COVID-19 as a chronic stressor and the importance of individual identity: A data-driven look at academic productivity during the pandemic.

The COVID-19 pandemic impacted personal and professional life. For academics, research, teaching, and service tasks were upended and we all had to navigate the altered landscape. However, some individuals faced a disproportionate burden, particularly academics with minoritized identities or those who were early career, were caregivers, or had intersecting identities. As comparative endocrinologists, we determine how aspects of individual and species-level variation influence response to, recovery from, and resilience in the face of stressors. Here, we flip that framework and apply an integrative biological lens to the impact of the COVID-19 chronic stressor on our endocrine community. We address how the pandemic altered impact factors of academia (e.g., scholarly products) and relatedly, how factors of impact (e.g., sex, gender, race, career stage, caregiver status, etc.) altered the way in which individuals could respond. We predict the pandemic will have long-term impacts on the population dynamics, composition, and landscape of our academic ecosystem. Impact factors of research, namely journal submissions, were altered by COVID-19, and women authors saw a big dip. We discuss this broadly and then report General and Comparative Endocrinology (GCE) manuscript submission and acceptance status by gender and geographic region from 2019 to 2023. We also summarize how the pandemic impacted individuals with different axes of identity, how academic institutions have responded, compile proposed solutions, and conclude with a discussion on what we can all do to (re)build the academy in an equitable way. At GCE, the first author positions had gender parity, but men outnumbered women at the corresponding author position. Region of manuscript origin mattered for submission and acceptance rates, and women authors from Asia and the Middle East were the most heavily impacted by the pandemic. The number of manuscripts submitted dropped after year 1 of the pandemic and has not yet recovered. Thus, COVID-19 was a chronic stressor for the GCE community.

Contrasting effects of transdermal and implant corticosterone treatments in the American bullfrog wound healing.

Glucocorticoid (GC) release is triggered by adverse stimuli that activate the hypothalamus-pituitary-adrenal/interrenal axis. Glucocorticoids may enhance or suppress immune functions depending on the level of elevation. In this study, we investigated the effects of transient and chronic increase of corticosterone (CORT) on the wound healing of the American bullfrog. Frogs were submitted to a daily transdermal hormonal application that acutely elevated CORT plasma levels, or vehicle as a control. Other frogs were surgically implanted with a silastic tube filled with CORT that resulted in chronic elevation of CORT plasma levels or received empty implants as a control. A dermal biopsy was performed to create a wound and was photographed every 3 days. Individuals treated with transdermal CORT started healing faster than their control 32 days after the biopsy. Frogs that received CORT implants tended to heal slower than control subjects. Plasma bacterial killing ability was not affected by treatment, which reinforces the constitutive nature of this innate immune trait. By the end of the experiment, frogs from the acute CORT treatment had smaller wounds compared with those receiving the CORT-filled implants, highlighting the differential effects of acute (immunoenhancing) and chronic (immunosuppressive) elevation of CORT plasma levels. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.

Relationships between hormone levels, metabolism and immune response in toads from a semi-arid region.

Steroid hormones (e.g. androgens [AN] and corticosterone [CORT]) modulate complex physiological functions such as reproduction, energy mobilization, metabolism, and immunity. The effects of these steroids on immunocompetence and its metabolic costs can also be affected by fluctuations in environmental resource availability and other factors such as parasitism. To understand these possible interactions, we studied AN and CORT, immune response [swelling response to phytohemagglutinin (PHA) injection and bacterial killing ability (BKA)], parasite load, resting metabolic rate (RMR) and post-immune challenge (PHA injection) oxygen consumption rates during two different phases of the annual cycle of Rhinella jimi toads from the Brazilian semi-arid region (Caatinga), where environmental conditions are highly seasonal. We observed an increase in O2 consumption rates after both PHA and saline (control) injections, indicating a metabolic response to adverse stimuli rather than the immune challenge. Toads showing higher RMR and VO2 after the adverse stimuli (PHA/saline injections) had lower field AN and CORT plasma levels, suggesting these hormones might mediate a metabolic energy conservation strategy both at baseline levels and after adverse stimuli. Parasite load appear to constrain the metabolic response to PHA and saline injections. Additionally, individuals with a higher swelling response to PHA had higher field CORT plasma levels (particularly when males are breeding), which opposes the idea of a possible trade-off between reproductive activity and other physiological traits, indicating the immunoenhancing effects of elevated CORT at physiological levels. BKA did not show a seasonal variation or correlation with body condition or hormone levels, indicating that the immune surveillance mediated by the complement remains constant despite ecological and physiological changes.

