September 20, 2015
Being a resident of the most filmed city in the world, there are some buildings that I have as much familiarity with from portrayals on the silver screen as I do from my daily commute home. One such building is our iconic City Hall, completed in the 1920s in a fashion one architect described as an architectural hybrid “Modern American” style. Built from concrete taken from sand from all 58 Californian counties and mixed with water from all 21 Missions, this classy behemoth has been featured in dozens of films and TV shows (my personal favorite cameo is Carpenter’s 1980s classic, “Escape from L.A.”).
Photos above by Estella Hernandez. All photos below by Kelsey Bailey. Standing at 450 feet, L.A.’s City Hall is a structural symbol of the growth and prosperity of its time, but to an urban biologist, the grounds surrounding it have a different potential; the opportunity for discovery of our wonderful wildlife. It was with this curious spirit that the NHMLA BioSCAN team partnered with LA City Councilmember Paul Koretz. We erected several insect traps on the grounds, in the trees, and on the south roof to see what types of bugs call City Hall their home. From just one summer month, we have so far identified several hundred species from over 90 families! Some of the insects collected are very common backyard residents that most would recognize (Argentine ants, green lacewings, European honey bees), but the vast majority are surprising dwellers at the core of the city! Below are just a select few of the thousands of insects we found from our brief survey.
Ants, bees, and wasps (all in the insect order Hymenoptera) are the largest group found in these traps in terms of diversity, but also the smallest in terms of size. Thousands of microscopic wasps only a few millimeters in size were collected, as well as 6 different species of bee. Low ant diversity was expected: the traps we used mainly to collect flying, not crawling, insects. Above, micro-wasps associated with figs in the families Pteromalidae and Agaonidae. Below, metallic sweat bee (genus Agapostemon).
Flies to tantalize your eyes! This astonishingly diverse group of insects in the order Diptera do everything from pollinating flowers to decomposing, to preying on other insects. Measuring at almost 1 inch in length, predatory robber flies were some of the largest insects we collected (below).
Some flies like to make love on the wing, as was evidenced by the two pollen-feeding “window” flies collected in our trap in copula (below).
The third most common group we collected from City Hall include a wide variety of insects such as aphids, hoppers, assassin bugs and stink bugs, to name a few. Although some are pests on plants, many have beautifully colored markings and ornate stained-glassed patterned wings, such as this lace bug and the smoketree sharpshooter (below).