|Male Chameleon Grasshopper at 30°C|
For most of us, lying in the sun turns us bright pink however the bright turquoise.
Found across the alpine peaks of the Australian Alps, male Chameleon grasshoppers will rapidly change from black to a bright turquoise colour with increasing temperatures, returning to back to black when they cool down.
In order for this temperature-dependent colour change to occur black males need to bask each morning for approximately 21-39 minutes at a temperature of ~25-30°C to transform into their brightest turquoise. Once this intial colour change takes place the body temperature of the grasshopper may lower below 25°C, but the grasshopper keeps its blue colour as the change back to black is not as fast, generally taking about 5 hours. These extraordinary males are also known to engage in fierce fighting amongst each other, as they compete for females (Check out the video below).
In this article they aimed to test whether the male chameleon grasshopper's turquoise phase is an intraspecific signal, a signal within this species of grasshopper that informs the females about male quality ( a intersexual signal, between male and female) or to other males (a intrasexual signal, between the males).To determine whether female grasshoppers had a preference to turquoise males or black males, three tests were carried out:
|Male Chameleon Grasshopper at 5°C|
- females were given the choice between turquoise (hot) and black (cold) males
- females were given the choice between two painted males (one turquoise, one black) to represent the different colour phases
- females were given the choice between weight-matched pairs of males both at a temperature of 30°C
And to assess if male mating success is influenced by turquoise brightness in males, trials in which five males competed for one female were carried out.
Results show that male colour is not a big factor in mate selection for females, as they chose randomly with no preference for the brighter males over the duller males. And there was no evidence that brighter turquoise males were more successful when it came to fighting other males for a female. However it is thought that the males, "check each other out" comparing themselves to other males of similar brightness to assess their own fighting ability. This allows them to make a decision whether or not to engage in a fight due to past experiences, brightness may be a cue to the fighting ability, so a duller male will most likely not chose the brightest male to contest but instead pick on someone his own colour.
So this goes to show that "appearance" isn't always everything when it comes to mate selection in nature... it doesn't matter if your blue or black! But when you want to fight someone, it pays to stick to picking on someone your own size or in this case colour!
I find these wee guys fascinating, such a cool colour change, may have to go see them myself one day!
Check out these males fighting!
For the full article:
Other articles on these colourful creatures:
Microsatellite Markers for the Chameleon Grasshopper (Kosciuscola tristis) (Orthoptera: Acrididae), an Australian Alpine Specialist
A temperature-controlled physiological colour response in the grasshopper Kosciuscola Tristis Sjost. (Orthoptera: Acrididae)
Thanks for reading :)