Toad

About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.

Chemical cues that attract cannibalistic cane toad (Rhinella marina) larvae to vulnerable embryos.

Abstract: Chemical cues produced by late-stage embryos of the cane toad (Rhinella marina) attract older conspecific larvae, which are highly cannibalistic and can consume an entire clutch. To clarify the molecular basis of this attraction response, we presented captive tadpoles with components present in toad eggs. As previously reported, attractivity arises from the distinctive toxins (bufadienolides) produced by cane toads, with some toxins (e.g., bufagenins) much stronger attractants than others (e.g., bufotoxins). Extracts of frozen toad parotoid glands (rich in bufagenins) were more attractive than were fresh MeOH extracts of the parotoid secretion (rich in bufotoxins), and purified marinobufagin was more effective than marinobufotoxin. Cardenolide aglycones (e.g., digitoxigenin) were active attractors, whereas C-3 glycosides (e.g., digoxin, oubain) were far less effective. A structure-activity relationship study revealed that tadpole attractant potency strongly correlated with Na+/K+ ATPase inhibitory activity, suggesting that tadpoles monitor and rapidly react to perturbations to Na+/K+ ATPase activity.

Morphological and morphometric study on the early developmental stages of the Egyptian toad Bufo regularies Reuss

Abstract: Aims: this study aimed to examine the developmental changes in external morphology characters for some embryonic larval period of Bufo regularis from river Nile, Assuit, Egypt. Methods: Our experiment started when tadpoles began to feed. the adapted embryos were divided into three large tanks, each with 200 embryos. collecting of samples started from feeding age every three days until end of metamorphosis (the absorption of tail). External measurements of the early developmental stages including body height (bH), body width (bW), eye diameter (ED), forelimb length (FLL), head-body length (H-bL), hind limb length (HLL), internarial distance (IND), interorbital distance (IOD), nostril diameter (ND), distance between nariel and orbital (NOD), tail length (tAL), tail height (tH), total length (tL), tail muscle height (tMH) and body weight (bWE) were recorded. results: the morphological description reported for each stage indicated many differences between the different developmental stages. conclusion: this study may be considered as morphological key for the different developmental stages of the Egyptian toad tadpoles (Bufo regularis). Alaa El-Din H. Sayed1, Ekbal T. Wassif1, Afaf I. Elballouz1,2 Affiliations: 1Zoology department, Faculty of Science, Assiut University, 71516Assiut, Egypt; 1, 2Zoology department, Faculty of Science, Misurate University, Misurate, Libya. Corresponding Author: Alaa El-Din Hamid Sayed, Zoology department, Faculty of Science, Assiut University, 71516Assiut, Egypt; Email: alaa_h254@yahoo.com (A. H. Sayed) Received: 21 October 2015 Accepted: 17 December 2015 Published: 29 February 2016