• Choose a category
• All
• Classic-Fiction

Marsh was correct, but despite the great complexity he discovered he still greatly oversimplified the “real” world of the moth’s population dynamics. At that time he could not have considered an even more fantastic phenomenon of some ichneumon parasitoids: polyembryony, in which one egg can divide to produce multiple genetically identical individuals. That is, the egg clones itself to make as many as 100 or more individuals, enough to consume the whole caterpillar. If two wasps each lay an egg into the same caterpillar, then there will be two clones—each with many individuals—developing simultaneously. And, in a newly discovered twist, some of the larvae of any one clone may be precocious and soon die, but not until they have acted as mobile jaws to kill possible competitors of other clones of both the same species and different species.

The resulting checks and balances of predators, parasites, hyperparasites and hyper-hyper-parasites, cannibalism, and disease organisms ensures that the summer mortality depends on population density (it is density-dependent), so that no one population can completely eliminate the other, and the forest—the other end of the chain of cause and effect—stays green all summer long.

Photographic Insert

Fig 1a. Crocus flower during the daytime, as opposed to night.

Fig 1b. Bloodroot flower as a result of temperature.

Fig. 2a. Caterpillars eaten by birds. Try to find the six different caterpillar disguises: two leaf-edge mimics, one petiole mimic, one twig mimic, one leaf midrib mimic, and one possible debris mimic. Four of the corresponding adult moths also palatable to birds have been included.

Fig. 2b. Four different “unpalatable” caterpillars and their adults (imagos).

Fig. 3a. A cecropia moth on a cocoon from which it has just emerged. The cecropia is one of the better-known saturniid silk moths, to which the luna (right), the io (lower center), polyphemus, and promethean also belong.

Fig. 3b. Caterpillars of North American saturniid moths.

Fig. 4a. A pair of promethea moths and one of their caterpillars.

Fig. 4b. The ichneumon wasps, Enicospilus americanus, and Gambrus nuncius, which parasitizes promethean moths. Only one of the first develops in a caterpillar, but usually twenty to forty (or more) of the second emerge from a single moth.

Fig. 4c. The big white-faced yellow-bellied tachinid, Belvosia bifasciata, a silk moth parasite that showed up near my camp for the first time in 2006.

Fig. 5. A sampling of longhorn beetles from northeastern North America.

1. Cosmosalia chrysoma. 2. Stictoleptura canadensis. 3. Judolia quadrata. 4. Typocerus confluens. 5. Stenodontes dasytomus (spotted stem borer). 6. Saperda cretata (spotted apple borer). 7. Clytus ruricola. 8. Strophiona nitens (chestnut bark borer). 9. Neoclytes approximates (redheaded ash borer). 10. Urugraphis despectus. 11. Tetraopes tetrophanus (red milkweed borer). 12. Monochamus notatus (northeastern sawyer), male. 13. Oberea affinis. 14. Desmocerus palliates (elderberry borer). 15. Glycobius speciosus (sugar maple borer).

Fig. 6. Life at a yellow-bellied sapsucker’s sap lick. Insects and hummingbirds also are attracted to the birch’s sap.

Fig. 7a. The plants that I picked and sketched on 12 May 2007. The leaves of seven of them are those retained from the previous summer.

Fig. 7b. The common bumblebee (Bombus) species that I expected to see.

Fig. 8a and 8b. A bunchberry (Cornus canadensis) flower in the fall, about five months after the usual time of bloom for this species. Bright red fallen maple leaf and yellow poplar leaf are to the top left and right, respectively. But note the green patch on the old weathered poplar leaf below the flower. It was caused by two caterpillars, one to the right and one to the left of the midrib, feeding inside the leaf and greatly delaying its senescence (see also sketch, where only one caterpillar is inside