Sex matters? Association between foraging behaviour, diet, and physiology in Magellanic penguins

Colominas-Ciuró, Roger; Bertellotti, Marcelo; D'amico, Veronica Laura; Carabajal, Eliana; Benzal, Jesús; Vidal, Virginia; Motas, Miguel; Barbosa, Andrés

doi:10.1007/s00227-021-04003-w

Cited by 5 publications

(4 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Free radical scavengers can be antioxidants (donate an electron) or antireductants (accept an electron) and we can also call them antiradicals. With this mechanism, it was possible to explain the extraordinary ability of red carotenoids such as astaxanthin to prevent oxidative stress, and this information has been used to analyze various experiments with carotenoids and also to explain observations of birds using carotenoids to indicate their “state of health” during the process of sexual selection [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. This idea was also useful to study the physiological effects of heat stress on poultry health [ 57 ].…”

Section: Resultsmentioning

confidence: 99%

To Prevent Oxidative Stress, What about Protoporphyrin IX, Biliverdin, and Bilirubin?

Martínez,

López-Rull,

Fargallo

2023

Antioxidants

View full text Add to dashboard Cite

The pigments responsible for eggshell color and patterning in birds are protoporphyrin IX (PP) and biliverdin (BV). Both are involved in the catalytic degradation of the hemo group. Bilirubin (BR), another pigment, is produced when BV is broken down. PP, BV, and BR are free radical scavengers. In this study, we theoretically investigated the antioxidant capacities of these three biological meaningful molecules using Density Functional Theory calculations. First, two antioxidant mechanisms were analyzed for PP, BV, and BR: electron transfer and Hydrogen Atom Transfer. Second, since PP and BV interact with the calcium carbonate matrix of the eggshell, we analyzed the interaction of these pigments with Ca2+ and investigated their chelate compounds. Third, we explored the pro-oxidant properties of PP and BV, which have been proposed for PP when photoactivated to the triplet state, but not for BV. Our results show that PP, BV, and BR are just as good antiradical as other important natural pigments (carotenoids). Neither the antiradical properties of PP and BV nor the UV-visible spectra change due to the presence of calcium, suggesting that the signaling function of these pigments is not affected by the link with Ca2+. Finally, we found that both PP and BV (alone and when linked to Ca2+) can transfer energy from its triplet state to molecular-oxygen-producing singlet oxygen, indicating their pro-oxidant capacity. This investigation answers important questions about the function of these pigments, which may help to understand their influence on the reproductive success of birds.

show abstract

Section: Resultsmentioning

confidence: 99%

To Prevent Oxidative Stress, What about Protoporphyrin IX, Biliverdin, and Bilirubin?

Martínez,

López-Rull,

Fargallo

2023

Antioxidants

View full text Add to dashboard Cite

show abstract

“…In 2018, 2019 and 2020, trophic levels were similar amongst individuals independently from their breeding location. Trophic shifts seem to have an important print on physiology as body condition is intimately linked to diet composition ( Wanless et al, 2005 ; Wilson et al, 2005 ; Jodice et al, 2006 ; Barrionuevo et al, 2018 ; Colominas-Ciuró et al, 2022b ). Changes in diet correlating to changes in stress levels may indicate slightly better or worse breeding seasons even if these changes do not visibly impact on breeding success ( Welcker et al, 2009 ; Blanco et al, 2022 ).…”

Section: Discussionmentioning

confidence: 99%

“…Physiological stress due to shifts in diet or nutritional deficiencies has also been described in many species ( Jodice et al, 2006 ; Colominas-Ciuró et al, 2022b ). In seabirds, years of lower prey availability have been linked to higher stress levels and lower breeding performance ( Kitaysky et al, 2007 ; Will et al, 2015 ; Fromant et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

The influence of tourist visitation on the heterophyl to lymphocyte ratios and trophic values of Magellanic penguins (Spheniscus magellanicus) at Martillo Island, Argentina

Harris,

Scioscia,

Raya Rey

2023

Conservation Physiology

View full text Add to dashboard Cite

Wildlife tourism is increasing worldwide and monitoring the impact of tourism on wild populations is of the utmost importance for species conservation. The Magellanic penguin Spheniscus magellanicus colony at Martillo Island, Argentina, was studied in the 2016–2020 breeding seasons. In all seasons, adults and chicks belonged to: (i) an area close to or within the tourist trail or (ii) an area far from the tourist trail and out of sight of the tourists. Blood samples were taken for carbon and nitrogen stable isotope composition, in order to estimate trophic niches, and for smears that were made in situ and were then stained in the laboratory where leucocyte counts and differentiation were made under optical microscope. Heterophil to lymphocyte ratios were used as proxies of stress. Repeated sampling showed individual stress levels reduced while wintering. In 2017, stress levels and trophic values were lower than 2018 for the same individuals. Trophic levels did not differ between tourism and no tourism areas within each season, and differed between 2017 and the remaining seasons, indicating a possible diet shift that year. Stress levels were higher for the tourism area than the no tourism area for adults and chicks in all years except for 2020, when stress levels in the tourism area were lower and similar to the no tourism area that year and previous years. Vessel transit within the Beagle Channel and tourist visitation to the penguin colony was greatly reduced in 2020 due to the Covid-19 pandemic. A combination of internal characteristics and external factors may be affecting the stress physiology of individuals. Therefore, future research should include sampling of multiple aspects of penguin physiology, behaviour and environmental context in order to evaluate each effect on Magellanic penguin stress and, ultimately, inform the conservation of this iconic species in time.

