The frog reproductive organ changes abnormally

The irrigation pipe of a farm seems to be a safer shelter for frogs instead of a gutter near the supermarket parking lot. But scientists at the University of Florida demonstrate that the new gutter is the right place.

In a study that has a wide range of applications for the long-running debate on whether agricultural chemicals are harmful to amphibians, animal researchers at the University of Florida found that frogs living in the suburbs are less likely to experience abnormalities in their reproductive organs than those living near the farm, where some frogs have both testicles and ovaries.

Lou Guillette, professor of zoology, said: 'When increasing agricultural development, the number of unusual characteristics also increases.'

Guillette is one of the authors of the University of Florida study, an article published online in the journal Environmental Health Perspectives. The author is Krista McCoy, this study is also part of her essay on Environment and Natural Resources at her University of Florida.

A few previous studies have suggested a link between herbicides that are commonly used in agriculture and gender-specific traits in tadpoles and frogs. This deformity may cause the number of frogs to decline in areas of destructive contaminants such as Sierra Nevada, Calif. Amphibians are declining worldwide, toxic substances used in agriculture are considered a cause. Other causes include infectious diseases and habitat loss.

Toad Bufo marinus.(Photo: fireflyforest.net)

In the past, comparisons of frogs collected in the natural environment with those of agricultural areas were conducted. Other studies have also focused on special chemicals, including herbicides Atrazine , which causes abnormalities. The University of Florida study is the first to look at studies of the same type to compare anomalies in wild toads that live in frog-intensive areas in both semi-agricultural and suburban areas. absolute box. The study emphasizes the difference in the impact of agriculture and the development process.

Guillette said: 'Our research for the first time raises a clear question: Is there an abnormal proportion of individual differences between the two areas of human intervention?'

Because the results of the study allude to the cause of agriculture, additional studies in the future may narrow the focus on agricultural chemicals.

McCoy said: 'We know that chemicals are used in farming areas, so we can proceed to demonstrate the use of chemicals causes anomalies by conducting controlled experiments with individual chemicals as well as combining them '.

The researchers gathered giant toads with the scientific name Bufo marinus from five different locations stretching from Lake Worth to Belle Glade, down toward Homestead in southern Florida. Bufo marinus is a large, strange and massive species but at the same time a deadly enemy to small animals. According to Guillette, the researchers looked at the species of toad in part because it was easy to catch them, and their large body size ensured enough blood to be studied. 'They are common in other agricultural regions around the world' , so they are ideal representations.

One of the study sites consists mainly of sugarcane fields or crops. The area of ​​cultivated land decreases in 3 other locations, the rest is completely suburban. The researchers calculated the land area of ​​each location by image from Google Earth.

Each site has an area of ​​2.1 square miles, experimental toad was collected in the central area. Because the toad's habitat range is about 1.2 miles, researchers only look for dwindling animals in the defined area. They collected at least 20 toads from each location in 2005 and 2006.

Examining modified toads reveals that: the higher the farming environment, the higher the genital anomaly ; These toads are called transgender toads that carry both male and female reproductive organs, unlike the normal toad or the majority of amphibians.

While the average four male toads were thicker and healthier than the four limbs of their offspring, many transgender frogs in agricultural areas had two thin and weak front limbs. Male transsexual frogs also have less nuptial pad - separate skin on legs used to clamp females when mating.

In areas where frog frog sex can be easily identified, males are the ones most affected. Ordinary males are brown, while toads add points with brown stripes. However, male toads live in agricultural areas with brown stripes like females.

In terms of internal structure, the more agricultural areas develop, the more feminine the reproductive organs are . Many have both ovaries and testicles. Not only that, both males affected or transsexuals also have fewer male hormones testoterone than normal males, so their fertility is also reduced.

Guillette and McCoy said the findings could have important implications not only for wild species but also for humans.

McCoy said: 'What we found in Bufo marinus could also happen to other animals, including amphibians and humans. In fact the anomalies in reproductive organs are increasing in the human community. This is probably somewhat related to pesticide exposure '.