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Excerpts from Jim Conrad's
Naturalist Newsletter
from the December 18, 2011 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
HARVESTMAN IN THE WOODS
We have those long-legged arachnids with oval bodies called harvestmen or daddy-longlegs down here, too, such as the pink-bodied one seen sprawling on a leaf above. Most Northerners think of harvestmen as living in dank basements and old buildings, but this one was in deep forest. Lots of species exist, in several genera, and they occupy many environments. Several species live in caves and are blind. The one in the picture let me get close enough to see the interesting features shown below:
Harvestmen are related to spiders but they're not considered to be spiders themselves. Spiders produce venom and silk, but harvestmen don't. Spiders typically have up to eight eyes, but harvestmen just have two, if they have any at all. In the picture the two objects looking like eyes are indeed simple eyes with single lenses. Technically they're called ocelli. In most harvestmen the ocelli are located on a bump known as the ocular tubercle, visible in the picture.
Below the eyes notice the slender, pale things bent beneath the body, looking like fangs. Wikipedia's harvestman expert assures us that while spiders have fangs, harvestmen don't. Our harvestman's fanglike items are called chelicerae, which are defined as "fanglike appendages near the mouth of an arachnid, often used for grasping and piercing." It sounds like you need to be an anatomist to appreciate the difference between a fang and a piercing chelicera.
Numerous species and genera of harvestmen are recognized and I'm not at all sure which one we have here. It's similar to North America's Hadrobunus grandis, so maybe it's closely related or in fact the same species.
from the April 7, 2007 Newsletter issued from Sierra Gorda Biosphere Reserve, QUERÉTARO, MÉXICO
HARVESTMEN ON MY WALL
The four days before I left for Cuatro Palos were more like days of the rainy season than what it is, the latter part of the dry season. The days were hot, then in the afternoons you heard thundering up in the mountains, and by day's end a storm rolled in. Maybe that's why Harvestmen, or Daddy Longlegs, gathered en masse high on my little casita's stucco walls, beneath the eaves where rain couldn't reach them.
When I decided to take their picture I set a ladder against the wall, climbed up, and the moment before I snapped the camera I exhaled and my breath caused them to scatter. You can see the scattering critters below:
Most of the time they're in a much compacter clump, their legs intertwined in a way that helps them stay on the wall despite some pretty good gusts of wind coming along. They're still there as I type this nearly a week after taking that picture.
Of course harvestmen are harmless, despite the "urban rumors" going around about their possessing the most deadly venom on Earth.