Petals in the diet of savanna lizardsAbstract
We recorded Chamaecrista petals from the stomachs of three lizards of two species (Cnemidophorus lemniscatus, Ameiva ameiva) in an Amazonian savanna. The petals completely filled the stomachs of the lizards, so they were not ingested incidentally. The lizards were encountered incidentally as they were killed by ants in mammal traps or found on the road. During the study period, we encountered only one other individual in similar conditions without petals, so most of the lizards in the area are probably ingesting petals. Nutritional analyses indicate that the petals are rich in water and carbohydrates and standard analyses indicate that they are not toxic. Although we cannot discount that the lizards ate the petals to obtain water, heavy rainfall during the period indicates that the petals were not ingested for water balance, so we believe that the petals are an important and overlooked source of nutrition for the savanna lizards.
Keywords
herbivory; florivory; diet; nutrition; reptile; Chamaecrista
INTRODUCTION
Many lizard species are highly generalist feeders, a characteristic that facilitates their survival in arid and seasonally dry environments. Primarily carnivorous lizards may also consume fruits, nectar, and other plant resources (Rocha 2000, Gomes et al. 2014, Paixão et al. 2021, Bezerra-Silva et al. 2024).
Florivory has been recorded in many species of lizards, especially in arid environments (e.g. Paixão et al. 2021, Correcher et al. 2023), which makes it surprising that it has not been recorded from Amazonian savannas. Cnemidophorus lemniscatus and Ameiva ameiva have been recorded eating fruits in an intensive study of lizard diets (Magnusson & da Silva 1993). Those authors did not record petals from the diets of the lizards, but analyses were carried out on preserved specimens, so it is likely that any discoloured largely dehydrated petals were discarded as incidental ingestion.
MATERIALS AND METHODS
We photographed lizards that we found dead during a small-mammal study in the savannas near Alter do Chão, Pará, Brazil (lat. -2.506893, long. -54.950279) between September 2024 and August 2025. The lizards were not collected for this study, but were encountered incidentally.
Approximately 300 g of petals were collected from many different individuals of Chamaecrista ramosa by Pedro Ganança in August 2025 and 100g were analysed using standard techniques recommended by AOAC International (2016) in the Laboratory of Functional Analysis and Food Chemistry, National Institute for Amazonian Research (INPA), Manaus, Amazonas, Brazil.
Toxicity was evaluated by a lethality bioassay following Meyer et al. (1982), with slight modifications (Bezerra et al. 2017, Salay et al. 2024). Briefly, Artemia salina cysts (100 mg) were hatched in 3.5% saline solution (35 g synthetic sea salt in 1 L distilled water) under continuous illumination at 28 °C for 48 h, and groups of 10 nauplii were exposed for 24 h to extract concentrations of 1000, 500, 250, 100, 50, and 25 micrograms/mL. Lapachol was used as a positive control and 1% DMSO as a negative control. Immobile larvae were counted after 24 h and LC50 and LC90 were estimated by probit analysis.
RESULTS
Although unrecorded from the most intensive study of lizard diet in the region, additional observations show that lizard florivory, specifically on Chamaecrista, is a regular occurrence in the Alter do Chão savannas. In September 2024 we recorded a Cnemidophorus lemniscatus with stomach full of Chamaecrista petals (Figure 1). The lizard died in a box trap set for small mammals. In August 2025 we recorded another C. lemniscatus with its stomach filled with Chamaecrista petals that died in a small-mammal trap, and a road-killed Ameiva ameiva with its stomach full of Chamaecrista petals. During the study period, we encountered only one other individual in similar conditions without petals, so most of the lizards in the area are probably ingesting petals. As we do not routinely kill and dissect lizards, these observations indicate that Chamaecrista petals are a regular part of the diet of the larger teiid lizards in the area.
Petals of Chamaecrista sp. found in the stomach of a Cnemidophorus lemniscatus killed by ants in a savanna near Alter do Chão, Pará, Brazil.
The Chamaecrista petals had about 75.7% water, 11.7% carbohydrates, 6.3% fibre, 5.1% protein, 0.77% ash and 0.36% lipids, with low toxicity in standard tests with larvae of Artemia salina (Extract 867.28 ± 0.3, 95% Fiducial limits 764.49 – 986.67; Lapachol 33.51 ± 0.3, 95% Fiducial limits 26.98 – 48.97).
DISCUSSION
Many other species of flowering plants occur in the area (Magnusson et al. 2008) and many bloom in the dry season (Sanaiotti & Magnusson 1995). Some species of lizards eat flowers in periods of food scarcity when other foods are limited (Correcher et al. 2023), but the dates when we found petals in the lizard stomachs correspond to the period of maximum growth of the lizards in the area (Magnusson 1987), so it seems unlikely that the florivory was due to extreme food scarcity.
Opportunistic consumption of plant material by tropical lizards is common and indicates that the lizards are actively seeking nutritional complements to their diet rather than accidental ingestion (e.g. Gomes et al. 2014, Paixão et al. 2021, Bezerra-Silva et al. 2024). Rocha (2000) reported that of the 19 plant species available to Liolaemus lutzae, only the four most nutritious were recorded to be ingested by the species. We therefore analysed the nutritional value of the Chamaecrista petals to obtain clues as to why the lizards were eating them.
Our results indicate that the petals could provide water, but 2025 had regular rainfall during the dry season, including the days on which the lizards were collected, so the lizards probably had access to plentiful sources of water, and it seems likely that the petals were eaten as a source of carbohydrates.
Chamaecrista petals are abundant, easier to collect than the invertebrates that form the greater part of the lizards´ diets, and they appear to have little chemical protection, so the contribution of petals to the diets, and indirectly to the population dynamics, of Amazonian savanna lizards deserves further study.
CONCLUSIONS
Petals make a large, and probably important, contribution to the diets of Amazonian savanna lizards towards the end of the dry season.
Acknowledgements
Funding for the fieldwork in this study was provided by grants CNPq 441260/2023-3, CNPq 406474/2022-2, FAPEAM 01.02.016301.02394/2024-50. The study was also financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brazil (CAPES)—PROEX n. 0742/2020, for PHSG (Ph.D. scholarship); Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Peld Oeste do Pará - PELD-POPA (441443/2016-8, 445954/2024-8).
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