Thursday, February 25, 2016

Exploding insects top bill at this year’s Insect Fear Film Festival

Exploding insects top bill at this year’s Insect Fear Film Festival

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In anticipation of the 33rd Annual Insect Fear Film Festival, which they will host Saturday on the U of I campus, this week’s commentary comes from three members of the Entomology Graduate Student Association : Josh Gibson, Todd Johnson, and Tanya Josek. Believe it or not, they’re here to talk real-life insects that explode.

Bombardier beetles (Todd)

One day Charles Darwin was returning from a collecting trip when he spotted an interesting beetle. His hands were full so he decided to transport it in his mouth. There, the beetle released an explosive chemical reaction causing Darwin to drop all of the insects he collected that day. We now know these insects as bombardier beetles, which get their name from a unique ability to direct a hot spray of chemicals from their posterior end. Recently, researchers found that these beetles open and close a valve inside their body while spraying, causing the spray to come out in a series of pulses. The pulses probably help protect the beetles from damaging themselves by limiting their exposure to the reactive chemicals. For bombardier beetles this is a very effective defense against predators looking for a quick meal.

Exploding ants (Josh)

In the forests of southeast Asia, it’s an ant-eat-ant world. Tree-dwelling ant communities are often dominated by species with large, aggressive colonies, which can make it difficult for others to establish nests. To do so requires a good defense . . . but sometimes a good defense is a good offense. Exploding carpenter ants have evolved a unique way of defending their nests from attack. When threatened, the workers of this species can compress their abdomens and cause dangerous chemicals to burst from their heads. This often kills nest intruders at the cost of the workers’ own lives. The ruptured ants stop scouts of more aggressive ant species from informing the rest of their colony of this valuable nest location, preventing a large-scale invasion. By sacrificing their own lives for the good of the colony, exploding carpenter ant workers allow their colonies to stand tarsus-to-tarsus with more aggressive ants and live to tell the tale – even if some of the workers themselves do not.

Parasitoid wasps (Tanya)

The science fiction hit Alien terrified audiences with the idea of aliens bursting out of astronauts. While most of the movie is fiction, some of the biology is not. Right here on earth, many arthropods are susceptible to attack by parasitoids, insects that develop while attached to or inside them. For example, there’s a certain tiny wasp female that seeks out tobacco hornworm caterpillars. When she finds one, she uses her stinger to inject eggs inside it. The caterpillar continues to eat and grow, unaware that wasp larvae are growing inside its body. Once the larvae fully develop, they chew their way out of the caterpillar’s body and spin cocoons, eventually emerging as adults. Shockingly, the caterpillar is alive throughout this entire process and only dies after the wasps have completed development.

Of course, if you think this stuff sounds wild, wait till you see the mutant cockroaches and gigantic, lava breathing  tarantulas in this year’s films. Doors to Foellinger Auditorium open at 6pm with an insect petting zoo, face-painting and balloon insects, insect-related artwork, and our first ever “talking cockroach.” Find further details

Thursday, February 18, 2016

Birding abroad: Part 2

Birding abroad: Part 2

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Although the other members of my family enjoy a range of outdoor activities when we travel together, I like to spend more time birding than they do. I especially enjoy staking out a spot where I can spend some quality time with my camera early in the morning. 

On the second stop of our tour in Senegal, this was just across the road from our lodging which was located on a narrow spit between the Senegal River and the Atlantic Ocean. The tidal flat there, featuring a newly established strip of mangroves, offered great opportunities to photograph a variety of herons and other waders, as well as shorebirds, gulls and terns.

Most of the birds I saw at this spot were new to me, but many of them were recognizable as counterparts to birds I’ve seen in North America: A large heron nearly undistinguishable from our great blue heron, a smaller egret like our snowy egret, and so on. Others were different from anything I’ve seen, including the most numerous and noisiest birds on the scene, spur-winged lapwings. These are medium-sized shorebirds with striking black and white markings that call to one another loudly throughout the day.

On the way back from this spot one day, I had stopped to watch birds in the trees around our hotel’s parking lot when I came upon the most colorful birds of our trip, little bee eaters. They were bright green above with a black mask, a vibrant yellow throat and various shades of orange below. They were flying out from a low branch to catch insects--everything from small wasps to dragonflies--and then perching again to eat.

In addition to the birding I did on my own, my family and I enjoyed some memorable excursions dedicated to wildlife watching. One day we traveled to the Djoudj National Bird Sanctuary in a van, along with a family of four from France, a local guide and a driver. The highlight of that trip was a boat ride to see the sanctuary’s enormous nesting colony of great white pelicans, but we saw many other birds along the way, as well as some interesting non-bird animals—west African crocodiles and warthogs among them.

Because I was interested in getting pictures, our guide insisted I ride in the front of the van on the way back, and our driver even stopped for me to get out for shots of some animals. (I don’t remember anyone from our party complaining about this, although I wouldn’t have been listening closely for that, either.)

Along the same lines, I benfited from the help of the guide who drove a boat we rode in during our time in the Saloum River delta, which is south of Dakar on the Atlantic. He would orient the boat just right, give the engine some gas and then cut it, which enabled us to drift in quietly for photos of birds among the mangroves. There our most memorable finds were an elusive white-crested tiger heron and a goliath heron, the largest heron on earth.

