Uroctonus mordax

On the evening of May 1, 2009, four adult female Uroctonus mordax were collected (among others) in Benton County located in western Oregon. All four were found in close vicinity to one another (within 10') hiding under discarded pieces of plywood.

The area was at roughly 1000' above sea level on a west-facing slope covered in patchy forest (primarily coniferous). Conditions were cool but not cold, and raining.

The four females, photographed the next day:

(To the right is a juvenile male collected the same night.)

The females were later designated as specimens 3, 4, 5, and 6.

Specimens were temporarily housed as pairs in large Kritter Keepers with artificial dividers (3 with 4, 5 with 6). Females would routinely bypass these dividers (no aggression was observed) and were eventually housed individually to prevent this. Individual housing ranged from 3.2-cup tupperware-style containers to large Kritter Keepers.

All females were given damp coconut fiber as substrate and offered some sort of shelter. Specimen 4 did not utilize this shelter and instead remained in the open. They were kept at unregulated room temperature which was estimated to be in the upper 70s Fahrenheit.

Specimen "4" was observed carrying young on her back on the afternoon of July 10. A quick inspection showed that none of the others had parturated yet.

Specimen 4:


July 10 was a Friday preceding a weekend away from home. Returning on the evening of the 12th revealed that specimens 3 and 6 had both parturated. Specimen 3 excavated a burrow beneath her provided shelter and sealed the entrance. Her brood was revealed by an inspection of the bottom of her enclosure.

Specimen 3:


Specimen 6:


An inspection on July 17 revealed two new developments: a single first-instar from Specimen 6's brood had wandered off of the female's back and away from shelter (at least a three-inch journey), and Specimen 5 was carrying a brood. Additional water was applied to the substrate surrounding the separated instar to prevent dehydration.

The lone first-instar (later nicknamed "Dr. Livingstone"):



Specimen 5:


Specimen 4's brood was observed in various stages of ecdysis to second instar on July 20.


July 21 found the majority of Specimen 6's brood following suit, with the exception of Dr. Livingstone. Dr. Livingstone successfully molted the next day, July 22, while NOT on his mother's back.

Enough juveniles had left Specimen 4's back by July 26th to warrant separating them.

Specimen 5 was inspected routinely and the brood was not found to have reached second instar until July 27th. The same day, both Specimen 3 and one of her offspring were found outside the previously sealed burrow. The majority of Specimen 3's brood was still in a chamber at the bottom of her burrow.

By August 1st all four broods had been separated and housed individually.


Synopsis
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Specimen 3
Birth: 7/12
Molt: Unknown
Count: 16

Specimen 4
Birth: 7/10
Molt: 7/20
Count: 26

Specimen 5
Birth: 7/17
Molt: 7/27
Count: 16 + 2 dead

Specimen 6
Birth: 7/12
Molt: 7/21 (Dr. Livingstone, 7/22)
Count: 30