A crab spider in Nepenthes mirabilis, Cambodia

After the mantis, here comes the spider.

This post will deal with a crab spider I observed in southern Cambodia in February 2010. Like I stated in the Nepenthes-praying mantis post, the Nepenthes associated arthropods are relatively poorly studied and though a bunch of fascinating papers have been published in the last decade, it would be great if these critters could pick the interest of some more scientists.

The first picture shows a typical wasteland in Cambodian countryside. This land is doomed to be turned into crops plantations or oil palm plantations. Some carnivorous plants can be found there; Drosera burmanii, a yellow species of Utricularia (I still don't know if it's U. odorata or U. bifida - I'll deal with that when I have some time) and Nepenthes mirabilis, the most common Nepenthes species in Cambodia.

N. mirabilis was quite common here but to to the enthusiast taxonomist that I am, this widepsread species showed little interest... until I looked inside the pitchers.

Most of the pitchers were inhabited by these famous crab spiders! One per pitcher. They all have dark abdomen with a red thorax.

A fascinating sight.

Like the literature stated, when disturbed these critters often dive into the fluid and stay still until the threat disappears. As these Cambodian spiders of the Thomisidae family are poorly studied, it is a gamble to associate them with Henriksenia labuanica, formerly widely known as Misumenops nepenthicola (Striffler & Rembold, 2009). I have no expertise in this field and I certainly don't know if this thomisid whether belongs to the genus Henriksenia (Lehtinen, 2005 ) or to another one. It is best to wait until it is properly studied by an expert, if that happens someday ;-)

This nepenthebiont thomisid spider was fairly common in that Cambodian area. I didn't have the time to observe it carefully. More time would have allowed to see how it behaves. I read that it feeds on mosquito larvae but that seems strange to me as the larvae swim in the fluid and most spiders are hiding (waiting?) in the inner walls of the pitcher that mostly contained drowned ants:

Yummy!

References:

-Lehtinen, 2005 : Taxonomic notes on the Misumenini (Araneae: Thomisidae: Thomisinae), primarily from the Palaearctic and Oriental regions. European Arachnology 2003 (Proceedings of the 21st European Colloquium of Arachnology, St.-Petersburg, 4-9 August 2003). Arthropoda Selecta, Special Issue, vol. 1, p. 147-184.

-Striffler, BF, Rembold, K, 2009. Henriksenia labuanica nom. nov., a replacement name for Misumenops nepenthicola Bristowe (1930) and clarification of the current taxonomic status of Misumenops nepenthicola Fage (1928) (Arachnida, Araneae, Thomisidae). Pitcher Plants of the Old World 2: 1334-1337, Redfern Natural History Productions, UK.