Post date: Jun 16, 2015 9:30:21 PM
#need to incorporate into the ms:
On 07/25/07, SMARC collected 15 E. sosorum. On 12/16/08 the COA brought us 42 additional salamanders that were previously used at a University of Texas [UT] at Austin lab by Mary Poteet and Andy Gluesenkamp to test the effects of elastomer tagging on their health. All 56 wild stock salamanders were originally caught from Eliza Springs. We sorted 14 salamanders (mixed males and females) collected by COA into each of three tank sections (ES3-U, ES3-M, and ES3-L) of the ES3 tank system. ES3-U means: ES = Eurycea sosorum
3 = tank system number, there are a total of 8 tanks in the building
U = upper tank section
M = middle tank section
L = lower tank section
Currently salamanders are separated by sex into different tank sections to prevent exceeding the tank systems capacity, to trigger reproduction in the event of a catastrophic event, and to control their genetics.
On 04-18-13, 45 wild stock tissue samples were collected for the genetics study from ES1 and ES3 tank systems. By this time, 11 of the 56 had died. ES1 tank system contained 8 of the original 15 caught by SMARC and ES3 contained 37 of the original 42 caught by the COA. It is likely that there were gravid females when we first got them on 12/16/08, but no eggs were oviposited until 2011.
Followup from Val, 17june15: I will contact DeeAnn to find out when they were collected.
The eggs of female Plethodontids are fertilized during the oviposition of eggs. The spermatophore packet can be stored over an extended period in females. Based on research conducted by Sever (1995) and Sever et al (2001), there is not sufficient evidence to suggest that spermatophores can remain viable in females for longer than six months. He states that claims that salamanders store viable sperm for several years are mostly anecdotal. Spermatophore storage of 2.5 years cited in the "Barton Springs Recovery Plan," is in reference to a salamander belonging to a different family Salamandrea: Salamandra salamandra. I don't believe the spermatophors in E. sosorum would remain viable for up to three years, however more research is needed to shed light on the spermatophore longivity in Plethodontids. I've included journals to the citations in case you would like them: Sever 1995, Sever et al. 2001.
from Val, 19june15: the date the 42 (marked and unmarked) salamanders, that you (DeeAnn) helped deliver here on 12-16-08, were collected: Those salamanders were collected 10/6/08 from Eliza Spring.
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thoughts:
ne=n with binomial sampling (random draw and make an offspring, on ave each pair chosen twice), constant pop size,
ne<n variance in number of offspring across mating pairs
ne>n force each pair to give two offspring; lower variance than binomial sampling -- the multiple tanks; contribution from outside (gravid upon collection); were the COA wildstock originally collected from the wild a long time ago or collected over multiple years?
More info from Val, 9july15:
On 25 July 2007, after collecting 15 wildstock (8 males and 7 females) from Eliza Springs, they were immediately separated by sex into two separate aquaria. They have spent most of their time separated except when we attempted to trigger reproduction by combining them for about two weeks at a time. This was attempted about 15 times. Of the 42 received in 2008, 27 were males, 10 females, and five unknowns. Of the original 57 founders, 35 were males, 17 females, and 5 unknowns. After searching, I could not find the bodies of the 5 unknowns to determine their sex.
From Val, 10july15:
Although we attempted to reproduce the original 15 salamanders 15 times, the last attempt was not officially counted because while trying to combine them with males, the females were accidentally moved into the male tank section where no vegetation was available for them to lay eggs. Of 14 similar trials, eggs were oviposited 10 times, 71% of the attempts. Of 583 eggs oviposited, 248 (32%) eggs hatched to larvae.
We kept the 42 salamanders separate by elastomer markings (14 with no marks, 14 with two marks, and 14 with five marks) to see if the marks had any long-term effects (not an official study). Unlike the original 15 salamanders which were combined and separated to trigger reproduction, the marked ones were maintained as they had arrived, as mixed males and females and by number of marks. When we first got them, we did not attempt to identify them by sex or keep track of the sex ratios. By 18 April 2014, the day tail clips were taken for genetic analysis, the trial had ended because the salamanders were separated by sex to control for reproduction and genetics. As of 18 April 2014, only five had died (3 without marks, one with two marks, and one with five marks; 88% survival for 53 months). These salamanders reproduced three times between 2011 and 2012. Of 123 eggs oviposited (29 eggs from salamanders with no marks and 94 from five marks), 53 (47%) eggs hatched to larvae.
Based on these observations, the marking process did not affect mortality nor prevent eggs from being laid.