Predicting the effects of body size, temperature and diet on animal feeding rates

• Published in: Functional ecology 2021-10, Vol.35 (10), p.2229-2240
• Main Authors: Nunes, Lucas T., Barneche, Diego R., Lastrucci, Naomi S., Fraga, Alana A., Nunes, José A. C. C., Ferreira, Carlos E. L., Floeter, Sergio R.
• Format: Article
• Language: English
• Subjects: bite rates; Body size; Body temperature; consumption rates; Detritus; Diet; Ecophysiology; Energy flow; Feeding rates; Food chains; Food webs; nutrients; Ocean temperature; Ophioblennius; Populations; Predictions; reef fish; Skewed distributions; Taxa; Temperature
• ISSN: 0269-8463; 1365-2435
• DOI: 10.1111/1365-2435.13872

Consumption rates constitute a fundamental, yet relatively elusive quantity in ecophysiology and ecosystem ecology. Measuring consumption rates of highly mobile animals is often challenging, especially in the wild, which makes scientists rely on proxies such as bite rates. However, we still lack a theoretical framework that formally bridges these quantities. Here we expanded a model based on the Metabolic Theory of Ecology to quantitatively characterise how consumption rates are related to bite rates, and predict how the latter should change with body size, temperature and diet. We test our predictions using mensurative experiments from eight populations of redlip blennies—genus Ophioblennius—across the Atlantic Ocean. Bite rates scaled with body size according to our theoretical predictions. On the other hand, they increased at a faster‐than‐predicted rate with rising temperatures. This finding might be explained if the energetic content of Ophioblennius spp. diet—which is primarily composed by detritus across all populations—decreases with temperature. Yet, they seem to be consistent with the idea that populations adapted to warmer environments exhibit higher‐than‐expected grazing pressure on primary producers. Current ocean warming is set to skew body size distributions towards smaller sizes, and our model indicates that the combined effects of smaller sizes and higher temperatures will increase mass‐specific consumption rates, with direct implications for how energy flows through food webs. Resumo As taxas de consumo constituem uma quantificação fundamental dentro daecofisiologia e ecologia de ecossistemas. Porém, medir a taxa de consumo deanimais é muitas vezes desafiador, especialmente na natureza, o que faz oscientistas utilizarem quantificações aproximadas, como a taxa de mordidas.Entretanto, ainda carecemos de um arcabouço teórico para conectar essas duasquantificações (taxa de consumo vs. taxa de mordidas). Neste estudo, nós propomos um modelo baseado na Teoria Metabólica daEcologia para, quantitativamente, caracterizar como as taxas de consumo estãorelacionadas às taxas de mordida e prever como esta última deve mudar com otamanho corporal dos indivíduos, temperatura do ambiente e dieta. Testamosnossas previsões usando dados observacionais de oito populações de peixesrecifais, do gênero Ophioblennius, distribuídas no Oceano Atlântico. Nós descobrimos que a taxa de mordidas está inversamente relacionada como tamanho corporal dos indivíduos de acor