Of Bugs and Men

This past week wasn’t a mundane week by any means. Setting out at 9am on a Monday morning, Danielle, Dan, Josh, Nate and I set out for Cambridge, Ontario to get samples of the insects inhabiting the Waterloo region. Our destination: the rare Charitable Research Reserve. The rare Charitable Research Reserve (rare) supports some of southern Ontario’s richest biodiversity. Nestled among 900 acres of floodplains, croplands, limestone alvars, cliffs, coniferous and deciduous forests, Rare is one of the meeting points of the Carolinian and Northern Hardwood forest zones. With a wide variety of habitats available, rare is without a doubt a prime spot for catching all kinds of interesting arthropods.

Since arthropods are so diverse, the first two things you need to collect a good sample is creativity and persistence. This week we used six different methods of trapping: Berlese funnels, flight intercept traps, pan traps, Malaise traps, pitfall traps and sweep nets.

Here we have two Berlese funnels. One contains decomposing wood, while the other has an assortment of oak and maple leaf litter
Here we have two Berlese funnels. One contains decomposing wood, while the other has an assortment of oak and maple leaf litter

Berlese funnels are used for trapping arthropods that live in the dirt or on the ground. These traps are made by gathering samples of soil, moss and leaf litter and placing them in large funnels above small containers full of ethanol. The principle behind these traps is that arthropods living just above and below the ground normally strongly dislike light. Since the large end of the funnel is exposed to light, arthropods travel downwards seeking the cool comfort of darkness. As the funnel constricts at the base, they are forced to burrow towards the smaller opening and eventually meet their fate dropping into the jar of ethanol.

Although the pan trap was only set up maybe a minute before this picture was taken, we had already caught a nice big spider!
Although the pan trap was only set up maybe a minute before this picture was taken, we had already caught a nice big spider!

Pan traps also help to catch ground-dwelling insects as well as insects attracted to colourful plants. Usually painted with primary colours, pan traps are bowls filled with soapy water. Each pan trap tends to attract slightly different insects as the colours mimic different food sources. As the insect approaches the bowl, it either falls into or gets caught in the soapy water. The soap in the water helps to break the surface tension preventing the insect from floating above the surface unharmed.

For a third kind of trap targeted to ground-dwellers, pitfall traps are designed just like they are named. A small pit is dug and a similarly sized cup filled with soapy water is placed inside the pit. Insects crawling over the ground stumble onto the lip of the pit and end up falling in. Since the sides of the cup are not smooth, the insects cannot crawl back out and get trapped.

A pitfall trap. The clear lid is used to help prevent leaves and rain from disturbing the sample
A pitfall trap. The clear lid is used to help prevent leaves and rain from disturbing the sample

If you are a regular reader of the blog, you may have previously read about the Malaise traps used in the School Malaise Trap Program. Malaise traps look like small sloped tents with a black lower half and a white upper half. The idea is that insects fly into the tent and – drawn to the lighter upper half – end up moving to the peak of the tent.  At the top end of the tent is a bottle filled with ethanol that traps and stores the insects.

A Malaise trap in action. In the background you can see a group of wild students sifting through the insects captured in their sweep net
A Malaise trap in action. In the background you can see a group of wild students sifting through the insects captured in their sweep net

Similar to Malaise traps, flight intercept traps are designed to collect other airborne insects. A long piece of screen is extended between two trees. If you can imagine what happens when you run full speed into a volleyball net, you may have an idea of how these traps work. Unsuspecting insects hit the trap mid-flight and fall into a pool of soapy water laid out at the base.

An intercept trap set up on the edge of a forest
An intercept trap set up on the edge of a forest

Last but not least, we spent a portion of the day sweep netting arthropods with giant burlap nets. This way we were able to capture some of the more evasive arthropods like spiders, beetles and hymenopterans. (If you’d like to hear more about our sweep netting, be sure to check out Nate’s blog this week!)

In full sweep netting mode. You can see the determination in my stance
In full sweep netting mode. You can see the determination in my stance

 

-Shannon

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