Immunoendocrinology and Ecoimmunology in Brazilian Anurans.

This paper reviews several aspects of immunoendocrinology and ecoimmunology in Brazilian species of anurans under investigation for more than a decade, including (1) patterns of annual covariation of circulating steroids, calling behavior and innate immunity, (2) endocrine and immune correlates of calling performance, (3) behavioral and physiological correlates of parasite load, (4) thermal sensitivity of immune function, and (5) endocrine and immunomodulation by experimental exposure to acute and chronic stressors, as well as to endocrine manipulations and simulated infections. Integrated results have shown an immunoprotective role of increased steroid plasma levels during reproductive activity in calling males. Moreover, a higher helminth parasite load is associated with changes in several behavioral and physiological traits under field conditions. We also found anuran innate immunity is generally characterized by eurythermy, with maximal performance observed in temperatures close to normal and fever thermal preferendum. Moreover, the aerobic scope of innate immune response is decreased at fever thermal preferendum. Experimental exposure to stressors results in increased corticosterone plasma levels and immune redistribution, with an impact on immune function depending on the duration of the stress exposure. Interestingly, the fate of immunomodulation by chronic stressors also depends in part on individual body condition. Acute treatment with corticosterone generally enhances immune function, while prolonged exposure results in immunosuppression. Still, the results of hormonal treatment are complex and depend on the dose, duration of treatment, and the immune variable considered. Finally, simulated infection results in complex modulation of the expression of cytokines, increased immune function, activation of the Hypothalamus-Pituitary-Interrenal axis, and decreased activity of the Hypothalamus-Pituitary-Gonadal axis, as well as reduced melatonin plasma levels, suggesting that anurans have a functional Immune-Pineal axis, homologous to that previously described for mammals. These integrated and complementary approaches have contributed to a better understanding of physiological mechanisms and processes, as well as ecological and evolutionary implications of anuran immunoendocrinology.

Fibroblasts as an experimental model system for the study of comparative physiology.

Mechanistic evaluations of processes that underlie organism-level physiology often require reductionist approaches. Dermal fibroblasts offer one such approach. These cells are easily obtained from minimally invasive skin biopsy, making them appropriate for the study of protected and/or logistically challenging species. Cell culture approaches permit extensive and fine-scale sampling regimes as well as gene manipulation techniques that are not feasible in vivo. Fibroblast isolation and culture protocols are outlined here for primary cells, and the benefits and drawbacks of immortalization are discussed. We show examples of physiological metrics that can be used to characterize primary cells (oxygen consumption, translation, proliferation) and readouts that can be informative in understanding cell-level responses to environmental stress (lactate production, heat shock protein induction). Importantly, fibroblasts may display fidelity to whole animal physiological phenotypes, facilitating their study. Fibroblasts from Antarctic Weddell seals show greater resilience to low temperatures and hypoxia exposure than fibroblasts from humans or rats. Fibroblast oxygen consumption rates are not affected by temperature stress in the heat-tolerant camel, whereas similar temperature exposures depress mitochondrial metabolism in fibroblasts from rhinoceros. Finally, dermal fibroblasts from a hibernator, the meadow jumping mouse, better resist experimental cooling than a fibroblast line from the laboratory mouse, with the hibernator demonstrating a greater maintenance of homeostatic processes such as protein translation. These results exemplify the parallels that can be drawn between fibroblast physiology and expectations in vivo, and provide evidence for the power of fibroblasts as a model system to understand comparative physiology and biomedicine.

