Fall Hiatus?

Summer days are fleeting by and there is even a slight chill in the air. Hopefully, your mosquito season service was successful and you had many happy customers. But now, with the cooler weather, your customers might be seeing fewer mosquitoes, so you are starting to get calls from folks who want to cancel their last mosquito service (or perhaps even the last two). What do you say to them? How do you attempt to convince them that they should not do this without sounding like a “revenue hound”? This article will provide you with some background and six key talking points that will hopefully be useful to you and your teams. Let’s begin by taking a brief look at a unique biological phenomenon known as “diapause.”

WHAT IS DIAPAUSE? The word “diapause” comes from the Greek word “diapausis,” which means “pause.” Hmmm. No real insight there! My unabridged Random House dictionary defines diapause as “a period of hormonally controlled quiescence, especially in immature insects, characterized by cessation of growth and reduction of metabolic activity, often occurring seasonally or when environmental conditions are unfavorable.”

Now, that is a real mouthful, especially if one is trying to explain this concept to customers or your mosquito service professionals. Therefore, I have whittled the definition down to “a resting stage, triggered by the environment, when bodily functions are shut down or greatly reduced.” Diapause is much more complicated than this, but this is a good working definition.

ESSENTIAL ASPECTS. Diapause is complicated and a sophisticated set of processes, but it greatly impacts mosquito control and public health. Here, in brief, are some of the essential aspects of diapause:

• There are similar, yet sometimes, different processes in other species beside mosquitoes, such as hibernation by bears, chipmunks and other creatures.
• Diapause by mosquitoes helps prepare the insects for next year’s invasion, as it allows them to remain in an area and not have to fly in or be transported the next season.
• Diapause is THE dominant life feature of mosquitoes.
• Diapause is the KEY mechanism for mosquitoes (and other animals) to bridge unfavorable seasons.
• Diapause helps to synchronize mosquito populations in an area for the next season, which can increase the risk of mosquito- borne diseases.
• In mosquitoes, diapause can occur in the egg, larval or adult stage, but the stage that it occurs in is species-specific.
• There are specific conditions that initiate diapause and terminate it. Most of these are environmental.
• Diapause is a physiological state of dormancy in which an organism’s tolerance for extreme environmental conditions increases and energy demands are lowered.
• A female mosquito preparing for diapause will seek a well- protected shelter, will move from blood feeding to nectar feeding and will change her egg-laying habits.

THE SIX PHASES. The scientific community generally recognizes six main phases of diapause. These are:

• Induction — Kind of like the “two-minute warning” that diapause is about to begin. The mosquito senses what are known as “token stimuli” (cues in the environment) that say, “It is time to get ready!”
• Preparation — The mosquito begins storing nutrients, especially carbohydrates, lipids and proteins needed for the long stretch ahead.
• Initiation — Diapause begins. This is generally tied to a decreasing photoperiod, i.e. the days get shorter.
• Maintenance — This is the main and longest period of diapause when the insect is essentially unresponsive.
• Termination — It’s time to wake up! Again, this is driven by “token stimuli.”
• Post-Diapause Quiescence — A quiet time, probably akin to how we humans feel while waking from a night’s sleep or perhaps a nap!

KEY COMMUNICATION POINTS. Now that you are all amateur “diapausologists,” what do you do with this information? How can it be useful to you and of value to your customers? Following are six key points regarding diapause and mosquito control. Last year, a national mosquito control company used this information to prepare scripts, videos, consumer-facing articles, and other communication tools, resulting in a significant reduction in service cancellations and the resulting increase in revenues.

1. Diapause is a mechanism that helps mosquito populations maintain in an area and spread rapidly. When female mosquitoes emerge from diapause, they are ready to seek a blood meal and start making more mosquitoes. This allows local mosquito populations to quickly build up and spread out early in the season and “new” mosquitoes don’t have to fly in.

2. Diapausing female mosquitoes may become active and bite. If cooler weather is interrupted by a spell of warm weather (an “Indian Summer”), females that have entered diapause may become active and bite. This could result in an increased risk of disease transmission.

3. Human pathogens, particularly viruses, will overwinter in diapausing female mosquitoes. This clearly has public health implications because viruses, such as West Nile virus, that successfully overwinter in female mosquitoes will be present and available for transmission early in the next season.

4. Killing diapausing female mosquitoes will help reduce population numbers the next season. This may seem obvious, but remember that after a single blood meal, a female mosquito can lay 250 eggs or more! Therefore, killing diapausing mosquitoes can put a big dent in next season’s population, especially early on.

5. Overwintering harborages are different. Mosquitoes seek eaves, under decks, cellars, crawlspaces, sheds, vents, animal burrows, etc. During mosquito season, mosquitoes are most often found resting in vegetation and a few other primary types of locations. Female mosquitoes preparing for diapause become “endophilic” = loving the indoors. Therefore, they want to be inside something, such as those sites listed above.

6. End-of-season treatments will target potential overwintering harborages. Be sure that your customers (and your service professionals) understand that the late-season services will specifically target the types of harborages used for diapause and not the traditional harborages during the season such as vegetation.

Experience teaches us that once customers understand, at least to some degree, why it is important to retain their mosquito service until the end of the season, they are much less likely to cancel. They will appreciate having the information and most likely will be impressed by the fact that you took the time and effort to educate them. Oh, and reduced cancellations result in increased revenue, at least the last time I checked!

Stanton Cope is vice president, Technical Products and Services, Catchmaster (AP&G), and past president of the American Mosquito Control Association.