Journal archives for July 2019

July 23, 2019

Range guidelines for Banded & Sycamore Tussock Moths in Ontario

We have a few cryptic species pairs in the province and the Banded Tussock Moth Halysidota tessellaris and the Sycamore Tussock Halysidota harrisii is one that we have some (hopefully) helpful guidance on. The species are visually identical as adults, but they can be separated in photographs as larvae. However, adult Tussock moths are one of the most reported species groups in the province so some guidance on the treatment of adult observations is needed.

The key is the host tree: H. tessellaris are generalists and therefore are widespread while H. harrisii are host-specific and rely on populations of American Sycamore. American Sycamore is at the northern edge of it's natural range mainly in Carolinian areas along the Lake Erie shoreline. Historical records misidentified some specimens of H. tessellaris as H. Harrisii, giving the impression of wider provincial distribution that is currently suggested. H. Harrisii is very uncommon and local. For example, despite extensive collecting in Ontario, there are no H. Harrisii record for Ontario in BOLD's public database.

After discussion with Chris Schmidt of the CNC and Mike Burrell of the NHIC, we are adopting the following guideline for observations of adult Halysidota species in Ontario:

Treating everything as Halysidota tessellaris unless the record is at/near known sites of H. harrisii, or in an area with a significant amount of sycamore.

For reference, current sites with H. harrisii records include some areas of Norfolk County near Port Rowan & Long Point, and Elgin County north of Port Bruce.

Posted on July 23, 2019 17:19 by dkaposi dkaposi | 0 comments | Leave a comment