Epigenomics as a paradigm to understand the nuances of phenotypes.

Quantifying the relative importance of genomic and epigenomic modulators of phenotype is a focal challenge in comparative physiology, but progress is constrained by availability of data and analytic methods. Previous studies have linked physiological features to coding DNA sequence, regulatory DNA sequence, and epigenetic state, but few have disentangled their relative contributions or unambiguously distinguished causative effects ('drivers') from correlations. Progress has been limited by several factors, including the classical approach of treating continuous and fluid phenotypes as discrete and static across time and environment, and difficulty in considering the full diversity of mechanisms that can modulate phenotype, such as gene accessibility, transcription, mRNA processing and translation. We argue that attention to phenotype nuance, progressing to association with epigenetic marks and then causal analyses of the epigenetic mechanism, will enable clearer evaluation of the evolutionary path. This would underlie an essential paradigm shift, and power the search for links between genomic and epigenomic features and physiology. Here, we review the growing knowledge base of gene-regulatory mechanisms and describe their links to phenotype, proposing strategies to address widely recognized challenges.

Elevated corticosterone levels are associated with increased immunocompetence in male toads, both when calling and under experimental conditions.

Circulating androgens can influence immune responses and sexual traits in male vertebrates. However, in the last 20 years, glucocorticoids have also been implicated as a possible source of variation in male sexual traits and immunocompetence. In this context, we studied the relations between male vocal mating display, immunity, androgens, and glucocorticoids in the explosive breeding toad Rhinella granulosa. In the field, males with high calling effort display either high- or low-corticosterone (CORT) plasma levels, but only males with both high calling effort and high CORT plasma levels showed high bacterial killing ability (BKA), suggesting that the acute CORT elevation can be immunostimulatory. CORT treatments increased BKA in laboratory experiments, confirming the functional relationship observed in the field. However, toads treated with a low dose of CORT increased BKA for 10 h after the treatment, while toads that received a high dose increased BKA for only 1 h after the treatment. These results indicate that different CORT doses can result in temporal differences in the immune response. We did not find any relationship between calling effort, immune response (BKA and PHA swelling response), and testosterone plasma levels in the field, or any effects of testosterone treatment on immunocompetence. Our results suggest a complex relationship between calling effort and immunity, mediated by CORT plasma levels.

Who Rules Over Immunology? Seasonal Variation in Body Temperature, Steroid Hormones, and Immune Variables in a Tegu Lizard.

Multiple factors can influence the immune response of ectothermic vertebrates, including body temperature (Tb), gonadal steroids, and seasonality, in ways that are thought to reflect trade-offs between energetic investment in immunity versus reproduction. Hibernating tegu lizards (Salvator merianae) are a unique model to investigate how immunocompetence might be influenced by different factors during their annual cycle. We assessed immunological measures (plasma bacterial killing ability, total and differential leukocyte count), plasma hormone levels (testosterone in males, estradiol and progesterone in females, and corticosterone [CORT] in both sexes), Tb, and body condition from adult tegus during each stage of their annual cycle: reproduction, post-reproduction/preparation for hibernation, and hibernation. Our hypothesis that immune traits present higher values during the reproductive phase, and a sharp decrease during hibernation, was partially supported. Immune variables did not change between life history stages, except for total number of leukocytes, which was higher at the beginning of the reproductive season (September) in both males and females. Average Tb of the week prior to sampling was positively correlated with number of eosinophils, basophils, monocytes, and azurophils, corroborating other studies showing that when animals maintain a high Tb, there is an increase in immune activity. Surprisingly, no clear relationship between immune traits and gonadal steroids or CORT levels was observed, even when including life history stage in the model. When gonadal hormones peaked in males and females, heterophil: lymphocyte ratio (which often elevates during physiological stress) also increased. Additionally, we did not observe any trade-off between reproduction and immunity traits, sex differences in immune traits, or a correlation between body condition and immune response. Our results suggest that variation in patterns of immune response and correlations with body condition and hormone secretion across the year can depend upon the specific hormone and immune trait, and that experienced Tb is an important variable determining immune response in ectotherms.

