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A long-term experimental study demonstrates the costs of begging that were not found over the short term.

Soler M, Ruiz-Raya F, Carra LG, Medina-Molina E, Ibáñez-Álamo JD, Martín-Gálvez D - PLoS ONE (2014)

Bottom Line: However, empirical evidence on this subject remains elusive because published results are often contradictory.Long-term studies frequently provide clearer results than short-term studies and, sometimes, relevant information not reported by the latter ones.Our long-term experiment shows (i) a clear effect on the immune response even since the first measurement (6 hours), but it was higher during the second (long-term) than during the first (short-term) test; (ii) evidence of a growth cost of begging in house sparrow nestlings not previously found by other studies; (iii) body condition was affected by our experimental manipulation only after 48 hour; (iv) a metabolic cost of begging never previously shown in any species, and (v) for the first time, it has shown a simultaneous effect of the three potential physiological costs of begging: immunocompetence, growth, and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biología Animal, Facultad de Ciencias, Universidad de Granada, Granada, Spain; Grupo Coevolución, Unidad Asociada al CSIC, Universidad de Granada, Spain.

ABSTRACT
Parent-offspring conflict theory predicts that begging behaviour could escalate continuously over evolutionary time if it is not prevented by costliness of begging displays. Three main potential physiological costs have been proposed: growth, immunological and metabolic costs. However, empirical evidence on this subject remains elusive because published results are often contradictory. In this study, we test for the existence of these three potential physiological costs of begging in house sparrow (Passer domesticus) nestlings by stimulating a group of nestlings to beg for longer and another group for shorter periods than in natural conditions. All nestlings were fed with the same quantity of food. Our study involves a long-term experimental treatment for begging studies (five consecutive days). Long-term studies frequently provide clearer results than short-term studies and, sometimes, relevant information not reported by the latter ones. Our long-term experiment shows (i) a clear effect on the immune response even since the first measurement (6 hours), but it was higher during the second (long-term) than during the first (short-term) test; (ii) evidence of a growth cost of begging in house sparrow nestlings not previously found by other studies; (iii) body condition was affected by our experimental manipulation only after 48 hour; (iv) a metabolic cost of begging never previously shown in any species, and (v) for the first time, it has shown a simultaneous effect of the three potential physiological costs of begging: immunocompetence, growth, and metabolism. This implies first, that a multilevel trade-off can occur between begging and all physiological costs and, second, that a lack of support in a short-term experiment for the existence of a tested cost of begging does not mean absence of that cost, because it can be found in a long-term experiment.

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Effect of the experimental treatment on mass excreted by nestlings based on the RM-ANOVAs for each experimental session.P-values associated to LSD post hoc test are indicated as ns: P>0.05; st: 0.1≤P≥0.05; *: P<0.05; **: P<0.001 and ***: P<0.0001. Numbers of nests (i.e. those with measurements from the four nestlings) used in each comparison are also shown.
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pone-0111929-g005: Effect of the experimental treatment on mass excreted by nestlings based on the RM-ANOVAs for each experimental session.P-values associated to LSD post hoc test are indicated as ns: P>0.05; st: 0.1≤P≥0.05; *: P<0.05; **: P<0.001 and ***: P<0.0001. Numbers of nests (i.e. those with measurements from the four nestlings) used in each comparison are also shown.

Mentions: We found no overall effect of the experimental treatment on the mass excreted by nestlings (see Table 2D and Fig. 5). We found one significant result and two trends for the interaction effects between treatment and nestling rank in time 6, time 36, and time 60, respectively (see Fig. 6). Namely, in time 6, HB-large nestling excreted more than LB-large nestlings, but the opposite happened in time 36; in time 60, HB-small nestlings excreted less mass than LB-small nestlings (see Fig. 6).


A long-term experimental study demonstrates the costs of begging that were not found over the short term.

Soler M, Ruiz-Raya F, Carra LG, Medina-Molina E, Ibáñez-Álamo JD, Martín-Gálvez D - PLoS ONE (2014)

Effect of the experimental treatment on mass excreted by nestlings based on the RM-ANOVAs for each experimental session.P-values associated to LSD post hoc test are indicated as ns: P>0.05; st: 0.1≤P≥0.05; *: P<0.05; **: P<0.001 and ***: P<0.0001. Numbers of nests (i.e. those with measurements from the four nestlings) used in each comparison are also shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221185&req=5

pone-0111929-g005: Effect of the experimental treatment on mass excreted by nestlings based on the RM-ANOVAs for each experimental session.P-values associated to LSD post hoc test are indicated as ns: P>0.05; st: 0.1≤P≥0.05; *: P<0.05; **: P<0.001 and ***: P<0.0001. Numbers of nests (i.e. those with measurements from the four nestlings) used in each comparison are also shown.
Mentions: We found no overall effect of the experimental treatment on the mass excreted by nestlings (see Table 2D and Fig. 5). We found one significant result and two trends for the interaction effects between treatment and nestling rank in time 6, time 36, and time 60, respectively (see Fig. 6). Namely, in time 6, HB-large nestling excreted more than LB-large nestlings, but the opposite happened in time 36; in time 60, HB-small nestlings excreted less mass than LB-small nestlings (see Fig. 6).

Bottom Line: However, empirical evidence on this subject remains elusive because published results are often contradictory.Long-term studies frequently provide clearer results than short-term studies and, sometimes, relevant information not reported by the latter ones.Our long-term experiment shows (i) a clear effect on the immune response even since the first measurement (6 hours), but it was higher during the second (long-term) than during the first (short-term) test; (ii) evidence of a growth cost of begging in house sparrow nestlings not previously found by other studies; (iii) body condition was affected by our experimental manipulation only after 48 hour; (iv) a metabolic cost of begging never previously shown in any species, and (v) for the first time, it has shown a simultaneous effect of the three potential physiological costs of begging: immunocompetence, growth, and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biología Animal, Facultad de Ciencias, Universidad de Granada, Granada, Spain; Grupo Coevolución, Unidad Asociada al CSIC, Universidad de Granada, Spain.

ABSTRACT
Parent-offspring conflict theory predicts that begging behaviour could escalate continuously over evolutionary time if it is not prevented by costliness of begging displays. Three main potential physiological costs have been proposed: growth, immunological and metabolic costs. However, empirical evidence on this subject remains elusive because published results are often contradictory. In this study, we test for the existence of these three potential physiological costs of begging in house sparrow (Passer domesticus) nestlings by stimulating a group of nestlings to beg for longer and another group for shorter periods than in natural conditions. All nestlings were fed with the same quantity of food. Our study involves a long-term experimental treatment for begging studies (five consecutive days). Long-term studies frequently provide clearer results than short-term studies and, sometimes, relevant information not reported by the latter ones. Our long-term experiment shows (i) a clear effect on the immune response even since the first measurement (6 hours), but it was higher during the second (long-term) than during the first (short-term) test; (ii) evidence of a growth cost of begging in house sparrow nestlings not previously found by other studies; (iii) body condition was affected by our experimental manipulation only after 48 hour; (iv) a metabolic cost of begging never previously shown in any species, and (v) for the first time, it has shown a simultaneous effect of the three potential physiological costs of begging: immunocompetence, growth, and metabolism. This implies first, that a multilevel trade-off can occur between begging and all physiological costs and, second, that a lack of support in a short-term experiment for the existence of a tested cost of begging does not mean absence of that cost, because it can be found in a long-term experiment.

Show MeSH
Related in: MedlinePlus