You are what, where, and when you eat: seasonal and ontogenetic changes in a tropical tadpole’s diet

Abstract

Tadpole diet is likely to vary in response to environmental conditions and nutritional needs throughout growth and development. We investigated seasonal variation in diet composition of Bokermannohyla saxicola tadpoles and compared diets between two developmental stages with a significant difference in size. We found that the diet of B. saxicola tadpoles was dominated by periphytic algae, in accordance with their benthic habits. Considering number of cells ingested, tadpole trophic niches were broader in more advanced developmental stages. Tadpole trophic niches were narrower during the summer (wet season) than during the winter (dry season), which may reflect increased consumption of more energetic food items during the warm period when primary productivity is expected to be higher. Tadpole metabolism is likely to be higher in the summer and increased energetic needs might be supplied in this manner. However, results differed when biovolume was considered instead of number of cells ingested, with larger items assuming a greater importance and niches being usually larger in the summer. In these cases, the increased ingestion of diatoms (likely to be more nutritive) in the summer may decrease the relative importance of large algae (e.g., Mougeotia sp.) that form the bulk of the diet. Both food availability/accessibility and tadpole feeding behaviour driven by nutritional needs may influence patterns of food acquisition. Given the importance of biofilms to tadpole diet, studies on the mechanisms by which tadpole nutritional needs and environmental conditions interact are likely to provide important insights into the dynamics of aquatic food webs.

Taste for pollen comes in different shapes: Consumption by tadpoles from three divergent ecomorphotypes

“…Tadpoles have long guts, already interpreted as an adaptive compensation for reduced peristaltic movements and lack of glands that produce efficient digestive enzymes (Altig et al, 2007). The presence of sand grains in tadpole guts has already been recorded (Kloh et al, 2018) and future studies should investigate the hypothesis that their ingestion could be intentional as a strategy to break resistant food items, such as pollen grains and rigid cellulosic or siliceous cell walls of algae and diatoms (Bacillariophyta). The presence of broken grains in the guts of all studied species corroborates an important adaptation for pollen digestion by the studied tadpoles.…”

“…For diet analyses, we removed the guts and divided them into three sections of equal length (Kloh et al., 2018) to compare pollen grain breaking levels: the proximal section includes the manicotto, the medial section corresponds to a portion of the small intestine, and the distal section includes the colon and the rectum ( sensu Pryor & Bjorndal, 2005). Each section was gently macerated not to damage gut contents and diluted in 1 mL distilled water on a Sedgewick‐Rafter counting chamber, which we examined under optic microscope at 400× magnification.…”

“…Pollen rains can greatly influence temperate aquatic food webs (Masclaux et al, 2013). The role of pollen in aquatic food webs in tropical regions has received little attention; however, the consumption of pollen by amphibian larvae has recently been reported on several occasions (Kloh et al, 2018(Kloh et al, , 2019(Kloh et al, , 2021a(Kloh et al, , 2021b, indicating that it should not be neglected. Pollen rains in temperate regions happen within a short time window and largely driven by wind pollinated gymnosperms (Filipiak, 2016;Masclaux et al, 2013).…”

Uncovering the significance of the ratio of food K:Na in bee ecology and evolution

“…Pollen germination can occur in vitro in the presence of solutions of sugar and water (Stanley & Linskens, 1974) and occurs in the consumer's gut (Roulston & Cane, 2000;Willmer, 2011), including in that of bees (Dobson & Peng, 1997;Kroon et al, 1974;Peng et al, 1985). Many invertebrates not specialized in pollen consumption, such as various spiders (Pfannenstiel, 2012;Smith & Mommsen, 1984;Wilder, 2011) and mantids (Beckman & Hurd, 2003), other predators, ants, various beetles (Lundgren, 2009), and many others (Filipiak, 2016), as well as vertebrates such as frogs, lizards, birds, bats, rodents, marsupials, and monkeys, supplement their diet with pollen due to its exceptional nutritional quality (Grant, 1996;Kloh et al, 2018;Mellink & Riojas-L opez, 2002;Olesen & Valido, 2003;Tattersall & Sussman, 1975;Willmer, 2011). Pollen is also commercially available as a healthy food supplement for humans, who also have access to the nutrient-rich interior of pollen grains through the above mechanisms.…”

Amfibi sebagai model untuk mengembangkan media dan alat peraga pembelajaran sains

“…Untuk mengoptimalkan hasilnya, amfibi dewasa melakukan seleksi tempat pemijahan (Magee, 2019). Seleksi breeding site didasarkan pada karakteristik kolam pemijahan, seperti ketersediaan sumber nutrisi (Jacobson et al, 2019;Kloh et al, 2018), kualitas air (Boyer & Grue, 1994), dan kehadiran predator dan parasit (Szuroczki & Richardson, 2018). Selain secara ovipar, terdapat juga spesies yang berkembangbiak dengan cara ovovivipar (Iskandar et al, 2014;Sandberger-Loua et al, 2016), dan fertilisasi secara internal tanpa bantuan air sebagai medium.…”