Effects of parasitic infection and reproduction on corticosterone plasma levels in Galápagos land iguanas,and

Michela Onorati, Giulia Sancesario, Donatella Pastore, Sergio Bernardini, Marilyn Cruz, Jorge E Carrión, Monica Carosi, Leonardo Vignoli, Davide Lauro, Gabriele Gentile

Research output: Contribution to journalArticlepeer-review

Abstract

In vertebrates, one main feature of stress response is the release of glucocorticoids (corticosterone in reptiles), steroid hormones whose synthesis is regulated by the hypothalamic-pituitary-adrenal axis (HPA). In the Galápagos Islands, populations of land iguanas are differentially impacted by a tick-transmitted apicomplexan hemoparasite of genusHepatozoon, which could cause diseases and ultimately reduce fitness. Using competitive enzyme-linked immunosorbent assays (ELISA), we examined baseline plasma corticosterone levels of two syntopic and highly parasitized populations of the land iguana speciesConolophus marthaeandC. subcristatusin Wolf volcano (Isabela Island). We also used a poorly parasitized population ofC. subcristatusfrom the same island (Bahia Urbina) as a reference. To better interpret the observed glucocorticoids patterns, we simultaneously performed the count of white blood cells (WBCs) in all individuals and investigated the reproductive status of females. We did not find evidence in support of either a positive or negative relationship between the tick load, hemoparasite infection, and glucocorticoid plasma concentration inC. marthaeandC. subcristatusat Wolf volcano. The comparison between parasitized and non-parasitized sites (V. Wolf and Bahia Urbina) would instead suggest an inverse relationship between corticosterone and parasites. Our findings support association between corticosterone plasma levels and reproduction.

Original languageEnglish
Pages (from-to)6046-6055
Number of pages10
JournalEcology and Evolution
Volume7
Issue number15
DOIs
Publication statusPublished - Aug 2017

Keywords

  • Journal Article

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