REPLY2: Moles and other Geophyte predators
Tue, 03 Jan 2006 05:44:19 PST
In a message dated 12/30/2005 3:39:28 PM Pacific Standard Time, 

Ernie ~
Well, Dave, I hate to throw cold water on the statement that moles are only 
carnivorous, but research has proven otherwise, right here in Oregon. An 
excellent book on the subject of moles is: _Of Moles and Men: The Battle for the 
Turf_ by Patrick H. Thompson.
Looks like obtaining and reading of this book will rank in the first five of 
my objectives for 2006!  

Interesting that this "ossified" description/understanding of moles (i.e., 
exclusively(?) insectivorous) is rather more widespread than realized, e.g., 
Webster defines Mole as an "insectivorous burrowing mammal."

As for throwing cold water (on statements, or otherwise!!), I spend the 
winters at home in Northern California where we have been getting cold water from 
the skies in near record amounts -- towns (Healdsburg, Guerneville) along the 
Russian River (the appellation where some of the world's best pinot noir is 
produced) are under as much as 45' of flood waters (Guerneville).  Much of the 
Napa Valley is flooded, as well.  In this area, we have received nearly two feet 
of rain this year, twice the normal amount -- and Winter is really just 
getting started!  I would imagine the local moles are using SCUBA to wait it out . 
. . 
 "The Townsend's Mole eats tulips, tigridias, bulbous irises . . . and these 
often form substantial portions of its fare.  Under field conditions, Moore 
documented the avidity of moles for tigridias. . . . In a study of commercial 
tigridia planting near Smith River CA, Moore found that 600 bulbs were consumed 
during a 10-day period. After two [!!! my comment] Townsend's Moles were 
trapped in the plots, no further damage to the remaining bulbs occurred. The two 
trapped animals contained 100 and 94% bulbs in their stomachs."
Loosely using the term "bulbs" in this thread, I feel, is misleading.  The 
cited research seems to indicate that corms and some "bulbs" (tulips) do form a 
minor to major portion of this animal's diet.  While I was just as guilty in 
loosely using the term, my knowledge base is really tunicate bulbs, in 
particular, Narcissus and Hyacinthus. I would certainly be the first to admit that I 
know nothing about most of the plant material being discussed in this forum.

Growing several hundred thousand daffodils on several acres, I have dug the 
occasional bulb that showed telltale incisor indentations indicating a gopher 
had sampled the bulb and, apparently, just as quickly backed off when the 
animal found it to be unpalatable.  That is not to say I haven't lost bulbs because 
of gophers, I have.  When, in their tunneling, they encounter a daffodil 
bulb, it is either moved out of the way into the spoil mound or transferred 
somewhere else in the tunnel complex from which it is unable to grow.

Moles, on the other hand, are the scourge of a daffodil grower!  Not because 
they consume the bulbs but because their tunneling causes major problems.  If 
tunneling occurs beneath the bulb, the roots are knocked off (a daffodil will 
grow only one set of roots each annual cycle); if above the bulb, the leaves 
expand into the tunnel and are unable to photosynthesize.  In either case, the 
life of the bulb is seriously compromised.  I have often dug bulbs later than 
I should have and had to remove the layer of soil over the row of bulbs (when 
the leaves are gone) to locate them before actually digging them.  Thus, the 
tunneling of moles becomes readily apparent.  When the tunneling animal 
encountered a daffodil bulb, it went around or, occasionally, dug and discarded the 
(smaller) obstruction into the spoil mound.  I have never found damage to a 
bulb that could be attributed to consumption by a mole.  If we were discussing 
slugs, on the other hand, I'd have some really interesting tales of damage to 
daffodil bulbs!!

The name "narcissus" descends from the Greek word narkissos meaning (broadly) 
sleep-inducing.  Narcissus bulbs contain an oxalate, the crystals of which 
are needle shaped (raphides).  When ingested, these crystals are released and 
lodge in the mucous membranes lining the mouth and esophagus causing the tissue 
to swell.  Diffenbachia sp. also contain this compound.  "Dumb cane" is a 
colloquial term used for this plant.  It has to do with an inability to speak and 
not, necessarily, to the relative smarts of the person ingesting the plant!!  
When chewed on by the unsuspecting (most frequently children under five 
years), swelling of the mucous membranes is so great as to prevent speech (hence, 
"dumb").  In the worst case, swelling could close off the airway causing death.

Oddly, the compound does not seem to be present in all tunicate bulbs, 
however, even Amaryllidaceae.  I also breed and grow Hyacinthus hybrids and have 
found on several occasions where a gopher had gotten (unnoticed) into the 
planting and devoured bulbs without suffering any ill effect (consumption of so great 
a quantity had to occur over a significant amount of time) .

Dave Karnstedt
Silverton, OR (Mar-Nov)
Windsor, CA (Dec-Feb)

More information about the pbs mailing list