Effects of corticosterone treatment and wound healing on reproductive traits of American bullfrogs.

During reproductive season, calling anuran males display high testosterone (T) and episodically high corticosterone (CORT) plasma levels, which are positively associated with higher calling rates and immunocompetence. However, exposure to constant stress stimuli can result in chronically elevated CORT levels, possibly leading to inhibition of reproductive and immune activity. Reproduction and immune responses are energetically expensive, so when an animal is immunologically challenged, a tradeoff might be expressed, with CORT potentially mediating it. Our aim was to test how episodic and chronic CORT treatments, alongside wound healing, would affect reproduction in American bullfrog males (Lithobates catesbeianus). Forty animals were divided in four groups: Episodic CORT (daily transdermic application of CORT), placebo (daily transdermic application of sesame oil), chronic CORT (subcutaneous CORT silastic implants), and sham control (subcutaneous empty silastic implants). One week after treatments began, animals were punctured in the leg with a biopsy needle and the wound was photographed after 45 days to determine wound healing status (WS). Blood samples were collected throughout the experiment to measure CORT and T plasma levels. After animal euthanasia, testes were dissected, fixed, and analyzed histologically to determine spermatogenic activity (germinative cyst [GmC] morphometrics). As expected, the episodic CORT treatment had no effect on T plasma levels or spermatogenic activity. On the other hand, chronic CORT treatment reduced GmC morphometric traits, indicating suppression of reproduction, although T levels were not altered. In addition, animals from sham control and chronic CORT treatments with higher T levels presented higher WS, which indicates an immune-enhancing T effect.

Challenges of a novel range: Water balance, stress, and immunity in an invasive toad.

Species introduced by human activities can alter the normal functioning of ecosystems promoting negative impacts on native biodiversity, as they can rapidly expand their population size, demonstrating phenotypic plasticity and possible adaptive capacity to novel environments. Twenty years ago, the guttural toad, Sclerophrys gutturalis, was introduced to a peri-urban area of Cape Town, with cooler and drier climatic characteristics than its native source population, Durban, South Africa. Our goal was to understand the phenotypic changes, in terms of physiology and immunity, of populations in native and novel environments. We evaluated body index (BI), field hydration level, plasma corticosterone levels (CORT), proportion of neutrophils: lymphocytes (N: L), plasma bacterial killing ability (BKA), and hematocrit (HTC) in the field, and after standardized stressors (dehydration and movement restriction) in males from the native and invasive populations. Toads from the invasive population presented lower BI and tended to show a lower field hydration state, which is consistent with living in the drier environmental conditions of Cape Town. Additionally, invasive toads also showed higher BKA and N:L ratio under field conditions. After exposure to stressors, invasive animals presented higher BKA than the natives. Individuals from both populations showed increased CORT after dehydration, an intense stressor for these animals. The highest BKA and N:L ratio in the field and after submission to stressors in the laboratory shows that the invasive population has a phenotype that might increase their fitness, leading to adaptive responses in the novel environment and, thus, favoring successful dispersion and population increase.

Helminth Parasites of Three Anuran Species during Reproduction and Drought in the Brazilian Semiarid Caatinga Region.

