temperatures. Thermal reaction norms for incubation duration and hatchling mass varied among locations under this common-garden experiment, indicating genetic differentiation or pre-ovulatory maternal effects. However, latitude, a commonly used proxy for geographic variation, was not a strong predictor of these geographic differences. Our findings suggest that this macroclimatic proxy may be an unreliable surrogate for microclimatic conditions experienced locally in nests. Instead, complex interactions between abiotic and biotic factors likely drive among-population phenotypic variation in this system. Understanding spatial variation in key life-history traits provides an important perspective on adaptation to contemporary and future climatic conditions.
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Affiliation(s)
- Brooke L. Bodensteiner
- Department of Ecology Evolution and Organismal BiologyIowa State UniversityAmesIowa
- Department of Biological SciencesVirginia Polytechnic Institute and State UniversityBlacksburgVirginia
| | | | | | | | - Timothy S. Mitchell
- Department of Ecology Evolution and BehaviorUniversity of MinnesotaSaint PaulMinnesota
| | | | - Fredric J. Janzen
- Department of Ecology Evolution and Organismal BiologyIowa State UniversityAmesIowa
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13
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Fanter CE, Lin Z, Keenan SW, Janzen FJ, Mitchell TS, Warren DE. Development-specific transcriptomic profiling suggests new mechanisms for anoxic survival in the ventricle of overwintering turtles. J Exp Biol 2019; 223:jeb.213918. [DOI: 10.1242/jeb.213918] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/18/2019] [Indexed: 12/28/2022]
Abstract
Oxygen deprivation swiftly damages tissues in most animals, yet some species show remarkable abilities to tolerate little or even no oxygen. Painted turtles exhibit a development-dependent tolerance that allows adults to survive anoxia ∼4x longer than hatchlings: adults survive ∼170 days and hatchlings survive ∼40 days at 3°C. We hypothesized this difference is related to development-dependent differences in ventricular gene expression. Using a comparative ontogenetic approach, we examined whole transcriptomic changes before, during, and five days after a 20-day bout of anoxic submergence at 3°C. Ontogeny accounted for more gene expression differences than treatment (anoxia or recovery): 1,175 vs. 237 genes, respectively. Of the 237 differences, 93 could confer protection against anoxia and reperfusion injury, 68 could be injurious, and 20 may be constitutively protective. Especially striking during anoxia was the expression pattern of all 76 annotated ribosomal protein (R-protein) mRNAs, which decreased in anoxia-tolerant adults, but increased in anoxia-sensitive hatchlings, suggesting adult-specific regulation of translational suppression. These genes, along with 60 others that decreased their levels in adults and either increased or remained unchanged in hatchlings, implicate antagonistic pleiotropy as a mechanism to resolve the long-standing question about why hatchling painted turtles overwinter in terrestrial nests, rather than emerge and overwinter in water during their first year. In sum, developmental differences in the transcriptome of the turtle ventricle revealed potentially protective mechanisms that contribute to extraordinary adult-specific anoxia tolerance, and provide a unique perspective on differences between the anoxia-induced molecular responses of anoxia-tolerant or anoxia-sensitive phenotypes within a species.
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Affiliation(s)
- Cornelia E. Fanter
- Saint Louis University, Department of Biology, 3507 Laclede Ave., St. Louis, Missouri, 63103, USA
| | - Zhenguo Lin
- Saint Louis University, Department of Biology, 3507 Laclede Ave., St. Louis, Missouri, 63103, USA
| | - Sarah W. Keenan
- South Dakota School of Mines & Technology, Department of Geology and Geological Engineering, 501 East St. Joseph St., Rapid City, South Dakota, 57701, USA
| | - Fredric J. Janzen
- Iowa State University, Department of Ecology, Evolution and Organismal Biology, 251 Bessey Hall, Ames, Iowa, 50011, USA
| | - Timothy S. Mitchell
- University of Minnesota, Department of Ecology, Evolution and Behavior, 1479 Gortner Ave. Saint Paul, MN, 55108, USA
| | - Daniel E. Warren
- Saint Louis University, Department of Biology, 3507 Laclede Ave., St. Louis, Missouri, 63103, USA
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14
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Mitchell TS, Janzen FJ, Warner DA. Quantifying the effects of embryonic phenotypic plasticity on adult phenotypes in reptiles: A review of current knowledge and major gaps. J Exp Zool 2018; 329:203-214. [DOI: 10.1002/jez.2187] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Timothy S. Mitchell
- Department of Biological Sciences Auburn University Auburn Alabama
- Department of Ecology, Evolution and Behavior University of Minnesota Saint Paul Minnesota
| | - Fredric J. Janzen
- Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames Iowa
| | - Daniel A. Warner
- Department of Biological Sciences Auburn University Auburn Alabama
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15
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Mitchell TS, Hall JM, Warner DA. Female investment in offspring size and number shifts seasonally in a lizard with single-egg clutches. Evol Ecol 2018. [DOI: 10.1007/s10682-018-9936-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Warner DA, Mitchell TS, Bodensteiner BL, Janzen FJ. The effect of hormone manipulations on sex ratios varies with environmental conditions in a turtle with temperature-dependent sex determination. J Exp Zool A Ecol Integr Physiol 2018; 327:172-181. [PMID: 29356364 DOI: 10.1002/jez.2085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 06/27/2017] [Indexed: 02/03/2023]
Abstract
Exogenous application of steroids and related substances to eggs affects offspring sex ratios in species with temperature-dependent sex determination (TSD). Laboratory studies demonstrate that this effect is most pronounced near the constant temperature that produces 1:1 sex ratios (i.e., pivotal temperature). However, the impact of such chemicals on sex determination under natural nest temperatures (which fluctuate daily) is unknown, but could provide insight into the relative contributions of these two factors under natural conditions. We applied estradiol (E2) and an aromatase inhibitor (fadrozole) to eggs of the painted turtle (Chrysemys picta), a species with TSD, and allowed eggs to incubate under natural conditions during two field seasons (in 2012 and 2013). Exogenous E2, fadrozole, and nest temperature contributed to variation in offspring sex ratio, but the relative contributions of these factors differed between years. In 2012, a much hotter than average season, sex ratios were heavily female biased regardless of nest temperature and chemical treatment. However, in 2013, a milder season, both nest temperature and chemical treatment were important. Moreover, a significant interaction between nest temperature and treatment demonstrated that exogenous estradiol induces female development regardless of nest temperature, but aromatase inhibition widens the range of temperatures that produces both sexes.
