More Articles
- May 2012
- April 2012
- March 2012
- February 2012
- January 2012
- December 2011
- November 2011
- October 2011
- September 2011
- August 2011
- July 2011
- June 2011
- May 2011
- April 2011
- March 2011
- February 2011
- January 2011
- December 2010
- November 2010
- October 2010
- September 2010
- August 2010
- July 2010
- June 2010
- May 2010
- April 2010
- March 2010
- February 2010
- January 2010
- December 2009
- November 2009
- October 2009
- September 2009
- August 2009
- July 2009
- June 2009
- May 2009
- April 2009
- March 2009
- February 2009
- January 2009
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- June 2007
- April 2007
Tree Snails on the Kalawahine Trail
Posted: January 22, 2009
With just a few hours of free time to spare, I decided to do something I had always been curious about but never took the time to do — explore the native snail habitat on the Kalawahine Trail above Makiki Heights.
The Kalawahine Trail is part of a larger system of interconnected trails over Makiki known as the Honolulu Mauka Trail System. The Kalawahine Trail starts near the top of Pu’u Ohia, the cinder cone better known today as Tantalus, at the top of Round Top Drive. The trail contours along the edge of Pauoa Valley and winds in and out of a number of gulches along the way.
For many years, I had passed the sign on the trail which tells hikers to treat this native snail habitat with care. A pair of signs mark the boundaries of the snail habitat, a small gully dominated by white ginger and other introduced plants.
The snails were not hard to find. I found several dozen of them on the leaves of white ginger and other plants in the gully. Most of the snails had retracted into their shells and were sleeping on the underside of leaves but some of them were crawling about on the ginger. The snail shells were brown in color and ranged in size from an eighth to a quarter of an inch. In the photo above, the dark spots on the leaves above the ginger flowers are snails.
Under the low light conditions on the trail in early morning, the snails appear to be dark brown. With additional lighting from a camera flash their shells take on a reddish-brown color. The snail above is about a quarter of an inch long and crawls on the backside of a ginger leaf.
The shells of these snails are a very thin and are almost translucent. The dark mottled pattern on their shells is created by the parts of their soft bodies that stick against their thin shells.
Snail expert, Daniel Chung — who is credited with the last sighting of a number of extremely rare native snails — identified these tree snails as Auricullela diaphana which are endemic to Hawaii. While they are not on the federal list of endangered species they are not commonly seen. Like Achatinella tree snails, Auricullela snails are aboreal, do not eat the plants they inhabit, and graze on microscopic algae and fungi that grow on plants. But Auricullela snails are different in that they lay eggs as opposed to Achatinella snails who bear live young.
As I made my way back out the trail I was pleased to have taken the time to explore the native snail habitat on the Kalawahine Trail and to finally see the interesting little creatures that live there.
–
SOURCES
Hawaiian native insects (and other invertebrates), Karl Magnacca’s Home Page
Manual of Conchology, Second Series: Pulmonata, Vol XXIII, By Pilsbry, Henry Augustus, b. 1862; Cooke, Charles Montague, 1874-1948, The Conchology Department, University of Philadelphia, 1915-1916
Personal communication with Daniel Chung, Snail Expert, University of Hawaii and Bishop Museum
Again you amaze me Nathan. I’ve hiked past there several times and never seen a single snail. Maybe next time if I hike at a snail’s pace I will also see those wonderful snails (Forgive the pun
.
Thanks,
Rich
Hi Rich… I too had passed by many times and never seen them. One has to stop and look to see them.
Regards,
Nathan
Hi,
I recently hiked the Kalawahine Trail (May 2009), and, after serendipitously noticing a snail on a ginger leaf right beside the trail, stopped to look for more too (and take pictures). I didn’t expect to find them so easily. There were many snails (I counted at least 20 on one tree) on almost every plant, and they seemed mostly active, crawling around (it was about 11:00 in the morning).
Interestingly, I also found a rosy wolf snail creeping up a ginger stem a few inches away from several Auriculella. It seems I had just stumbled upon an ecological drama. Fortunately, I managed to dispatch the marauding Euglandina.
Which confuses me: If there are so many rosy wolf snails around Tantalus, how can it be that a small gully full of native snails without some sort of excluding fence could survive until today?
Thanks for identifying the snails as Auriculella diaphana. I couldn’t find such information elsewhere on the internet or with google scholar.
E. Liaw
Hi E. Liaw… Good thing you dispatched the rosy wolf snail. It’s amazing that this little gully has become a sanctuary for these snails. I don’t know why this population of snails have managed to survive at this location but let’s hope their good fortune continues. Regards, Nate