Chaetorellia acrolophi
Encyclopedia
Chaetorellia acrolophi is a species of tephritid fruit fly
known as the knapweed peacock fly. It is used as an agent of biological pest control
against noxious knapweeds
, especially spotted knapweed
(Centaurea maculosa).
The adult fly is light greenish brown with brown-banded wings and iridescent green eyes. It is 3 to 5 millimeters long. The female lays about 70 eggs beneath the bracts on immature flower heads
. When the larva
emerges from the egg a few days later it burrows into the flower head and feeds on the developing florets. As the larva grows it begins to feed on the developing seeds, often consuming the entire contents of the flower head during its two-week larval stage. It pupa
tes inside the empty flower head.
This fly is native to Europe. It was first released as a knapweed biocontrol in the 1990s in Montana
, and it is currently established in much of the western United States. It is host-specific to invasive knapweeds, preferring spotted knapweed, and has not been known to attack any native plants. The fly is often outcompeted by other species that attack knapweed flower heads, such as certain weevils, so it does best where there are no competitors.
Tephritidae
Tephritidae is one of two fly families referred to as "fruit flies", the other family being Drosophilidae. Tephritidae does not include the biological model organisms of the genus Drosophila , which is often called the "common fruit fly". There are nearly 5,000 described species of tephritid...
known as the knapweed peacock fly. It is used as an agent of biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
against noxious knapweeds
Centaurea
Centaurea is a genus of between 350 and 600 species of herbaceous thistle-like flowering plants in the family Asteraceae. Members of the genus are found only north of the equator, mostly in the Eastern Hemisphere; the Middle East and surrounding regions are particularly species-rich...
, especially spotted knapweed
Centaurea maculosa
Centaurea maculosa, the spotted knapweed, is a species of Centaurea native to eastern Europe.It has been introduced to North America, where it is considered an invasive plant species in much of the western United States and Canada. In 2000, C. maculosa occupied more than in the US.Knapweed is a...
(Centaurea maculosa).
The adult fly is light greenish brown with brown-banded wings and iridescent green eyes. It is 3 to 5 millimeters long. The female lays about 70 eggs beneath the bracts on immature flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
. When the larva
Larva
A larva 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...
emerges from the egg a few days later it burrows into the flower head and feeds on the developing florets. As the larva grows it begins to feed on the developing seeds, often consuming the entire contents of the flower head during its two-week larval stage. It pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
tes inside the empty flower head.
This fly is native to Europe. It was first released as a knapweed biocontrol in the 1990s in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
, and it is currently established in much of the western United States. It is host-specific to invasive knapweeds, preferring spotted knapweed, and has not been known to attack any native plants. The fly is often outcompeted by other species that attack knapweed flower heads, such as certain weevils, so it does best where there are no competitors.