Species distribution and assembly patterns of frog larvae in rainforest streams of Madagascar

Abstract

Many tropical rainforests harbour speciesrich assemblages of frogs and, consequently, of tadpoles. These larvae are often morphologically highly diverse, especially in their oral structures. Whether this might represent an important axis of ecological partitioning in frog assemblages remains an untested hypothesis. In general, it is poorly known how diverse tadpole assemblages are organised. Using information from Madagascar's remarkably species-rich stream tadpole assemblages, we analysed the distribution and co-occurrence of 44 species. We also assessed the importance of phylogenetic history and eco-morphological adaptation for habitat selection at two functional and two spatial levels. We show that both rare and common species exist in most morphological clusters and phylogenetic groups of tadpoles. Habitat characteristics of the streams and surrounding forest influence species composition. Whereas there is a general trend in preferring wide and deep streams without a steep slope for most species, some of the morphological clusters separate along specific habitat variables. Stream choice is influenced both by phylogenetic history and morphological adaptation. Within streams, tadpoles partition microhabitat mainly according to their morphological cluster but without phylogenetic signal. Species dissimilarities of habitat selection on both spatial scales are not correlated. We found no evidence for competition in the tadpole assemblages studied.

Transcriptomic and macroevolutionary evidence for phenotypic uncoupling between frog life history phases

“…For larvae, a dataset of 117 characters for 170 mantellid species was assembled for this study, based on tadpole voucher specimens that had previously been identified by DNA barcoding25. Data sets of adult and tadpole measurements overlapped and were jointly analysed for 113 mantellid species.…”

Contrasting effects of functionally distinct tadpole species on nutrient cycling and litter breakdown in a tropical rainforest stream

“…We also recognised seven types of mouthparts, according to the classification proposed by Strauß et al. (): sand eater, reduced teeth, generalised, podgy generalised, fossorial, suctorial and funnel mouthed. Among these, generalised and funnel‐mouthed groups account for more than 70% and 10% in abundance, respectively, of all tadpoles.…”

“…We recorded 27 tadpole species (Ramamonjisoa, 2017) belonging to four genera of Mantellidae: Mantidactylus, Boophis, Spinomantis, Gephyromantis and Guibemantis. We also recognised seven types of mouthparts, according to the classification proposed by Strauß et al (2013): sand eater, reduced teeth, generalised, podgy generalised, fossorial, suctorial and funnel mouthed. Among these, generalised and funnel-mouthed groups account for more than 70% and 10% in abundance, respectively, of all tadpoles.…”

“…However, nutrients bound in faecal pellets are not readily available, but must be mineralised (Liess & Haglund, 2007), suggesting that egestion from tadpoles may represent an important but latent source of nutrients in their respective habitats. Tropical tadpoles are often morphologically highly diverse, especially in their oral structures (Strauß, Randrianiaina, Vences, & Glos, 2013). Mouthparts typically influence diet, which may consequently affect the quality and the quantity of recycled nutrients in tadpoles (Liess et al, 2015).…”

The tadpoles of nine Cameroonian Leptodactylodon species (Amphibia, Anura, Arthroleptidae)

“…Umbelliform oral apparatus or funnel-mouths, are generally hypothesized to be used in microphagous filter-feeding from the surface tension (e.g. Smith 1926;Inger et al 1986;Hoff et al 1999;Altig et al 2007;Grosjean et al 2011;Strauß et al 2013). However, there is evidence that this might not hold true, at least in some tadpole species.…”