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Wildlife spectacles and “scant regard for food-chain decorum”

by Timber Press on October 23, 2017

in Gardening, Natural History

In her article “Birds Beware: The Praying Mantis Wants Your Brain,” Natalie Angier details the unexpected hunting habits that are driving some researchers to consider mantises a class all their own. With 3D vision and “scant regard for food-chain decorum,” mantises may be less like insects and more like aspiring vertebrates.

Inspired, and a little unnerved out to be honest, by Angier’s article, we are revisiting Vladimir Dinet’s Wildlife Spectacles: Mass Migrations, Mating Rituals, and Other Fascinating Animal Behaviors for some strange and unsettling insect dining habits.

A garden is an artificial ecosystem where species from different parts of the world are thrown together; it is not fully self-regulating and requires human attention. But you can still see a few interesting features of the so-called food chain in your garden.

One thing they didn’t tell you in school is that many species can jump up and down the food chain depending on the circumstances. One spring I noticed that the scrub-jays that lived in our garden began to eat other birds’ eggs and chicks. I started adding eggshells to the mix in our bird feeder, and the jays returned to their normal diet of seeds, complemented with an occasional moth or snail. Apparently they used larger prey only as a source of calcium.

Chinese mantises were accidentally introduced to North America from Asia, where they fed only on insects, and here they found a new prey: hummingbirds. Every fall I have to watch my hummingbird feeders to make sure there are no mantises hanging head-down under the bottom. They can sit there for days or even weeks waiting for their chance; if you shake them off, they climb the tree and somehow find their way back to the feeder. Sooner or later they score, catching a hummingbird, killing it by piercing its chest with the long spikes on their front legs, and eating it. These mantises are females (males are smaller), and they need good protein meals to produce their egg sacks. The sacks are made of foam that hardens when exposed to the air; the foam protects the eggs so well that they survive the winter.

There are lots of interesting questions here. How did the mantises learn to hunt hummingbirds? How do they know to wait at the feeders? How do they find their way back to the feeder from the ground through the maze of tree branches? I don’t know the answers to any of these mysteries; if you have a lot of free time, you can try to come up with some experiments to figure them out.

Last April two climbing roses in our backyard were attacked by aphids. We don’t use chemical pesticides, so I applied horticultural oil to a few buds that were most densely covered by the insects, then just waited. Within a few days the cavalry came to the rescue. First arrived ladybugs, then lacewings, and finally hoverflies. If I looked at the roses closely, I could see where they laid their eggs: ladybug eggs looked like tiny cantaloupes, hoverfly eggs like little cucumbers packed in white silk, and lacewing eggs were minuscule white ovals on long, hairlike stalks.

The aphids kept multiplying. They are good at it: females can reproduce asexually, giving birth to small copies of themselves at an impressive rate. They seemed unstoppable. Then the predators’ larvae emerged from the eggs: tiny, slow-moving monsters covered in protective spikes. They were compulsive eaters. Everywhere I looked, they were plowing through the aphid ranks, leaving death and destruction in their wake. By the time the larvae grew up and began to turn into pupae, I couldn’t find a single aphid anywhere. It didn’t mean that every single one of them was eaten—some managed to fly away in time. But I didn’t have to worry about my roses anymore.

Ants love sugary water. They can eat only liquid food, so they can’t eat any of the stuff they carry to their colonies, such as insects they have killed, grass seeds, or bread crumbs from your kitchen.

They have to feed these items to their larvae, and then the larvae regurgitate some of it in liquid form to feed the adults. The droplets of sugary water produced by aphids and leafhoppers are often the only thing worker ants can use as snacks away from home. Some ant species have become fully dependent on these insects: they herd them like cows, defend them from predators, and sometimes even build little barnlike structures to protect them from the elements. When a young winged female ant leaves her home to mate and become queen of a new colony, she takes a little aphid larva with her, and this larva becomes the founder of the ants’ domestic herds (remember, aphids can reproduce asexually).

Vladimir Dinets was born in Russia and immigrated to the United States as a young man. He has a PhD in zoology, with a focus on animal behavior. Vladimir has traveled and photographed extensively around the globe, becoming the first zoologist to find and photograph saola tracks in the wilds of Vietnam. He is a research assistant professor at the University of Tennessee, where he studies behavioral ecology and its applications to conservation.

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Click the image below for a look inside this book.

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“With inspired passion, Vladimir Dinets introduces us to diverse wildlife spectacles, the natural history that drives them, and a checklist of amazing experiences—many of which are closer to home than you might think.” —Mark Elbroch, lead scientist of Pumas with Panthera, coauthor of Peterson Reference Guide to the Behavior of North American Mammals

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