We investigated the mean abundance of helminths and analyzed helminth composition and structure at the infracommunity and component community levels for 3 anuran species (Pleurodema diplolister, Rhinella jimi, and Rhinella granulosa) from the Caatingas, a semiarid Brazilian region characterized by accentuated seasonality and unpredictability of rains. Data were collected during the reproductive period and during drought, when P. diplolister estivated buried underground but R. jimi and R. granulosa remained foraging actively. We expected higher parasitological parameters during the reproductive period when compared to drought for these 3 anurans. We also expected higher parasite infection in the Rhinella species and higher similarity between their helminth parasite communities when compared to the estivating species, P. diplolister. Contrary to our hypothesis, the season was not related to parasite community structure. As predicted, the Rhinella toads shared more similar species composition of parasite communities. These similarities in the composition of the parasite community between Rhinella species could be due to similar temporal/spatial patterns of activity and phylogenetic proximity. Pleurodema diplolister hosted a more restricted helminth fauna, a result that might be associated with estivation restricting the temporal window available to acquire parasites. This study also presents new helminth fauna records for R. jimi and P. diplolister, and the first helminth fauna record of R. granulosa from the Caatingas in semiarid Brazil.

Biomarker-based assessment of the muscle maintenance and energy status of anurans from an extremely seasonal semi-arid environment, the Brazilian Caatinga.

Strongly seasonal environments pose challenges for performance and survival of animals, especially when resource abundance seasonally fluctuates. We investigated the seasonal variation of key metabolic biomarkers in the muscles of males from three species (Rhinella jimi, R. granulosa and Pleurodema diplolister) of anurans from the drastically seasonal Brazilian semi-arid area, Caatinga. We examined the expression of proteins regulating energy turnover (AMP-activated protein kinase [AMPK] and protein kinase B [AKT]), protein synthesis and homeostasis (total and phosphorylated eukaryotic initiation factor 2α [eIF2α and p-eIF2α] and chaperone proteins [HSP 60, 70, and 90]) in muscles predominantly related to reproduction and locomotion. Cytochrome c oxidase (COX) activity was also assessed as an index of the muscle aerobic capacity. The expression pattern of metabolic biomarkers indicates that the maintenance of muscular function is regulated in a species-specific manner during the drastic seasonal variation. Rhinella jimi and R. granulosa that remain active during the drought appear to maintain muscles through more energy expensive pathways including elevated protein synthesis, while the aestivating P. diplolister employs energy conservation strategy suppressing protein synthesis, decreasing chaperone expression and increasing expression of AMPK. Two (P. diplolister and R. granulosa) of the three studied species activate cell survival pathways during the drought likely to prevent muscle atrophy, and all three studied species maintain the muscle aerobic capacity throughout the year, despite the resource limitation. These strategies are important considering the unpredictability of the reproductive event and high demand on muscular activity during the reproductive season in these amphibians. SUMMARY STATEMENT: We studied seasonal variation of key metabolic biomarkers in the muscles of anurans that experience drastic variation in environmental conditions and differ in seasonal activity patterns.

Exposure to fluctuating temperatures leads to reduced immunity and to stress response in rattlesnakes.

Ectothermic organisms often experience considerable variation in their body temperature throughout the circadian cycle. However, studies focusing on the measurement of physiological traits are usually performed under constant temperature regimes. This mismatch between thermal exposure in the field and experimental conditions could act as a stressor agent, as physiological functions are strongly influenced by temperature. Herein, we asked the question whether constant thermal regimes would cause a stress response and impact the immunity of the South American rattlesnake (Crotalus durissus) when compared with a fluctuating thermal regime. We addressed this question by determining heterophil:lymphocyte (H:L) ratio, plasma bacteria-killing ability (BKA) and corticosterone (CORT) levels in snakes kept under a constant temperature regime at 30°C, and under a fluctuating regime that oscillated between 25°C at night and 35°C during the day. The experiments had a mirrored design, in which half of the snakes were subjected to a fluctuating-to-constant treatment, while the other half was exposed to a constant-to-fluctuating treatment. The shift from constant to fluctuating thermal regime was accompanied by an increase in plasma CORT levels, indicating the activation of a stress response. Exposure to a fluctuating thermal regime at the onset of the experiments induced a decrease in the BKA of rattlesnakes. H:L ratio was not affected by treatments and, therefore, the shift between thermal regimes seems to have acted as a low-intensity stressor. Our results suggest that removal from temperatures close to the snake's preferred body temperature triggers a stress response in rattlesnakes.

