Wednesday, March 31, 2010
Tuesday, March 30, 2010
A native to Europe and Asia, this beetle is a pest of viburnums (which is a genus of flowering shrubs that are popular as garden or landscape plants).
The VLB lays its eggs in the twigs of the shrubs, and at high densities (which often occurs in North America) they can completely defoliate shrubs. After a couple years of defoliation, the shrub can often die.
VLB causes economic problems due to the effects it has on the popular shrubs. Also, ecologically, the VLB is a threat to native viburnum species and may also decrease the number of berries available to birds and other animals through the winter.
The egg masses leave a distinctive marking on viburnum stems:
Sunday, March 28, 2010
photo credit Richard Webb (www.forestryimages.com)
Recently the ALE lab and collaborators Andy Michel (OSU), Doug Landis (MSU), Matt O'Neal (ISU), and David Lusch (MSU) received a $494,000 grant from the USDA to study the impacts of common buckthorn, an invasive shrub. This plant was introduced as a landscape plant in the early 1800's and has since spread throughout the north central states. It can be found invading woodlots and agricultural fence-rows. So why is common buckthorn a triple threat? Unfortunately this plant is the overwintering host of the soybean aphid (see last week's insect of the week). This pest spends the winter in the egg stage on common buckthorn and about this time of year, hatches and begins feeding on buckthorn leaves. In early summer, the aphid disperses from common buckthorn into soybean fields.
In soybean, the soybean aphid can reach populations of thousands per plant, and producers often apply insecticides 1 or more times per year to control this pest. The presence of soybean aphid has allowed the multicolored Asian lady beetle (pictured in Chelsea's previous post and the March 19 edition of Insect of the Week) to increase in abundance. This lady beetle feeds on soybean aphid and other aphid species within crop fields.
Predation of soybean aphid by the multicolored Asian lady beetle is a positive, but unfortunately there are some significant negative impacts associated with the presence of this exotic lady beetle. First, this is the lady beetle that invades homes in the fall looking for a place to spend the winter. In addition to being an annoyance, some people have asthmatic reactions to their presence. Second, in the late fall multicolored Asian lady beetles can move into vineyards and feeds on ripe grapes. When the grapes are harvested the beetles become a contaminate in wine, giving it a distinctive bitter taste. Finally, the multicolored Asian lady beetle has been implicated in the decline in native lady beetles. It is known to eat the eggs and larvae of other lady beetle species.
The multi-state research team studying the impacts of common buckthorn will be examining whether the abundance of buckthorn in the landscape influences the abundance of soybean aphid and multicolored Asian lady beetle. Our goal is to determine if the presence of buckthorn has facilitated the success of these other invasive species, and if so determine the spatial scale at which buckthorn removal efforts should be made to reduce the impacts off this entire invasive triple threat.
Recently we were interviewed about this project by science reporter Spencer Hunt of the Columbus Dispatch. To read the full article on the project click on the "share me" link below.
Posted using ShareThis
Saturday, March 27, 2010
These where found on her garage floor, and they are pretty good examples of H. axyridis because they show the variation in spots that can occur within this species.
Thanks Michele and Andy!
Friday, March 26, 2010
Here is an example of a bee box, where solitary stem-nesting bees would love to live! Many bees cannot make their own nesting holes, so you can provide them with a home in your backyard. Each hole will eventually be found by a single female bee, who will line her nest with such things as mud or leaves depending on the species, and lay eggs inside. While this bee box is plastic and purchased online, you can create your own by simply drilling holes in a 2x4, or any piece of wood you have lying around. Different size holes will attract different types of bees, so experiment with any size from 5-15mm. Just make sure to clean the nests once a year to avoid spreading infection from bee to bee, and you will be running a 5-star hotel in no time!
Thursday, March 25, 2010
Wednesday, March 24, 2010
Our t-shirts for Buckeye Lady Beetle Blitz have arrived!!! Hilary is modeling one of them for us in front of our building. They come in sizes S, M, L, XL, and XXL so get one for the whole family!
They are only $16 a piece and order forms can be found on the BLBB website.
Tuesday, March 23, 2010
The Soybean Aphid
The soybean aphid, which is native to Asia, was first observed in the Midwest United States in 2000. Since then, it has spread though almost half of the US, and into Canada. Aphids suck sap from their host plants, and at high populations they can cause a significant decrease in soybean yield. The aphids can also transmit viruses into plants causing a further loss of yield.
The aphids overwinter on buckthorn. In the spring, their eggs hatch and the soybean aphid completes a couple generations of sexual reproduction on the buckthorn. Soon after, winged females (that are fertile without mating colonize soybean early in the summer. They deposit live young who are also female, as well as fertile, and after about a week this new generation reaches reproductive age. Eventually after about 15-18 generations winged aphids begin to emerge (still all females) and they migrate back over to the buckthorn, where males are produced and sexual reproduction can then occur again, after which eggs are laid for overwintering until the next summer.
