Midsummer Activity – Pollinators, Predators, and Prey

August 15, 2023

In the middle of summer, the heat intensifies, especially out on the valley floor. My colleagues and I try to accomplish our field work early to avoid the heat but there are times such as this week when I was still walking along the riparian corridors observing wildlife as the temperature climbed. Even in the heat, there are many creatures still going about their important business of eating, hunting, pollinating, and drinking the quickly disappearing creek water.

One of the fascinating creatures I found this week was the caterpillar of the Anise Swallowtail Butterfly, Papilio zelicaon, on a fennel plant, Foeniculum vulgare. The bright yellow, green, and black colors and patterns of the lone caterpillar blend in beautifully with the fennel and I can see that it has been eating many of the flowers. The Anise Swallowtail is one of the five species of swallowtails found in California.

As I walk along the riparian corridor of Outlet Creek the hum of pollinators reaches my ears. I notice many non-native Western Honeybees, Apis mellifera, working the many blooming summer flowers, including California rose, Rosa californica, Pennyroyal, Mentha pulegium, and one of my favorites, Western goldenrod, Euthamia occidentalis. Amongst all the honeybees, I see many species of native bees. One of the common ones is the Yellow-faced bumble bee, Bombus vosnesenskii, with its bright yellow face, black body, and yellow band near its lower abdomen. It is found on the Pacific coast from Canada to southern California and likes a variety of flowers as is confirmed as I watch this bumble bee go from one kind of flower to another.

California mugwort, Artemisia douglasiana, is all around me, some of the plants are over six feet tall and even though it is a plant in the Asteraceae or Sunflower family, its flowers are small and inconspicuous. As I look closer there are some unusual creatures like a small juvenile California Red-sided Garter snake, Thamnophis sirtalis infernalis, that is about three feet above the ground. I know it is hunting for insects or amphibians that are hiding in these lush plants. Just then I spot a Chorus Treefrog high up in a willow tree above the mugwort. In between the willows and the mugwort, I found my favorite large spider, the Black and Yellow Garden spider, Argiope aurantia. The two I find are females in large webs with their signature transverse bar stitching below them. This time the distinct black pattern on their abdomens really stands out and looks like a large beetle.

Again, I am struck by how much can be seen if a person just slows down and pays attention for even just a few minutes!