Biological Control
30 August
In the Garden at Fritz we practice biological control of pests - here, control of Tomato Hornworm larvae is inadvertent provided by Cotesia congregata - a parasitoid wasp. This is fascinating. Read on for an explanation of what this white protuberances, which are not insect eggs, actually are.
Quote:
Adult wasps lay their eggs in tomato hornworm (Manduca quinquemaculata) larvae in their 2nd or 3rd instar and at the same time injects symbiotic viruses into the hemocoel of the host along with some venom. The viruses knock down the internal defensive responses of the hornworm. The eggs hatch in the host hemocoel within two to three days and simultaneously release special cells from the egg's serosa. These special cells, called teratocytes, grow to become giant cells visible to the naked eye. The teratocytes secrete hormones which work in tandem with the virus and the wasp venom to arrest the development of the host. Following hatching in the caterpillar, the wasp larvae will undergo 2 molts inside the host caterpillar's hemocoel and, after 12 to 16 days post oviposition, the 3rd instar wasp larvae will emerge from the caterpillar and spin cocoons from which the adult wasps fly about 4 to 8 days later.
In case you were wondering …
Why do birds with no better night vision than we have, migrate at night
Greener Cities - it can be done
Since the park took shape, creatures great and small have been rushing in like Black Friday door-crashers. Swallows, terns and red-winged blackbirds fly above the sparkling river. Bass, pike and walleye swim up and down it. Butterflies come to feed on the flowers and dragonflies to snap up the bugs.
At the risk of anthropomorphizing, they all seem delighted to have discovered this oasis in the heart of the city. Even local naturalists are surprised how quickly the fauna have made themselves at home. After all, the new river channel runs through the Port Lands, an old industrial district whose soil was heavily contaminated. Traffic streams along the nearby Gardiner Expressway. The soaring towers of the city’s downtown are only a few minutes away.