Ento-musings from the University of Kentucky Department of Entomology

Saturday, March 23, 2013

We're Starving the Monarch Butterflies

A recent blog post by Chip Taylor, director of Monarch Watch, said: "All in all, it was not a good year for monarchs." 

You can say that again. A March 13th press conference held by the World Wildlife Fund-Mexico and CONANP (Comisíon Nacional de Áreas Naturales Protegidas) revealed that the total area occupied by Danaus plexippus in the Trans-Mexican Volcanic Belt over the winter of 2012-2013 declined precisely 59% since the previous season.

Granted, the monarch butterfly population has a tendency to fluctuate annually—even greater shifts have been observed in the past—but this past winter's numbers are the lowest since the monarchs' overwintering locality was discovered by science in 1975. Moreover, a very statistically significant decline has occurred overall in the past 19 years. 

Of course, we Americans' first instinct would be to point fingers at the Mexicans, who have chronically logged the subtropical pine-oak forest upon which D. plexippus depends; but, although conditions at the Monarch Butterfly Biosphere Reserve remain sub-optimal, according to the press release, "by protecting its sanctuaries and practically eliminating large-scale deforestation, Mexico is doing its part."

Concurrently, 25.5 million more acres of corn and soybeans were planted last year in the United States and Canada than as recently as 2006. What's the connection? Monarch caterpillars feed only on milkweed (Asclepias sp.) (along with a number of other insects), a plant that grows in unkempt grasslands, often occurring along the edges of roadways and fields; but this habitat is disappearing as cropland expands—not, apparently, due to a greater need for food, but because of our (yes, our) increasing demand for the biofuels that are vaunted as "green". 

The proximal cause of the 2012-2013 monarch decline was probably the severe drought of 2012: temperatures above 95°F are often lethal to D. plexippus caterpillars. In the long run, however, the decline of Asclepias is to blame. So: what's to be done? For Monarch Watch, the answer is straightforward: plant milkweed. Lots of it. It is urgently needed.

And no, this is not a plug for the politically powerful milkweed-grower's lobby. 

Saturday, March 16, 2013

Zorapterans Are Worthy of Our Notice

On my visit two months ago to a prospective college that will remain unnamed (since it was notgasp—UK),  I toured Incognito University's insect-pest-research lab. Therein I saw bedbugs of all instars eagerly imbibing rabbit blood (and hoping for a taste of the human kind too), and also termite colonies in every stage of development: including a few that were a decade old, and (uniquely in 2002) had been founded in captivity; these lived in forearm-deep 3-foot-long Rubbermaid tubs filled to the brim with mulch. Up in a corner shelf, I noticed one of these tubs to be conspicuously labeled "Zoraptera", not Isoptera: referring to an order of Insecta of whose existence even many systematic entomologists are unaware, and which I had never seen. 

Upon request, my graduate student guide brought down and opened the bin, which contained no termites—my guide informed me that this mulch had been abandoned by the wood-chewers for some time, leaving it to the fungus-browsing zorapterans: inconspicuous things, being only 3-4 mm. long. I knew little of these insects, other than their habitat, their obscurity, and their subsociality; and I inquired if Incognito University was researching them.

Apparently not: according to my guide, these zorapterans were just baggage that came along with the mulch; nobody there really bothered with them. This is unfortunate, for the Zoraptera are far more interesting than most will give them credit for (http://gentlecentipede.blogspot.com/2013/03/patriarchy-and-other-eccentricities-of.html).