Sphinx Moths

Photographed after disturbance [4]

A banded sphinx moth (Sphingidae: Eumorpha fasciatus) flutters its wings furiously in preparation for flight, after I knocked it down from its resting position about 3 meters high on a leaf. Because sphinx moths require such a high rate of wingbeats to fly in hummingbird fashion, they require a period to warm up the wing muscles prior to take off. This is consistent with their behavior of vibrating the wings for up to a couple of minutes while sometimes climbing around with the legs before zipping away. In my experience the duration of wing vibration is greater in larger-bodied hawkmoths, probably owing to the greater energy requirement to power larger flight muscles.

The genus Eumorpha contains about a dozen or so species, each moth exhibiting intricate bands and contours on the dorsal surface of the forewings and usually pinkish highlights on the small hindwings. Their caterpillars are equally appealing morphologically, ranging from green to red to yellow with lateral abdominal spots and a posterior horn that becomes more reduced every successive molt. Most late instar Eumorpha larvae have a single dorsal posterior eyespot, showcasing high variation in the shape and size of that structure. Two species are known to even mimic blinking through palpitating the eyespot, while others are thought to mimic snakes via flattened heads with twin eyespots (e.g. Eumorpha labruscae). No geographical or ecological correlates have been found to be associated with eyespot morphology so far, but nevertheless, Eumorpha remains a fruitful clade to test hypotheses regarding the evolution and function of eyespots.

Photographed after capture [5] at a light the previous night

A virginia creeper sphinx moth (Darapsa myron)— one of the numerous insects veering towards street lamps this summer. Although not the most colorful or large sphingid, it belongs to the unambiguous best family of moths 😉 which have been my favorite ever since I first held a white-lined sphinx (Hyles lineata) when I was very young. As caterpillars, Darapsa myron feed on grapevine (Vitis spp.), virginia creeper (Parthenocissus quiquefolia), and peppervine (Ampelopsis spp.).

Hawkmoth flights in slow motion, Tarapoto, Peru, 2015; filmed under controlled conditions [6]
Defensive displays in Sphingidae, Costa Rica, 2017; filmed after disturbance [4]

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