On an aphid hunt

Today, two special entomologists came to Ames for a short visit: Dr. Dave Voegtlin (Natural History Survey, Champaign, IL) and Dr. Dave Hogg (University of Wisconsin-Madison). Dr. Voegtlin is an aphid taxonomist, aka, he specializes in aphid biology and identification. There are only a few people like him in the world and I really appreciate his expertise and (Canadian) sense of humor. I met with the "Daves," Matt O'Neal (ISU soybean entomologist) and my postdoc, Thelma Heidel-Baker to talk about the state of affairs in the aphid world. It is easy to absorb their energy about aphids and we could have talked for days about emerging research projects.

The Daves are touring the north central region scouting for soybean aphids. They look at buckthorn every spring and fall. You might be (or should be?) wondering why they were looking for soybean aphid when most of the beans in Iowa aren't planted or haven't emerged yet. They are scouting for aphids on buckthorn, the overwintering host of soybean aphid. Yes, their primary host is a woody shrub commonly found in shelter belts around the north central region. They move to their secondary host, soybean, every summer. Their life cycle is complicated and I won't go into details here, but they want to learn more about their movement between the primary and secondary host.

Dave Voegtlin explained how he searches for soybean aphid on buckthorn. Photo by Thelma Heidel-Baker. 

Dave Hogg and Matt O'Neal hoping to find aphids. Photo by Thelma Heidel-Baker. 

Close-up of buckthorn, note smooth leaves with reduced venation. 

Thelma was practicing her photography skills. 

Although we spent some of the morning looking around the ISU campus (there is a LOT of buckthorn on campus because there used to be a breeding program!), we did not find any aphids. Sniff sniff. They did find aphids at previous stops before Iowa and I tried using a special camera lens to take close-up photographs.

Dr. Voegtlin giving me a camera tutorial. It is actually difficult to take pictures of very small animals! Photo by Thelma Heidel-Baker. 

My best photo shows a few soybean nymphs on a buckthorn plant. 

Seeing these aphids on buckthorn is kinda like seeing a unicorn. I've worked with soybean aphid since 2001 and have NEVER seen spring colonies on buckthorn. So this was a special work day for me - thanks to the Daves for stopping by today!

A spider wedding in my lab tomorrow?

My technician, Greg, has been rearing a few black widow spiders in my lab for a few months. It all started with an egg sac donated from the Insect Zoo (thanks?). He has an interest in spiders and is the "go to" guy if you need a spider ID. Since I am not a huge fan of spiders, I don't take the time to learn how to identify them or get to know much about them. I will go 5 soybean rows out of the way to avoid an orb-weaving spider in August.

Why do we care about black widow spiders? The females are considered highly venomous, but human deaths are rare compared to the number of people envenomated. People bitten by a female black widow may have swelling, redness, muscle pain, nausea, headache, and cramping. The venom contains several toxins and in general sounds like a painful experience. The good news is they are predators, and eat insects and pretty much anything that gets caught in their web. There are a few species of black widow in the U.S. and they have a wide distribution in the southern states. It is possible for black widows to live in Iowa, but finding them here is more likely because they were accidentally introduced instead of established.

Today Greg let me know that a female and male black widow have reached adulthood. It took constant care to feed them (live) flies and clean their cages every week. The spiders are not large, with females about 1.5 inches long and 0.25 inches in diameter. Females are shiny black with a classic, red marking on the belly (ventral) side of the abdomen. 

Adult, female black widow, Latrodectus mactans. Photo by wiki.

I have to admit, males are not impressive (insert game show sound here) - smaller, and dull in color. The adult body is about 0.25 inch in diameter.

Adult, male black widow, Latrodectus mactans. Photo by Center for Invasive Species Research, University of California-Riverside. 

It was hard to take a good picture of the male and female spiders through the plastic rearing chambers in my lab. I didn't feel brave enough to take the lids off and get a close-up. 

Female black widow spider. Note all the dead flies on the bottom of the cage. She is an efficient predator and quickly kills her prey. 

Greg is going to put them together in the same cage tomorrow and see if they mate. Can you hear wedding bells? Male spiders are often wary of females because they are potential prey. So they spin a sperm web and put the packet on one of his palps (kinda like short legs used for bringing food to the mouth). The male will attempt to deposit the sperm in the female before becoming dinner!

I wonder what will happen at the spider wedding tomorrow? 

Male is currently in the left cage. 

If successfully mated, a female can produce several egg sacs that contain a few hundred eggs. There is a lot of cannibalism with spiderlings, and so not many actually survive very long. Males don't live very long after becoming an adult, but females could live a few years. Sounds like we have a pet spider in the lab...