A railroad worm is a
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
or
larviform female adult of a
beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
of the genus ''Phrixothrix'' in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Phengodidae, characterized by the possession of two different colors of
bioluminescence
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some b ...
.
It has the appearance of a
caterpillar
Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths).
As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sy ...
. The eleven pairs of luminescent organs on their second thoracic segment through their ninth abdominal segment can glow yellowish-green, while the pair on their head can glow red;
this is due to different
luciferase
Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words '' luciferin'' and ''luciferase'' ...
s in their bodies, as the reaction substrate, called luciferin, is the same.
The "railroad worm" name arises because these glowing spots along the body resemble the windows of train cars internally illuminated in the night.
The light emissions are believed to be a warning signal to nocturnal predators of their unpalatability.
The term "railroad worm" is also sometimes applied to the
apple maggot.
References
External links
*
Phengodidae
Bioluminescent insects
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