show abstract

“…Endogenous ROS produced during immune response have been identified as a key factor in male infertility (Dowling & Simmons, 2009;Nassan et al, 2018); subsequently dietary supplementation of antioxidants has been suggested as a suitable way to increase sperm quality in males struggling with fertility (Nassan et al, 2018;Zini et al, 2009). There is evidence that vegetarian, non-meat diets are rich in antioxidants (Benzie, 2003), and research on sex-based dietary differences in Magellanic penguins (Spheniscus magellanicus) found that significantly lower levels of the antioxidant αtocopherol were associated with higher trophic level foraging in males (Colominas-Ciuró et al, 2022).…”

Section: Resultsmentioning

confidence: 99%

Reproductive Fitness in Male Tuatara (Sphenodon punctatus) and its Implications

Lamar¹

View full text Add to dashboard Cite

Sexual selection and variation in mating success in the mate-limited sex provide the underpinning for the evolution of many unique traits. Understanding the evolutionary costs of and relationships among these traits can inform our knowledge of sexual selection across the tree of life and provide species-specific improvements in conservation practices. Despite facing an ongoing extinction crisis, the evolution of sexual traits and variation in reproductive fitness is understudied in reptiles. Tuatara (Sphenodon punctatus) are culturally significant reptiles endemic to Aotearoa New Zealand. The sole survivors of the once widespread reptile order Rhynchocephalia, they are of extreme evolutionary, and thus conservation, importance. While many conservation successes have been achieved since tuatara were at their lowest numbers following severe human-associated range restrictions, we still know very little about reproductive fitness in males of this species. Thus, I undertook a large study investigating male sperm quality, dietary intake, immune function, morphological characteristics, and the relationship among these factors in a population of tuatara living on Takapourewa (Stephens Island). I provide the first description of tuatara, and thus Rhynchocephalian, mature sperm, including: summary statistics of sperm head length, midpiece length, tail length, percent viability, and curvilinear velocity. I found that tuatara sperm are long and fast but have poor viability relative to other reptile species. I did not find any significant trade-off between percent viability and curvilinear velocity in male tuatara, but there was weak support for the influence of tail length and midpiece length on sperm swim speed. Tail length was positively associated with faster sperm swim speeds, while midpiece length was negatively associated with faster sperm swim speeds. I also carried out preliminary work exploring the efficacy of different buffers and cryopreservatives at maintaining sperm cell membrane integrity and swim speed after freezing and thawing. I found that PBS was an effective buffer and that Lake’s cryoprotectant is not suitable for use in this species. Next, I used morphological measurements and stable isotope analyses (Δ13C and Δ15N) to establish that tuatara with larger gapes have higher levels of marine-associated (seabird) carbon in their diets. Additionally, tuatara with larger gapes tended to have better overall body condition, be longer (larger snout-vent length), and have larger caudal fat stores. Tuatara are sexually dimorphic, with males being larger and larger males dominating mating opportunities. These results indicate that male tuatara most likely to mate consume a disproportionately larger amount of seabird material on Takapourewa. Using historical blood smears collected from tuatara living on both Takapourewa and a resource-restricted island (North Brother Island), I established reference intervals for tuatara leukocyte profiles for the first time and explored the factors influencing tuatara immune function. I found that tuatara leukocytes display circannual rhythm and that the source population and date of sample collection were the most consistent predictors of leukocyte profile makeup in this species. Interestingly, I found that individuals from a resource-restricted, inbred population with poor body condition and showing evidence of chronic stress (determined via increased heterophil: lymphocyte ratio) were still able to mount responses to immune challenge, as measured by nitric oxide production. Finally, I looked at the trade-off between the many factors explored in this thesis: morphological characteristics known or thought to be under selection from female mate choice (body condition, gape size, and dorsal and nuchal spine number/area), dietary intake (Δ13C and Δ15N), immune status (heterophil:lymphocyte ratio, total number of leukocytes, and ectoparasite load), and sperm quality (viability and curvilinear velocity). I found evidence of an immunocompetence handicap, with both measures of sperm quality being negatively associated with body condition and the ratio of heterophils:lymphocytes. These relationships are likely the result of testosterone-induced immunosuppression and an increase in metabolic rate. I also found evidence of signal dishonesty in relation to tuatara sperm swim speed. Faster sperm were associated with smaller spine area, a trait known to be negatively associated with female mate choice. Lastly, I found evidence of the effects of diet on tuatara sperm swim speeds. Tuatara with higher (less negative) Δ13C values had slower swimming sperm, possibly a consequence of oxidation damage associated with marine-derived dietary items. These results combine to provide support for a trade-off between immune and endocrine system investment, mediated by diet, in this unique reptile. This work expands our understanding of sexual selection and the costs of reproductive fitness to a new order and provide important context for future conservation practices in this species.

show abstract

Sex matters? Association between foraging behaviour, diet, and physiology in Magellanic penguins

Cited by 5 publications

References 73 publications

To Prevent Oxidative Stress, What about Protoporphyrin IX, Biliverdin, and Bilirubin?

To Prevent Oxidative Stress, What about Protoporphyrin IX, Biliverdin, and Bilirubin?

The influence of tourist visitation on the heterophyl to lymphocyte ratios and trophic values of Magellanic penguins (Spheniscus magellanicus) at Martillo Island, Argentina

Reproductive Fitness in Male Tuatara (Sphenodon punctatus) and its Implications

Contact Info

Product

Resources

About