Helpers at the nest of White-banded Tanager Neothraupis fasciata benefit male breeders but do not increase reproductive success

Abstract

In cooperatively breeding birds, breeders can adjust their parental care investment without affecting nestling survival probability and save energy to invest in other activities, such as feeding, mating or territory defense. Furthermore, helpers at the nest can improve nestling nutrition and hence the reproductive performance of the breeding pair. We determined the influence of helpers on nestling feeding effort and reproductive success of breeders in the neotropical White-banded Tanager (Neothraupis fasciata). We monitored nests during the breeding seasons of 2006 and 2007 in central Brazil. Males showed a compensatory reduction of their food delivery rate in the presence of helpers, whereas females exhibited the same parental effort regardless of having helpers. Total food delivery rate was higher for nests with helpers, but there was no effect of helpers on reproductive performance of breeders (clutch size, hatching rate, fledgling productivity and reproductive success). Our results indicate that cooperative breeding in the White-banded Tanager appears to be important for males to reduce their parental care effort and, hence, invest in their survival or future reproductive attempts. Zusammenfassung Bei kooperativ brütenden Vögeln können Brüter ihren Brutpflegeaufwand anpassen, ohne dass dies die Ü berlebenswahrscheinlichkeit der Nestlinge beeinträchtigt, und Energie sparen, die dann in andere Aktivitäten, wie Nahrungsaufnahme, Paarung oder Revierverteidigung, investiert werden kann. Außerdem können Helfer am Nest die Ernährung der Nestlinge und somit die Fortpflanzungsleistung des Brutpaares verbessern. Wir haben ermittelt, wie sich Helfer auf den NestlingsFütterungsaufwand und den Fortpflanzungserfolg von brü-tenden neotropischen Flügelbindentangaren (Neothraupis fasciata) auswirken. Wir haben Nester während der Brutsaisons 2006 und 2007 in Zentralbrasilien überwacht. Männchen zeigten eine kompensatorische Reduktion ihrer Fütterungsrate in Anwesenheit von Helfern, während Weibchen denselben Elternaufwand zeigten, unabhängig davon, ob sie Helfer hatten oder nicht. Die Gesamtfütterungsrate war für Nester mit Helfern höher, doch Helfer hatten keinen Einfluss auf die Fortpflanzungsleistung von Brütern (Gelegegröße, Schlupfrate, Flügglingsproduktion und Fortpflanzungserfolg). Unsere Ergebnisse deuten darauf hin, dass kooperatives Brüten bei Flügelbindentangaren für Männchen wichtig zu sein scheint, um ihren Brutpflegeaufwand zu reduzieren und folglich in ihr Ü berleben oder weitere Fortpflanzungsversuche zu investieren.

Striped-tailed Yellow-finch nesting success in abandoned mining pits from central Brazilian cerrado

“…Fully understanding of the migration patterns of the species remain uncertain; however it is known the species is not found in the central Brazilian cerrado outside the rainy season (Braz, 2008). Our data also gives support to the hypothesis derived from Skutch's (1949) that nests become more vulnerable towards the fledging date, probably in response to higher activity at the nest towards the fledging date (Roper and Goldstein 1997), and were similar to other studies performed in the neotropics (Mason, 1985;Francisco, 2006;Auer et al, 2007;Manica and Marini, 2012).…”

Age, but not sex and seasonality, influence Haemosporida prevalence in White-banded Tanagers (Neothraupis fasciata) from central Brazil

“…For example, if females are the main incubator, this behavior could lead to higher vector exposure and consequently higher chances of infection (Greenman et al 2005). Females of White-banded Tanagers are the main incubators (Manica and Marini 2012), which increase exposure to vectors during a period that females are generally more immunologically depressed. This could explain the lack of sex-biased haemosporidian prevalence in this study.…”

“…Helpers are chiefly males that assist the main breeding pair with provision of food to current offspring (Manica and Marini 2012 females, 4 sub-adult females and 13 juveniles were captured. All individuals were banded with a metal ring from the Brazilian birding agency (CEMAVE/IBAMA) and 50uL of blood was obtained from the femoral or braquial vein by using disposable needles or lancets (license issued by IBAMA/ICMBio, number 15256-1).…”

The role of social environment on parental care: offspring benefit more from the presence of female than male helpers

“…This cannot be explained by relatedness since the high levels of EPP (Brouwer et al 2011) mean that helpers are on average less related to the offspring than the dominant female, but not the dominant male. Helpers could also invest less in parental care since they spent time on other behaviours such as searching for breeding vacancies (Young, Carlson & Clutton-Brock 2005) or displaying to extra-group females to gain extra-pair matings, although dominant Legge (2000b), 18 Curry & Grant (1989), 19 Hodge (2007), 20 Allain et al (2000), 21 S anchez et al (1999), 22 Rowley (1981), 23 Browning et al (2012), 24 Vanderwerf & Strahl (1990), 25 Manica & Marini (2012), 26 Meade et al (2010), 27 Lessells (1990), 28 Russell et al (2007). 29.…”