Butterflies on Noxious Weeds

As I mentioned in my last post, regal fritillaries are out in high numbers in our Platte River Prairies.  We’re watching – among other things – what plant species they’re using for nectaring, and are interested to see if that use is similar to what we saw last year.  Right now, the most attractive plant to fritillaries is one that might surprise you – musk thistles.

On the other hand, if you’ve spent much time watching butterflies, you’ll not be too surprised at the attractiveness of this noxious weed to butterflies and other pollinators.  Native thistles are recognized as important nectar sources, but non-native thistles, especially those we’re legally obligated to eradicate, don’t always get the same positive attention.  This week our technicians were out looking for both musk thistles and regal fritillaries (for different reasons) and they were finding both simultaneously!  We ended up killing a lot of thistles out from under butterflies.

Here is a selection of photos from last Friday, showing fritillaries getting what they can out of these noxious weeds before we kill them off (the thistles, not the butterflies…)

It seemed like every musk thistle had a regal fritillary on it...

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This fritillary flattened itself against a strong wind gust.

Photo of the Week – January 21, 2010

Bumblebees are fascinating creatures.  Like honey bees, they are social insects that split foraging and brood rearing chores between groups of workers.  However, unlike their non-native cousins, bumblebee colonies die off at the end of the year, leaving only a few fertile females to overwinter.  Those females emerge from hibernation in the spring, find a suitable nesting site, and begin building up a new colony of bumblebees that can reach several hundred individuals in size – all within a single season.

This bumblebee kept lifting and lowering its leg as I photographed it. The Nature Conservancy's Platte River Prairies, Nebraska.

This particular bumblebee was sitting on a rosinweed flower in a dew-covered prairie one morning.  As I began photographing it, it started lifting and lowering one of its legs.  I have no idea why it was doing that.  It could probably be construed as either a greeting (or perhaps the opposite!) but was probably more of a stretching exercise as the bee began warming up in the early sunlight.

To learn more about bumblebees, and to find an easy identification guide (at least for the 17 Nebraska species) go to the University of Nebraska’s bumbleboosters site.