This species is currently an interest to me because it is an important prey species for the multi-colored Asian lady beetle (Harmonia axyridis), another exotic species from Asia. The arrival of the soybean aphid may have facilitated the establishment of H. axyridis.
photo credit: Bob O'Neil (Purdue University)
Monday, March 22, 2010
Across the world, pollinator decline has emerged as a significant threat. Declines in bee populations in the U.S. have been linked to disease, introduction of exotic competitors and parasites, loss of habitat, and exposure to toxins. Bees are found throughout our environment and utilize a large range of habitats for foraging and nesting. Recently, we were awarded a grant to examine the diversity and concentration of chemicals collected by foraging bees within their environment. The use of chemicals is often considered only in agricultural habitats, but, municipalities, businesses and home owners also apply chemicals for control of pests and diseases. We will compare the concentration of key pesticides collected by pollinators foraging across urban, suburban and rural landscapes. We will also launch a citizen science program called Bee Healthy Landscapes where we will work with bee keepers to evaluate pesticide accumulation in commercial hives in Ohio.
Friday, March 19, 2010
The Multi-Colored Lady Beetle
It's that time of the season again! I was at the gym last night and every once in a while I would notice one of these flying past my head while I was working out.
As late Autumn approaches many people begin to complain about lady beetle infestations in their homes. H. axyridis is attracted to light colors and warmth and can find their way into people's homes since they get can fit though tiny cracks.
My first experience with H. axyridis was when I was a little kid...On the soccer field, when I was more interested in looking at bugs than looking out for the soccer ball, I found one of these little guys and was shocked when it bit me. I had always been taught that lady beetles are beneficial insects, and had the image of the happy little lady beetle in my head. Later I learned that this was not the lady beetle that I was used to. It was an invader! For years after that experience I was weary of picking up lady beetles until I learned how to tell the difference between the "nice" and the "mean" lady beetles. I never thought I would be working with the "mean" lady beetles every day!
For a portion of my research, I am investigating their effect on native lady beetle populations in Ohio. I am interested in studying the hypothesis of intraguild predation (when predators within the same guild eat eachother). We think that H. axyridis may be eating the eggs and larvae of native lady beetles in the wild. Laboratory studies have been done that show that H. axyridis can and does prey on native lady beetles, but we still need to find out if it happens in their habitat.
Wednesday, March 17, 2010
We are interested in how farming practices influence the amount of biological control that is provided by these natural enemies, specifically insect predators. The way that we measure this is by putting out an insect prey and determining the amount of this prey consumed by predators. In the above picture, we have placed corn earworm eggs in two treatments: an open treatment where natural enemies can consume the eggs and a caged treatment which prevents predators from accessing the eggs but exposes them to environmental conditions. We leave these treatments in the field for 48 h and then re-count the eggs. We consider the difference in the proportion of eggs missing in the open and caged treatments to be amount of biological control provided to that site.
With this experiment we can compare the amount of biological control provided to different types of crops, crops which receive different amounts of agricultural inputs (such as pesticides) or crops which are embedded in different types of landscapes.
Tuesday, March 16, 2010
I thought I'd blog a bit about stinging, as many are afraid to get close to bees. The sting is actually a modified ovipositor, or egg laying organ. So only female bees have stings! Honey bee workers (above) die within minutes of stinging humans, as there are little barbs on the sting that get stuck in the skin and pull the organ from the bees' body. However, native bees (bumble bees, etc.) do not have barbed stings. Thus they will not die and are free to sting as much as they like.
That said, do not be afraid when you are in the garden. I like to think of them as lots of little chipmunks (bees are vegetarians) peacefully storing up pollen and nectar.In fact my only experience with a bee sting was a result of opening a bumble bee research nest. As long as you don't threaten them or their families (which I did by breaking and entering), all will be well. When visiting flowers, bees could care less what you're up to...they're busy grocery shopping!
Friday, March 12, 2010
During the last part of our workshop participants examined pinned natural enemy insects and pollinators. We really enjoyed talking with everyone and hope that the information was useful. If any of you were at the workshop and have questions, please post them or send us an email. Thank you to Morgan, Amanda, Nicole and Jim for inviting us!
Tuesday, March 9, 2010
This summer we hope to observe lady beetles collected from the field for emerging D. coccinellae larvae (and other parasitoid species as well). We then want to compare parasitism rates between native and exotic lady beetle species.
Wednesday, March 3, 2010
I found this paper from 1946 about Entomology as a Career (sorry the picture is so small, it is readable if you click on it!). It states that "the present day entomologist is a far cry from the much-cartooned, bespectacled patriarch chasing butterflies" Hmm.... the patriarch part may have changed but the running around with a net part remains the same!