For episode #99, Bryan and Steve discuss the three biggest reasons German cockroaches would avoid gel bait. They also share stories about elevator pit infestations and Steve’s recent cricket infestation.
In addition, Bryan introduces his ACE Challenge. He’ll be interviewing PCOs about the victories and challenges they face while preparing for the ACE exam.
German Cockroach Bait aversion: Is when the target pest avoids the bait, or more commonly, consumes a non-lethal dose.
Why roaches would avoid a bait. In no particular order:
- Learned behavior
- If a roach ingests a non-lethal dose of bait and they sense something is going wrong, they could regurgitate it, consume lots of water or eat a different food source to dilute the toxicant or push it through the body faster. After they weather the storm, they’ll make a mental note to avoid that stuff.
- A common roach-bait ingredient is corn syrup. Corn syrup is sweet, it has a lot of glucose and fructose, which are simple sugars. Roaches generally love sweets because they have lots of carbohydrates. However:
- Some roaches are what they call glucose-averse. We don’t know for sure if glucose actually tastes bitter to a glucose-averse roach, but we do know that glucose triggers their bitter receptors. When this type of roach stumbles across sugars, it runs in the opposite direction.
- Roaches could be avoiding the type of proteins, inert ingredients.
- Nutrition – At different stages, roaches need different ratios of nutrients.
- German cockroaches are survivors. If need be, their bodies can overcome nutritional shortcomings. Just one of many examples is that if there’s a lack of protein available, roaches can conserve uric acid. If, however, their nutritional needs can be met through some additional foraging, they’ll seek out the food source that will give them the nutrient(s) in need. Which caught me off guard, because I’m from the school that good bait placement is all you need. I thought roaches would feed off of the first food source they stumbled across, but that’s not always the case.
- So to combat that, manufacturers try to find ways to either compliment the roaches current diet by offering materials not readily available, or be able to “out-compete” the other foods available. Here’s where it gets tough. Not only do manufacturers have to come up with a food matrix the roaches will choose over other available foods, they have to be able to put it in a tube, ensure it will withstand moderately hot and cold temperatures, stay pliable for a decent amount of time (it would get too hard, too fast), make sure the different ingredients don’t separate , etc.