Which frog's legs do froggies eat? The use of DNA barcoding for identification of deep frozen frog legs (Dicroglossidae, Amphibia) commercialized in France

Abstract

Abstract. Several millions frogs captured in the wild in Indonesia are sold for food yearly in French supermarkets, as deep frozen frog legs. They are commercialized as Rana macrodon, but up to 15 lookalike species might also be concerned by this trade. From December 2012 to May 2013, we bought 209 specimens of deep frozen frog legs, and identified them through a barcoding approach based on the 16S gene. Our results show that 206 out of the 209 specimens belong to Fejervarya cancrivora, two to Limnonectes macrodon and one to F. moodiei. Thus only 0.96 % of the frogs were correctly identified. Unless misclassification was intentional, it seems that Indonesian frog leg exporters are not able to discriminate between the species. The quasi absence of L. macrodon in our samples might be an indication of its rarity, confirming that its natural populations are declining rapidly, in agreement with its "vulnerable" status according to the IUCN Red List. Our results show that the genetic and morphological diversity of the frogs in trade is much higher than the genetic and morphological diversity measured so far by scientific studies. These results underline the need for large scale studies to assess the status of wild populations.

A new frog of the Eleutherodactylus abbotti species group (Anura: Eleutherodactylidae) from Hispaniola, with bioacoustic and taxonomic comments on other species

“…Padial et al (2014) did not include E. notidodes and E. melatrigonum in their analysis, but recognized them as different species within the E. abbotti species group. We are aware that our phylogeny is limited to the 16S rRNA gene, and thus constitutes a matrilineal genealogy only; however, this gene has proven to be very useful for species delimitations in amphibians (ie: Vences et al, 2005;Vences et al, 2008;Maya-Soriano et al, 2012;Grosjean et al, 2015;Rockney et al, 2015;Ohler and Nicolas, 2017). Eleutherodactylus geitonos sp.…”

Using the 2020 global pandemic as a springboard to highlight the need for amphibian conservation in eastern Asia

“…Rana aurora draytoni and Rana pipiens ; Jennings and Hayes, 1985 ; Lannoo et al, 1994 ) and France (e.g. Rana temporaria and Rana esculenta ) has already impacted amphibians through the loss of large populations of some species ( Le Serrec, 1988 ; Neveu, 2004 ; Ohler and Nicolas, 2017 ). These countries are now relying on imported frog meat that is generally not traceable ( Ohler and Nicolas, 2017 ; Krishnasamy and Zavagli, 2020 ).…”

“…Rana temporaria and Rana esculenta ) has already impacted amphibians through the loss of large populations of some species ( Le Serrec, 1988 ; Neveu, 2004 ; Ohler and Nicolas, 2017 ). These countries are now relying on imported frog meat that is generally not traceable ( Ohler and Nicolas, 2017 ; Krishnasamy and Zavagli, 2020 ). In addition, a significant proportion of the current amphibian trade for food and pets is unsustainable, likely to involve laundering of wild-caught specimens as captive-bred ( Krishnasamy and Zavagli, 2020 ; Warkentin et al, 2009 ), and likely to spread batrachochytrids ( Gratwicke et al, 2010 ; Kolby et al, 2014 ) and other pathogens ( Gilbert et al, 2013 ).…”

Tadpole soup: Chinantec caldo de piedra and behavior of Duellmanohyla ignicolor larvae (Amphibia, Anura, Hylidae)

“…Frogs have been part of the human diet since the early Pleistocene and archeological remains suggest that this consumption was not random ( Kyselý 2008 ; Blasco et al 2011 ). This practice continues in different cultures across the globe ( Cooke 1989 ; Onadeko et al 2011 ; Akinyemi and Ogaga 2015 ; Ohler and Nicolas 2017 ) and in some cases it can become a tangible species threat. For example, in Indonesia, Fejervarya cancrivora (Gravenhorst, 1829) (Least Concern) and Limnonectes macrodon (Duméril & Bibron, 1841) (Least Concern), are exploited for both local consumption and large scale exportation.…”