It didn't start that way. In early spring, when I turned rocks or dead wood around our house, instead of the interesting tenebrionid beetles I was looking for I found fat, hairless brown caterpillars. They were everywhere, even under dry cow pies. They were so indistinct that I got no reaction when I posted one on Bugguide and it took Eric Eaton's blog on cutworms to make me realize what they were. I learned that they do not feed on dead wood, fungus or dry cow dung, they just hide under it during the day. At night they go out to chomp off young plants at the base, hence the name.
This year, our winter rains made the desert annuals sprout, so lots of caterpillars had food to develop into adults. My first cutworm moth of the season had crawled behind one of my paintings on display at an out-door art show. As it darted out (Dart is the other name mostly applied to the adult moths) my customer backed off in disgust. After the show, another moth, or maybe the same art loving creature, got itself loaded into my van, woke up at night during the drive home and fluttered into my face. At least it kept me from falling asleep on Interstate 10.
|Heliolonche carolus and Schinia miniana|
Then Dave Wagner, author of several books on eastern moths, visited and got me to look more closely at some day active Owlets, very pretty and in the same family as the cutworms.
Striacosta albicosta, Euxoa serricornis, Abagrotis reedi, Anarta trifolii
I have two lights, one in our driveway and one at our neighbors' house across the street. Both places have sandy soil, lots of Creosote, Saguaros, Palo Verdes, Ironwood Trees and a few Mesquites. The annuals are mostly Fiddle Neck Amsinckia intermedia, Scorpion Weed Phacelia, Bajada Lupine Lupinus concinnus, Filaree Erodium cicutarium, Evening Prim rose Oenothera primiveris, a small mustard and a small very common Cryphantha species. This relatively limited number of food plants supports an amazingly divers population of cutworms.
|Only the last one in this row is identified so far: Anarte mutata|
Cutworm or Dart moths form the subfamily Noctuinae in the huge family of the Noctuidae, the Owlet Moths.
From my own observations I'm pretty sure that cut worm moth populations here in the desert sharply increase in years with winter rains and resulting spring flower emergence. I can very well imagine how constant irrigation and spring seeding of crops offer ideal conditions for high Cutworm populations in agricultural settings. Under those conditions some species in this group can become economically important pests.