Immunomodulation by testosterone and corticosterone in toads: Experimental evidences from transdermal application.

Androgens and glucocorticoids play important roles in vertebrate's reproduction and display complex immunomodulatory functions that may affect survival. In anurans, testosterone and corticosterone are correlated to sexual behavior, reproduction, and immune function. Male toads (Rhinella jimi) were treated with acute doses of testosterone (T) and corticosterone (CORT) and immune variables (plasma bacterial killing ability [BKA], swelling after phytohemagglutinin [PHA] injection and the time point of maximum PHA swelling response) were measured. Transdermal T and CORT application increased androgen (T-DHT) and CORT plasma levels after 1 h of treatment, respectively, without a dose-specific effect. Transdermal T treatment did not affect BKA or PHA swelling response. Individuals treated with transdermal CORT showed an earlier maximum PHA swelling response and a tendency of lower BKA 15 h after treatment. Our results indicated that an acute experimental increase of CORT plasma levels diminished time for inflammatory resolution and suppressed non-cellular innate response.

Behavioral, physiological and morphological correlates of parasite intensity in the wild Cururu toad (Rhinella icterica).

Large numbers of parasites are found in various organs of anuran amphibians, with parasite intensities thought to modulate the host's Darwinian fitness traits. Interaction between the anuran hosts and their multiple parasites should modulate the host's phenotypic characteristic, such as those associated with high energetic demand (such as calling effort and locomotor performance), energy balance (standard metabolic rate), and morphological plasticity (as indicated by organ masses). The present study investigated the impact of parasite intensities on the behavioral, physiological, and morphological traits of wild adult male Rhinella icterica (Anura: Bufonidae). We tested as to whether individuals with higher parasite intensities would present: 1) lower vocal calling effort in the field, as well as poorer locomotor performance and body-condition index; and 2) higher standard metabolic rates and internal organ masses. Measurements included: calling effort in the field; standard metabolic rate; locomotor performance; parasite intensity; internal organ masses (heart, liver, kidneys, intestines, stomach, lungs, hind limb muscle, and spleen); and the body-condition index. Results showed a negative association of parasite intensities with locomotor performance, and standard metabolic rate of R. icterica. A positive association between parasite intensities and relative organ masses (heart, intestines and kidneys) was also evident. Toads with higher pulmonary and intestinal parasites intensities also showed higher total parasite intensities.

Seasonal Patterns of Variation in Steroid Plasma Levels and Immune Parameters in Anurans from Brazilian Semiarid Area.

Elevated androgens and glucocorticoids displayed by males during the reproductive season have been proposed to mediate a possible trade-off between reproduction and immunocompetence. Anurans living in arid and semiarid environments display a strong seasonal reproduction, which could accentuate the variation in physiological, immunological, and behavioral parameters. We studied covariation between steroid plasma levels, morphometric variables associated with body condition and immunity, leukocyte profile, parasite load, and response to an immunological challenge across different phases of the annual life-history cycle of three anuran species from a Brazilian semiarid area. Our results showed a seasonal pattern of covariation among leukocyte parameters, kidney mass, and steroid plasma levels, with higher values measured during the reproductive season, particularly when males were sampled during calling activity. Moreover, these anurans showed a stronger response to an immunological challenge during the reproductive period. The immunosuppression during the dry period was particularly evident for the species that aestivate, indicating that the availability of energetic resources might be an important factor determining seasonal variation in inflammatory response. Intensity of the helminth infection was associated with eosinophil count but showed a more complex pattern with regard to androgens levels. These data emphasize that variations in the intensity of helminth infection might be more closely related to specific aspects of the immune response than to the general seasonal patterns of variation in steroid plasma levels, total circulating leukocytes, and inflammatory response.

