What species of beetle is it? (And what should you do if you see one?)

Thank you so much for sharing this vivid (and so realistic) nighttime encounter in the bathroom! That thud against the lamp is undeniable – and yes, it really does make you jump.

You've already done half the work by realizing it's not a cockchafer. Let me confirm your identification, explain its presence in your bathroom, and, most importantly, tell you what to do (and what mistakes to avoid) if you find another one.

✅ First of all, the good news: the cockchafer is harmless to you.

First, take a deep breath. The cockchafer (   Melolontha melolontha  ), sometimes also called the "May beetle" or "earthworm," is not dangerous   to humans or domestic animals.

• It doesn't bite or sting.    The pincers on its head? They're for eating plant leaves, not for pinching people.

• It is non-toxic.    Poison-free, non-irritating.

• It does not infest houses.    It is an insect that lives outdoors and accidentally entered the house, attracted by the bathroom light.

So why did she choose your bathroom in particular? You've probably already guessed:    the light   .

🪲 Why was it in your bathroom?

Cockchafers are nocturnal and strongly attracted to light sources, especially white or bright light. The light in your bathroom, reflected off the shiny tiles and porcelain, acted like a beacon for them.

They also appear in late spring (April-May) for their short adult flight period, which lasts only 4 to 6 weeks. During this time, the males fly noisily at dusk and during the night in search of females. It is at this time that they are most likely to accidentally enter a room lit by an open window, or even a fireplace.

Its bathroom offered all the ideal conditions:

• A bright light is on at night ✅

• An open window or a gap around a ventilation opening ✅

• Warm, humid air (which they find inviting) ✅

He wasn't looking for a new place to live. He was simply lost.

🔍 Cockchafer vs. Junebug: How to identify it

You mentioned initially thinking it was a cockchafer. This is a very common mistake. Here's a simplified explanation:

Special function	cockchafer	June cockchafers
Size	Larger (1 to 1.5 inches / 25 to 35 mm)	Smaller (½ to 1 inch / 12 to 25 mm)
Color	Dark reddish-brown with a black head	shiny metallic greenish-brown
Movement	Clumsy, noisy, bumps into objects	Buzzing, unpredictable, but a little more agile
Active Season	Late April to May (only 4 to 6 weeks)	Late May to June
Silhouette	Solid, rather oval	Slightly thinner

The cockchafer is also much noisier in flight – hence the unpleasant clattering you heard. They are anything but graceful birds in flight.

🛠️ What to do if you find one (What you did exactly correctly)

You did perfectly. Here are the step-by-step instructions:

1. Don't panic!    They can't hurt you. Even if one of them lands on you, it will just crawl away or try to fly off.

2. Turn off the bathroom light and close the door.    The darkness will calm him and he will stop hitting the surfaces.

3. Open a window (if possible) and turn on an outside light.    The animal will be attracted to the light and then fly away on its own. This is the gentlest method.

4. Another method: gently catch it.    Use a cup and a piece of paper or stiff cardboard. Slide the paper under the cup, take it outside, and release the animal on a tree or bush (not directly on the ground; it needs to be able to climb).

What you should NOT do:

• Do not crush (it's messy and unnecessary).

• Do not flush it down the toilet (it is alive and can survive for some time in the pipes – it is cruel and ineffective).

• Do not use insecticides in the bathroom (it is excessive and introduces chemicals into your living space).

• 🏠 Will more May beetles enter the house?

  Probably not. The flight period of adult moths is very short (4 to 6 weeks). You might see one or two more if you leave the bathroom light on at night with the windows open. However, they don't reproduce  or nest    in your house. For their larval development, they need soil and plant roots, which your bathroom doesn't provide.

  If you wish to avoid any future confusion among your visitors:

  • Keep bathroom windows closed or fitted with mosquito nets on May evenings.

  • For lighting near open windows, use a low wattage bulb or a yellow insect repellent lamp.

  • During cockchafer season, turn off unnecessary lights at night.

  🌍 One last point: cockchafers are actually beneficial for the garden.

  Adult cockchafers feed on leaves (which can annoy gardeners). In their larval stage, they aerate the soil and decompose organic matter. Most importantly, they are a vital food source for bats, birds, and hedgehogs.

  Their population collapsed in the 20th century due to pesticides. But it is slowly recovering, and many ecologists see this as a positive sign for biodiversity. Thus, their nocturnal visitor was not just a clumsy insect: it was a small indicator of the recovery of local ecosystems.