Friday, October 29, 2010

Pumpkin time!

My first field season is officially done! The perennial flowers have been planted in half of my collaborator's farms, and will be managed by the farmer for a year before they are allowed to fully grow. In my two test sites in West Salem and Piketon I harvested the pumpkins that we studied back in August. In order to assess the level of pollination, Ian and Chris have been counting the seeds in the fully-developed pumpkins like the ones in our Piketon site pictured above.

As some of you may know, pumpkins are the most fun fruit. Not only can you carve them, but thousands of teenagers around the country revel in smashing your hand-crafted works of art the night before Halloween. There has been one long-standing tradition in one neighbor in Cleveland revolving around pumpkin sledding.

Many county fairs have a variety of pumpkin growing contests. Some of the trade secrets to growing an exceptionally large pumpkin are kept under lock and key, but include ritualistic daily care to ensure that the pumpkin is healthy, as mentioned in this news report.

Perhaps next year, after the demolition derby when there are a bunch of useless smashed-up cars laying around, the Wayne County Fair will introduce some new competitions: pumpkin launching, shooting and dropping.

Thursday, October 28, 2010

Spooky Spider

Halloween is fast approaching (and I am unfortunately lacking a costume idea), and it's the perfect time to highlight one of Ohio's most feared spiders: the black widow. These spiders are in the cobweb weaving family Therididae.

Two species live in our state, the common black widow (Latrodectus mactans) and the northern widow (L. variolus). The one pictured above is the common widow, which you can tell because of its complete hourglass on the bottom of the abdomen. The northern widow has an hourglass that is usually split in the middle, though both species can show variation in patterns and could even lack the red markings.

These spiders are referred to as widows because of the idea that the female will eat the male after copulation. This is not always the case, and is really only likely if the female lives in an environment with few prey sources. However, the black widow is cannibalistic as a spiderling. Out of a few hundred hatchlings, only a few will continue on after eating most of their siblings.

Bites from a black widow are rarely fatal, but nevertheless could require medical attention. Pain from the bite wound might not even begin until a few hours later, along with nausea, muscle cramps, dizziness, sweating, and vomiting. Therefore it's good to know if and where these spiders are adding to your Halloween yard decorations in order to remove them or just stay away.

Tuesday, October 26, 2010

Insect of the Week!


The American Burying Beetle

Nicrophorus americanus

I talk about native lady beetles and their declining numbers in many posts on here...while the Convergent lady beetle is getting harder to find every year, it is still not endangered.

There are insects on the endangered species list though! The American Burying Beetle is a popular one among entomologists.

They are important because they are carrion beetles, which means that they scavenge the remains of animals and are important for recycling that material back into the environment. They have a really interesting behavior. When they find a dead animal, such as a mouse, the male and female work together to move the remains until they find ground that is soft enough to dig. They then bury the remains. This is done at night time to avoid flies laying eggs on the remains (the flies are active during the day). Then they strip the fur or feathers from the body and form in into sort of a compact ball. They use secreted liquids to preserve the carcass, and about 30 eggs are laid in a tunnel near the carcass. Unlike most insects though, the larvae receive parental care!

At one point this beetle could be found in 35 states, and into Canada.

Now this beetle is found in six states

The reasons for it's disappearance is unknown, but it may be due to a loss a habitat.

Monday, October 25, 2010

No Guts, No Glory....

I have spent a lot of time over the last couple of weeks dissecting lady beetle abdomens. Why you ask would someone spend their time doing this? Worthwhile question for sure.

We are interested in determining the proportion of native and exotic lady beetles that are attacked by a parasitoid wasp, Dinocampus coccinellae. The female wasps sting the lady beetles and deposit an egg inside. the egg hatches and the wasp larva feeds on the lady beetle. If you look closely you can see the dead larva in the dissected abdomens above. I circled it in the top picture and there is a close up in the bottom picture. Eventually the wasp will emerge from the lady beetle and form a cocoon underneath the beetle. For more pictures and information about the wasps, see Chelsea's posts on March 9 and August 9 2010.

The goal of our study is to determine if either the type of crop or natural habitat within which the lady beetles are found, or the composition of the larger-scale landscape surrounding each habitat influences rates of parasitism among native and exotic lady beetle species.

The results of this study will be presented by our lab at this years Entomological Society of America meeting in December in San Diego, so we have a lot of beetles to dissect in a hurry!

