''Zelia vertebrata'' is a species of bristle fly in the family

Tachinidae The Tachinidae are a large and variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. Over 1,300 species have been described in North America alone. Insects in this family ...

. It is a long-bodied fly with strong abdominal bristles and a distinctive abdominal pattern that resembles

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

. It has a widespread North American range, with records stretching from east to west from Washington to Maine, north to south from Québec to Florida. Its larval stage parasitizes

beetles 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 ...

. It is most active during the day.

Biology

''Zelia vertebrata'' is a generalist

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

, targeting beetle larvae in the families

Passalidae Passalidae is a family of beetles known variously as "bessbugs", "bess beetles", "betsy beetles" or "horned passalus beetles". Nearly all of the 500-odd species are tropical; species found in North America are notable for their size, ranging from ...

Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...

Tenebrionidae Darkling beetle is the common name for members of the beetle family Tenebrionidae. The number of species in the Tenebrionidae is estimated at more than 20,000 and the family is cosmopolitan in distribution. Taxonomy ''Tenebrio'' is the Latin gen ...

, and

Cerambycidae The longhorn beetles (Cerambycidae), also known as long-horned or longicorns, are a large family of beetles, with over 35,000 species described. Most species are characterized by extremely long antennae, which are often as long as or longer than ...

. In 1948, Mangrum conducted the most thorough examination of host-parasite interaction of this species, finding that gravid female ''Zelia vertebrata'' give birth to live larvae instead of eggs near the entrances of host larval tunnels. These worm-like parasitic larvae crawl through these host tunnels until they encounter a host that they can burrow into. The parasitic larvae possess a modified respiratory system to better take advantage of their hosts. They breathe using spiracles located on their terminal abdominal segments, allowing them to breathe while almost entirely immersed in host tissue. The host's

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

responds to this breach by surrounding the protruding larva, enclosing almost the entire length of the parasitoid in cuticle. As the larva grows within its host, it must disengage from this outgrowth of the host's cuticle in order to better access untapped tissues. ''Zelia vertebrata'' is known as saproxylic, depending on moist rotting wood to serve as a habitat for its larval hosts.

Distribution

''Zelia vertebrata'' can be found across North America, ranging from northern regions of Canada to Northwest Mexico. While more records exist in the eastern portion of the United States, the species has been recorded in Utah.,

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Taxonomy

The genus ''Zelia'' was erected in 1830 by André Jean Baptiste Robineau-Desvoidy. The synonymous genera ''Leptoda, Metadexia, Euzelia,'' and ''Minthozelia'' were described after the founding of the genus ''Zelia'' by van der Wulp, Coquillett, Townsend, and Townsend respectively. The species epithet for ''vertebrata'' was coined by Say in 1829, describing synonym ''Dexia vertebrata.'' Other synonyms include ''Zelia rostrata'' and ''Dexia gracilis''. James E. O'Hara and John O. Stireman collected a morphologically similar fly in the

Red River Gorge The Red River Gorge is a canyon system on the Red River in east-central Kentucky. Geologically it is part of the Pottsville Escarpment. The gorge lies within the Daniel Boone National Forest and was subsequently designated the Red River Gorge G ...

in eastern Kentucky. Mitochondrial molecular COI and morphological data supported that this was a distinct species to ''Zelia vertebrata''.

References

{{Taxonbar, from=Q14399884 Dexiinae Diptera of North America Taxa named by Thomas Say Insects described in 1829