Sexual Dimorphisms in Metabolism, Organ Mass, and Reproductive Energetics in Pre-breeding American Toads (<i>Anaxyrus americanus</i>)

Finkler, Michael S.; Hayes, Christopher J.; Rifai, Lina

doi:10.1643/cp-13-167

Cited by 9 publications

(6 citation statements)

References 33 publications

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“…Our study also revealed that, after taking into account differences in body size, females had about a 50% higher production of VCO 2 than males. The direction of this sexual dimorphism for RMR is similar to the results observed for salamanders (Finkler et al ., 2003), mammals (bank voles, Boratynski & Koteja, 2010), and insects (desert fleas, Krasnov et al ., 2004), but different from results on other ectotherms (toads, Finkler et al ., 2014; lizards, Garland and Else, 1987; tarantula, Shillington, 2005; wasp, Tomlinson & Phillips, 2015). Yet, our result is similar to those of a previous study on the frog Xenopus laevis , where females exhibited higher standard metabolic rate than males in populations at the invasion front compared to those from the center of the range (Louppe et al ., 2018).…”

Section: Discussionmentioning

confidence: 99%

“…Regarding amphibians, most studies have focused on salamanders (Finkler et al ., 2003) and showed either higher metabolism in gravid females (Finkler et al ., 2002; Finkler, 2006) or post‐gravid females (Finkler et al ., 2003) than in males or no sex differences (Ryan & Hopkins, 2000). However, studies of sexual dimorphism in RMR in anurans are scant (but see Grafe et al ., 1992; Finkler et al ., 2014). Yet, it is known that investment in reproduction is generally more substantial for females than males, primarily because of the higher mass of eggs compared to sperm.…”

Section: Introductionmentioning

confidence: 99%

“…Gametogenesis in both sexes is driven by gonadotropins, but is more dependent upon net energy balance in females than males, at least in temperate zone anurans (Jørgensen et al ., 1979). One study exploring RMR in cane toads during the breeding season showed that RMR was not different between sexes, yet the positive relationship between (dry) body mass and oxygen consumption at rest was higher in males than females suggesting differences in the ability to allocate resources to physical activity, mate finding, or gametogenesis (Finkler et al ., 2014). However, outside the breeding season, in a non‐reproductive state and under resting condition, it remains unclear whether male and female anurans show differences in resting metabolic rate.…”

Section: Introductionmentioning

confidence: 99%

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Do female frogs have higher resting metabolic rates than males? A case study with Xenopus allofraseri

et al. 2020

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The energetic costs of body maintenance can have a profound influence on the energy that an individual can allocate to other functions such as growth, locomotion, or reproduction. Therefore, resting metabolism can ultimately affect an individual's survival or reproductive success, especially when food is limited. Although males and females often differ in their body composition (e.g. sex organs and fat accumulation) and body size, the occurrence and direction of sexual dimorphism in resting metabolism remains poorly understood in anurans. In the present study, we investigated whether males and females of the false Fraser's clawed frog Xenopus allofraseri differ in their resting metabolic rates. We used an open-flow pushthrough respirometry system to measure the volume of carbon dioxide (VCO 2) produced by animals at rest. Variation in VCO 2min was explained by ambient temperature, body size, and sex. For a similar body size, our results revealed that females had about a 50% higher resting metabolic rate (RMR) than males. We suggest that the enhanced investment in gamete production in females compared to males may explain this difference. We further suggest that a lower RMR in males compared to females at similar body size could be selectively advantageous as unallocated energy may be devoted to costly mating, in support of the 'compensation' hypothesis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Do female frogs have higher resting metabolic rates than males? A case study with Xenopus allofraseri

et al. 2020

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“…A pesar de que una dieta similar puede sugerir la presencia de competencia intraespecífica por los recursos tróficos (Crnobrnja-Isailović et al, 2012), es probable que en C. rhodopis sea mínima, dadas las diferencias intersexuales en el tamaño de las presas; además del bajo número de individuos sin comida. El efecto de la talla de las ranas en el tamaño de las presas, en el que ranas más grandes consumieron presas de mayor tamaño, en comparación con las más pequeñas, podría ser resultado de una estrategia para cubrir la inversión energética designada a la reproducción, mayor en hembras y machos de mayor talla, como se ha reportado para otras especies (Chen, Tang, Fan, Wang, & Pike, 2013;Finkler, Hayes, & Rifai, 2014). El efecto significativo de la interacción del sexo y el tamaño de las ranas sobre el número de presas consumidas, sugiere que la competencia intraespecífica entre adultos podría ser mayor entre machos grandes y hembras pequeñas, ya que son de tamaño similar y consumieron mayor número de presas que las hembras grandes y los machos pequeños.…”

