Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability

Abstract

Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpoles in water with either high (80mg/l CaCO 3), medium (50mg/l CaCO 3), or low calcium hardness (20mg/l CaCO 3), each was combined with high (1.74 mg/l PO 4) or low (0.36 mg/l PO 4) phosphate levels. We found that calcium supplementation significantly improved tadpole survival from 19% to 49% and that low calcium treatments had 60% SLS that was reduced to about 15% at the medium and high calcium treatments. Phosphate supplementation significantly reduced SLS prevalence in low calcium treatments. This experimental research clearly links SLS to the calcium: phosphate homeostatic system, but we were unable to completely eliminate the issue, suggesting an interactive role of other unidentified factors.

Captive breeding, embryonic and larval development of Ranitomeya variabilis (Zimmermann & Zimmermann, 1988), (Anura, Dendrobatidae)

“…Or, it may be related to the proliferation of lethal bacteria or fungi resulting from food decomposition ( McWilliams 2008 ). More recently, deaths of larvae and metamorphs have been linked to Spiny Leg Syndrome, a common anomaly of musculoskeletal origin associated with captive breeding of amphibians ( Camperio Ciani et al 2018 ; Lassiter et al 2020 ). The factors that trigger Spiny Leg Syndrome are still not entirely clear, but studies indicate that factors such as water quality, lack or excess nutrients and minerals are related to this anomaly ( Barrows et al 2017 ; Camperio Ciani et al 2018 ; Lassiter et al 2020 ).…”

“…More recently, deaths of larvae and metamorphs have been linked to Spiny Leg Syndrome, a common anomaly of musculoskeletal origin associated with captive breeding of amphibians ( Camperio Ciani et al 2018 ; Lassiter et al 2020 ). The factors that trigger Spiny Leg Syndrome are still not entirely clear, but studies indicate that factors such as water quality, lack or excess nutrients and minerals are related to this anomaly ( Barrows et al 2017 ; Camperio Ciani et al 2018 ; Lassiter et al 2020 ). Given our small sample size, we assume that it may be premature to infer that the high mortality in our sample is integrally related to this syndrome.…”

Observations on spindly leg syndrome in a captive population ofAndinobates geminisae

“…The change in the phosphate:calcium ratio of the tadpole rearing water was unintentional and so we are not presenting a new putative SLS factor. However, in light of multiple instances of correlation between an increased phosphate:calcium ratio in tadpole rearing water and increased prevalence of SLS and the recent experimental demonstration of this phenomena by Lassiter et al (2020), the body of data currently available points to phosphateinduced calcium deficiency as a candidate hypothesis for the etiology of SLS and provides ex-situ conservation projects with important information to consider when designing husbandry protocols for populations afflicted by SLS.…”