Numbers
13 species in 3 genera in North America; 28 species in the world, with only members of one genus,
Boreus, occuring anywhere outside of the Pacific US states. (
World Checklist)
Identification
Adult: dark-colored with an elongated rostrum ("beak"), long antennae, vestigial wings, and long hind legs adapted to jumping; female has a straight ovipositor about the same length as the rostrum, and tapering to a point; males have a blunt rounded abdominal tip
Larva: similar in appearance to caterpillars but have no abdominal prolegs or conspicuous dorsal setae
Range
Holarctic in overall distribution; in North America, Alaska to New Brunswick, south in the east to Virginia and Tennessee, south in the west to California and Arizona.
Boreus are widespread throughout the Holarctic Region, with 10 spp. in North America and only two in eastern part of the continent (B. brumalis and B. nivoriundus)
Hesperoboreus (2 species) are restricted to the US west coast from California to Washington
Caurinus is represented by a single species (C. dectes), found so far only in Oregon
Habitat
on surface of snow at high elevations in southern part of range; on snow in various habitats farther north
Season
adults active from November to March in southern part of range; spring and summer in the far north (e.g. Alaska)
Food
larvae and adults feed on leafy parts of mosses and liverworts
Remarks
The mating behavior of Boreus, the most common and widespread genus, differs from other Mecoptera. The male grasps the female with his slender, hardened wings and moves her to a position above his back, with the lower part of her elongate ovipositor inserted into his ninth (genital) segment. [George Byers, Emporia U., Kansas]
See
photo of mating couple. The female, at left, on the male's back, has the base of her ovipositor contacting the tip of the male's upturned abdomen. This female-on-top position is unusual in the insect world.
Internet References
description, habitat, mating behavior and live image of adults mating (George Byers, Emporia U., Kansas)
Winter Insects of Eastern New York; PDF doc - photocopy of the original detailed technical description of
Boreus nivoriundus and
B. brumalis by Asa Fitch in 1847 (Walter Reed Biosystematics Unit, Smithsonian Institution)
checklist and distribution of worldwide species, listing states, provinces, or countries of each species (California Academy of Sciences)
Insects of Quebec show pinned adult images labeled as male and female "probably
brumalis" but in fact both are
B. nivoriundus females
