September 2021

White-lined Sphinx Moths (Hyles lineata)

Along our backyard fence line, I have planted a half dozen grape vines. About a week ago I was sitting in our back patio towards evening, enjoying an iced tea. It was dead calm, but I noticed here and there among my vines, grape leaves were quivering, as if a light breeze was skimming through them. Intrigued, I got up to take a closer look. To my surprise I saw large, bright green caterpillars, perfectly matched in color to my grape leaves, happily munching away on the same.

Every thing in nature, of course, is connected, and water dependent. On extreme drought years, plant growth is minimal, negatively impacting all other life forms, as plants feed everything, or not. This summer’s “monsoon season” in this part of Arizona has been exceptional, with far more moisture than usual. All life wakes up and thrives. Gene Hall, insect collection manager at the University of Az., Tucson, sums it up this way, “The plants are doing very well right now, so the insects that feed on them are doing very well as well.”

Anyhow, intrigued by the plethora of “very wells” creeping and munching among my vines (which by the way I don’t begrudge), I plucked one of these squirmy brings green things off one of my vines, and conveyed it temporarily into my den for a little “get-to-know.” I fired up my computer, and surfed the net. Aha! What was scooting across my desk was the caterpillar form of what would morph into a White-lined Sphinx Moth!

I’ve attached a photo of both the caterpillar and adult moth at the close of this blog.

Sphinx moths, as adults, are chunky, with plump football-shaped bodies. Mine mirrors that, but I will spare you a picture. The moths grow to up to three inches in length. I grew up to 6 ft., but with age morphed back to 5-11.  Turns out that missing inch was not lost, just incorporated mid-point into my football shape.

The moths have one up on me, however, in agility. They have the unique ability to be able to zip side to side, very quickly. I never was good at that, even during my prime football days. As for feeding habits, I am a voracious omnivore. White-lined Sphinx Moths are entirely nectar feeders. They favor many of the same flowers as hummingbirds. and will hover over the flowers they feed on exactly as does a hummingbird. Because of their large size and their movements, Sphinx moths are often mistaken for hummingbirds when feeding. The little birds of course probe for a flowers nectar with their long beaks and tongues, while the moths have a proboscis. My nose, again, sells me short.

Sphinx moths are great pollinators, and essential for the survival of desert flora. Like bats, they are evening and night active. And yes, they navigate by and are attracted to light. So, if you leave porch lights on, expect hordes of moths. If that bothers you, the easy fix is to leave porch lights off except when needed, and eliminate or lessen light emanating from indoors by closing curtains or Venetian blinds. The good news is that Sphinx moths are harmless to us, even if they find a way indoors. They cannot bite or sting, and they are not wool eaters, so no threat to our clothes.

An adult Sphinx moth will live 1 to 3 months. Usually towards the lower number. Plump and juicy, they are a choice morsels for about everything that walks, crawls, or flies. We have a pair of flycatchers that regularly flit around our front entryway, and on any given next morning this time of year, we will find at least a half dozen sets of Sphinx moth wings discarded on the ground. Adios amigos.

Primroses, spiderlings, penstemon flowers, tubular blooms of a variety of flowers, Virginia Creepers, and of course grape vines are favored foods of the Sphinx moth at various life stages. Come summer, the adults lay their tiny, round, green eggs on the underside of preferred leaves. The eggs hatch in from 6 to 9 days, and develop into bright green caterpillars.

On their posteriors are gripping horns, that help them cling to plants as they wiggle along and climb. Feeding starts immediately upon hatching, and continues for about 25 days, at which point the big caterpillars drop to the ground and seek out suitable soil to burrow down into and winter over in chrysalis form, slowly morphing into their adult stage. Unlike butterflies, they do not spin an above ground cocoon.

The summer monsoons this year have blessed us with an abundance of fascinating little life forms. Take a moment to look closely. To marvel, appreciate, give thanks.

Anthony de la Torre
Sun City Grand resident