Insects of the Lake Huron Coastal Dunes

Recently, interest has increased in the insect fauna that inhabit the dune systems of Lake Huron, in part because of the designation of Pitcher’s Thistle as an endangered species and the need to better know the species that share its habitat.  Scientists such as Dr. John Morton at the University of Waterloo and Dr. Steve Marshall at the University of Guelph have been particularly active in the study of insects of the dunes.  To date, well over 1,000 species of insects have been identified in these habitats, many of them considered very rare, and several that are new to science.  Some of the most interesting dune insects are discussed below.

Grasshoppers, Locusts and Crickets (Orthoptera)

The Lake Huron Locust (Trimerotropis huroniana) is found only on large, relatively-undisturbed open dune systems and sand beach habitats along Lake Huron.  It is considered globally rare, and is extremely rare in the province of Ontario.  It was collected during the summer of 2002 at Carter Bay, Manitoulin Island and there are historic occurrences for Southampton, Bruce County (its type locality) and Giant’s Tomb Island in Georgian Bay, Simcoe County. This insect, which exposes its yellow wings and clicks distinctively in flight, is threatened by dune development and pedestrian traffic.
Beetles (Coleoptera)

Many species of beetles are found primarily in sandy habitats such as dunes.  The Beach Dune Tiger Beetle (Cicindela hirticollis) is among the most characteristic insects of Lake Huron dune systems.  Otherwise, it is a very rare insect in Ontario, preferring undisturbed gently sloping sand beaches and adjacent dunes.  Another tiger beetle, Cicindela patruela, is restricted in Ontario to the Pinery – Port Franks area, although it was historically found at Constance Bay, near Ottawa.  It prefers backshore dunes, scrubby sand barrens and openings in oak woodlands.  The Little White Tiger Beetle (Cicindela lepida) is somewhat more widespread in the province, but is still very rare.  It is common in sandy habitats at St. Williams near Long Point, Lake Erie, and occurs on the dunes at Wasaga Beach.  It formerly was found on the Bruce Peninsula and Grand Bend.  This tiger beetle prefers white sand dunes, inland dunes, sand barrens and sandy patches in oak savannahs.  Other beetle groups associated with Lake Huron dunes include Serropalpus species, such as Serropalpus vestitus.

RETURN TO TOP

Butterflies and Moths (Lepidoptera)

Dunes are outstanding habitat in which to see butterflies.  As botanist and entomologist Dr. John Morton points out, “Who can but marvel in early July at the myriads of European Skipper butterflies that jostle for position on the milkweed and Pitcher's Thistle flowers, or be inspired by the Monarch butterflies that drift lazily across the dunes, stopping occasionally to sip nectar from the wealth of flowers on and behind the dunes?  …Similarly, the beautiful Canadian Swallowtail with its 3½ inch wingspan is a familiar sight on the dunes.”  

A total of well over 600 species of butterflies and moths have been recorded from dune habitats on Manitoulin and adjacent islands.  Most are not specifically restricted to the dune habitat and are either species visiting from nearby forests or are common species found in a wide variety of habitats.  However, some of the species occur at almost all the Manitoulin dune sites, even though they are not confined to them.  Examples include three large fritillary butterflies (Speyeria aphrodite, S. atlantis and S. cybele).  The caterpillars of these fritillaries feed on violets, which are usually common in marshy interdunal depressions.  The Dorcas Copper butterfly (Lycaena dorcas) is also usually common on Manitoulin dunes and feeds on Shrubby Cinquefoil (Potentilla fruticosa), but is equally abundant on alvars and rocky shores where the food plant also grows.  According to Dr. Morton’s research, the following moth species are characteristic of Manitoulin area sand dunes:  Eupithecia cretaceata, Apamea inordinata, Apantesis figurata, Euxoa aurulenta, E. perpolita, E. pleuritica, E. quebecensis, E. scandens, E. detersa, E. sinelinea, Oncocnemis riparia, Crambus praefectellus, Prionapterix nebulifera, Pyla arenacola, Xanthophysa psychialis, Eucosma lathami, E. serapicana and Phaneta montanana.

Many of the moths and butterflies of the Lake Huron dunes are considered rare to extremely rare.  Species known in Ontario almost exclusively from dune-associated habitats in the Grand Bend – Pinery – Port Franks area include Mottled Duskywing (Erynnis martialis), which prefers scrubby, open, sandy areas on backdunes, sand barrens, and limestone pavements having the host plant New Jersey Tea (Ceanothus).  Dusted Skipper (Atrytonopsis hianna) is found in moist interdunal meadows, while Bleeding Flower Moth (Schinia sanguinea), is also found in interdunal meadows that have the host plant Cylindric Blazing-star (Liatris cylindracea). Barrens Dagger Moth (Acronicta albarufa) is a species of sand barrens, including sand dunes.  A noctuid moth, Cobubatha dividua, prefers backdune forests and savannahs. Trembling Sallow (Chaetaglaea tremula) and a geometer moth, Idaea violacearia, both occur in backdunes and scrubby sand barrens, as well as oak woodlands.  The host plant for Newman’s Brocade (Meropleon ambifusca), another very rare species, is believed to be Little Bluestem, a common grass on dunes in the Pinery area.

Ants, Bees and Wasps (Hymenoptera)

Ants, bees and wasps are also well represented in the dry, open dune habitats of the LakeHuron coast.  According to recent studies by the University of Guelph, twelve species of Ontario’s hunting wasps (Speciform wasps) are found almost solely in the dune grasslands. These include Mellinus abdominalis and Diploplectron peglowi, which were until recently known only from western North America.  Perdita octomaculata is one of several species of bee associated with dunes, as is a kind of velvet ant.

RETURN TO TOP

Flies (Diptera) Dasymutilla canella

Several families of flies are evident on Lake Huron dune systems. These include robber flies (Asilidae), bee flies (Bombiliidae) and stilleto flies (Therevidae).  A robber fly, Proctacanthela cacopiloga is known in Ontario only from backdunes and scrubby sand barrens in the Pinery – Port Franks area and St. Williams in the Haldimand – Norfolk region. The bee fly, Dipalta banksi, is parasitic on the larvae of ant lions, and is restricted in Ontario entirely to dune systems along Lake Huron; it is otherwise found only along the United States shores of the Great Lakes.  The larvae of the only North American species of the Curtonidae fly family, Curtonotum helvium, develop on grasshopper egg pods buried in the dune sand.

RETURN TO TOP

Spittlebugs

Another group of insects that includes species largely restricted to dune and sand barren habitats are the spittlebugs, whose larvae live in a saliva-like substance attached to the stems and leaves of plants.  The Sand Prairie Spittlebug(Philaenarcys killa) is known only from dune habitats in the Pinery Provincial Park - Port Franks area and several other locations in Lambton County.  Several other species of spittlebug (Clastoptera hyperici, Fitchiella robertsoni, Prosapia ignipectis and Lepyronia gibbosa) have very restricted distributions in Ontario, confined to backdune areas, scrubby sand barrens or tall-grass prairies.  Spittlebugs often are dependent on the presence of specific food plant species.  For example, Lepyronia gibbosa, is found only in association with shrubby St. John’s-worts (Hypericum kalmianum and H. prolificum).

For more information about many amazing insects, please visit the University of Guelph's INSECT COLLECTION page created by Dr. Steve Marshall of the Department of Environmental Biology at Guelph.

RETURN TO TOP

Author of www.pitchersthistle.ca: Jarmo Jalava, 2005

If you have any questions about the website, please email us.