Don't let the bed bugs bite
Bed bugs lurk in the nooks and crannies around your bed. And when night falls they creep out and use smell and temperature to track you down and to drink your blood! The bites they leave behind are large, they're red and they're intensely itchy. Nearly eradicated half a century ago, these pests are making a comeback though and a very serious nuisance of themselves. So much so that more than 100 researchers across the globe have now collaborated to sequence the genetic code of the bed bug in the hopes of finding a way to control them. Felicity Bedford spoke with lead author Joshua Benoit...
Joshua - Here in the US we have a common saying "don't let the bed bugs bite". So we'll say that most people don't even know what bed bugs were but here, the number of bed bugs that are found is increasing pretty much every year since 2000. So people would use a lot of pyrethroids and other pesticides but now these bed bug populations are showing thousands to tens of thousand fold resistance to these chemicals, so they're becoming more prevalent. And so, for a long time in say cities like London, New York, they weren't really endemic, so people would travel and away and bring them back, but now there's almost endemic populations of bed bugs present within all these cities.
Felicity - Is this just a case of changing the type of pesticide that we use? Why are you investigating the genetics exactly?
Joshua - We've almost run the course of every single pesticide that is actually available to use and what our goal with the genome is to actually begin to start seeing if we can, maybe, find some kind of novel target. Either some sort of gene or some sort of interference that can be new and, hopefully, bed bugs won't have resistance to this at least for a few years so we can begin to control this exploding population of bed bugs.
Felicity - Was this project solely about finding out how they've evolved to resist these pesticides or is there more to it than that?
Joshua - No, there's actually more to it than that. Bed bugs are actually interesting biologically a little bit too. The first thing is, they feed solely on blood and they have all these novel adaptations and we want to look at those, and their sensing and odour receptors are adapted to finding their vertebrate host. And the second one is their mating style is very unique, so they mate by a process called traumatic insemination. The mating process involves a lot of conflict between the male and the female and for this, the male actually ends up piercing the underside of the female through a special organ and then depositing the sperm into her abdomen rather than through the reproductive tract like a lot of other insects. And so we look at some of the genes potentially involved in this topic.
Felicity - So at this stage, what you've got is that you've got a genome and you've decided these are the interesting bits, these are the genes we need to be looking at because we know that they're involved in the really interesting biology and, moving forward from here, there's a lot more research to do. What is the next step?
Joshua - So the idea is to potentially look at them and how populations of bed bugs move throughout areas and using the genome as a resource to analyse that. But then, also, what they want to do as well is they want to see if we can take the genome and look for potentially novel bed bugs specific genes that are critical to their survival and then, hopefully, find chemical targets that we could actually then use to control the bed bugs.
Chris - Sincere apologies to anyone who's now feeling the intense urge to scratch like we are! That was Joshua Benoit from the University of Cincinnati speaking with Felicity Bedford and his bed bug genome study was published this week in the journal Nature.