- Scientific name: Cicindelidia marginipennis
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Endangered (MA Endangered Species Act)
Description
Cobblestone tiger beetle (Cicindelidia marginipennis)
Tiger beetles are so named because of their “tiger-like” behavior of chasing down and capturing prey with their long mandibles. The cobblestone tiger beetle (Cicindelidia marginipennis) is 11-14 mm (0.45-0.55 in) in length (Pearson et al. 2015). It ranges from medium brown to olive green in color, with a metallic sheen. Maculation (marking) on the elytra (wing covers) consists of a single, toothed white band around the entire outer edge. The abdomen is bright orange in color, typically only visible when the elytra are raised for flight.
Life cycle and behavior
In Massachusetts, adult cobblestone tiger beetles are active in July and August, when they forage, mate, and females lay eggs. The details of this species’ life history, in particular the immature stages, have not been well studied.
Distribution and abundance
The cobblestone tiger beetle ranges from New Brunswick south to New Jersey, and west to Indiana, with disjunct populations in Alabama and Mississippi (Pearson et al. 2015). This species is rare and localized throughout its relatively small range. In Massachusetts, this species is only known to occur in Franklin County.
Distribution in Massachusetts. 2000-2025. Based on records in the Natural Heritage Database.
Habitat
The cobblestone tiger beetle inhabits river shorelines, specifically banks, beaches, and bars consisting of a mixture of cobblestone and sand. Larvae burrow in the sand between and under cobblestones.
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Riverbank consisting of a mixture of cobblestone and sand, habitat for the cobblestone tiger beetle.
Threats
The cobblestone tiger beetle is threatened by alteration of the natural hydrology of its river shoreline habitat, particularly flooding that builds and maintains cobblestone and sand banks, beaches, and bars by preventing vegetation overgrowth and by depositing cobblestone and sand. Other potential threats include invasion by exotic plants, eutrophication or other water pollution, riverbank armoring, aerial insecticide spraying, and off-road vehicles. The effect of a warming climate may not be detrimental to the cobblestone tiger beetle in Massachusetts; its range extends south to Alabama, suggesting adaptation to warm temperatures. However, other effects of climate change, in particular changes in precipitation and hydrology, may be detrimental.
Conservation
Habitat (river) management is the primary conservation need of the cobblestone tiger beetle in Massachusetts. In particular, river hydrology should be restored and managed as close to natural conditions as possible.
Survey and monitoring
In Massachusetts, there is only one known population of the cobblestone tiger beetle. The existence of an undiscovered population is possible, though not likely. The Franklin County population of this species should be surveyed to document persistence at least once every 25 years; every 10 years is more desirable when practicable.
Management
Management of river hydrology can benefit a diversity of species. For the cobblestone tiger beetle, a relatively natural flow regime that builds and maintains cobblestone and sand banks, beaches, and bars is of particular importance. Control of invasive exotic plants in such habitats is imperative. Habitat condition should be monitored and management adapted as needed.
Research needs
The basic natural history and conservation needs of the cobblestone tiger beetle are relatively well known. However, the details of this species’ life history, in particular the immature stages, need further study. In addition, the future effects of climate change on this species are unpredictable and should be documented.
References
Pearson, D.L., C.B. Knisley, D.P. Duran, and C.J. Kazilek. 2015. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, New York. 251 pp.
Contact
| Date published: | April 15, 2025 |
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