David Wagner – one of our sponsors and the author of Caterpillars of Eastern North America: A Guide to Identification and Natural History – recently published a journal article on moth decline in the Northeastern United States in News of the Lepidopterists’ Society. This paper joins several out of the UK (Thomas 2005; Conrad et al 2006) addressing the decline of moths around the world.
Dr. Wagner reports diminished numbers of moths, particularly the larger saturniids and sphingids. These declines are supported by anecdotal reports from many collectors throughout Wagner’s home state of Connecticut, where 65 Lepidoptera species are thought to be extirpated.
Decreases in moth abundance can be attributed to habitat loss (particularly loss of early successional habitats), development, overgrazing by deer and climate change. Light pollution may also play a role in declines but this factor has not yet been experimentally supported.
Additionally, parasitic flies such as Compsilura concinnata that were introduced to control pest species like gypsy moths (Limantria dispar) and brown-tail moths (Euproctis chrysorrhoea) also prey on native and non-pest species as well.
The bottom line is that more data are needed, particularly from long term monitoring studies to really document observed declines in moth species.
Conrad K.F, M.S. Warren, R. Fox, M.S. Parsons, and I.P. Woiwod. 2006. Rapid declines of common, widespread British moths provide evidence of an insect biodiversity crisis. Biological Conservation 132: 279-291.
Thomas J.A. 2005. Monitoring change in the abundance and distribution of insects using butterﬂies and other indicator groups. Philosophical Transactions of the Royal Society B 360: 339–357.
Wagner, DL. 2012. Moth decline in the Northeastern United States. News of the Lepidopterists’ Society 54(2): 52-56.