Section: Discussionunclassified

Dieta de la rana de hojarasca Craugastor rhodopis (Anura: Craugastoridae): una especie abundante en la región montañosa del este de México

Luría‐Manzano

Oropeza-Sánchez

Aguilar-López

et al. 2019

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La composición de la dieta en anfibios puede ser influenciada por diversos factores que causan su variación intraespecífica, como pueden ser la distribución geográfica, ontogenia, estacionalidad, y el sexo de los organismos. El objetivo de este estudio fue analizar la composición de la dieta en adultos de la Craugastor rhodopis (rana hojarasquera común) en la región montañosa del centro de Veracruz, México. Un total de 77 individuos adultos fueron colectados durante la época de lluvias de 2012, de los cuales 66 tuvieron contenido estomacal. Se realizó un análisis de la variación intersexual en la diversidad de la dieta, y el volumen, número de presas, y número de categorías de presa consumidas. La dieta de C. rhodopis estuvo compuesta por 20 categorías, de las cuales predominó Orthoptera en cuanto a número, volumen, frecuencia de ocurrencia e importancia relativa. Los machos consumieron presas de menor tamaño en relación a las hembras. Aunque ambos sexos consumieron similar número de presas, se encontró un efecto significativo de la interacción del sexo y el tamaño de las ranas sobre esta variable de la dieta, en la cual las hembras pequeñas consumen más presas que las grandes, y los machos grandes consumen más presas que los pequeños. El alto consumo de ortópteros (al menos en cuanto a volumen) es un fenómeno común dentro de la familia Craugastoridae y posiblemente está relacionado con el éxito de algunas especies en los ecosistemas donde habitan. A pesar de que la composición de la dieta fue similar entre sexos en C. rhodopis, se sugiere que la competencia intersexual por los recursos tróficos es mínima, dadas las diferencias en el tamaño de presas consumidas por machos y hembras.

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“…In contrast, DEE and exposure to predation risk for males often peaks during the mating season for species with female-only parental care [ 7 ]. Sex-related asymmetry in timing of energy allocation towards reproduction can also be augmented by sexual selection that drives the evolution of secondary sexual characteristics, including an energetically expensive increase in body and ornament size (sexual dimorphism), as well as sexual displays and contests between males for access to mates [ 8 , 9 ]. Given the trade-off between energy acquisition and risk of predation, many have hypothesized that sex differences in the timing of energy allocation towards reproduction would generate seasonal differences between sexes in time budgets with respect to foraging activity and risk-aversive behaviours.…”

Section: Introductionmentioning

confidence: 99%

The secret life of ground squirrels: accelerometry reveals sex-dependent plasticity in above-ground activity

et al. 2016

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The sexes differ in how and when they allocate energy towards reproduction, but how this influences phenotypic plasticity in daily activity patterns is unclear. Here, we use collar-mounted light loggers and triaxial accelerometers to examine factors that affect time spent above ground and overall dynamic body acceleration (ODBA), an index of activity-specific energy expenditure, across the active season of free-living, semi-fossorial arctic ground squirrels (Urocitellus parryii). We found high day-to-day variability in time spent above ground and ODBA with most of the variance explained by environmental conditions known to affect thermal exchange. In both years, females spent more time below ground compared with males during parturition and early lactation; however, this difference was fourfold larger in the second year, possibly, because females were in better body condition. Daily ODBA positively correlated with time spent above ground in both sexes, but females were more active per unit time above ground. Consequently, daily ODBA did not differ between the sexes when females were early in lactation, even though females were above ground three to six fewer hours each day. Further, on top of having the additional burden of milk production, ODBA data indicate females also had fragmented rest patterns and were more active during late lactation. Our results indicate that sex differences in reproductive requirements can have a substantial influence on activity patterns, but the size of this effect may be dependent on capital resources accrued during gestation.

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Sexual Dimorphisms in Metabolism, Organ Mass, and Reproductive Energetics in Pre-breeding American Toads (Anaxyrus americanus)

Cited by 9 publications

References 33 publications

Do female frogs have higher resting metabolic rates than males? A case study with Xenopus allofraseri

Do female frogs have higher resting metabolic rates than males? A case study with Xenopus allofraseri

Dieta de la rana de hojarasca Craugastor rhodopis (Anura: Craugastoridae): una especie abundante en la región montañosa del este de México

The secret life of ground squirrels: accelerometry reveals sex-dependent plasticity in above-ground activity

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