Thursday, October 21, 2010

Cellar Spider

As I've been reading, thinking, and discussing with Mary, my thesis project idea has been veering toward arthropod predators and their ecosystem services. Most obviously, they eat many pest herbivores, which in turn increases plant productivity. Many are also considered indicator species for conservation purposes, as predators are usually very sensitive to habitat destruction.

There are many predators in the urban environment, but most are generalist consumers because they eat a wide variety of insects and can maintain themselves in an uncertain habitat. Of course, some of the most obvious to humans are the spiders, which are the maligned creatures I'd like to delve into for the next few blog entries.

I've had many encounters with cellar spiders (family Pholcidae) in my day; my own basement is probably some sort of utopia for them. These are the spindly, long-legged spiders you may find hiding in corners or windows. They spin irregular, wispy webs which they do not eat before leaving the way many other spiders do (neighboring cobweb spiders don't help the mess, either).

This is a female carrying her newly hatched babies. The red background is the bucket she was hiding in (Flickr).

Cellar spiders eat many annoying house pests such as gnats, flies, small moths, and mosquitoes. Their webs are not adhesive, but these spiders are quick to act and wrap up their prey when it gets lost in their irregular nets. The spiders' quick movements are also useful for another hunting techniques. Cellar spiders will go to other spider webs, tap the lines to imitate prey, and then attack when the owner comes to investigate. Pholcidae are also known for their vibrations when provoked.

Wednesday, October 20, 2010

Sheet Web Spiders at OARDC

Yesterday it was very cool and foggy in Wooster and I took some pictures of spider webs in the shrubs outside the Entomology building at OARDC. These belong to sheet web spiders (Linyphiidae). This is a large family (over 4,000 known species) of very small spiders (most are between 4-10 mm). The close-up shots show webs spun by a "bowl and doily spider" in the genus Frontinella. The web consists of a dense bowl-shaped web with a flat sheet web (the doily) underneath. The spider hangs on the underside of the bowl and eats small flies, aphids, and other insects that become trapped in the non-sticky silk that makes up the web.

Monday, October 18, 2010

The Sweeper

Today we realized the true extent of The Sweeper's (AKA Chelsea) activities this summer. We went though all three of our storage freezers and pulled out all of the Sweeper's samples, counted, and organized them by date to make sorting them easier. We have determined that over 1,008 sweep samples were collected during the summer! These samples were collected to determine how the diversity and abundance of arthropod predators present in a soybean, alfalfa, or grassland site influenced lady beetle egg predation.

Progress on these samples was a little slow today as the many different predators which may eat lady beetle eggs were counted. We will push forward though, after all it was very hard work for the Sweeper to collect all that data!

-- Mary, Ian, and Chris

Friday, October 15, 2010

Taxonomist vs Systemicist

Recently, I have had to teach my students the difference between taxonomy and systematics when classifying species. Taxonomists describe the observable features and functions of an organism, and systemicists find hypothetical relationships between them. I found it easiest to explain it with cars...*

Clockwise top left: Dodge Rampage, Ford Ranchero, and Chevrolet El Camino

The vehicles pictured above could be described by a taxonomist as car-pickup truck hybrids dating back to the 1970s. The flatbed space is comparable, the number of doors is the same amongst all three specimens, and I would suspect all three have bench seats and rear-wheel drive. A taxonomist may realize the small differences in these vehicles, but would generally classify these as similar. A systemicist would take things one step further and find out how they are related. In this case, there is no relation! They have all stemmed from different vehicular lineages: Dodge, Ford and Chevrolet. When taxonomists observe enough vehicles over a long time systemicists review their observations to find links in the chain and piece together phylogenetic trees like this one. Many more cars have come and gone since the three above in the face of capitalistic selection pressures, resulting in vehicles like those below. They look very different; as different as elephants and pigs, and opossums and kangaroos! But, they are still related.

Clockwise top left: Dodge Viper, Ford F650, Chevrolet Volt

*Depending on your browser and screen resolution, the pictures may not actually appear in a clockwise pattern.

Thursday, October 14, 2010

Solitary Pollinators

To wrap up my posts on bees, this week I wanted to highlight some solitary bee pollinators.

Most bees are in fact solitary, and in one study of urban gardens in New York City they comprised 50% of the individuals sampled. The two most common families found were Colletidae and Halictidae. The latter are commonly known as sweat bees, and the genus Agapostemon is by far my favorite. How cool is a green bee?

