Ask An Entomologist Profile picture
Jun 25, 2018 17 tweets 4 min read Twitter logo Read on Twitter
Bed bug sex is incredibly violent, and never voluntary.

The male's penis is a dagger he uses to forcibly inseminate the female, puncturing her body wall and injecting sperm directly into the bloodstream.

So how does he know when he's found a female?

He doesn't.

Again, before we continue...bed bug sex does not resemble anything human sex should resemble.

See disclaimer:

Early on in bed bug research, it was apparent to researchers that something wasn't right with the mating recognition systems of these insects.

Male bed bugs didn't seem to be too discriminatory, and would attempt to mount pretty much any well fed insect...male and female. first glance, it would seem that bed bugs exhibited some bisexual behavior.

However, the attempts to mate with males were a bit different than what you'd see with females.

When mounting other males, they'd get right up to the point of insertion...and then quit.
So, clearly there's something weird going on here.

Most bugs can tell the boys from the girls from afar...but bed bugs can't recognize females until they're pretty much touching them.

There's another thing...same-sex mating attempts produced a distinct odor.
Bed bug sex is a traumatic event.

Traumatic events in insects living in groups are typically associated with alarm pheromones.

So in 2009, Camilla Ryne asked a really obvious question.

What happens when you block the pheromones w/nail polish?
Blocking the male's ability to release alarm pheromones doesn't change the frequency of mountings, however it does change their behavior.

Males which can't produce pheromones are mounted longer and more violently.
When you take mating male/female pairs of bed bugs, and flood the chamber with the scent of male bed bug alarm pheromones, mating tends to end pretty quickly.

It ends in 1/4th the time.

So...alarm pheromones regulate sex-specific patterns in bed bugs.

Case closed, right?
Well, there's another layer of complication here.

Male bed bugs aren't the only bed bugs which produce alarm pheromones.

Female bed bugs, and nymphs produce alarm pheromones as well.

The males seem to only react to the alarm pheromones of other males, and nymphs.
We know what's in the bed bug pheromones, and we can detect those smells.

Adults produce a mix of (E)-2 Hexenal (think green apple flavoring), and (E)-2-octenal (a mix of citrus and cucumber).

The nymphs produce 4-5 different things, but the main one is (E)-4-oxo-2-hexenal.
I'm not entirely sure what that last one smells like, by the way.
So...when we see male/male mating attempts, we see them emitting a specific pattern of chemicals.

They're mainly producing that chemical which smells a bit like apples.
Females, however, seem to produce these two chemicals in a ratio that's a bit more even.

However, in general, they're releasing more of the citrusy-type chemical when mounted by a male.
Nymphs, on the other hand, drive off the males using 4-oxo-(E)-2-hexenal...which is a compound that's a bit different than what we see in male/male pairings.
So...why is this important?

Sex is something that's frequently happening in bed bug colonies, and it only happens with living insects. By definition, it only happens in breeding colonies.

If we know what bed bug sex smells like, we can design better diagnostic tests.
From a pure science perspective, it also explains why an insect with such a bizarre and violent mating system would not only occasionally pair with members of the same sex...but also explains why we see the pattern of backing off.

Bed bug sex makes a little more sense now.
Again, I want to re-state the disclaimer we began this thread with.

Insect sex is a bit horrifying, and we should not draw any conclusions about how humans should act from the ways insects do act.

We are different from insects, and they are not role models.

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Ask An Entomologist

Ask An Entomologist Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @BugQuestions

Aug 26, 2018
Yeah, we get pictures/videos of this occasionally.

Ants don't really do 'funerals'; even the dead in their own colonies are put into a garbage dump rather unceremoniously.

There's a handful of possibilities for this behavior...
1.) They may be attempting to bury it, especially if it's on a hard surface.

Lots of ants bury large food items to protect it from scavengers, other ants, and to absorb liquid which comes out from the prey.
2.) The critter happened to fall into the colony's trash pile.

Ants put waste (dead ants, poop, shedskins, etc) into a large pile called a 'midden pile' which functions just like our landfills.

If something ended up in that pile, they could be moving stuff out of the way.
Read 4 tweets
Aug 25, 2018
I think this problem hits at the heart of the issue when it comes to Eckbom's, because it's often not about infestations.

This deserves it's own thread to describe how complicated this problem is, and how poorly understood it is.
So...first, I believe that these people are accurately describing their perceptions of medical issues.

Urban IPM Extension people can go through samples to find insects, inspect homes for infestations (bed bugs, fleas, etc), get someone to do skin scrapings for Scabies, etc.
However, after that, they need to be passed onto a doctor.

Often times, attempts at self-treatment can cause skin irritation. Pesticide poisoning can also cause crawling sensations.

Brain tumors, autoimmune diseases, even cold weather can do this as well.
Read 4 tweets
Aug 25, 2018
Scientists make their living using their brains to interpret data.

So what happens when that organ breaks, and a respected researcher becomes mentally ill?

In this week's second #DeepDive, let's explore the case of Jay Traver.

CW: Mental illness
Jay Traver was one of the early entomological pioneers. Her career centered mainly around aquatic insects, specifically mayflies.

Most of her work-which is still cited to this day-revolved around describing the lifecycles of mayflies.
In 1951, Traver published a paper where she claimed to have experienced an infestation by a mite called Dermatophagoides scheremetewskyi.

This is a mite which lives in homes, and although it causes allergic reactions, it was known at the time to not be parasitic.
Read 15 tweets
Aug 24, 2018
A new meme going around FB claims the WoodLouse Spider is a "deadly new species" wrecking havoc in the Southern US

It's a completely harmless spider, but it still has a neat story to tell.

For the first of this week's two #DeepDives, let's explore the biology of Dysdera crocata
So, for the first tweet in this series, let's put these rumors to rest with data.

There's a lot of verified bites from D. crocata in the medical literature-which is rare. One person allowed themselves to be purposely bitten multiple times.

No deaths; everyone was just fine.
D. crocata gets it's name-the woodlouse spider-from it's food.

They live in dark, moist, areas and are adapted to feeding on sow bugs...sometimes called rollie-pollies.

They use those huge mandibles to foil the isopod's defensive rolling.

Read 8 tweets
Aug 21, 2018
It is with a heavy heart that we announce that one of our colleagues, Vazrick Nazari, has been arrested for possession of child pornography.

We cannot tolerate exposing our followers to this sort of person, and have blocked him from our feed.…
We did consult him for help with moth IDs here on Twitter, and although there's no way we could have known he was doing this, we still feel the need to apologize for exposing our readers to-and let's just put it as bluntly as possible-an alleged child predator.
We try to be careful about who we consult, and let into our conversations.

Unfortunately, it's not always possible to know what's going on behind the scenes.

Needless to say, we will not be requesting any more assistance from this person.
Read 4 tweets
Aug 18, 2018
With Glyphosate being in the news due to a recent court ruling, let's take this opportunity to explore the history of pest control in this week's #DeepDive.

It's a huge and complex topic, so the best we can do is a brief overview.
It's not really known when humans started using pesticides.

The first agricultural societies began about 10,000 BCE, with several independent shifts around the world from relatively nomadic lifestyles to those tending crops.
The first records of pesticides being used is in Sumeria, where they used elemental sulfur to control crop pests.

This is largely an accident of geography; Sulfur deposits are abundant in a stretch between Mosul and Fatha...which allowed easy access.
Read 27 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!


0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy


3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!