Manduca sexta Eggs Hatch

Our tobacco hornworn (Manduca sexta) eggs have started to hatch.

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Even in our cool climate, Manduca sexta eggs must hatch incredibly fast. Today, several dozen of them hatched by the end of the day and the rest of the eggs look pale and clear -- just about ready to pop. 

When the larvae first hatch they are completely white, down to the head capsule, legs, and horn. They tan quite quickly, probably in only about 10 minutes, and the horns become black. They measure a tiny 3.5 mm in length. 

After they started hatching, we put them in an airtight container with a sprig of tomato (Solanum). Unlike most Saturniids, these things start feeding immediately after putting them on the host. As specialists on herbaceous plants, many of which are cultivated as in the one we used, it is no wonder they are so good at this. It is hard to find a better combination than this for host plant suitability. In fact, they started eating from the center of the leaves; it is much more typical for larvae, especially newborns, to bite from the edges to bypass the leaves' structural defenses such as trichomes. Clearly, they must have very well adapted mandibles for this specific host plant group, which can also explain their small size (larger newborns are usually an adaptation for battling tough host leaves). By the time we put in the newborns that hatched in the evening in, the ones from the morning were already green and noticeably larger. They also should be extremely efficient at converting plant matter to biomass. We expect that they'll be out of here in a few weeks. 

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Authors
Brian Liang

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