Biological Control (ENT 650)

Many of the current entomology graduate students, and some undergraduates have been working hard on a class project throughout the quarter for our Biological Control course.

After many conversations between the Columbus and Wooster students over the video link, we decided on the focal habitats and methods for our study. We also had much assistance from our professors (Dr. Canas and Dr. Grewal) as well as our TA (Harit).

Our goal for this project was to assess the biological control services provided by organisms in three different habitats (conventional farm, community garden, and forest). We were interested in looking at both above and below ground control.

The below ground method involved placing larvae into cages and burying them in the soil. They were left there for 2-3 days, then retrieved and checked for fungal, bacterial, or nematode infection.

For surveying biological control services that occur above or on the ground we used three methods: Larvae on sticky cards, larvae hanging in cages, and aphid counts.

The larvae on sticky cards was a method that came up with ourselves, and I am unaware if this method had been used before to survey biological control services. The sticky cards are usually used to survey for flying insects in fields (lady beetles for example). We decided to stick the larvae on them and see if any predators attacked them. This method was not without flaws though. We found that the larvae were very active and were able to escape from the glue on the trap. Our solution was to use scotch tape to keep the larvae in place, and it worked in some cases.
We also placed the larvae in hanging cages, and we were hoping that they might be attacked by parasitoids.
The final method, aphids, is a method that is commonly used to asses biological control services in fields. This method involves placing plants infested with aphids in the field. One is covered with a net to exclude predators, but still be affected by the weather conditions. The other plant is left open (without a net) so predators are able to munch away on the aphids as they please. The idea is to compare the number of aphids on that closed plant with the number of aphids on that open plant after a period of time in the field (one week in our case) to get an idea of the effect predators have on aphid colonies. We would expect to have higher aphid counts in the closed plant treatments.


The class is now busy analyzing the data and putting together presentations!

There's always a better way

Science is about sharing, and simplifying. Many scientists meet at conferences to talk about results of their work and about their methods for getting them. One of the most satisfying things for me is to find out that someone has devised an easier or better way to accomplish a task. For instance, in determining which type of larval parasitoids are hiding out in the body cavity of a really small insect. You could wait for them to emerge, spending weeks keeping the host insect alive and fed. Or, with the right instruction you could simply cut them open and look within days of collecting them. What a time saver!

So, in the spirit of this, how many of you have been tying your shoes wrong? Watch the video below to find out.

Cost Effective Window Trap

This summer the ALE lab is working with the Cleveland Metroparks to study insect communities in some of the park's forests. The Metroparks have established 30 plots in beach maple forests throughout their system where they have completed and intensive inventory of plant diversity and relative abundance. Within each of these plots our lab will determine if the insect fauna is influenced by the quality of the plant community found. We are mainly interested in measuring beneficial insects including predators and parasitoids.

When designing this project I thought about several possible types of traps we could use. The understory in this plots is very open and most plots experience significant deer browse. I decided to use window traps to collect dispersing insects moving though each of the plots. Typically you make a window trap out of Plexiglas and suspend it within a frame. Then you place a pan of water underneath. When the insects hit the Plexiglas they fall into the pan of water. We priced out Plexiglas for 30 2 x 2 foot window traps and the price was too high for our budget. At a local hardware we ended up buying plastic sheeting for $1/foot. This is flexible, slightly heavier than a shower curtain material. We stretched the material between two posts and let the trap collect insects for 1 week. We found that this material worked great. It remained in position for the whole week despite several storms. We collected a diversity of flies, wasps and beetles which is what we hope to collect using the trap. If you need to build a large number of window traps and have limited funds this method may work for you.

Late May or October?

The first few weeks of field work each spring usually involve some last-minute changes of plans. This year is no exception. Today Scott Prajzner began the first of three experiments to measure pollinator activity within vacant lots and urban gardens in Cleveland. Today we took 48 blooming sunflowers to 8 sites. Scott is using the sunflowers to measure pollination services. He will collect them in 7 days and compare seed set in flowers which were exposed to pollinators with those that were bagged to prevent pollinators from accessing them. He will then determine if the pollination services supplied to vacant lots or urban gardens is significantly different. In addition to using the sunflowers to measure pollination services we also planned to monitor the community of bees visiting the plants within each site. We also plan to measure bee activity at other flowering plant species within each site.

Unfortunately with high winds, rain, and temperatures of ~45 degrees there was nothing to monitor. We were the only animals that decided today would be a good day to visit these sites! We are going to try again on Friday when it is supposed to finally stop raining.

Costs of doing business, traditional versus citizen science

So what does it cost to collect entomology data? Using data collected by the Buckeye Lady Beetle Blitz program, I am working on a paper with co-authors from the Lost Ladybug Project and UK Ladybird Survey to measure the accuracy of citizen-collected lady beetle data. We are interested in the costs both monetarily and in data accuracy of utilizing citizen science. We are comparing the costs of traditional science (researchers collect data), verified citizen science (citizens collect data that is checked by researchers) and direct citizen science (citizens collect data which is analyzed without being verified by researchers).

We compared the monetary costs associated with collecting a yellow sticky card trap using each type of science. Cost estimates included sampling supplies, labor costs, travel, workshops for volunteers, and website development and maintenance. We found that to collect one sticky card using traditional science costs approximately $132! To collect one sticky card using verified or direct citizen science costs $65.31 and $43.74 respectively. Therefore programs that employ verified citizen science can collect 2 times as many samples for the same cost when compared to traditional science. Since all data is verified by researchers, accuracy rates for species identification should be equivalent using traditional science and verified citizen science. The only loss of data quality would be due to errors in the way the sample was collected, so programs utilizing citizen science need to be sure to provide clear instructions to their volunteers. Direct citizen science will provide 3 times the samples of traditional science for the same cost. The tradeoff here is a potential loss of accuracy. Accuracy rates among the three programs examined ranged from 53-94% of lady beetles correctly identified by volunteers. Therefore, high levels of accuracy can be attained using direct citizen science but programs should consider some type of data verification at least in the beginning so that an error rate among citizen-supplied data can be calculated.

Luna moth!

Our Saturniid emerged today, and it was a beautiful male Luna moth (Actias luna)! Ian, Caitlin and I had fun playing with it today. We thought it was a male because of its small abdomen. Here are some pictures of the shed pupal casing, and the moth.

Watch these 2 videos to see it in action!

1. Flight muscle warm-up
2. Take-off!

If you would like to raise your own Saturniid, just keep it in a dry container with something for it to crawl up nearby. Holometabolous insects need something to rest on until their wings harden up for flight. Other insects that do this are butterflies, dragonflies and cicadas. Enjoy the weekend!