Breeding under unpredictable conditions: Annual variation in gonadal maturation, energetic reserves and plasma levels of androgens and corticosterone in anurans from the Brazilian semi-arid.

Anurans living in arid and semi-arid habitats are subjected to unpredictable rain patterns. Consequently, they should be prepared to reproduce at the onset of rain events. We investigated the covariation between calling behavior, testicular maturation, abdominal fat body index (FBI), plasma levels of androgens (T-DHT) and corticosterone (CORT) of males from three species of anurans in the Brazilian semi-arid during the reproductive period and drought. One of these species aestivates during the drought, while the other two species remain foraging. Although the three species display different behavioral strategies during the dry period, they present the same general reproductive patterns. T-DHT levels on the plasma and germinative cyst diameters were higher during the reproductive and breeding period compared to the drought. Additionally, the germinative cysts had all cell stages including sperm bundles during the dry season, however, it was only during the breeding event that free spermatozoa were found in the cyst lumen. These results suggest that these species present the reproductive pattern typical of desert anurans, consisting of opportunistic breeders that reproduce when triggered by a rain stimulus. Rhinella jimi and Pleurodema diplolister had higher CORT when males were calling. Moreover, Rhinella granulosa and P. diplolister showed lower FBI during breeding event, when males were calling. The high levels of CORT and lower FBI during reproductive period are associated, indicating that CORT modulates the recruitment of energy stores to prepare and maintain reproduction, particularly the expensive calling effort.

Nematoda of Kinosternon scorpioides (Testudines: Kinosternidae) from Northeastern Brazil.

The scorpion mud turtle (Kinosternon scorpioides) is a small freshwater turtle broadly distributed in South America and commonly consumed in some Brazilian regions. This study aimed to identify the species of helminths that parasitize the digestive tract of K. scorpioides and report infection parameters such as parasite prevalence, mean intensity of the infection, abundance, and the relationship between these nematodes and host body size in this species. We captured 20 adult male K. scorpioides, and 6 animals had nematodes in their gastrointestinal tract. These animals had Serpinema magathi (prevalence = 0.3) and Spiroxys figueiredoi (prevalence = 0.25). There were no correlations between the number of total parasites and carapace length (rs = 0.17, n = 6, P = 0.74) or the length of the gastrointestinal tract (rs = 0.18, n = 6, P = 0.73).

Helminth parasites of Hypsiboas prasinus (Anura: Hylidae) from two Atlantic forest fragments, São Paulo State, Brazil.

Seventy-seven males of Hypsiboas prasinus from 2 Atlantic forest fragments in the municipalities of Botucatu and Jundiaí, São Paulo State, Brazil, were examined for endoparasites. The frogs were captured in summer (January until March) and winter (July/August) of 2008 and 2009. Thirty-three males (75%) from Botucatu were infected with Rhabdias cf. fuelleborni , cosmocerciid nematodes, and Cylindrotaenia americana . Twenty-five tree frogs (78.5%) from Jundiaí were infected by Rhabdias cf. fuelleborni , Physaloptera sp., and cosmocerciid nematodes. Only cosmocerciid nematodes presented a statistically significance difference in prevalence (z  =  4.345; P < 0.001) and mean abundance (t  =  562.0; P < 0.001) between Botucatu and Jundiaí during the winter. Also, the cosmocerciids exhibited higher mean abundance (t  =  196.0; P  =  0.034) in winter when compared with summer at the Jundiaí site. Moreover, to our knowledge, this is the first report of C. americana in the Brazilian Hylidae. This study presents 4 new records of nematodes in H. prasinus .