The five-spotted hawkmoth is a brown and gray hawk moth of the Sphingidae family. The caterpillar,
often referred to as the tomato hornworm, can be a major pest in gardens. Tomato hornworms
are closely related to the tobacco hornworm. This confusion arises because caterpillars
of both species feed on the foliage of various plants from the family Solanaceae, so either
species can be found on tobacco or tomato leaves, and the plant on which the caterpillar
is found does not indicate its species. The larvae of these species can be distinguished
by their lateral markings: tomato hornworms have seven V-shaped markings while tobacco
hornworms have seven diagonal lines. Furthermore, the caterpillars can be distinguished from
the larval stage onwards by the color of the horns on their back ends: M. quinquemaculata
caterpillars have black horns, while M. sexta caterpillars have red horns. The moths can
be distinguished by the number of spots on their abdomens, with M. quinquemaculata having,
as its name suggests, five.
Range M. quinquemaculata is found throughout the
United States, northwestern Mexico, and even southern Canada, but is less frequently found
throughout the Great Plains and the southeast. Food plants
Tomato hornworms are known to eat various plants from the family Solanaceae, commonly
feeding on tomato, eggplant, pepper, tobacco, moonflowers and potato. Accordingly, they
are often found on defoliated tomato plants, the caterpillar clinging to the underside
of a branch near the trunk. They are difficult to spot due to their green coloration. Tomato
hornworms fluoresce differently from tomato leaves. Using an ultraviolet light source
of 375 nm and viewed behind a blue-blocking filter, a tomato hornworm fluoresces in bright
green while a tomato leaf appears deep red/amber. This sharp color contrast helps gardeners
locate tomato hornworms at night. They can be reduced by planting marigold flowers around
these plants. Life cycle
Egg Hornworm eggs are spherical to oval in shape,
measure about 1.5 mm in diameter, and vary in color from light green to white. Eggs are
deposited principally on the lower surface of foliage, but also on the upper surface.
Duration of the egg stage is two to eight days, but averages five days.
Larva The tomato hornworm is a green caterpillar,
with eight light-green v-shaped markings which extend from the dorsal line to its sides.
At the rear end, the caterpillar has a black, bumpy horn, from which the name for the "hornworm"
is derived. Nine spiracles appear on each side of the body and are used for respiration.
Caterpillars can be prey to parasitoid wasps of the family Braconidae.
Pupa During the summer months, moths will emerge
from pupae in about two weeks. Moths emerge from the soil, mate, and then begin to deposit
the eggs of the next generation on tomato plants. By early fall, the pupae will remain
in the soil all winter and emerge as a moth the following spring. They have been found
on other green leaf plants such as moon flowers. Images
References ^ "CATE Creating a Taxonomic eScience - Sphingidae".
Cate-sphingidae.org. Retrieved 2011-11-01. ^ a b c Villanueva, Raul. "Tobacco Hornworm".
Retrieved 2006-10-21. ^ "Marigolds". Davis Wiki. 1999-02-22. Retrieved
2011-11-01. External links
The Tomato Hornworms Colorado State University Cooperative Extension, Denver County
Manduca quinquemaculata, Butterflies and Moths of North America
tomato hornworm on the UF / IFAS Featured Creatures Web site