Radar Love: Antennae, Sex Pheromones and Bug Love
Pat Kelley, BCE - President of Insects Limited
When I get lonely and I’m sure I’ve had enough
She sends her comfort coming in from above
We’ve got a line in the sky
We’ve got a thing called Radar Love
– “Radar Love” Lyrics by Golden Earing - 1976
Insects Limited is all about pheromones
We synthesize insect pheromone, blend pheromones, test pheromones and provide pheromones to our customers around the globe.
Simply stated, the concept for sex pheromones is that a chemical scent is launched into the air by a female insect and that scent ultimately translates into boy bug finding girl bug.
While many people know this much about pheromones, most don’t understand the process that goes into making the male behave this way.
To explain the process that goes on inside the insect’s brain, we must first understand all of the mechanisms that take place in the insect’s antennae.
Insect Antennae
The antenna is a quite complicated structure in and of itself (see diagram below).
An Indian meal moth (Plodia interpunctella) antenna and a close-up image showing some of the thousands of sensilla (sensory hairs) that detect the pheromone and cause the male to seek out the pheromone source. (Image by Patrick Kelley, Insects Limited)
Antennae Capture and Absorb Pheromone
Once the sex pheromone hits the antenna of an insect, the magic begins. Below is a list that breaks down the pathway that a pheromone takes through an insect’s antenna and into its brain:
1. The male insect’s antenna first comes in contact with the pheromone. The antenna is made up in part of a long segment called the “flagellum”. The flagellum comprises much of the length of the antennae.
2. On the surface of the flagellum are thousands of olfactory sensilla (hair-like structures) that capture and absorb the pheromone through microscopic pores on the surface of each.
3. The pheromone travels through these pores in the sensilla down to nerve cells located inside the antenna.
4. When that nerve cell is stimulated by the correct pheromone from the virgin female of that specific insect species, the cell translates that chemical pheromone into an electrical pulse.
5. That electrical nerve pulse is sent directly to the insect brain in an area of the brain called the Antennal Lobe (see diagram below). The Antennal Lobe is the primary “smell” center of the bug brain.
6. The brain of the male insect reacts immediately when an electrical pulse is received through the Antennal Lobe. The very predictable result is that he is immediately is called into action. That electrical signal causes him to instantaneously begin flying or crawling upwind to find a potential mate.
Indian meal moth brain including the antennae & Antennal Lobe. Image by Patrick Kelley, Insects Limited
If the origin of the scent is a female moth, the male usually will go into a mating ritual upon locating her.
He will often emit his own pheromone that calms the female and helps initiate mating.
If the source of that scent is a pheromone lure in a trap, he will follow that pheromone until he is captured in the trap.
Either way, the pheromone path is through the hairs on the male insect’s antenna - it is then translated into an electrical pulse and is finally jolted into his insect brain through the Antennal Lobes.
The male’s reaction to that brain jolt is to first locate his mate – then initiate a mating ritual and finally attempt to copulate. This reaction to sex pheromones is repeated as long as the male insect remains alive and healthy. Just another example of Radar Love.
Video: A male insect will use his antennae to locate his mate's distinct pheromone.
The antennae translate the pheromone into nerve pulses that result in the extraordinary process of first locating his mate – then initiating a mating ritual and finally attempting to mate. This process is repeated as long as the male insect remains alive and healthy.
Reference:
Zhang, J., Walker, W. B., & Wang, G. (2015). Pheromone reception in moths: from molecules to behaviors. Progress in Molecular Biology and Translational Science, 130, 109-128.
Insects Limited, an Insect Pheromone Company
Insects Limited, Inc. researches, tests, develops, manufactures and distributes pheromones and trapping systems for insects in a global marketplace. The highly qualified staff also can assist with consultation, areas of expert witness, training presentations and grant writing.
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