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Affiliation(s)
- Daniel A Warner
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa.,Department of Biological Sciences, Auburn University, Auburn, Alabama
| | - Timothy S Mitchell
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa.,Department of Biological Sciences, Auburn University, Auburn, Alabama
| | - Brooke L Bodensteiner
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa
| | - Fredric J Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa
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17
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Hulbert AC, Mitchell TS, Hall JM, Guiffre CM, Douglas DC, Warner DA. The effects of incubation temperature and experimental design on heart rates of lizard embryos. J Exp Zool 2017; 327:466-476. [DOI: 10.1002/jez.2135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/15/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Austin C. Hulbert
- Department of Biological Sciences; Auburn University; Auburn Alabama
| | | | - Joshua M. Hall
- Department of Biological Sciences; Auburn University; Auburn Alabama
| | - Cassia M. Guiffre
- Department of Biological Sciences; Auburn University; Auburn Alabama
| | | | - Daniel A. Warner
- Department of Biological Sciences; Auburn University; Auburn Alabama
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Mitchell TS, Moots RJ, Wright HL. Janus kinase inhibitors prevent migration of rheumatoid arthritis neutrophils towards interleukin-8, but do not inhibit priming of the respiratory burst or reactive oxygen species production. Clin Exp Immunol 2017; 189:250-258. [PMID: 28369741 DOI: 10.1111/cei.12970] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2017] [Indexed: 01/08/2023] Open
Abstract
Neutrophils play a crucial role in the pathophysiology of rheumatoid arthritis (RA) via the release of reactive oxygen species (ROS), proteases and cytokines. Orally active Janus kinase (JAK) inhibitors (JAKi), e.g. baricitinib and tofacitinib, have high clinical efficacy in RA but are linked with neutropenia and increased infections. Our aim was to determine the effect of JAK inhibition with baricitinib and tofacitinib on healthy control and RA neutrophil lifespan and function. RA (n = 7) and healthy control (n = 7) neutrophils were treated with baricitinib or tofacitinib for 30 min, prior to incubation in the absence or presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) or interferon (IFN)-γ. JAKi prevented GM-CSF- and IFN-γ-induced apoptosis delay in RA and healthy control neutrophils in a dose-dependent manner. Baricitinib decreased the rate of chemotaxis towards interleukin (IL)-8, but not f-Met-Leu-Phe (fMLP) in RA neutrophils. While healthy control neutrophils incubated with GM-CSF became primed to produce ROS in response to stimulation with fMLP and phorbol-12-myristate-12-acetate (PMA), RA neutrophils produced increased levels of ROS without the need for priming. JAKi prevented ROS release from primed healthy control neutrophils in response to fMLP, but had no effect on ROS production by RA neutrophils. Baricitinib reversed GM-CSF priming of ROS production in response to fMLP in healthy control, but not RA, neutrophils. We conclude that incubation with JAKi prevents chemotaxis of RA neutrophils towards IL-8, but does not prevent the production of ROS or increase the level of apoptosis. This may be due to the in-vivo exposure of RA neutrophils to priming agents other than those that activate JAK/signal transducer and activator of transcription (STAT) signalling.
