Saturday, June 23, 2012

Evening...Brown

This is an Evening Brown Butterfly, Melanitis leda, a species most active in the early morning and late afternoon. We have seen many of these butterflies around, but this one ended up inside so I decided to take a few photos. I was quite taken by the comical appearance of the face in particular.



The species has excellent camouflage while sitting within dry leaf litter, usually spending periods of inactivity sitting motionless on the forest floor. It has a distinct wet-season and dry season colour form, this is obviously the dry-season form.

Wednesday, June 13, 2012

Two-spined Spider

This is Poecilopachys australasia, a small orb-weaver aptly named the Two-spined spider. This species builds a small orb-web at night and dismantles it at dawn each day, presumably to avoid diurnal predators. She has the remnants of last night's web still in her chelicerae.




This is a young female, her colours will become more vivid as she matures and her abdomen will be less hirsute. She is currently in our backyard only metres away from me now as I type - hopefully she survives to adulthood and if so, I will post another blog about her then.

Sunday, June 10, 2012

Would you like peppermint with that?

This is Megacrania batesii, the Peppermint Stick Insect. It is the only member of the genus in Australia, and has a specialist diet feeding; only on Pandanus tectorius in the wild. Despite the plant being relatively widespread in north Queensland, M.batesii is confined to only a few areas; Cape Tribulation, Mission Beach and Innisfail.

These insects spend almost their entire lives sitting longitudinally along the pandanus leaves, which they feed upon periodically. Their common name is derived from their characteristic chemical defence. They have glands behind the head that can direct a considerable jet of a peppermint scented chemical at anything harassing them. I have had it on my hands countless times without issue, but getting it your eyes is another matter entirely. For a small predator, a blast of this at close range is bound to make it hesitate. The major component of the chemical is Actinidine which oddly enough is very similar to nepetalactone, the active component of Catnip.
The ducts to the chemical glands are located on the pronotum immediately behind the head. They seem to have an ability to direct the spray in the direction of the threat.

A close-up showing the turret-like openings that direct the chemical blast.