I thought I would do my first, but not my last, bird of paradise. Certainly one of the best cases of elaborate courtship displays and extreme sexual dimorphism. With so many birds to choose from, it was difficult to know where to start but I think I landed on a good bird to start with. The Twelve-Wired Bird of Paradise, Seleucidis melanoleuca.

In this dramatically sexually dimorphic species, the males, aside from being brightly coloured, has a set of highly modified display plumes and a pair of coral coloured legs and feet. This is in stark contrast to the females who are smaller and have a mixture of black and brown plumage.

As in real estate, courtship is all about location, location, location. Males begin the process by finding a bare, dead tree snag from which to display from. Once there he lets out three distinct vocalisations, two of which appear to be for advertisement and one is for the display. Once the female has arrived the real singing begins.

In company with the singing comes the dancing, holding the wings open to maximise display of his brilliant colours. This includes leg postures that better present his beautiful coral legs are one of two factors of the display that are unusual. The other gives the bird its name, the wire-wipe display.

During this, the male performs many slow and exaggerated body movements by hopping to this alterante foot postions, all the while pointing his wires towards the female so that he can, very delicately, brush them across her face which impresses her. The paper goes into great detail in explaining the whole process but its too much writing so I will just put a video up.

References
Frith C. B. & Beehler, B. M. (1997). Courtship and mating behaviour of the twelve-wired bird of paradise seleucidis melanoleuca. Emu, 97(2), 133-140.

It is often the case that sexual dimorphism in animals leaves the males more colourful and with extra appendages that are used to impress females. However this is not the case in socially monogamous birds, such as the Blue-footed Booby, Sula nebouxii.

Both male and female Blue-footed Booby’s both have brightly coloured blue feet used during courtship. The reasons behind the females having ornamental structures like the males have seldom been documented. In this case it is in the interest of both the females and males to have nice blue feet.

A study has found that the bluer and brighter a females feet, the more attractive she is to the males. Through an experiment of temporarily changing females feet to a duller shade of blue, scientists found that they received less intra- and extrapair courtship than the control females. They concluded that the blue colour of the feet is favoured by sexual selection through male preference.

In a similar study, the opposite was tested. Scientists found that the brightness of the males feet colour was related to the overall health of the bird. When deprived of food for 48hrs, the blue colour became duller as an indication of its ill health. This study also found that this had an influence on how much reproductive investment the female put in.  After the first egg was laid, the male responsible was taken and his feet were temporarily modified to appear duller and less attractive. In response females decreased the size of their second egg as their partner appeared to be in ill condition. They concluded that female Blue-footed Booby’s continually evaluate the health of their partners to determine the amount of their reproductive investment.

References

Torres R & Velando A. (2005). Male preference for female foot colour in the socially monogamous blue-footed booby, Sula nebouxii. Animal Behaviour, 69(1), 59-65.

Velando A, Beamonte-Barrientos R & Torres R. (2006). Pigment-based skin colour in the blue-footed booby: an honest signal of current condition used by females to adjust reproductive investment. Oecologia, 149(3), 535-542.

This week I will talk about animal that would not immediately come to most people’s minds when discussing elaborate courtship displays. It is the Peacock spider, Maratus volans.

Although male jumping spiders are known for being quite ornamented compared to the female, peacock spiders, which are endemic to Australia, are an exceptional example. When courting, a male peacock spider will display his brightly coloured opisthosomal flaps that usually stay tucked away around its abdomen. This will be waved around in synchrony with a pair of ornamental legs to impress the female.

A study on the courting behaviour of the male peacock spider however, has found that they employ a multi-modal signalling structure i.e. using multiple tactics when trying to impress. In particular the study showed that the males use visual cues and vibratory modalities in their display. As far as visual displays, certain behaviours were observed such as pedipalp flicker, opisthosomal bobbing, 3^rd leg wave, fan dance, fan-flapping, and pre-mount display.

These behaviours can be observed in the accompanying video where we see one of these amazing courtship displays taking place.

References

Girard MB, Kasumovic MM, Elias DO.2011. Multi-Modal Courtship in the Peacock Spider, Maratus volans. PLoS one 6(9): e25390.