Washington, Oct 16 : While hybrids of many species are often infertile or dysfunctional, the hybrids of doves are actually bastards when it comes to defend their territory- a necessity for further reproduction.
In a new study, Dutch biologist Paula den Hartog focussed on the ring-necked dove and the vinaceous dove and the hybrid that resulted on crossing the two functional and reproducing species.
Coincidentally, biologists discovered the existence of a hybrid dove alongside the ring-necked dove and the vinaceous dove in a region of Uganda.
Usually, for mating, a male dove coos to defend his territory and attract females. The coos of the ring-necked dove and the vinaceous dove are different and the hybrids have their own coo as well, which is still functional.
For the study, Den Hartog investigated the role of cooing in the process of species formation and hybridisation. The study was aimed at determining the degree to which male doves of different species react to the coos of their own species, to those of the other species and to the coos of the hybrids.
Thus, the researchers recorded the coos of the different species of males and subsequently played these recordings in the wild.
After placing loudspeakers in the territory of a male dove to measure the response of the dove to other doves' coos, the researchers observed that on hearing another male's coo, a male dove will coo and try to chase away the intruder from his territory. This sometimes leads to fights.
The male does this to defend his territory and a male dove cannot reproduce unless he has his own territory.
However, a male dove can only chase off intruders from his territory if the intruders can 'understand' his coo and recognise the threatening message and vice versa. Thus, a strange coo can hinder a successful sex life.
When the male doves in the study recognised a coo and noticed the loudspeakers, they immediately started an attack. They recognised the coo as being the coo of a rival.
The response of the hybrid males to the coos of the hybrid doves was found to be the same as their response to the ring-necked and vinaceous doves.
In the area occupied by the hybrid doves, the hybrid coo is just as effective as the coos of both parental species. Besides, the coos of the hybrid males can sound unique but also sound like the coo of one of the parental species. In the latter case it may be possible for them also to hold their own within a population of that parental species.
This led Den Hartog to suspect that it is possible for the hybrid species to continue to survive and multiply, as the hybrid coos seem to work well in obtaining a territory.
And also, there is also quite a lot of variation in the hybrid coos, which would therefore appear that hybrid animals are not always weaker than their parental species.