Adrenal and white cell count responses to chronic stress in gestating and postpartum females of the viviparous skink Egernia whitii (Scincidae)

Cartledge, Victoria A.; Gartrell, Brett D.; Jones, Susan

doi:10.1016/j.cbpb.2005.04.008

Cited by 14 publications

(8 citation statements)

References 31 publications

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“…Compatible with other studies in reptiles (Aguirre et al 1995; Morici et al 1997; Cartledge et al 2005), we observed an increase in the ratio of heterophils to lymphocytes (H:L) that was consistent with population differences observed in baseline CORT. Saad and Elridi (1988) report that CORT acts to lyse lymphocytes in the lizard Chalcides ocellatus , resulting in depressed overall number of lymphocytes.…”

Section: Discussionsupporting

confidence: 91%

Variation in stress and innate immunity in the tree lizard (Urosaurus ornatus) across an urban–rural gradient

2008

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The urban environment presents new and different challenges to wildlife, but also potential opportunities depending on the species. As urban encroachment onto native habitats continues, understanding the impact of this expansion on native species is vital to conservation. A key physiological indicator of environmental disturbance is the vertebrate stress response, involving increases in circulating glucocorticoids (i.e., corticosterone), which exert influence on numerous physiological parameters including energy storage, reproduction, and immunity. We examined how urbanization in Phoenix, Arizona influences corticosterone levels, blood parasitism, and innate immunity in populations of tree lizards (Urosaurus ornatus) to determine whether urbanization may be detrimental or beneficial to this species. Both baseline and stress-induced corticosterone concentrations were significantly lower in urban lizards relative to the rural ones, however, the magnitude of the increase in corticosterone with stress did not differ across populations. Urban lizards also had a lower ratio of heterophils to lymphocytes, but elevated overall leukocyte count, as compared to lizards from the natural site. Urban and rural lizards did not differ in their prevalence of the blood parasite, Plasmodium mexicanum. Taken together, these results suggest that urban tree lizards may have suppressed overall corticosterone concentrations possibly from down-regulation as a result of frequent exposure to stressors, or increased access to urban resources. Also, urban lizards may have bolstered immunocompetence possibly from increased immune challenges, such as wounding, in the urban environment, or from greater energetic reserves being available as a result of access to urban resources.

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Section: Discussionsupporting

confidence: 91%

Variation in stress and innate immunity in the tree lizard (Urosaurus ornatus) across an urban–rural gradient

2008

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“…The increase in G:L ratio was probably in response to the air exposure component of trawling9 and may also be related to the increased cost to mount an immune response during pregnancy, because energy allocated to immune function is often diverted towards the greater energetic demands of reproduction29324041. Elevations of sex-steroids associated with reproduction were also found to be immunosuppressive and affected leukocyte proliferation in female little skates, Leucoraja erinacea 42.…”

Section: Discussionmentioning

confidence: 99%

Prenatal stress from trawl capture affects mothers and neonates: a case study using the southern fiddler ray (Trygonorrhina dumerilii)

Guida

Awruch

Walker

et al. 2017

Sci Rep

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Assessing fishing effects on chondrichthyan populations has predominantly focused on quantifying mortality rates. Consequently, sub-lethal effects of capture stress on the reproductive capacity of chondrichthyans are largely unknown. We investigated the reproductive consequences of capture on pregnant southern fiddler rays (Trygonorrhina dumerilii) collected from Swan Bay, Australia, in response to laboratory-simulated trawl capture (8 h) followed immediately by air exposure (30 min). Immediately prior to, and for up to 28 days post trawling, all females were measured for body mass (BM), sex steroid concentrations (17-β estradiol, progesterone, testosterone) and granulocyte to lymphocyte (G:L) ratio. At parturition, neonates were measured for total length (TL), BM and G:L ratio. Trawling reduced maternal BM and elevated the G:L ratio for up to 28 days. Trawling did not significantly affect any sex steroid concentrations relative to controls. Neonates from trawled mothers were significantly lower in BM and TL than control animals, and had an elevated G:L ratio. Our results show that capture of pregnant T. dumerilii can influence their reproductive potential and affect the fitness of neonates. We suggest other viviparous species are likely to be similarly affected. Sub-lethal effects of capture, particularly on reproduction, require further study to improve fisheries management and conservation of chondrichthyans.

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“…Furthermore, as female skinks Egernia whitii seem to have reduced numbers of lymphocytes during pregnancy than afterwards (Cartledge et al, 2005), a greater decrease in the CMI response of experimental female lizards in our study suggests that females submitted to low temperatures may also suffer immunological costs. As the CMI response may be implicated in defense against parasites, we could expect that females with low CMI response had also higher blood parasite loads.…”

Section: Discussionmentioning

confidence: 74%

Pregnant female lizards Iberolacerta cyreni adjust refuge use to decrease thermal costs for their body condition and cell‐mediated immune response

2007

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Lizards often respond to increased predation risk by increasing refuge use, but this strategy may entail a loss of thermoregulatory opportunities, which may lead to a loss of body condition. This may be especially important for pregnant oviparous female lizards, because they need to maintain optimal body temperatures as long as possible to maximize developmental embryos rate until laying. However, little is known about how increased time spent at low temperatures in refuges affects body condition and health state of pregnant female lizards. Furthermore, it is not clear how initial body condition affects refuge use. Female Iberian rock lizards forced to increase time spent at low temperatures showed lower body condition and tended to show lower cell-mediated immune responses than control females. Therefore, the loss of thermoregulatory opportunities seems to be an important cost for pregnant females. Nevertheless, thereafter, when we simulated two repeated predatory attacks, females modified refuge use in relation to their body condition, with females with worse condition decreasing time hidden after attacks. In conclusion, female lizards seemed able to compensate increased predation risk with flexible antipredatory strategies, thus minimizing costs for body condition and health state.

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Adrenal and white cell count responses to chronic stress in gestating and postpartum females of the viviparous skink Egernia whitii (Scincidae)

Cited by 14 publications

References 31 publications

Variation in stress and innate immunity in the tree lizard (Urosaurus ornatus) across an urban–rural gradient

Variation in stress and innate immunity in the tree lizard (Urosaurus ornatus) across an urban–rural gradient

Prenatal stress from trawl capture affects mothers and neonates: a case study using the southern fiddler ray (Trygonorrhina dumerilii)

Pregnant female lizards Iberolacerta cyreni adjust refuge use to decrease thermal costs for their body condition and cell‐mediated immune response

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