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Affiliation(s)
- T S Mitchell
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - R J Moots
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - H L Wright
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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Mitchell TS, Myers EM, Tucker JK, McGaugh SE. Righting ability in hatchling turtles does not predict survival during dispersal in the field. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12896] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Timothy S. Mitchell
- Department of Ecology, Evolution and Organismal Biology; Iowa State University; Ames IA 50011 USA
- Deptartment of Biological Sciences; Auburn University; 101 Life Sciences Building Auburn AL 36849 USA
| | - Erin M. Myers
- Department of Biology and Biochemistry; University of Houston; Houston TX 77204 USA
| | - John K. Tucker
- Illinois Natural History Survey; 1816 S. Oak Street Champaign IL 61820 USA
- Retired
| | - Suzanne E. McGaugh
- Department of Ecology, Evolution and Organismal Biology; Iowa State University; Ames IA 50011 USA
- Department of Ecology, Evolution, and Behavior; University of Minnesota; 100 Ecology Building 1987 Upper Buford Circle Saint Paul MN 55108 USA
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Telemeco RS, Gangloff EJ, Cordero GA, Mitchell TS, Bodensteiner BL, Holden KG, Mitchell SM, Polich RL, Janzen FJ. Reptile Embryos Lack the Opportunity to Thermoregulate by Moving within the Egg. Am Nat 2016; 188:E13-27. [DOI: 10.1086/686628] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Bodensteiner BL, Mitchell TS, Strickland JT, Janzen FJ. Hydric conditions during incubation influence phenotypes of neonatal reptiles in the field. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12382] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Brooke L. Bodensteiner
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames Iowa 50011 USA
| | - Timothy S. Mitchell
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames Iowa 50011 USA
| | - Jeramie T. Strickland
- U.S. Fish and Wildlife Service Upper Mississippi River National Wildlife and Fish Refuge Thomson Illinois 61285 USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames Iowa 50011 USA
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Affiliation(s)
- Timothy S. Mitchell
- Department of Ecology, Evolution and Organismal Biology Iowa State University 251 Bessey Hall Ames Iowa 50011 USA
| | - Jessica A. Maciel
- Department of Ecology, Evolution and Organismal Biology Iowa State University 251 Bessey Hall Ames Iowa 50011 USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution and Organismal Biology Iowa State University 251 Bessey Hall Ames Iowa 50011 USA
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Mitchell TS, Maciel JA, Janzen FJ. Does sex-ratio selection influence nest-site choice in a reptile with temperature-dependent sex determination? Proc Biol Sci 2014; 280:20132460. [PMID: 24266033 DOI: 10.1098/rspb.2013.2460] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evolutionary theory predicts that dioecious species should produce a balanced primary sex ratio maintained by frequency-dependent selection. Organisms with environmental sex determination, however, are vulnerable to maladaptive sex ratios, because environmental conditions vary spatio-temporally. For reptiles with temperature-dependent sex determination, nest-site choice is a behavioural maternal effect that could respond to sex-ratio selection, as mothers could adjust offspring sex ratios by choosing nest sites that will have particular thermal properties. This theoretical prediction has generated decades of empirical research, yet convincing evidence that sex-ratio selection is influencing nesting behaviours remains absent. Here, we provide the first experimental evidence from nature that sex-ratio selection, rather than only viability selection, is probably an important component of nest-site choice in a reptile with temperature-dependent sex determination. We compare painted turtle (Chrysemys picta) neonates from maternally selected nest sites with those from randomly selected nest sites, observing no substantive difference in hatching success or survival, but finding a profound difference in offspring sex ratio in the direction expected based on historical records. Additionally, we leverage long-term data to reconstruct our sex ratio results had the experiment been repeated in multiple years. As predicted by theory, our results suggest that sex-ratio selection has shaped nesting behaviour in ways likely to enhance maternal fitness.
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Refsnider JM, Mitchell TS, Streby HM, Strickland JT, Warner DA, Janzen FJ. A generalized method to determine detectability of rare and cryptic species using the ornate box turtle as a model. WILDLIFE SOC B 2011. [DOI: 10.1002/wsb.14] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Xenopus laevis embryogenesis is controlled by the inducing activities of Spemann's organizer. These inducing activities are separated into two distinct suborganizers: a trunk organizer and a head organizer. The trunk organizer induces the formation of posterior structures by emitting signals and directing morphogenesis. Here, we report that the fibroblast growth factor receptor (FGFR) signaling pathway, also known to regulate posterior development, performs critical functions within the cells of Spemann's organizer. Specifically, the FGFR pathway was required in the organizer cells in order for those cells to induce the formation of somitic muscle and the pronephros. Since the organizer influences the differentiation of these tissues by emitting signals that pattern the mesodermal germ layer, our data indicate that the FGFR regulates the production of these signals. In addition, the FGFR pathway was required for the expression of chordin, an organizer-specific protein required for the trunk-inducing activities of Spemann's organizer. Significantly, the FGFR pathway had a minimal effect on the function of the head organizer. We propose that the FGFR pathway is a defining molecular component that distinguishes the trunk organizer from the head organizer by controlling the expression of organizer-specific genes required to induce the formation of posterior structures and somitic muscle in neighboring cells. The implications of our findings for the evolutionarily conserved role of the FGFR pathway in the functions of Spemann's organizer and other vertebrate-signaling centers are discussed.
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Affiliation(s)
- T S Mitchell
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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Mitchell TS. Screening for prostate cancer. Urol Nurs 1994; 14:9-11. [PMID: 7512282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Mitchell TS, Lee S, Gittes RF. Calcium and phosphorus metabolism in uremia and renal transplantation: an experimental model. Invest Urol 1974; 12:186-92. [PMID: 4613687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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