[Nhcoll-l] Wooden storage cabinets

[Douglas Yanega]

On 10/7/21 9:12 AM, Callomon,Paul wrote:
>
> Doug et al.,
>
> I’ve also often wondered why the insect world persists with wooden 
> cases. It may be because there are few calcitic structures in most 
> insects – my limited understanding of them is that they are made 
> mostly of protein and carbohydrates like chitin – so Byne’s, which is 
> specific to calcium carbonate (and perhaps calcium phosphate, 
> mammalogy colleagues?) is less likely to rear its fuzzy head.
>
Insect exoskeleton is predominantly made of sclerotin, which is a 
modified form of chitin:

"As it matures, freshly formed sclerotin becomes a hard, horn-like 
substance with a range of yellow-brown colors. As animals adapted to 
life on land, increasingly diverse needs for organic stiffening 
components arose (as opposed to mineral stiffening components such as 
calcium carbonates and phosphates). Among the invertebrates, this need 
was met largely by the development of sclerotins and other cross-linked 
proteins that allowed insects to adapt to existence on the land and 
later to develop wings. Sclerotin is biochemically variable; different 
species incorporate different proteins in different proportions, and the 
same insect will use different compositions in forming the different 
components of its body. In general, however, it is formed by 
cross-linking the various protein molecules with phenolic compounds – a 
tanning process under enzymatic control."

along with resilin, a remarkable elastomeric protein:

"Resilin is often found as a composite with chitin in insect cuticle, 
where chitin serves as the structural component."

While it may not contain anywhere nearly as much calcium as a mollusc or 
crustacean specimen, it seems reasonable to expect that after decades of 
exposure to acid fumes, an insect specimen *will* suffer. Given that the 
average insect specimen also has two or three labels, it is probably 
helpful that most collections have switched to using only acid-free 
paper for their labels, but - in reality - I think the switch was made 
not to protect the specimens, but to avoid problems with the labels 
disintegrating over time. Of course, it might be that label 
disintegration has never been solely a matter of intrinsic acidity, but 
exacerbated by outgassed VOCs, in which case we may STILL have labels 
falling apart decades from now, even *with* acid-free paper. That's the 
kind of thing people might want to know about.

Why we persist is, I think, simply a matter of cost and practicality. An 
insect drawer made of poplar wood with a glass top costs less than $50, 
and if properly constructed affords very good protection from dermestids 
and other pests, along with structural protection from vibration and 
impacts and chemicals. They can also be produced by anyone who has a 
modest woodworking skill and the right tools. I'm not sure that any 
alternative material (like acrylic) would necessarily be cheaper (simple 
acrylic boxes seem to cost in the range of 25-50 dollars, an acrylic 
insect drawer would probably cost more because of specialized design and 
more limited market), or not have its own chemical outgassing issues, 
but maybe it would be worth investigating. Such investigation might be 
tricky, if one cannot manufacture "test models" of alternatives easily 
or cheaply.

Peace,

-- 
Doug Yanega      Dept. of Entomology       Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314     skype: dyanega
phone: (951) 827-4315 (disclaimer: opinions are mine, not UCR's)
              https://faculty.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20211007/b367de5b/attachment.html>