Go here for some more awesome photos by Cyrus Khamak. Actually, I suggest just browsing through Flickr's photostream of insect macro (or search for jumping spiders).

Because many solitary bees nest in cavities, urban areas can provide a lot of suitable habitat with artificial structures. However, soil nesting bees are most abundant in forests, but the ground compaction by gardening and lawn care reduce the amount of suitable habitat in cities. I think this is a really interesting example of how community dynamics can change in urban ecosystems.

This leaf cutter bee (family Megachilidae) is using a brick wall as a nesting site:

Bees in the Megachilidae family are often used commercially for fruiting trees. They can be attracted with wood bored with holes.

Solitary bees are not known for their sting, though the females will do so if squashed or grabbed.

Tuesday, October 12, 2010

Someone was checking out my camera...

While watching the hours of video I have from the field I caught a image of this curious little bird:
As I have mentioned in earlier posts, the point of these cameras is for me to observe what is eating lady beetle eggs in the field. The hypothesis is that the Exotic lady beetles are eating the egg masses of the native lady beetles.

So far I have seen a few different types in invertebrates munching on the eggs (things such as slugs, and daddy long legs), and have been documenting each encounter.

I look forward to each clip of video since they are all different, and I am still making new observations each day!

Monday, October 11, 2010

Introducing Buckthorn Watch!

Common buckthorn has been present in the U.S. since the early 1800's when it was introduced by settlers though landscaping. Unfortunately this fast growing plant which can spread by both roots and seeds has become a widespread invasive species. Common buckthorn is found along forest edges, in between farm fields, along roadsides, in parks and campgrounds, and in railroad and power line right-of-ways. Within these habitats, common buckthorn reduces light penetration to the forest floor, resulting in a loss of native herbaceous plants often replaced by common buckthorn seedlings. Below is a picture of an invaded forest floor covered with buckthorn seedlings.
In addition to negatively impacting natural areas, common buckthorn also has a significant impact within agroecosystems. This invasive plant is the overwintering host of the soybean aphid. Soybean aphids spend the winter in the egg stage on common buckthorn, in the spring the aphids hatch and feed for 1-3 generations before winged aphids are produced that migrate to soybean fields. During the summer multiple generations of winged and wingless aphids are present in soybean. Aphid populations can reach 1,000's per plant, reducing yield and increasing pesticide use to control their populations. In the fall, when soybean plants begin to dry soybean aphids migrate back to common buckthorn to mate and deposit their overwintering eggs. One interesting fact about the soybean aphid is that during the entire year the only time that male aphids are present is in the fall, when males and females mate to produce overwintering eggs. During the rest of the year, only females are present and they are clonal, reproducing without mating! Below is a picture of winged and wingless aphids on common buckthorn.

The presence of soybean aphid not only damages soybean production but also has led to increased abundance of the multicolored Asian lady beetle. We have had several posts about this beetle, it has been implicated in the decline of native lady beetles and interactions between this insect and native lady beetles is one research focus of Chelsea Smith.

The Buckthorn Watch Program is a new regional citizen science program which will examine the relationship between these invasive species. This project was funded by the USDA and is a corroborative effort of the ALE Laboratory and Dr. Andy Michel at OSU, Dr. Doug Landis and Megan Woltz at Michigan State University, and Dr. Matt O'Neal at Iowa State University. We are currently looking for volunteers willing to help us map the distribution of this plant across the north central U.S. To register as a Buckthorn Watch member visit our new website. Check back in on this site as I continue to add new information, including a video describing the Buckthorn Watch program!

In addition to reporting common buckthorn infestations, we are also tracking the utilization of common buckthorn by the soybean aphid. Each spring and fall we will hold an Aphid Hunt, where volunteers will survey common buckthorn for soybean aphid. Anyone who reports a common buckthorn infestation is able to participate in Aphid Hunt.

I know that we have blog readers outside of Ohio who would like to participate in our Buckeye Lady Beetle Blitz program. I am excited to introduce this new, regional project and I hope that you will help us to reduce the impacts of this invasive plant!

Thursday, October 7, 2010

Cause of CCD uncovered?

There's lots of online talk today about the recent PLoS ONE article regarding honey bee Colony Collapse Disorder. A research team composed mainly of scientists from the University of Montana in Missoula and the Army's Edgewood Chemical Biological Center in Maryland have uncovered a virus-fungus tag team present in collapsing bee colonies.

