Fantastic Floristic Features at Corriell Preserve

The sand prairie at Corriell Preserve

This past weekend, Bur Oak Land Trust offered a glimpse of Corriell Nature Preserve (normally not open to the public) to visitors for Blooming Cactus Weekend. Although the stunning yellow cactus flowers on the sand prairie were a highlight, a special treat was a guided tour with Dr. Thomas Rosburg of Drake University, to talk about the floristic survey he is conducting at the site. 

Katydid nymph

Attendees were given a list of the more than 300 plant species Dr. Rosburg had documented so far, and a hike through the preserve provided the opportunity for both Dr. Rosburg and Jason Taylor, Executive Director of Bur Oak Land Trust, to share information about plants of interest, the history and current state of the site, as well as how a floristic survey is conducted.

Describing the species present at any location--much less almost 200 acres of diverse habitats including wetlands, forests, sand prairie, and pasture grassland--takes multiple visits over the course of the growing season and over multiple years. Because different plants may be more or less conspicuous at different points in their growth, visits from early spring through summer and into fall are necessary to capture the widest variety of species possible. Conditions may change from year to year as well; Dr. Rosburg told of a pond, full of water this year, that was much drier a previous year, allowing access to plants that may otherwise be inaccessible. 

It is impossible to summarize all of the information provided during the hike, so I will limit this post to sharing some of the plants we encountered and strongly encouraging you to both visit Corriell Preserve when the opportunity next arises, as well as find and attend a similar event with Dr. Rosburg! Be sure to follow the Iowa Native Plant Society to learn about future opportunities.

Grasses, Sedges and Rushes

There were many sedges and rushes, normally very easy to overlook, pointed out by Dr. Rosburg.

Gray's Sedge

Davis Sedge

Great Plains Flat Sedge

Great Plains Flat Sedge

Schweinitz's Flatsedge

Dudley's Rush

Scribner's Panic Grass

Forbs

Some spectacular, some subtle...an amazing variety of flora.

Wild Senna

Western Ragweed

Virginia Plantain

Virginia Plantain

Carolina Geranium

Wild Petunia

A single large Butterfly Milkweed was
crawling with pollinators.

Prairie Rose

Prairie Larkspur flowers,
a little past their prime.

Prairie Larkspur foliage.

Sleepy Catchfly. The red stripes on the stems are sticky.

Green Milkweed

Ladybird, ladybird

Polished Lady Beetle
(Cycloneda munda)

Cicadas may be the trendy insect this summer, but ladybugs have a special place in many people's hearts. Their rotund form, bright colors, and simple patterns make them easy for even children to pick out in a crowd. Generally pictured as shiny, round, red beetles with black spots on their hard forewings (elytra), ladybugs can actually come in various colors and may have many or no spots at all. Some may even have stripes! Their pronotum (the shield-like structure behind their head) has different patterns, often in black and white, that can be useful to help identify different species.

(The common name "ladybug" is convenient and will be used here, though technically only around half of all ladybugs are "ladies" and none of them are true "bugs" in an entomological sense. They are more properly called "ladybird beetles" or "lady beetles.")

Convergent Lady Beetle
(Hippodamia convergens)

BugGuide notes a total of 81 species occurring in Iowa. iNaturalist shows more than 20 different species of lady beetles spotted in Iowa, with the most popular by far being the non-native Asian Lady Beetle (Harmonia axyridis), possibly due to its habit of overwintering in human homes making them more visible than other species, which may overwinter in sheltered places such as under rocks or bark, or in leaf litter or protected snags. Ladybugs will overwinter as adults, sometimes in groups.

Like butterflies and bees, ladybugs are holometabolous, meaning they undergo complete metamorphosis from their larval stage to adulthood, with a pupal stage in between. Ladybug larvae are often described as "alligator-like": long, segmented, and spiky, often sporting similar red-and-black coloration to the adults but otherwise little resembling their future selves. Both larvae and adults eat aphids and other pest species, making them welcome visitors for gardeners. 

The bright red and black elytra of many species are an example of aposematic coloration, warning potential predators that their potential meal may be toxic (or at least have a foul taste). Nevertheless, ladybugs may be preyed upon by frogs, birds, spiders, and other insects including dragonflies and ants. 

Seven-spotted Lady Beetle
(Coccinella septempunctata)

Although many species of ladybugs are common, a few have experienced drastic declines in their populations in recent decades. The Lost Ladybug Project is a citizen science program that attempts to document the Nine-spotted Lady Beetle (Coccinella novemnotata) as well as the Two-spotted Lady Beetle (Adalia bipunctata), both of which are thought to be vexed by the common refrain of habitat loss combined with competition from introduced species (including the common Seven-spotted Lady Beetle pictured at right). 

All the ladybugs pictured here were spotted over the course of an hour along the Greenway one recent sunny day. 

Ladybug larva with aphids

Sources/Additional Reading:

• Lost Ladybug Project
• Bug Guide: Family Coccinellidae
• Cornell University - Biological Control: Lady Beetles
• Xerces Society: Nine-spotted Lady Beetle
• University of Minnesota Extension: Lady beetles