Fireflies are bright ...

24 June

There have been a number of scary headlines in the media in recent days about declining number of Fireflies in the world, and that may well be true in general. Lots of insects are in trouble, so why not fireflies?

I’ll mention later why they are threatened - but I can say with considerable pleasure that if anything, numbers are higher in our garden than we have seen for some time. We had noticed adult beetles (they are not “flies”) in the garden during the daytime recently and then last night, a little after 9pm, we were treated to a veritable firework display of little moving sparks of light all over the garden. This hot and humid weather is just what they like.

This is a firefly (Photinus pyralis) I photographed a year or two ago, if you are looking to see them in daylight:

The light displays occur when males and females are signalling to one another. Displays of different species vary widely in colour, duration, and timing.

Why are we seeing a good show? Primarily because we don’t have a lawn. Fireflies want long grasses and other greenery and some humidity and those are features we have deliberately encouraged in the garden. They also want an absence of artificial light and again, our garden is dark. They are especially drawn to areas with damp soil as their larvae live in the soil and leaf litter where they eat worms, slugs, and snails.. If you have a garden then you can be part of the solution.

I have tried over the years to get photographs of the light show, and failed. It not at all a simple thing to achieve. However, I found this image and it is quite close to what we are seeing each evening from our deck.

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What can we do to support our local fireflies?

Reasons affecting firefly populations are as follows. Several of them are easy for anyone with a garden to mitigate … if we choose to do so.

1. Provide and Protect Natural Habitat

• Set aside a part of your garden to remain wild and undisturbed. Leave areas with native grasses, shrubs, and trees, and avoid over-mowing your lawn—taller grass and unmown edges provide cover for fireflies. Plant native vegetation of varying heights to retain soil moisture and provide shelter and food sources for both larvae and adults.

• Leave leaf litter and logs on the ground, as many firefly larvae develop in damp leaf layers and rotting wood. Create brush or wood piles to offer safe places for larvae and adults to live and hunt.

2. Reduce Light Pollution

• Turn off outdoor lights at night, to help fireflies communicate and find mates. Draw blinds to minimize indoor light spilling outside. If you absolutely must have lights at night, put them on proximity switches so they are not shining continuously. Artificial light interferes with mating.

3. Avoid Pesticides and Lawn Chemicals

• Do not use pesticides or herbicides, as these can kill fireflies directly or harm their prey and degrade their habitat.

4. Install a Water Source

• Fireflies thrive in moist environments. Adding a small pond or water feature can attract them. If that is not possible think about occasionally using sprinklers when necessary to keep an area moist

5. Minimize Soil Disturbance

• Avoid frequent tilling or ground disturbance, which can destroy larval habitat. If soil improvement is needed, use gentle methods rather than deep tilling. Let leaf litter lie.

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While we are talking insects, and I have your attention, here’s an exploration of an existential question:

Why are we so bugged by bugs?