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Archive for June 14th, 2007

The Amphibians of Mount Gede Pangrango and Mount Salak, Indonesia

Posted by Miqe on June 14, 2007

By Mirza D. Kusrini, A. Fitri, W. Endarwin and M. Yazid

Although there is good evidence that amphibian declines are a global problem, most reported amphibian declines have occured in developed countries or in countries that have a strong research culture. Almost no declines have been reported in Indonesia. However this may be due to a lack of research and long-term monitoring in this country (Iskandar & Erdelen, 2006).  

    In 2003, we conducted amphibian surveys in two mountainous areas in West Java province: Mount Gede Pangrango National Park (highest peak 3,400 m above sea level) and Mount Salak (part of Mount Salak-Halimun National Park; with the highest level of 2211 m). Both mountains represent some of the few remaining pristine areas of the heavily populated West Java province. Liem (1971) described 19 species of amphibians in the Cibodas Trail of Mount Gede from 1961 to 1964. Unfortunately, there are no further available reports of Mount Gede amphibians after this time. There are no comprehensive surveys of the amphibian fauna of Mount Salak region either, and only a few reports on amphibian biodiversity in adjacent areas. Surveys by The Indonesian Insitute of Science (LIPI) in 1999-2001 in Mount Halimun region found 27 species of frogs (Mumpuni, 2002).

    We conducted Visual Encounter Surveys (Heyer et al., 1994) in several locations inside the national park with different types of habitat encompassing the forest floor, water bodies and surrounding vegetation. The occurrence of a species was determined by finding adults as well as larvae and if possible by male vocalization. Surveys in Mount Gede were conducted from September 2004-February 2005, comprising nine locations ranging from 700-2740 m asl including locations reported by Liem (1971). A second series of monitoring surveys has been underway since November 2006.  Surveys in Mount Salak were conducted in 7 locations, ranging from 700-340 m asl from December 2005-June 2006.  Each location was visited once, for four days in a row.

    In total we found 19 and 21 species from five families (Bufonidae, Megophrydae, Microhylidae, Ranidae and Rhacophoridae) for Mount Gede Pangrango NP and Mount Salak NP respectively.  The number of species found in Mount Gede Pangrango NP were less than those found by Liem (1971) and species composition differed. Four species from Liem’s result were not found in the first survey: Fejervarya cancrivora, Bufo bipocartus, Microhyla palmipes and Rana nicobariensis. Instead, we found additional species: Rana hosii, Leptophryne borbonica, and Limnonectes macrodon. During our second year monitoring in Mount Gede Pangrango NP (November 2006-February 2007) we found the missing M. palmipes. A particularly important finding was of a caecilian Ichthyophis hypocyaneus in Bodogol (700 mm asl). This is the first record of a caecilian in Mount Gede Pangrango NP.  No mass mortalities were found on either mountain, however, an adult Limnonectes kuhlii was found dead, floating in a small pu!
ddle of water on the side of a walking trail in Chevron Geothermal Concessions in Mount Salak.

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Posted in Amphibians, International articles and news., Science/Scientific papers | 1 Comment »

Study shows lizard moms dress their children for success

Posted by Miqe on June 14, 2007

SANTA CRUZ, CA–Mothers know best when it comes to dressing their children, at least among side-blotched lizards, a common species in the western United States. Researchers at the University of California, Santa Cruz, have found that female side-blotched lizards are able to induce different color patterns in their offspring in response to social cues, “dressing” their progeny in patterns they will wear for the rest of their lives. The mother’s influence gives her progeny the patterns most likely to ensure success under the conditions they will encounter as adults.

In a paper published June 10 in the online early edition of the journal Ecology Letters (and in a later print issue), the researchers reported that female side-blotched lizards give an extra dose of the hormone estradiol to their eggs in certain social circumstances. The extra hormone affects the back patterns of lizards that hatch from those eggs, creating either lengthwise stripes down their backs or bars stretching from side to side. Whether they get stripes or bars depends on the genes for other traits.

“This is the first example in which exposure to the mother’s hormones changes such a fundamental aspect of appearance. Even more exciting is that the mother has different patterns at her disposal, so she can ensure a good match between back patterns and other traits that her offspring possess,” said Lesley Lancaster, a UCSC graduate student and first author of the paper.

Coauthor Barry Sinervo, professor of ecology and evolutionary biology, is Lancaster’s adviser and has been studying side-blotched lizards for nearly 20 years. He said the lizards’ main predator, the coachwhip snake, is a highly efficient hunter, and the lizards need just the right combination of traits to avoid being eaten.

“The females are dressing their progeny for success, because they need a different back pattern in different conditions,” Sinervo said. “It’s like fashion–she wants to make the rare, fashionable progeny that won’t be caught by predators.”

Lancaster used a combination of laboratory and field experiments to tease apart a complex set of interactions involving hormones, genetics, social interactions, behavioral strategies, and predators. Previous studies by Sinervo and his collaborators have described three different behavioral strategies that correlate with throat color in side-blotched lizards. Orange-throated males are highly aggressive and usurp territory from other lizards; yellow-throated males sneak into the territories of other males to mate with females; and blue-throated males form partnerships and cooperate to protect their territories. In females, throat color correlates with different reproductive strategies.

According to Lancaster, the maternal effect on back pattern is important because survival in these lizards depends on different combinations of traits in different circumstances. Females use social cues to predict the circumstances their progeny will encounter. Maternal influences like this probably occur in many species, but are very difficult to detect, Sinervo said.

“Maternal effects are a nebulous thing to study, because you know there are genes for these traits, and it’s really hard to tell the maternal effects apart from the effects of the genes,” he said.

Lancaster began by treating side-blotched lizard eggs with an array of different hormones. That revealed a striking influence of estradiol on back patterns. She also tested eggs from lizards captured in the wild and found a wide range of naturally occurring estradiol concentrations in the egg yolks.

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Posted in Herps in the news, International articles and news., Lizards, Science/Scientific papers | Leave a Comment »

 
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