Spiders and Bugs, Oh My!

Insects and spiders seem to be everywhere in the fall.  Some of the reasons for this seeming abundance are:

  1. populations have been building all summer
  2. they are moving around looking for overwintering places
  3. favored food sources are dwindling and they are looking further afield for food. 

Let’s take a quick look at some of the insects we are seeing the most of right now (late September to early October) and why they are so abundant.  Remember it is the first frosts that trigger lady beetles and boxelder bugs to move, so expect that in the next few weeks.  It is a great time of the year for all of us insect-lovers!

Minute pirate bugs

Small little bug with a very painful bite?  You have encountered the minute pirate bug.  These small insects feed on other insects all year long and are beneficial as they feed on garden pests like aphids.  In the fall their normal prey items are diminishing and the minute pirate bugs take flight to look for more food.  They don’t really think they can eat us, they are just using their mouthparts to see what we are.  Although they do not consume our blood, they can cause localized allergic reactions in some people. 

Yellowjacket wasps

If you have tried to enjoy the last warm days of 2016 with a picnic or tailgating you have almost certainly encountered yellowjacket wasps.  These wasps live in colonies that have been hard at work all summer rearing young and new queens and kings.  In the fall the colonies have built up impressive numbers of workers (typically hundreds to thousands) and those workers are mostly done rearing young and are left to their own devices.  The workers naturally feed on flower nectar, but are fine with any type of sugar and seem to know that human food is a great source of sugars.  Luckily when they are foraging away from their colonies they are less likely to sting, but it is good to be cautious, especially if you are allergic to wasps.  Keep food, pop cans and garbage covered.


Arachnophobia!  (How many of you remember that movie?)  The fear of spiders is very common.  Many of us maybe do not fear them, but we are not really fond of them.  At any rate, no one seems happy about the abundance of spiders in the fall.  So why do there seem to be so many?  Again, populations have been building up all summer and the spiders are often on the move in the fall looking for protected spots to overwinter.  If you seem to have lots of spiders near your house try reducing outdoor lighting at night.  The lights attract insects which are food for the spiders.


Depending on where you live grasshoppers are aplenty in the fall.  As you walk through any grassy vegetation they will be leaping in all directions.  There are many different species of grasshopper in Iowa and can be great fun to look at if you can catch one!  If you want to check out grasshoppers that occur in the U.S. go ahead and click around in BugGuide.net for a while, the diversity is amazing!   Grasshoppers do have one annoying habit late in the year – chewing on anything they can.  We don’t know why they do this, but it is especially annoying when they damage things like window screens.

A minute pirate bug on human skin
The minute pirate bug, AKA the insidious flower bug, is a beneficial predator until it starts biting unsuspecting people in the fall.
Yellowjacket sample on white cloth
Yellowjacket wasps are shiny and bright yellow-and-black.
An irregular hole in the screen caused by grasshoppers
Grasshoppers chew irregular holes in window screens -- for no apparent reason!

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