Like many other travelers, I can talk about a trip for much longer than anyone might reasonably be expected to stay tuned. To avoid that here, let me invite you to look at photographs online here:

Thursday, February 11, 2016

Contemplating courtship rituals for Valentine’s Day

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Whether or not you planned well for it, Valentine’s Day is here. I won’t comment on the human behavior associated with this holiday, but I can provide a bit of diversion and give suggestions about where to see animal courtship spectacles in Illinois.

Consider, suggests May Berenbaum, who is head of the UI Department of Entomology, the bizarre (to us) behavior of some pyralid moth males. In the process of courtship they beat females over the head with the tip of their abdomen. This behavior may look like abuse to us, but in reality its purpose is to transfer aphrodisiacs. Or think of how good your gift ideas look when compared to the offerings certain male insects present to their prospective mates: hangingflies, for example, which proffer dead flies, or certain empid fly males, which court females with empty balls of saliva.

Makes a box of chocolate look pretty special after all, doesn’t it?

Chris Phillips, who is a herpetologist with the Illinois Natural History Survey, points out that in the world of amphibians it’s not unusual for courtship to involve a communal aspect, because mating requires frogs, toads, salamanders and others to come together at bodies of water. (Forget cozy dinners for two at candlelit restaurants!) That’s where their eggs will be laid so their young, which must live in water, can develop before going off to breathe air live on land and as adults.

Barring unusual weather, the rains that fall in late February and early March will get Illinois amphibians moving. Male spring peepers and wood frogs will vie for mates by singing (or calling if you prefer, beauty being in the ear of the beholder) in a chorus that can be uncomfortably loud for human observers.

[Spring peeper and prairie chicken photos by author.]

A male wood frog that lands a mate grasps her in an embrace called “amplexus,” which may look much like a human hug. But he is apt to hang on for hours, or even days, his grip secured by rough pads that develop on his thumbs during the breeding season just for that purpose.

If you’re more interested in birds, UI avian ecologist Mike Ward calls attention to two courtship spectacles that can be witnessed in Illinois.

One is the performance of male greater prairie chickens in the lek, a daily gathering during the breeding season where they compete for the attention of females. Males spar with each other to occupy the best positions in the field, and then put on a highly choreographed performance that puts the funky chicken to shame.

Prairie chickens hang on in only a couple of very small isolated populations in Illinois, within the confines of the Prairie Ridge State Natural Area southeast of Effingham. If you want to witness their courtship it’s best to make arrangements through the office there.

It’s much easier to catch the hardly-less-impressive courtship of American woodcocks, which takes place throughout the state, including a number of sites in Champaign and Vermilion counties. Beginning sometime in March, at dawn and dusk male woodcocks put on a display that culminates in the “sky dance,” famously described by Aldo Leopold in “A Sand County Almanac.”

A number of groups, including the Urbana Park District, the Champaign County Audubon Society and the Champaign County Forest Preserve District, lead “woodcock walks” in March.

Maybe you could make a date to join up with one.

Thursday, February 04, 2016

Birding abroad

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The city of Dakar, which is the capital of the West African nation of Senegal, is not a birding destination. Some two and a half million people live there, and the streets are crowded with traffic that includes everything from people on foot and horse drawn carts, to motor scooters, taxis, private cars, and a variety of buses, among them the colorful and jam-packed cars rapide.

But Dakar is home base for my daughter Jane, a UI junior majoring in Global Studies who is studying in Senegal for the academic year. So that’s where our family’s two-week visit with her over the recent holidays began, and where I had my first opportunity to see African birds.

[Photos by author: yellow-billed kite, pied crow, red-billed firefinch.]

On the cab ride from the airport to our hotel, I was amazed to see that the skies over the city were filled with large, soaring birds of prey that were unlike any I had seen before—dark brown both above and below, with a deeply forked tail they used as a rudder. These were easy enough to identify in my field guide, which I’d gotten last fall and spent time browsing in anticipation of our trip; they were yellow-billed kites. As you might expect from a bird of prey that can live in a city, yellow-billed kites are described as “extremely opportunistic” feeders; they eat everything from insects and small vertebrates to food scavenged from garbage and carrion.

One of the great pleasures of birding is the way it expands a person’s engagement with the world. Nonbirders looking out from a high window in a city on a new continent may enjoy the view of the architecture or the people in the street, but birders immediately begin expanding their catalog of “life birds,” whether they keep that list written down or in their head.

From the sixth floor of the Hotel Faidherbe I discovered that some of the large birds soaring over the city were not kites at all, but hooded vultures, which were also new to me but easy to identify thanks to my book. There were gregarious flocks of crows in the sky, too, although unlike the uniformly black species we’re accustomed too, these sport white on the chest that wraps around their shoulders and back to give them a distinctive collar; they’re called pied crows.

One of the most productive bird habitats I encountered in Dakar was the oasis around our hotel’s pool, which was located in a courtyard surrounded by high walls that were hung with bougainvillea vines. There I saw for the first time laughing doves, which are a more colorful analog to our mourning doves, and common throughout much of sub-Saharan Africa. Late in the afternoons the doves would be joined by noisy flocks of house sparrows and related weaverbirds, as well as some that seemed more exotic (to me, anyway), prettiest among which were red-billed firefinches.

Now, we’re getting near the end of this commentary and I haven’t gotten beyond the city where we landed in Senegal, despite the fact that the best birding of my family’s tour in the country took place during stays in more natural settings. I’ll follow up some on that next week.