Manduca quinquemaculata

Species of moth

Manduca quinquemaculata, the five spotted hawkmoth, is a brown and gray hawk moth of the family Sphingidae. The caterpillar, often referred to as the tomato hornworm, can be a major pest in gardens; they get their name from a dark projection on their posterior end and their use of tomatoes as host plants. Tomato hornworms are closely related to (and sometimes confused with) the tobacco hornworm Manduca sexta. This confusion arises because caterpillars of both species have similar morphologies and feed on the foliage of various plants from the family Solanaceae, so either species can be found on tobacco or tomato leaves. Because of this, the plant on which the caterpillar is found does not indicate its species.

M. quinquemaculata is found across North America and Australia. The tobacco hornworm, a close relative of the tomato hornworm, tends to dominate the south while tomato hornworms are more prevalent in the northern United States.

Tomato hornworms are known to eat various plants from the family Solanaceae, commonly feeding on tomato, eggplant, pepper, tobacco, moonflowers and potato. Females prefer to oviposit on young leaves near the stem of host plants, and early instar caterpillars can often be found here during the day. Oenothera caespitosa, and Mirabilis multiflora. Most of the food plants they target have large, fragrant white flowers.

Hawkmoths, including M. quinquemaculata, are the primary pollinators of D. meteloides. The length of the moth’s proboscis (around 10 cm), which is an elongated, tubular mouthpart used for sucking and feeding, is well suited for retrieving nectar from the flowers. Aside from being a host plant for M. quinquemaculata, D. meteloides has also been used by humans for its psychoactive effects. D. meteloides contains tropane alkaloids, which are present throughout the plant including in the flowers. The female decides where to lay eggs based on an assessment of the risk of predation her offspring will face. On the tobacco plant Nicotiana attenuata, young leaves close to a plant's stem are more protected from predators and larvae that grow there gain more mass than larvae grown elsewhere on the plant; females prefer to oviposit, or lay their eggs, on these leaves. Eggs are large and range in color from pale green to off white.

M. quinquemaculata larvae are large green caterpillars reaching a length of up to 10 cm (3.9 inches) when fully grown. Caterpillars hatch in late spring to early summer. They develop through five instars to reach maturity. Past research, observing that the two species are similar, referred to the two as sister species. However, a recent phylogenetic analysis from Kawahara et al. (2013) found that the two species, though closely related, are not sister species. The authors tracked the ancestral origin of both species to Central America, where the two species diverged from one another.

Because the larvae are pests of crop plants such as tomatoes and tobacco, biological control agents and traps have been used to control their populations. Gardeners whose tomato plants are predated by the tomato hornworm pick the caterpillars off of their plants. A second parasitoid wasp, Cotesia congregata of the family Braconidae, also kills M. quinquemaculata. Adult females lay their eggs inside the skin of the hornworm caterpillar. After hatching, the wasp larvae use the organs and tissues of the caterpillar as food sources before burrowing out of the skin and pupating on the back and sides of the caterpillar. Once the wasps have emerged from their cocoons, the weakened caterpillar dies. Like the parasitoid wasp mentioned above, these wasps have also been suggested as a means of biological control of the tomato hornworm.

Adult M. quinquemaculata are most active in flight after dark.