Communal Nutrition in Ants

School of Biological Sciences and Centre for Mathematical Biology, The University of Sydney, NSW 2006, Australia.
Current biology: CB (Impact Factor: 9.57). 05/2009; 19(9):740-4. DOI: 10.1016/j.cub.2009.03.015
Source: PubMed


Studies on nonsocial insects have elucidated the regulatory strategies employed to meet nutritional demands [1-3]. However, how social insects maintain the supply of an appropriate balance of nutrients at both a collective and an individual level remains unknown. Sociality complicates nutritional regulatory strategies [4-6]. First, the food entering a colony is collected by a small number of workers, which need to adjust their harvesting strategy to the demands for nutrients among individuals within the colony [4-7]. Second, because carbohydrates are used by the workers and proteins consumed by the larvae [7-14], nutritional feedbacks emanating from both must exist and be integrated to determine food exploitation by foragers [4-6, 15, 16]. Here, we show that foraging ants can solve nutritional challenges for the colony by making intricate adjustments to their feeding behavior and nutrient processing, acting both as a collective mouth and gut. The amount and balance of nutrients collected and the precision of regulation depend on the presence of larvae in the colony. Ants improved the macronutrient balance of collected foods by extracting carbohydrates and ejecting proteins. Nevertheless, processing excess protein shortened life span--an effect that was greatly ameliorated in the presence of larvae.

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    • "Many animals also live in groups or populations that simultaneously contain individuals of differing developmental stages, and there is abundant evidence that nutritional requirements change throughout an individual's life cycle (Raubenheimer et al. 2007; Simpson and Raubenheimer 2012). Social insects such as ants, for example, live in colonies with overlapping generations, where optimal diets range from the protein-rich diet needed by growing larvae to the carbohydrate-rich diet eaten by nonreproductive adults for colony maintenance (Dussutour and Simpson 2009). Finally , even where individuals appear the same sex and age, heterogeneity in many other traits that may correlate with nutritional requirements is readily observable; examples include between-individual variation in metabolic rate, body size, and life-history strategy (Cam et al. 2002; Honěk 1993; Huchard et al. 2014; Lim et al. 2014; Mathot and Dingemanse 2015). "
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    • "Adult ants cannot properly digest protein; thus, in the absence of developing brood, colonies accumulate too much protein and die [60]. When brood are present, their requirement for protein regulates the amount of protein and carbohydrates the foraging workers bring back to the colony [60]. In both instances, animals and insect colonies, specialised components regulate the intake of nutrients (brain and peripheral organs in animals, foraging workers and brood in ants). "
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    • "Regulation of nutrient intake has already been observed in several ant species, e.g. Solenopsis invicta (Sorensen et al., 1985), Iridomyrmex humilis (Markin, 1970) and Rhytidoponera metallica (Dussutour and Simpson, 2009), as well as in honeybees (Apis mellifera) (Schmickl and Crailsheim, 2004). Thus, social insect colonies are generally able to satisfy the nutritional needs of queen, larvae and workers (Altaye et al., 2010). "
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