FAQ
Why are there more insects this year?
There actually aren’t more everywhere. We’ve heard from some people that they’re seeing more, but some are seeing fewer insects.
For those who are seeing more, it’s most likely because of the amount of rain we had in the spring. That moisture prompts plant growth, and insects depend on plants for food and habitat. In drier years, when levels of ephemeral bodies of water like vernal pools or intermittent streams recede, there’s less habitat for larvae of some insects, like mosquitoes and the dragonfly larvae that eat mosquitoes. Water also helps bugs like lightning bugs and scarab beetles that live their larval stage underground, and they suffer when the soil isn’t moist enough.
Some insects put out multiple generations each year, and some just one. So when the weather changes and becomes drier, those that have multiple generations may be less prevalent. We’ve heard from some people who had an abundance of insects earlier in the year that things have gotten very quiet as the weather pattern has dried out.
How does the ecosystem benefit or react when there are more insects?
Insects are food for other animals in the food web, like birds and bats and rodents. And insects have a role in nutrient cycling, though that’s not always seen as a good thing. For example, when a species eats lots of leaves off of trees, they’re returning nutrients to the soil, but it also can negatively impact the trees.
Last year was a mast year for oak trees – they produced a lot more acorns. But more acorns lead to an increase in the mouse population, and mice love to eat the cocoons of spongy moths, which helps suppress population of that pest, protecting the oak trees from further damage.
What is the impact on farms and gardens?
Some insects help plant growth – having more dung beetles around means they’re processing more waste, and that’s good. On the other hand, having more striped cucumber beetles means a need for more management so they don’t destroy crops.
Many insects provide pollinator services, of course, and some even are predatory and can help reduce pressure of other pets. Eastern yellowjackets will pick cabbage worms off kale all season!
Does having more insects one year tell us anything about what the next year will be like?
With mosquitoes, it depends on what happens over the winter. Most mosquitoes overwinter as larvae, and if the winter and spring are dry, the larvae won’t survive. Those that overwinter as eggs won’t be impacted in the same way.
It also depends on where insects ride out the winter. The hemlock woolly adelgid stays on the needles of hemlock trees all winter, so a cold snap can kill many of them off. But Asian longhorned beetle and other wood-boring pests live deep inside of trees, and are protected from the weather. Insects living just under the soil will also benefit from an insulating blanket of snow that keeps them from freezing during cold spells. Lack of snow cover may make some insects more susceptible to weather, but can also extend the tick season.
Why are insects attracted to me, and how can I make them less so?
There’s some correlation between the amount of CO2 you’re emitting when you breathe and how much insects are attracted to you. So if you’re exerting yourself more, mosquitoes and black flies and other bugs may bother you more. There are other chemical compounds, like lactic and carboxylic acids, that occur in sweat and can be attractants.
Some say that flying insects are attracted to yellow – that’s why so many traps are yellow – so you might want to avoid wearing yellow when you’re outside if you are trying to avoid insects. Insect repellent is also a good option - it confuses insects by making it harder for them to pick up the scent of the attractants you’re putting out. Not every repellent works on all insects, and some bugs don’t seem to be deterred at all by any of them, so consider wearing long sleeves and long pants – loose-fitting, not tight, so you won’t get bitten through the fabric. And in some locations at certain times of the day or year, it might make sense to just stay inside!
What time of day are biting insects most active?
Mosquitoes are busiest during crepuscular hours – dawn and dusk, but especially in the evening. Some evidence suggests that there is an evolutionary benefit to this because it matches their activity to mammals who are also active at the same time and whose blood they need to be able to reproduce. Ticks (technically arthropods, not insects) are active at all times. Deer flies are busiest during the day. Black flies are active mid-morning and then for a few hours before sunset. In general, insects are cold-blooded, so they get charged up by energy offered by the sun. When it cools down and gets dark, day-flying insects slow down.
At what point in the season will the insect population start to decrease?
In general, insect populations drop off when frost hits in the fall. But different types of insects peak at all different parts of the growing season. Some species of mosquitoes are abundant in the spring and some in the summer. As we get into late August and temperatures decline and daylight hours get shorter, they start to go into hiding at night rather than trying to breed or feed. When it gets below 60 degrees adult mosquitoes start to slow down, die off, or hibernate.
But there are also certain moths that don’t emerge as adults until August or September. When you start to see big underwing moths (Catocala species) at night you know it’s almost fall. And some moths, like the winter moth or fall webworm, don’t even emerge until the first frost hits. There are even some insects that have proteins in their blood that keep them from freezing and help them survive the winter.