Genetic evidence for promiscuity in the Ornate Tinamou<i>Nothoprocta ornata</i>(Aves: Tinamiformes)

Abstract

Tinamous have male-only parental care. For their mating system, simultaneous polygyny and sequential polyandry is proposed as an optimal model and is confirmed in all species according to the existing literature, except in the Ornate Tinamou. For the Ornate Tinamou a monogamous mating system is reported. However, this knowledge is based only on few direct observations in the field. Social monogamy in association with promiscuity would probably expose males to cuckoldry and, at the same time, constrain additional mating opportunities for them. To understand the evolutionary context for monogamy in the Ornate Tinamou, the present study aimed to determine whether this species is genetically monogamous or not and whether males are subjected to cuckoldry. We used polymorphic microsatellite markers to perform a sib-ship and paternity analysis based on samples from eggs and feathers of incubating males from four clutches. Promiscuity was found in all nests and the observed rate of cuckoldry ranged from 0% to 33.3%. These results rebut the consideration of monogamy for the Ornate Tinamou. Thus, the optimal model with polygynous males and polyandrous females prevails as an evolutionary stable strategy among tinamous, even in different social mating systems and despite high levels of cuckoldry.