The ailanthus webworm moth (Atteva aurea) ranges from eastern Canada to Costa Rica. In temperate eastern North America, its caterpillars feed exclusively on tree-of-heaven (Ailanthus altissima), an invasive weed. This same tree is the favored host of the introduced spotted lanternfly. A question is whether invasion of eastern North America by the spotted lanternfly reduced abundance of the ailanthus webworm moth.

Giant silk moths (Saturniidae) are among the world’s largest and most charismatic insects, with 28 species native to the eastern United States. Many species of giant silk moth here have been reported as declining, with one remarkable exception: the polyphemus moth (Antheraea polyphemus). It has been reported as increasing. One hypothesis to explain this surprising increase is that the polyphemus moth is uniquely tolerant of urbanization.

Animals have biological clocks that run in total darkness. Experimentally, circadian rhythms have run in total darkness for days. A single pulse of light that interrupts this darkness shifts the circadian rhythm of emergence of fruit flies.

The ailanthus silk moth, also known as the cynthia moth, is a giant silk moth indigenous to China and introduced in 1860 into Philadelphia. Its wingspan may reach 15 centimeters (5.9 inches). Its favorite host plant is tree of heaven (Ailanthus altissima), native to Asia. This tree thrives in harsh urban landscapes

Artificial lighting has been blamed for declines in abundance of giant silk moths. It can disrupt all their life functions, including flight, navigation, vision, migration, dispersal, oviposition, mating, feeding, crypsis, circadian rhythms, and photoperiodism. It may increase predation by birds, bats, spiders, and other predators.

Jumping spiders ordinarily use their big, forward-facing eyes to hunt in bright sunlight, without the use of webs. They stalk and pounce on prey. At porch lamps at night on Cape Cod, Massachusetts, the jumping spider Platycryptus undatus used artificial light to hunt prey attracted to the light.

This book explores the history of natural history in Philadelphia. Here I present one example. In 1745 John Bartram, a nurseryman and naturalist in Philadelphia, described the black and yellow mud dauber (Sceliphron caementarium), which is native to North America. He detailed how the wasp makes a mud nest consisting of cells provisioned with spiders that it had paralyzed.

By breaking up habitats, cities interfere with dispersal of plants and animals. A small liverwort I observed growing in pavement cracks apparently engages arthropods (springtails) to disperse its spores.

Inadvertent introduction of the Japanese beetle into North America in a nursery just outside Philadelphia in the early twentieth century unleashed a plague. Henry A. Dreer, the nurseryman responsible for this catastrophe, dismissed the beetle’s danger and undermined efforts to control it. His denial of the science likely contributed to the failure of entomologists to eradicate this pest from North America.

One theme of this book is that mating systems of plants and animals in cities are adaptive, or pre-adaptive, to the city. For example, flowering plants may accomplish pollination where pollinators are scarce or even absent.

Spotted lanternflies (Lycorma delicatula) first appeared in North America in southeastern Pennsylvania in 2014. By 2020, spotted lanternflies were ubiquitous in Philadelphia. Adult spotted lanternflies swarmed around tall buildings downtown.