Geographic Range
The goldenrod gall fly is found in eastern and midwestern North America.
Habitat
The entire life cycle of
Eurosta solidaginis
is closely connected to the goldenrod plant. Goldenrod gall flies can be found where
there is goldenrod in the northeastern and midwestern portions of North America.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- savanna or grassland
- forest
- Other Habitat Features
- suburban
- agricultural
Physical Description
The adult goldenrod gall fly is tawny in color with speckled wings and is about five
mm long. Females are slightly larger than males.
Eurosta solidaginis
shares many characteristics with its close relatives, the fruit flies (
Melanogaster
), such as a wide head and large, compound iridescent eyes.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
The eggs hatch between seven and ten days after being oviposited in the terminal bud
of a goldenrod plant. The larva then chews through the bud and down into the stem.
There the saliva of the larva stimulates the plant to form a gall. The inside of
the gall is rich in protein and starch, and the larva feeds off this as it matures.
As the larva grazes on this inner layer, the plant compensates for the nuitrient loss
by sending more nutrients to the inner wall lining of the stem, maintaining the larval
food source. In the fall, the outside of the gall becomes dry and corky, forming a
protective layer. The maggot will chew an a hole to the outside, although it wont
actually emerge untill the following spring. After overwintering inside of the gall,
the maggot pupates in spring, emerging from the gall as an adult.
- Development - Life Cycle
- metamorphosis
Reproduction
Males sit waiting for females on the tip of goldenrod plants. When a female is attracted
to a particular male, she will fly over to him, they will copulate, and then she flies
away again to lay her eggs. He attracts the female by dancing, or making a special
display that consists of flicking his wings.
After mating, the female inserts her fertilized eggs using a tube-like structure called
the ovipositor into the terminal bud of a goldenrod plant. A female goldenrod gall
fly can lay up to one hundred eggs.
- Key Reproductive Features
- semelparous
- fertilization
- oviparous
After eggs are layed in suitable locations for larval success, there is no further parental investment.
- Parental Investment
-
pre-fertilization
- provisioning
-
protecting
- female
Lifespan/Longevity
The life of a Goldenrod Gall Fly consists of fifty weeks as a larva living inside
of the gall, and two weeks as an adult.
Behavior
The female gall fly will fly from plant to plant searching for the perfect host for
her offspring. When she lands, she inserts her ovipositor into the plant and "tastes"
the host with her reproductive organs and her feet. If the host plant is not suitable,
she flies on and tries another plant.
Communication and Perception
The main communication between gall flies occurs while the female is searching for
a mate. The male sits on the tip of a goldenrod plant and flicks his wings in a way
that attracts the female and entices her to fly over and mate with him.
- Communication Channels
- visual
Food Habits
Larvae feed off of the protein-and-starch rich inner layer of the gall. The gall
provides all of the food necessary for the growth and development of the maggot.
Adults do not eat at all.
- Primary Diet
-
herbivore
- lignivore
- Plant Foods
- wood, bark, or stems
Predation
While the adult gall fly has few predators, the maggot is consumed by a great variety
of animals. Some birds, such as the downy woodpecker (
Picoides pubescens
), and carolina chickadee (
Parus carolinensis
) will break open galls to eat the larva during winter months when food is more difficult
to find. Other insects will also attack the larvae. The larvae of
Mordellistena unicolor
, a type of beetle, also prey upon gall fly larvae.
Eurytoma gigantea
and
Eurystoma obtusiventris
are two wasp species who lay their eggs inside goldenrod galls. When the eggs hatch,
the wasp larvae feed upon the developing
Eurosta solidaginis
.
Ecosystem Roles
The goldenrod gall fly reduces seed yield in affected plants. The larvae of the insect
provide food for birds and squirrels during the winter months. Galls formed by
Eurosta solidaginis
provide a home for certain species of parasitic wasps and beetles.
- Ecosystem Impact
- creates habitat
Economic Importance for Humans: Positive
Scientists are currently studying the goldenrod gall fly to see if it will provide
ways to preserve organs used for transplants. The gall fly larva survives long periods
of time in extremely cold climates. The larva produces the cryoprotective compounds
glycerol and sorbitol, which prevents the larvae from freezing to death during the
winter months by preventing ice formation within cells. Scientists have been able
to use these compounds to freeze collections of like cells and preserve cells in sperm
and blood banks, sometimes for several years.
- Positive Impacts
- source of medicine or drug
- research and education
Economic Importance for Humans: Negative
There is no known negative economic impact caused by the goldenrod gall fly.
Conservation Status
This particular species is in no real danger of becoming endangered or extinct.
Additional Links
Contributors
Sara Diamond (author, editor), Animal Diversity Web.
Elisabeth Reyna (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- tropical savanna and grassland
-
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
- savanna
-
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
-
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- metamorphosis
-
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
- semelparous
-
offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- visual
-
uses sight to communicate
- visual
-
uses sight to communicate
- chemical
-
uses smells or other chemicals to communicate
- drug
-
a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease
- herbivore
-
An animal that eats mainly plants or parts of plants.
References
Barnes-Svarney, P. 1992. Insects in Deep Freeze. Technology Review , v. 95 no 3: 20.
Cappuccino, N. 1992. The Nature of Population Stability in Eurosta solidaginis, a Nonoutbreaking Herbivore of Goldenrod. Ecology , v. 73 no. 5: 1792-1801.
Moran, M. 2005. "Goldenrod Gall Fly" (On-line). Study of Northen Virginia Ecology. Accessed October 07, 2008 at http://www.fcps.edu/islandcreekes/ecology/goldenrod_gall_fly.htm .
Shealer, D., J. Snyder, V. Dreisbach. 1999. Foraging Patterns of Eastern Grey Squirrels (Sciurus carolinenis) on Goldenrod Gall Insects, a Potentially Important Winter Food Source.. The American Midland Naturalist , v.142 no 1: 102-109.
Weis, A., W. Abrahamson. 1998. Just Lookin' for a Home. Natural History , v. 107 no7: 60-63.
Williams, T. 2001. Earth Almanac: The Gall of Goldenrod. Audubon , January-February. Accessed October 07, 2008 at http://www.audubonmagazine.org/earthalmanac/almanac0101.html .
1993. Fruit Fly. Columbia Encyclopedia , 5th Edition.