Mirror, Mirror ….. In the Cob-Web?

July 31, 2017 by Savita Shetty 39 Comments

[Please Note: I would like to state that I have not experienced / seen any of the facts mentioned here. I am curious about the various unusual phenomenon occurring in nature. (As they say: Once a researcher, always a researcher) I have only researched and compiled these facts together. The images presented in this blog are not photographed by me. Thank you.]

Somethings seems to be wrong with the title, right? Shouldn’t it be Mirror, mirror on the wall? No, here it is correct, as we are talking about the Mirror Spider.

It is also known as sequined spider or the twin peaked Thwaitesia. The scientific name of this arachnid is Thwaitesia argentiopunctata. It is mainly found in Australia. The body length of a male is around 3 mm and for females, it is 4 mm.

These creatures have reflective plates on their abdomen which appear like pieces of mirrors. These shimmery scales are composed of reflective guanine — crystalline deposits which mainly contain guanine, a waste product of the gut cells guanocytes.

With these reflective plates this spider looks like an artwork of stained glass.

It would be natural to assume that these shiny mirrors would act as beacon and attract the predators, thereby landing the spider in danger. However, the scientists studying this species feel that the reflecting places on its abdomen probably reflect and scatter the light, thus confusing the predators.

When faced with adversity, the spider can shrink its shiny mirrors, thus changing colour.

There is another theory that some species of mirror spiders (when threatened) can contract fine muscles and the guanocytes are pulled into a tight mass. Because of this the sequined plates shrink in size and other pigmented cells become more visible (Above photograph). Thus it appears as if the spider has changed its colour. It is no more shiny and not easily visible.

The shimmery plates are smaller with wider gaps in between

When the spider is at rest, the mirror plates slowly expand

Here the mirror plates of the resting spider, have expanded completely to fill the abdominal area

Singapore based photographer Nicky Bay has extensively photographed and studied this spider species. He has published a series of photographs explaining how the shiny plates slowly expand when the spider is at rest, how the space in between the plates fills up and then how the plates completely fill the abdominal area.

He (Photographer Nicky Bay) has created an animation showing the expansion and contraction of the mirror plates:

All the photographs here are by: Nicky Bay.