Testosterone identifies hatchling sex for Mojave desert tortoises (Gopherus agassizii).

The threatened Mojave desert tortoise (Gopherus agassizii) exhibits temperature-dependent sex determination, and individuals appear externally sexually monomorphic until sexual maturity. A non-surgical sex identification method that is suitable for a single in situ encounter with hatchlings is essential for minimizing handling of wild animals. We tested (1) whether plasma testosterone quantified by enzyme-linked immunosorbent assay differentiated males from females in 0-3 month old captive hatchlings, and (2) whether an injection of follicle-stimulating hormone (FSH) differentially elevates testosterone in male hatchlings to aid in identifying sex. We validated sex by ceolioscopic (laparoscopic) surgery. We then fit the testosterone concentrations to lognormal distributions and identified the concentration below which individuals are more likely female, and above which individuals are more likely male. Using a parametric bootstrapping procedure, we estimated a 0.01-0.04% misidentification rate for naïve testosterone samples, and a 1.26-1.39% misidentification rate for challenged (post-FSH injection) testosterone samples. Quantification of plasma testosterone concentration from small volume (0.1 mL) blood samples appears to be a viable, highly accurate method to identify sex of 0-3 month old hatchlings and could be a valuable tool for conservation measures and investigation of trends and variation in sex ratios for in situ wild nests.

A comparison of non-surgical methods for sexing young gopher tortoises (Gopherus polyphemus).

Many turtle species have temperature-dependent sex determination (TSD), raising the prospect that climate change could impact population dynamics by altering sex ratios. Understanding how climate change will affect populations of animals with TSD requires a reliable and minimally invasive method of identifying the sexes of young individuals. This determination is challenging in many turtles, which often lack conspicuous external sexual dimorphism until years after hatching. Here, we explore four alternatives for sexing three age classes of captive-reared young gopher tortoises (Gopherus polyphemus), a terrestrial turtle of conservation concern native to the southeastern United States: (1) naive testosterone levels, (2) testosterone levels following a follicle stimulating hormone (FSH) challenge, (3) linear morphological measurements, and (4) geometric morphometrics. Unlike some other turtle species, male and female neonatal gopher tortoises have overlapping naive testosterone concentration distributions, justifying more complicated methods. We found that sex of neonates (<7 days old) is best predicted by a "random forest" machine learning model with naive testosterone levels and morphological measurements (8% out-of-bag error). Sex of hatchlings (4-8 months old) was predicted with 11% error using a simple threshold on naive testosterone levels, or with 4% error using a simple threshold on post-FSH testosterone levels. Sex of juveniles (approximately 3.5 years old) was perfectly predicted using a simple threshold on naive testosterone levels. Sexing hatchlings at >4 months of age is the easiest and most reliable non-surgical method for sex identification. Given access to a rearing facility and equipment to perform hormone assays, these methods have the potential to supplant laparoscopic surgery as the method of choice for sexing young gopher tortoises.

Obstacles to a randomised controlled trial of intensive dynamic psychotherapy: an account of the New South Wales Section of Psychotherapy outcomes project.

OBJECTIVE: This paper examines the obstacles to a randomised controlled trial (RCT) of intensive dynamic psychotherapy (IDP) by reference to the fate of the New South Wales Section of Psychotherapy outcomes project. METHOD: Planning was complete and the final research protocol was about to be implemented when funding difficulties led to suspension of the project. The opinions of the research subcommittee regarding the main obstacles to the ultimate success of the project are now analysed in the expectation that better research strategies will follow. RESULTS: With hindsight, six of the eight members of the research subcommittee reported that the project was not feasible. By choice of questionnaire items they identified the greatest threats to a successful trial as: standardisation of the procedures, termination at 24 months, the availability of funding and the choice of treatment procedures. The most frequently volunteered concerns related to the enlistment and cooperation of the trial therapists (5), standardisation of the experimental therapy (3), probable shortfall in trial subjects (3) and the availability of funding (2). CONCLUSIONS: The most powerful general obstacles to success of the project related to the standardisation of procedures and the failure to maintain sufficient cooperation of trial therapists. The protocol required IDP therapists to terminate procedures at 24 months, which contradicted their usual practices and led to some alienation from the project. Amendments to the protocol might improve the possibility of a successful trial. However, one might also conclude that it is premature to attempt a naturalistic RCT of IDP.