First trip of 2020 season

April 11, 2020

Jon Nikkila, his sons and I went on a trip to Box Elder SWMA in Lincoln County (in two cars practicing social distancing) Saturday April 11 for our initial foray for Lepidoptera.  The weather was nice, with temps in the 70s, but of course windy.  It was early for most flying Lepidoptera, but our main pursuit was the coolest bug very few people even know exists – Megathymus yuccae or the Yucca Giant Skipper.  Sighting adults is extremely difficult.  Fortunately for us finding the larval/pupal stages is marginally easier.  We were lucky enough to find a couple of these.  A little life history on this species.  Adults emerge in the spring (April and May) and females lay eggs on yucca plants.  After hatching and feeding for a short time above ground the larvae bore into the center of the plant where they feed below ground in the root.  They build a silken “tent” above ground (which resembles a fingertip) where they expel frass (fancy word for poop).  They feed there the entire summer and pass the winter there as well.  In the spring they pupate in the burrow and  emerge in late April/early May to start the cycle again.  Here is a picture of one we found (GPS coordinates 41 01’726″, 100 34’367″).

Yucca skipper tent

This is a rather recent discovery in Nebraska, having first been found in 1984, probably due to it’s early flight period and remote locations.  However once found further searches in suitable habitats have proved fruitful.  In Nebraska this species is restricted to the western half of the state with most records coming from the southwest corner.  It has not yet been found in the Sandhills.

Distribution of Megathymus yuccae in Nebraska

Females are slightly larger than males and have yellow spots on the hindwings.

female Megathymus yuccae
male Megathymus yuccae
Megathymus yuccae

Our second find of the day was one Olympia Marblewing flying up and down the steep slopes as if daring us to follow which of course we could not.  They are named for the green “marbling” present on their ventral hindwing.  Olympia Marblewings (Euchloe olympia) fly in a single flight for a couple of weeks in the spring, laying eggs on mustards which are in bloom at that time.  The larvae feed on the fresh growth, growing quickly and then pupate where they spend the rest of the year waiting for next spring to emerge and start the cycle again.  They are found statewide, but are rarely common.

Euchloe Olympia – Olympia Marblewing
Distribution of Euchloe Olympia in Nebraska

Citizen science – Searching for yucca skipper tents is generally a frustrating experience.  I spent an afternoon at Harlan County Reservior searching yucca hills without success (I have found two tents there over the years), so don’t be discouraged if you look and come up empty.  But if you think you might have found one snap a pic and send it with the GPS coordinates to NebraskaButterflies@gmail.com.  I’ll try to come by and check it out later this year.  We’ll get you into the record books with a county record.  Ditto for pics of Olympia Marblewings if they are new to a county.

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