Saturday, June 21, 2025

No such thing as a free lunch...


Beetle socks? Clown shoes? What is going on with this Margined Leatherwing's little feets and their coordinating attachments?


With difficulty, it walked along the leaf margin like a dog reluctantly wearing shoes, lifting and shaking its legs in an attempt to unencumber itself from these orange globs. 


For a bit, it attempted to use its mandibles to loosen them...


with limited success, before with a short flight returning to the source of its discomfort:


Beautiful, fragrant Common Milkweed flowers have a fascinating structure. Upon blooming, the petals of the flower fold downward, forming a kind of skirt below the corona, which is where all the action happens.


Each corona has five "hoods" that hold the nectar pollinators so desire—nothing tricky there. But in between those hoods are slits into which the leg of a butterfly, fly, bee, or beetle may slip. When the leg is pulled out, it may catch a structure called the corpusculum, from which dangle a pair of pollen packets called pollinia. 

If an insect successfully extracts its leg, pollinia and all, its continued foraging on other milkweed flowers will hopefully (for the milkweed at least) bring the pollinia into contact with another slit. A pollinium thus delivered can slip into the "stigmatic chamber" contained inside, where it will make contact with the stigma and fertilize the flower.  

This process can be dangerous for the insect: sometimes their leg may become stuck and they may lose it...or even perish if they are unable to get free. Our Margined Leatherwing, fortunately, has so far escaped that fate.



Sources/Additional Reading:

Saturday, May 31, 2025

A shortgrass prairie plant in a tallgrass prairie state

A little tumbling flower beetle (Mordella spp., tentative)
on a spike of Buffalograss.

As you walk along the trail, look down and you're apt to see the flower spikes of low-growing Buffalograss, a beautiful native grass with fine blades that may have more of a blue or gray tinge to them than the surrounding grasses. 

A drought-resistant denizen of the shortgrass prairies of the Great Plains, Buffalograss tops out at around five inches — quite a contrast to the flashy tallgrass specimens of Big Bluestem or Indiangrass, both of which regularly reach six feet tall. It is an important food source for bison and other mammals, hence the common name, and many grasshoppers, including the Admirable Grasshopper, Syrbula admirabilis. 

What a pretty grass!
Male flowering spike of Buffalograss.

Buffalograss is generally dioecious, meaning male and female flowers are found on separate individuals. The conspicuous male flowers are held above the grass on short spikelets, which are arranged on a spike that has been described as resembling a comb or eyelash. To see the female flowers, you have to get down on the ground and look closely (so closely, perhaps, that your behavior prompts a kind passing cyclist stop to make sure you aren't in need of assistance). The seed-producing female flowers grow closer to the base of the plant, with reddish-purple styles to catch the wind-distributed pollen from those male flowers up above. 

Most other grasses hold their seeds high above, making for easy distribution. Why does Buffalograss tuck theirs way down low to the ground? Some sources mention that the low profile helps prevent the seeds from being munched and destroyed by the bison and other browsers who find the grass so palatable. Other sources note that its placement encourages consumption by bison, whose digestive process helps break down the seed's coating, and deposits it in a rich bed of fertilizer. 

Tiny, hidden female flowers of Buffalograss grow low to the ground.

Sources/Additional Reading

Saturday, May 3, 2025

The Crepitator

 zzzzt 

There it was again. I had noted the sound for several days as I walked along the trail: a soft buzzing, so faint and sporadic it could have been a gentle breeze making a piece of grass vibrate like a reed.  But recurring frequently enough that I suspected an arthropod origin. So I walked on. And I listened.

zzzzt  

And again. The same sound, the same duration. Too far away to investigate though: meters away from the trail. I walked on. 

zzzzt  

I stop. Peer intently into the tall, dry grass but see no movement. The sounds doesn't repeat. I walked on.

zzzzt     zzzzt             zzzzt  

I freeze. The sound came from three different points around me, in quick succession.

zzzzt     zzzzt             zzzzt  

And again! Definitely not wind and grass, responding to itself from multiple locations. I creep toward the sound of the nearest zzzzt  and stand motionless but for my eyes, which scanned and darted in search of the slightest movement. And then....

zzzzt 

I catch movement coinciding with the sound, a reasonably large insect flying a short distance low to the ground, landing in an area where the grass had been tamped down enough to get a good view. I crept closer. I sidled silently. I squatted...awkwardly. 

Got him!


Look at that big boy! With fully-developed wings already in late April, it must be one of the few grasshoppers that overwinters as a nymph or adult, as the majority of species overwintering as eggs would emerge as tiny nymphs and require several weeks to reach adulthood. iNaturalist suggests Green-striped Grasshopper, Chortophaga viridifasciata.

This widespread grasshopper tends to live in moist, grassy areas; their diet, unsurprisingly, is a variety of grasses, including foxtail barley and Kentucky bluegrass. It does indeed overwinter as a later-stage nymph, after hatching from eggs towards the end of summer (which is when many other grasshopper species are in full-blown adulthood). They will become dormant through the cold months, emerging in March as the days become longer.

The zzzzt sound, called crepitation, is made by their wings rubbing together; the Green-striped Grasshopper may crepitate regularly during flight, with males also crepitating to attract females. An interested female will approach, crepitating herself before they woo each other with a seductive femur-tipping dance.

But what about that name? Striped, sure...I guess I can see that. But green? Chortophaga viridifasciata actually comes in two colors: green or brown. Females are generally green, with males normally brown...though both sexes can come in either color (I am calling this one "big boy" but I can't declare with 100% certainty it is actually a boy). 

Check out the interesting stripe through the compound eye!

And listen closely for the soft zzzzts (you can hear them fairly clearly at 0:00:03, 0:00::06, and around 0:00:20):



Sources/Additional Reading: