Coelopa frigida
| Coelopa frigida | |
|---|---|
.jpg)
| |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Order: | |
| Family: | |
| Genus: | |
| Species: | C. frigida
|
| Binomial name | |
| Coelopa frigida (Fabricius, 1805)
| |
Coelopa frigida is a species of seaweed fly or kelp fly. It is the most widely distributed species of seaweed fly.[1] It can be found on most shorelines in the temperate Northern Hemisphere.[1] Other species of seaweed flies include Coelopa nebularum and Coelopa pilipes.[2] C. frigida feeds primarily on seaweed, and groups of C. frigida flies tend to populate near bodies of water. Climate change leads to an increase in C. frigida blooms along shores, which creates a pest problem for human beach-goers. C. frigida is also an important organism for the study of sexual selection, particularly female choice, which is influenced by genetics.
Description
.jpg)
C. frigida are the most common seaweed fly.[3] They tend to aggregate on beaches with an abundance of stranded algae, but occasionally swarm inland.[4] Their physical features include a dark brown to black body, a set of lighter colored legs, and large, translucent wings. Males are typically larger than females, though there is a wide range of adult sizes within the species.[3] C. nebularum is currently suggested as a close cousin or even possible subspecies of C. frigida. This article therefore includes specifics regarding C. nebularum.[4]
Distribution
C. frigida are commonly found on beaches with a relatively steady supply of stranded kelp, as the fly species is dependent on the decaying green and brown algae for both feeding and breeding. The geographic range, which is well documented, extends up the North Atlantic Coast into Iceland and encompasses the coasts of Russia, the North Sea, and Faroe Islands. Other regions reported to contain C. nebularum are found on the Pacific Coast of North America, the coast of Japan's Kuril Islands, and the eastern coasts of Russia.[3]
Habitat
C. frigida need a constant supply of algae to feed and lay their eggs. Thus, coastal beaches with stranded seaweed are their preferred environment. The significant factors that determine the population density and spread are the age of algae, the presence or absence of high winds or storms, the rate of decay of algae, and temperature.[5]
Influence of weather
Research shows that storms and their accompanying harsh weather conditions cause an overall decrease in the life expectancy of C. frigida.[6]
Lower temperatures allow for beached seaweed to remain fresh for a longer period of time. Lower temperatures also force C. frigida to incubate in the egg stage to a greater extent before hatching. Meanwhile, higher temperatures cause an acceleration in the decomposition of algae and also increases the rate of egg development. There has been no significant research done on differentiating the average lifetimes of C. frigida exposed to different temperatures.[6]
Taxonomy
The first documented discovery of C. frigida was in 1805 by Fabricius. He later named the fly after the word frigidaire, which means frigid air. This label was most likely derived from the chilly sea breeze that is always present near the beached-algae habitats the flies live in.
Throughout history, there have been many additions and changes suggested. Haliday discovered different size of C. frigida on the coast of Ireland and gave them the names: C. gravis, C. simplex, and C parvula. Stenhammer, similarly found the species on the coast of Scandinavia, and dubbed them: C. nitidula and C. eximia. It was only after Aldrich and Hennig's revision of the entire Palearctic fauna of Coelopa did the current standing of nomenclature come to light.
Currently, C. frigida is the official name for this species of fly. There is an ongoing dispute to whether C. nebularum is considered a subspecies of C. frigida or recently speciate species of Coelopa.[4]
Life history
Egg
.jpg)
C. frigida's egg phase is on average 18 days, but changes depending on the presence of alcohol dehydrogenase or higher temperatures. The eggs are laid en masse in the leaves of stranded algae.[5]
Adult
The adults emerge from their pupal shells ready to fly in search of mates. Their wings are typically 6 mm and once dry carry them around their current seaweed plot or to other stranded algae. Their bodies are colored a light brown to black, with a few yellow specks. Lastly, their legs are much longer than before eclosion and have hooked attachments at the end to better grip onto seaweed.[3][4]
The fly oviposits in dead kelp that washes up on beaches.[7] This is the only place it lays eggs, and it can do so on many species of kelp and seaweed,[8] including species of Laminaria and Fucus.[9] A female fly lays up to five clutches of 80 eggs each.[10] The larvae feed upon the bacteria coating the dead kelp.[8] The life cycle is about 11[1] or 12[10] days long.
Food resources
The main food source for C. frigida is seaweed that has washed up onto the beaches. The brown and green algae are usually of the genus Lamniaria or Fucus. The algae also provides a safe habitat to live in and a perfect moist environment to lay eggs. Most adults stay in their birthplace or seaweed patch until it returns to the ocean, at which point the adults fly in search of alternative algae bunches to feed, live, and mate on.[4]
Morphology
There are 4 defining characteristics of C. frigida. The first is the size of the body, which ranges from 5 mm to 6 mm. The size of the body depends on the specific alpha or beta alleles associated with chromosomal inversion. The alpha genes causes individuals to grow to a larger size with a "peacock's tail". However, these larger individual typically spend 2-4 more days throughout he development process before becoming adults. The bodies range from a dark brown to black. The second is color of the legs. The legs of C. frigida are mostly all the same size, with the only difference being in color. The hue of the legs range from a light brown, to yellow, to black. The third and fourth features are their tergite and accompanying bristles. Most individuals of C. frigida have 6 tergites. Their size may differ according to how far along each individual is in their adult life. The color of their tergites maintains a dark palette of brown. Lastly, the accompanying bristles on the tergites vary in different lengths. Most are proportional to the overall body or tergite size. The color of such setae are either black or the color of the attached tergite.[4]
Mating
Mating behavior in C. frigida is dictated by larger males attempting to copulate with smaller females. Larger males have an increased mating success rate than their smaller counterparts. Thus, sexual selection tends to favor males that are larger or can latch on to females more tightly. This sexual selection for larger males is countered by natural selection for smaller males. Smaller males have a lower incubation time, and thus are more likely to survive past their developmental age to adulthood. C. frigida are polygynous, with females devoting the majority of resources to laying eggs to increase their reproductive success. Meanwhile, the males choose to mate with as many receptive females as possible to increase their reproductive success.[3]
Laboratory studies
This fly is sometimes cultured in the laboratory.[10] Its behavior is studied in an effort to understand sexual selection, especially female choice.[11] Studies suggest that female flies of this species prefer larger males to smaller.[12][13] The species engages in lekking and sexual conflict.[14] Females perform rejection behaviors when mounted by males, and may mate with larger males because larger males are more able to force the mating.[14] As females are more likely to successfully reject smaller males, sexual selection favors larger ones.[14] Mating behaviors are genetically influenced, as evidenced by a preference for smaller males among females of a certain genotype.[15]
Genetic research
There are two main focuses of genetic research on C. frigida. The first aspect is the differentiation of C. frigida from similar looking flies and C. nebularum. The second focus is on the chromosomal inversion of certain alleles to produce flies of differing sizes, and natural selection on certain sizes.
The initial discovery of C. frigida was confused due to their variance in size. This dispute was mostly cleared by delving past their physical characteristics into their genetics, in which most of the seaweed flies were found to belong to C. frigida. The only majorly differing genetic line was associated with C. nebularum. C. Nebularum had only recently speciated from C. frigida due to geographic differences, thus it is still widely debated if they belong in the same species or if they're close cousins.[4]
The chromosomal inversion of the alpha or beta allele in C. frigida produces a distinct difference in adult size. Individuals homozygous for the alpha allele are physically larger and more developed. They benefit from the physicality with increased longevity and increased fecundity. However, these individuals have 2–4 days more in their developmental phases to grow to such an extent. These may be precious days that the seaweed bed is washed back into the ocean, killing the C. frigida. On the other hand, individuals homozygous for the beta allele are physically smaller. They benefit by growing into their adult phase faster, but have more trouble finding receptive mates.[3][5]
Enemies
C. frigida competes with another seaweed fly, C. pilipes, for resources.[9]
Mutualism
This fly is host to the mite Thinoseius fucicola.[2] It provides food for seabirds, including the purple sandpiper (Calidris maritima).[16]
Human interaction
Typically, the leks that C. frigida form stay within their optimal environment of seaweed batches. However, due to increasing changes in climate more algae is washed ashore and accompanying it is an increase in the population density of C. frigida. "Blooms" of the flies occur at times, possibly when temperatures and amounts of kelp increase.[7] These aggregations are known to pester and annoy beachgoers, but may also be blown inland to city dwellers.[4]
References
- ^ a b c "Kelp Fly". Marine Wildlife Encyclopedia. Oceana.
- ^ a b Gilburn, AS; Stewart, KM; Edward, DA (2009). "Sex-biased phoretic mite load on two seaweed flies: Coelopa frigida and Coelopa pilipes" (PDF). Environmental Entomology. 38 (6): 1608–12. doi:10.1603/022.038.0612. PMID 20021755.
- ^ a b c d e f A. S. GILBURN, S. P. FOSTER, & T. H. DAY (2 October 1991). "Female mating preference for large size in Coelopa frigida (seaweed fly)" (PDF). Nature, Heriditary.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b c d e f g h Laamanen, T. R.; Petersen, F. T.; Meier, R. (April 2003). "Kelp flies and species concepts - the case of Coelopa frigida (Fabricius, 1805) and C. nebularum Aldrich, 1929 (Diptera: Coelopidae)". Journal of Zoological Systematics and Evolutionary Research. 41 (2): 127–136. doi:10.1046/j.1439-0469.2003.00209.x. ISSN 0947-5745.
- ^ a b c T. H. DAY, T. DOBSON, P. C. HILLIER, D. T. PARKIN and BRYAN CLARKE (1980). "DIFFERENT RATES OF DEVELOPMENT ASSOCIATED WITH THE ALCOHOL DEHYDROGENASE LOCUS IN THE SEAWEED FLY, COELOPA FRIGIDA" (PDF). Nature, Hereditary.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b Butlin, R.K.; Day, T.H. (April 1989). "Environmental correlates of inversion frequencies in natural populations of seaweed flies (Coelopa frigida)". Heredity. 62: 223–232.
- ^ a b Mather, Kate (June 18, 2011). "South Bay beaches hit by swarms of kelp flies". Los Angeles Times. Retrieved June 18, 2011.
- ^ a b Cullen, Sally J.; Young, Alison M.; Day, Thomas H. (1987). "Dietary requirements of seaweed flies (Coelopa frigida)". Estuarine, Coastal and Shelf Science. 24 (5): 701. doi:10.1016/0272-7714(87)90108-9.
- ^ a b Edward, Dominic A.; Newton, Jason; Gilburn, André S. (2008). "Investigating dietary preferences in two competing dipterans, Coelopa frigida and Coelopa pilipes, using stable isotope ratios of carbon and nitrogen". Entomologia Experimentalis et Applicata. 127 (3): 169. doi:10.1111/j.1570-7458.2008.00692.x.
- ^ a b c Burnet, B.; Thompson, U. (2009). "Laboratory Culture of Coelopa Frigida (Fabricius) (Diptera: Coelopldae)". Proceedings of the Royal Entomological Society of London A. 35 (4–6): 85. doi:10.1111/j.1365-3032.1960.tb00672.x.
- ^ MacDonald, C.; Brookfield, J. F. Y. (2002). "Intraspecific molecular variation in the seaweed fly Coelopa frigida consistent with behavioural distinctness of British and Swedish populations". Molecular Ecology. 11 (9): 1637–46. doi:10.1046/j.1365-294X.2002.01559.x. PMID 12207715.
- ^ Gilburn, A S; Foster, S P; Day, T H (1992). "Female mating preference for large size in Coelopa frigida (seaweed fly)". Heredity. 69 (3): 209. doi:10.1038/hdy.1992.118.
- ^ Gilburn, A. S.; Day, T. H. (1994). "Sexual Dimorphism, Sexual Selection and the Formula Chromosomal Inversion Polymorphism in the Seaweed Fly, Coelopa frigida". Proceedings of the Royal Society B: Biological Sciences. 257 (1350): 303. doi:10.1098/rspb.1994.0130.
- ^ a b c Shuker, D. M. (2002). "Mate sampling and the sexual conflict over mating in seaweed flies". Behavioral Ecology. 13: 83–86. doi:10.1093/beheco/13.1.83.
- ^ Blyth, Jennifer E.; Gilburn, Andre S. (2011). "The function of female behaviours adopted during premating struggles in the seaweed fly, Coelopa frigida". Animal Behaviour. 81: 77–82. doi:10.1016/j.anbehav.2010.09.013.
- ^ Summers, R. W.; Smith, S.; Nicoll, M.; Atkinson, N. K. (1990). "Tidal and sexual differences in the diet of Purple Sandpipers Calidris maritima in Scotland". Bird Study. 37 (3): 187–94. doi:10.1080/00063659009477056.