Obligate brood parasitism on Neotropical birds

URSINO, CYNTHIA A; DE MÁRSICO, MARÍA C; FIORINI, VANINA D.; REBOREDA, JUAN C

Behavioral Ecology of Neotropical Birds

Springer

Lugar: Cham; Año: 2019; p. 103 - 131

Obligate brood parasites do not build their nests nor do feed and take care of their nestlings. Instead, they lay their eggs in nests of individuals of other species (hosts) that rear the parasitic progeny. For behavioral ecologists interested in coevolution, obligate brood parasites are pearls of the avian world. These species represent only 1% of all the living avian species, and their peculiar reproductive strategy imposes on them permanent challenges for successful reproduction. At the same time, the hosts are under strong selective pressures to reduce the costs associated with parasitism, such as the destruction of eggs by parasitic females and the potential fitness costs of rearing foreign nestlings. These selective pressures may result in parasites and hosts entering in a coevolutionary arms race, in which a broad range of defenses and counterdefenses can evolve. Females of most species of parasites have evolved behaviors such as rapid egg laying and damage of some of the host?s eggs when they visit the nest (Sealy et al. 1995; Soler and Martínez 2000; Fiorini et al. 2014). Reciprocally, as a first line of defense, hosts have evolved the ability to recognize and attack adult parasites (Feeney et al. 2012). Parasitic eggs typically hatch earlier than host eggs decreasing host hatching success and nestling survival (Reboreda et al. 2013), but several host species have evolved recognition and rejection of alien eggs, which in turn selected for the evolution of mimetic eggs in the parasite (Brooke and Davies 1988; Gibbs et al. 2000). Parasitic young are often morphologically and behaviorally adapted to manipulate host?s parental effort, but sometimes host parents are able to discriminate against them (Liang et al. 2017). In addition to tricking hosts into raising them by mimicking gape markings (Payne et al. 2001), plumage color (Langmore et al. 2011), and begging calls (De Mársico et al. 2012), brood parasites also face the challenge of recognizing their conspecifics to interact and reproduce in the future. Yet, how parasitic juveniles identify and join their own kind is poorly understood. Over the past 50 years, avian brood parasitism has been the focus of a plethora of studies that have substantially contributed to our understanding of the evolution of adaptations between parasites and their hosts, encompassing all the stages of the parasites? lifecycle (for a recent and comprehensive review, see Soler 2017). Thereare about 100 obligate brood-parasitic species worldwide distributed in seven phylogenetically independent groups (Sorenson and Payne 2002). In the Neotropics, eight species have been described in three of these groups: four cowbirds (Molothrus, Icteridae), three New World cuckoos (Dromococcyx and Tapera, Cuculidae, subfamily Neomorphinae), and the black-headed duck (Heteronetta atricapilla, Anatidae), which is the only precocial obligate brood parasite (Table 6.1). In this chapter, we present a compendium of the characteristics and behaviors of these species that aid our understanding of how natural selection shapes the interactions between parasites and their hosts.Neotropical parasites reflect a wide range of strategies, from specialization toextreme generalization in host use, from nestmate tolerant to nestmate killing, and the unique nidifugous brood parasite. Unfortunately, most of these species have been incompletely studied and the extension devoted to each one in this chapter reflects this unbalance in the available information.