COS 87-2 - Survival, reproduction and thermal ecology of a population of the Mexican dusky rattlesnake (Crotalus triseriatus)

Thursday, August 11, 2016: 1:50 PM
Floridian Blrm BC, Ft Lauderdale Convention Center
José Luis Jaramillo Sr. and Hibraim Adán Pérez Sr., Ecología, FES Iztacala, UNAM, Mexico City, Mexico
Background/Question/Methods

Basic ecological information from Mexican rattlesnakes is still scarce. As a consequence, possible management and conservation plans for this reptiles lack the necessary quantitative background for its implementation. In this study we estimate survival, describe reproductive attributes and obtained the thermoregulation indices (Hertz) in a population of the Mexican dusky rattlesnake (Crotalus triseriatus) in "La Malinche" National Park (3200 m s.n.m.), Tlaxcala, Mexico. To estimate survival, mark-recapture data from 2015-2016 were analyzed in program MARK through Cormack-Jolly-Seber models (CJS). We used Hertz protocol to calculate the quantitative indices summarizing thermal population ecology: the accuracy of thermoregulation (db), thermal quality of the habitat (de) and the effectiveness of thermoregulation (E).

Results/Conclusions

Daily activity on this species was restricted from 9:00 to 17:00 h. The observed sex ratio was 3.4 males for female, which is a common trend in rattlesnakes. Snakes were precise thermo-regulators despite the cold environment they inhabit, which is reflected in a high index of thermoregulation (E = 0.65), and relatively high compared with other snake studies. Preliminary results show that population size of adults is relatively small (26 to 46 individuals), nevertheless more data is needed. For reproductive traits, we report data from 5 litters. Average litter size was 8.6 snakes, which is not statistically different from the previously reported litter size 7.85 ± 2.1. We found no relationship between SVL and litter size. These results are consistent with previous records and are similar to litter sizes reported for other rattlesnakes species like C. horridus and C. polystictus.