Smooth Sumac Insects

Smooth Sumac, Rhus glabra, is just beginning to bloom.  I have an abundance of this plant along the trail leading up the hill behind the house.  It gets mowed about every three years and blooms heavily the second year after mowing.  The result is a massive display of blooms at just about eye level.  It’s just perfect for viewing visiting insects.

A flower head forms at the end of each branch.  Smooth Sumac is a common species that is recognized by its hairless stems.

The buzz of nectar eaters never ceases.  Bees, wasps, flies and beetles are frequent visitors of these flowers.  Hairstreak butterflies also make use of this nectar, but I have yet to see any of the hairstreak species this year.

Tachinid Flies were the noisiest of the various visitors.  Tachinids come in a variety of sizes and colors, but my preference is for these large types.

Tachinid larvae develop inside a living host, usually a specific insect species.  The adult flies are so numerous it’s almost impossible not to see them when you’re in the field.  Despite seeing thousands of adults, I’ve never seen a host insect containing a Tachinid larva.

This is a Yellow-collared Scape Moth.  I see this day flier on many different flower species that produce large flower heads.  The moth tends to take advantage of the flower cluster to partially hide itself while feeding.

 

Beetles abound in the flower cluster.  Most try to remain hidden among the small flowers.

I think this is some type of Soft Winged Flower Beetle.  I couldn’t tell if it was actually feeding inside the flower or searching for something on the outside.

Of course the little green bees were there.  I have yet to find a flower that doesn’t attract these bees.

I think sumacs are one of the preferred flowers of Bumblebees.  I always find an abundance of Bumblebees on these blooms.  I like to watch flowers because of the wide assortment of insects that they attract.  When they are busy feeding, insects are easy to approach and observe.  I’ll be spending a lot of time around the sumacs for the next week or so in hopes of seeing something new and unusual.

Smooth Sumac

There are many plants just starting to display some showy blooms at Blue Jay Barrens, but this plant will draw your eye from them all. This is the seed head of Smooth Sumac, Rhus glabra. This vibrant crimson display can be seen for a long way across the field.

A closer look at the sumac fruit. Even though the fruit is now beginning to ripen, birds won’t be paying it much attention until mid to late winter. This seems to be one of those survival foods and it does its job well. These plants hold their fruit and remain standing through the toughest of winter weather.

Sumacs quickly form a thicket and at Blue Jay Barrens, will grow to a height of about 12 feet. I mow most of the sumac areas every two to three years as part of my management effort to maintain open fields. One result of the mowing is an increase in Sumac fruit production. This particular area is into its second growing season and is producing an impressive amount of fruit.

Regrowth is rapid after mowing. This plant was cut in February of this year and is now about five feet tall. The mowing cycle maximizes the leaf area to root mass ratio for maximum growth. It also causes the type of plant stress that stimulates production of fruit. Mowing too often would cause the plants to begin dieing and mowing less often would cause the growth to get tall and woody. Tall growth stops sending up these vigorous young sprouts and is very susceptible to winter kill. The areas of sumac that I do not mow are a tangle of dead and fallen trunks. These areas are often slow to recover following a winter die off.

This is the last of the Smooth Sumac blooms for 2009. Many types of pollinators visit these large flower clusters.

Sumac patches are often a collection of cloned sprouts. Since they all share the same genetic schedule, the stage of fruit development on one plant is mirrored on all of the related plants.

Some of these seed heads are massive. I disturbed a bird busily digging for something inside this seed head. It didn’t seem to be after the fruit, but was digging for something hidden in the cluster. You can see where it exposed the white skin of fruits that received no sunlight.