"Sexual dimorphism in desiccation responses of the sand scorpion Smeringurus mesaensis", or...

[edesign]

...females handle dehydration better than the males due. Interesting info in this study and includes references to other species and how they compare. Below is only a tiny bit of what's in the PDF. I'm not a biologist or anything but I was able to muddle my way through most of it with a vague idea of what was being said lol. Once it got really technical with the experiment details I skipped on to the discussion section.

Mainly I thought it was interesting in the suggestion of why the two sexes' body masses were dimorphic.

http://www.gefenlab.com/uploads/2/0/9/5/20958696/2008_gefen.pdf (Eran Gefen, 2008)

When desiccated, scorpions regulate both haemolymph volume and its osmotic concentration by mobilising water from the hepatopancreas to the haemolymph. These regulatory capacities depend on the metabolic rate, water-loss rate, composition of the catabolised metabolites and their long-term availability (Gefen and Ar, 2005). This role of the hepatopancreas as a water reservoir, and the significantly larger organ size of females (Warburg et al., 2002), suggest possible sexual dimorphism in response to desiccation stress.

Both wet and dry hepatopancreas mass of female S. mesaensis were significantly higher than those of males (p<0.001). In fact, these explained most of the observed sexually dimorphic body size, as dry body mass excluding the hepatopancreas was not significantly different between females (0.2992 +/-0.0267 g; n=8) and males (0.2753 +/- 0.0162 g; n=9) (t15=0.79, p=0.44).

Results in this study indicate that high osmoregulatory capability of scorpions is even more prevalent than previously thought. The osmotic response of female S. mesaensis to desiccation (Fig. 2) is comparable to those reported for surface-dwelling Buthidae, despite being an obligate fossorial species which spends 92–97% of the time in its burrow (Polis, 1990). The haemolymph osmolality of another burrowing Vaejovid, Paruroctonus aquilonalis, was reported to increase steadily with desiccation of up to 40% loss of initial mass (Riddle et al., 1976). However, haemolymph osmolarities of males desiccated to 10% of their initial mass were not different from initial values (Fig. 3 and Table 1 therein).

 

[The Toecutter]

Thanks for the link, good read....downloaded