Second Problem Any conservation program oriented toward incubation of eggs collected in the wild would require expensive precision temperature-control chambers costing thousands of dollars. These chambers are required initially to determine the temperatures that normally produce each sex. In addition, to assess the temperature-sensitive window as well as individual sex, embryos must be killed and autopsied.
Third Problem Many endangered reptiles live in remote areas that are difficult to access. The relative expense of providing reliable electricity, particularly in Third World countries, is prohibitive. Even if on-site electrical generators are used, these machines are expensive and require maintenance and fuel. Finally, items such as egg incubators in remote sites must be made secure.
Solution Implement hormone-spotting method in remote sites. This method guarantees the production of female hatchlings. It is simple, effective, and inexpensive, costing approximately $20 for 250,000 eggs. Natural nests would be excavated, the eggs treated, and the eggs re-buried to incubate. This method has been shown to be effective in both sea turtles (Ridley) and freshwater turtles (Cagle's map), both of which are threatened.
Synopsis of Research Work by Reptile Conservation International Until recently it has been assumed that all vertebrates had sex chromosomes and the sex of the offspring fixed at fertilization. With sex chromosomes the sex ratio is 1:1 and apparently immutable. However, many reptiles do not have sex chromosomes; rather, sex is determined during the mid-trimester of development by the temperature at which the egg is incubated. This process is called temperature-dependent sex determination or TSD. In TSD, the effect of incubation temperature is unequivocal. The offspring is either a male or a female; hermaphrodites or intersexes are extremely rare. In addition, research using the red-eared slider as a model system has shown that application of steroid hormones can override the effect of temperature. Thus, both temperature and sex hormones can determine sex in many egg-laying reptiles. The importance of TSD is not of esoteric interest only to herpetologists. TSD represents the primitive sex-determining mechanism that gave rise to systems using sex chromosomes in mammals, including man.
TSD also has ecological significance. The majority of endangered reptiles are TSD species, including sea turtles, Galapagos tortoises, alligators and crocodiles. Perhaps the best-known of these examples is the sea turtle. Because of their economic value, sea turtles have been exploited to the point of extinction in many areas of the world. Many conservation programs worldwide presently collect eggs and incubate them in captivity, usually in Styrofoam buckets, to prevent predation and poaching. These programs are not only logistically difficult but many, ironically, produce a high number of male sea turtles. These practices thus can have a negative effect on conservation of wild populations by skewing the sex ratio toward males.
Skip navigation home about cancer cancer types breast cancer bowel cancer cervical cancer lung cancer more... viagra dosagem maxima buy cheap viagra cancers in general what is cancer symptoms and screening tests treatment trials for patients preventing cancer smoking alcohol diet obesity more... can you buy viagra over the counter in ireland viagra from cananda without prescription cancer statistics key facts incidence mortality survival more... Viagra usarlo howtosmudge.com/pjn-cheapest-viagra-online-pharmacy-hc/ More about cancer coping physically, emotionally, practically cancer chat support us donate regular donation single donation by cancer type special occasion more... Efficacy of viagra for daily use viagra pills for sale Events race for life relay for life sport challenges stand up to cancer more... viagra 10 cena happens if women use viagra volunteer volunteer with us help at an event work in a shop find a role near you more... viagra dosagem maxima http://classicmotocrossimages.com/mbs-viagra-cheap-buy-canada-gi/ do your own fundraising fundraising pack raise money online fundraising ideas pay in your money more... how to buy viagra in canada medicaresupplementspecialists.com/pfz-sale-viagra-rp/ more... real viagra for sale buy generic viagra Campaign for us donate in memory leave a legacy corporate partners your local shop news & resources latest cancer news search news stories search press releases science blog podcast press office public policy what we think working with government more... viagra price cvs pharmacy Resources for teachers publications â£15m fund to provide advanced radiotherapy to 8… a new â£15 million fund could provide nearly 8,000 more cancer patients with access to an advanced radiotherapy technique... viagra dosagem maxima Read article funding & research research we fund who and what we fund research highlights research strategy how we deliver research funding for researchers find a grant how to apply application deadlines funding committees manage a grant manage online (egms) update your profile financial faqs manuscript notification our progress progress on different cancers cancer drugs radiotherapy a history of progress more... online pharmacy buy viagra from india Research jobs and training terms and conditions drug development office announcements, awards and events about us what we do our story research information influencing government how we fundraise our organisation how we are governed annual report and accounts annual review our strategy 2009-2014 contact us cancer information nurses sign up for e-newslett. purchase viagra online Quality generic viagra The discovery that the topical application of estrogen will fully override the masculinizing effects of temperature to produce a female hatchling has immediate practical implications for conservation biology. Research at the University of Texas at Austin by David Crews with leopard geckos indicates that these estrogen-induced individuals grow up to lay eggs as would a normal female. Thus, the estrogen-induced sex determination would not only help rectify past conservation efforts, but quickly lead to the recovery of populations of endangered turtles and crocodilians by skewing the sex ratio towards more breeding females. This method also circumvents the need for transporting costly egg incubators into primitive nesting beach locations. This method is "low-tech, low-cost;" $25 of hormone is sufficient to treat 250,000 eggs!
The impact of the technique can be seen in the following example. Let us assume that 10 breeding females exist and that each female will produce 30 eggs each year. Let us assume also that the young become sexually mature in their third year. Finally, we will assume that a 50:50 sex ratio occurs in unmanipulated animals. In all examples no mortality is considered and each female produced has equal fecundity. [These assumptions clearly are unrealistic, but any decreases in production will be equivalent in the various scenarios.] With the use of hormone-induced sex determination, the number of females will increase exponentially, with 10,200 females being produced over a four-year period compared to 2,700 females produced with no manipulation; at the end of seven years this difference becomes 633,100 versus 56,150!
Reptile Conservation International, Inc. (RCI), a non-profit organization dedicated to the conservation and restoration of endangered reptiles, was established in 1992. This organization has been awarded a tax-exempt 501(c)(3) status by the United States Internal Revenue Service. The estrogen-spotting method has been patented (U.S. patent 5,201,280 "A method for preferential production of female turtles, lizards and crocodiles"). All patent rights to the process of estrogen-induced female development have been assigned to RCI. Further, since the patent also covers "synthetic mimics" of estrogen, all chemicals classified as endocrine disruptors are also covered. All income produced by application of this method to captive-farming enterprises or to environmental monitoring, goes to support future research with endangered species. RCI is presently working with conservation programs in Mexico and Brazil to implement the method; it has already been found to work with three threatened and endangered reptiles: the Olive Ridley sea turtle, the freshwater Cagle's map turtle, and the New Caledonian gecko. The method has also been shown effective in the commercially-farmed muggers crocodile.
reptileconservation.org/sgb-557559/ http://reptileconservation.org/sgb-557857/ reptileconservation.org/sgb-559925/ viagra buying reptileconservation.org/sgb-555206/ http://reptileconservation.org/sgb-557277/ reptileconservation.org/sgb-556740/ reptileconservation.org/sgb-558415/ where to buy viagra in johannesburg http://reptileconservation.org/sgb-558348/