The researchers used a method developed by the military called mass spectrometry-based proteomics (MSP), a tool that identifies peptide sequences which are screened against a database to identify pathogens. Two previously unidentified RNA viruses were found in the studied bee populations; a variety of RNA viruses thus far have been the main culprits in CCD. However, the real surprise was the identification of a co-occurrence of a DNA virus, an invertebrate iridescent virus (IIV), and a Nosema fungus. Nosema had been pinpointed previously in some collapsing populations, but the finding of an IIV is going to shift new research away from RNA viruses. The exact identity of the IIV is still unknown because not all known types in the virus family have been peptide sequenced.

The virus-fungus correlation is very strong, as the researchers found their co-occurrence in sampled US apiaries from 2006-2007, an observation colony that demonstrated collapse over the time of the study, and separate colonies in Florida experiencing CCD. As an illustration, the peptides of the pathogen pairing were shown to increase in the observation colony as bee forager flights decreased.

Bees sampled from a Montana colony and also bees shipped from Australia with no history of CCD did not contain the lethal pairing. Laboratory inoculations also supported the field studies' findings.

A major question, however, is if this virus-fungus pairing is the true cause of CCD. Are collapsing colonies just more susceptible due to something else, and the two pathogens together burn down the house? The lead researcher from the University of Montana, Dr. Jerry Bromenshenk, cautions, "We truly don't know if these two pathogens cause CCD or whether the colonies with CCD are more likely to succumb to these two pathogens."

Tuesday, October 5, 2010

The Power of Natural Selection!

With both my Entomology course, and the Biology 101 labs I am teaching, Natural selection has been stuck in my mind for the past week or so.

After teaching natural selection to students, who may have never studied evolution before, it made me realize how complicated it can seem to someone who never thought about it!

I found this cute graphic (that of course includes an insect) to help explain it...

This mechanism can apply to many different situations! The important thing to note, is that the green beetle can't pass the "green gene" on to future populations because it is eaten by the bird before it has a chance to reproduce. The beetles with the "brown gene" were able to produce more offspring because they lived longer.

This is one of the mechanisms that lead to such an amazing diversity of insects today!!

Monday, October 4, 2010

I'm Back!

I am back at the OARDC after attending the Aphidophaga 11 conference in Perugia Italy. This conference was held in the Faculty of Agriculture, University of Perugia which is housed in St. Peter's Abbey. The setting was far from your typical conference, with presentations held in the Abbey and posters set up in an outdoor square.
The conference was an excellent opportunity to meet biological control researchers from across the U.S. and Europe. During the conference, I met Dr. Helen Roy and several members of her lab. Dr. Roy is an ecological entomologist who runs a diverse laboratory interested in many aspects of insect ecology and invasion dynamics. She also runs a lady beetle survey across the UK,, and has data on lady beetle populations for 30 years!
I also was able to catch up with my collaborator Dr. Audrey Grez, a professor at the Universidad de Chile, Santiago, Chile. Dr. Grez is studying biological control of aphids in alfalfa. She is also interested in interactions between native and exotic lady beetles, and the contributions of exotic lady beetles to native lady beetle decline. I will be working with Dr. Grez to measure the biological control service that lady beetles provide to alfalfa pest management beginning in 2013. I am really excited about the opportunity to travel to Chile to conduct experiments with her and her laboratory!

Friday, October 1, 2010

Bike study

For my stats class I will be conducting a small study on the campus of OSU. Which type of bicycle is ridden the most? Out of four categories (road, mountain, hybrid and cruiser) the availability of cheaply-produced mountain bikes is much higher than road bikes, cruisers and hybrids. Therefore, I hypothesize that the bike commuters within OSU campus purchase and ride mountain bikes more than the three other styles of bicycle.

The Cruiser features high handlebars and a low seat for an upright riding position, a stiff frame and usually has a unique swooping top tube shape.
The road bike features a high seat and low handlebars for an aerodynamic seating position, stiff frame, large diameter skinny tires, and large gearing.

The mountain bike features a variety of suspension systems, but can also have stiff frames. They are noted for their small diameter knobby tires and flat handlebars.
The hybrid bikes feature qualities of both the road and mountain bike varieties. The flat bars, frame geometry and suspension on the front forks mimic many mountain bikes, but the gearing and large diameter skinny tire size often denote road bike influence.

There are pros and cons to each style, depending on your commuting area. Which one would you ride?

Have a good weekend!