American Golden Longhorn (Callicera erratica)

Hoverfly Added to the Vineyard Checklist

While exploring the fields at The Nature Conservancy’s Hoft Farm Preserve in West Tisbury on May 3, 2025, I came across a strange-looking fly as it perched on a shaded patch of bare, damp soil. About a centimeter long, the fly was mostly covered with obvious, yellowish fur; even the eyes were visibly hairy. But what really struck me were the antennae, which were long and blade-like – an unusual shape for a fly, shared mostly by some types of soldier flies (Stratiomyidae) and a few genera of hover flies (Syrphidae). Making some camera adjustments to accommodate the dim light, I shot about a half-dozen pictures as the fly sat there, turned around, and then abruptly departed.

Given the distinctive anatomy and the fact that I was reasonably sure the fly was a Syrphid, it did not take long to come up with a tentative identification: Callicera erratica, a member of a small genus (only three North American representatives) in the subfamily Eristalinae. I entered the fly as an observation in iNaturalist, tagging Trina Roberts, one of my Syrpid fly mentors; she quickly confirmed the identification.

To go with its unusual appearance, C. erratica has a peculiar life history. Larvae reportedly live in water-filled cavities in trees, and some sources report that the larval stage may require as long as five years to develop fully. Adults are generally arboreal, visiting flowers in the tree canopy, though (like mine) they are sometimes observed on the ground, taking in minerals from wet soil.

A New York Natural Heritage web page on the species describes it as “arboreal, canopy-dwelling…[and] confined to old growth pine/oak forests with senescent trees where the larvae live in rotholes and water-filled cavities of old living conifers (often high up in the canopy).” That habitat description is not a good match for where I found this species, so C. erratica presumbly has some flexibility in its habitat requirements. The old growth requirement that New York website suggests is thought to stem from the length of time it takes for trees to grow large enough to produce the type of rot holes this fly requires for successful reproduction. Perhaps the notorious humidity of the Vineyard climate accelerates the process of tree rot, producing suitable cavities in younger trees.

A recently published field guide to the Syrphid flies of the Northeast describes this species as rare, though my guess is that part of its apparent rarity comes from the fact that adults in the tree canopy are hard to detect. In any event, Callicera erratica is known only from well-scattered records in the eastern portion of North America. My fly appears to represent just the second record for Massachusetts; a specimen taken in Amherst on May 4, 1963, resides in the National Museum of Natural History. Bugguide.net includes no Bay State records prior to my own, and in iNaturalist.org, there are no previous Massachusetts observations and only one from all of New England, near Hartford, Connecticut.

C. erratica represents the 50th taxon added the Martha’s Vineyard Atlas of Life Syrphid fly checklist, and it is not the first Vineyard Syrphid species that can be considered regionally rare. For this fly family as well as many other kinds of insects, Martha’s Vineyard offers high-quality habitat. So you never know what you’ll encounter when you’re searching for flies.