Ormia ochracea
Encyclopedia
Ormia ochracea is a small yellow nocturnal fly
, a parasitoid
of cricket
s. It is notable because of its exceptionally acute directional hearing. The female is attracted by the song of the male cricket and deposits larvae on or around him, as was discovered in 1975 by the zoologist William H. Cade
. The fly is found throughout the southern the US and into Mexico, though its exact range is not known.
The mating call of the male field cricket is used by Ormia ochracea in locating the cricket. Once a female fly finds a host (male cricket) she deposits a larva which then quickly burrows into the host, emerging about 7 - 10 days later, killing the host. Flies have been observed responding to a variety of cricket songs, but seem to be limited to the family Gryllidae.
Ormia ochracea has become a model organism
in sound localization
experiments because of its unique "ear
s", which are complex structures inside the fly's prothorax
near the bases of their front legs. The animal is too small for the time difference of sound arriving at the two ears to be calculated in the usual way, yet it can determine the direction of sound sources with exquisite precision. The tympanic membranes of opposite ears are directly connected mechanically, allowing resolution of nanosecond time differences and requiring a new neural coding strategy. Efforts to build directional microphones based on the structure of the fly's ear are underway.
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
, a parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
of cricket
Cricket (insect)
Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...
s. It is notable because of its exceptionally acute directional hearing. The female is attracted by the song of the male cricket and deposits larvae on or around him, as was discovered in 1975 by the zoologist William H. Cade
William H. Cade
Dr. William H. "Bill" Cade is a biologist and a former president of the University of Lethbridge. He researches the role of acoustic signals in field cricket mating behaviour.-Education:...
. The fly is found throughout the southern the US and into Mexico, though its exact range is not known.
The mating call of the male field cricket is used by Ormia ochracea in locating the cricket. Once a female fly finds a host (male cricket) she deposits a larva which then quickly burrows into the host, emerging about 7 - 10 days later, killing the host. Flies have been observed responding to a variety of cricket songs, but seem to be limited to the family Gryllidae.
Ormia ochracea has become a model organism
Model organism
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...
in sound localization
Sound localization
Sound localization refers to a listener's ability to identify the location or origin of a detected sound in direction and distance. It may also refer to the methods in acoustical engineering to simulate the placement of an auditory cue in a virtual 3D space .The sound localization mechanisms of the...
experiments because of its unique "ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
s", which are complex structures inside the fly's prothorax
Prothorax
The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
near the bases of their front legs. The animal is too small for the time difference of sound arriving at the two ears to be calculated in the usual way, yet it can determine the direction of sound sources with exquisite precision. The tympanic membranes of opposite ears are directly connected mechanically, allowing resolution of nanosecond time differences and requiring a new neural coding strategy. Efforts to build directional microphones based on the structure of the fly's ear are underway.