Mayfly identification - Oregon

Found in a web by a very small, slow moving stream. Douglas-fir forest in Gales Creek area, April 28.

Order Ephemeroptera: The Mayflies

We have previously tackled all the things about terrestrial insects. How their eggs, nymphs and adult forms can thrive in narrow holes and even those insects that can live inside our very homes. However, like any other complex traits of each creature under Kingdom Animalia, not all of them solely live in dry lands throughout their whole life. Like for example, the insects under the order Ephemeroptera. They may have died on land, but they emerged from clean, flowing bodies of water.

Mayfly in the classroom

Mayfly in the Classroom is the Wild Trout Trust’s flagship education programme. It aims to connect school children to their local river habitats and uses the lifecycle of Mayflies to teach them about the broader themes of biodiversity, ecology and the links between aquatic and terrestrial biodiversity. For more information on mayflies and the Mayfly in the Classroom concept, see the following PDFs:

A prime example of MiC was piloted by the WTT & Eden Rivers Trust (ERT) in Cumbria and MiC is now taught in 11 primary schools in that county.

Click here for examples of successful MiC projects

An article on Mayfly in the Classroom was published in the National Association for Environmental Education’s 2013 newsletter which can be seen by clicking here .

A fantastic report from a new partnership — Wear Rivers Trust is available from projects run in 2014. Please see by clicking here . The report offers excellent information about how the project is run, how it fits the curriculum and how much the children enjoyed it!


Aquatic invertebrates lend themselves to education about aquatic conservation very readily. The lifecycle of Mayflies perfectly illustrates requirements for good aquatic habitat. They also play a pivotal role in linking aquatic and terrestrial biodiversity. A whole variety of other activities can be tailored to highlight local issues including:

  • How land-use affects stream ecology
  • Efficient use of domestic water supplies and the impacts of over-abstraction
  • The importance of ​ “ indicator species” like mayflies and trout
  • Diverse and healthy food-webs

These less well known aspects of their biology would (for most people) include the way in which mayflies are a crucial food sources for their many predators. All activities are linked (differentiated accordingly) to specific National Curriculum Key Stages.

Adámek, Z. 1972. The contribution to the distribution of Brachyptera braueri (Klapálek, 1900) in the ČSSR. (Plecoptera, Taeniopterygidae). Zprávy Čs. spol. entomol ČSAV, Praha. 8: 85–88. (in Czech).

Adámek, Z. 1974. The effect of heated discharges on biology of the lower stream of the Oslava river. Dissertation. Purkyně University Brno. 53 p. (in Czech).

Adámek, Z. in press. Mayflies (Ephemeroptera) of the lower catchment of the Svratka river. (in Czech).

Adámek, Z. & Obrdlík, P. 1977. Food of important cyprinid species in the warmed barb-zone of the Oslava river. Folia Zool. 26: 171–182.

Adámek, Z. & Zelinka, M. 1973. The effect of heated water on the biology of wivers. Vodní hospodářství 23 B: 97–98. (in Czech).

Durret, Ch. W. & Pearson, W. D. 1975. Drift of macroinvertebrates in a channel carrying heated water from a power plant. Hydrobiologia 46: 33–43.

Hamilton, L.A. 1969. On estimating annual production. Limnol. Oceanogr. 14: 771–782.

Hae, F. P. 1935. The effect of temperature on the distribution of the mayfly fauna of a stream. Pub. Ontario Fish. Res. Lab. 50: 3–76.

Illies, J. & Botosaneanu, L. 1963. Problèmes et methodes de la classification et de la zonation écologique des eaux courantes. considérés, surtout du point de vue faunistique. Mitt. Internat. Ver. Limnol. 12: 1–57.

Kamler, E. 1971. Reactions of two species of aquatic insects to the changes of temperature and oxygen concentration. Pol. Arch. Hydrobiol. 18: 303–323.

Kočková, E. 1975. The research of changes of physical-chemical water parameters below the energetical and industrial resources of thermal pollution. Závěrečná výzkumná zpráva, VÚV Brno. 117 p. (in Czech).

Kubíček, F. 1969. The use of dry cell centrifuge for the determination of biomass. Biologia. 24: 245–249. (in Czech).

Landa, V. 1969. Mayflies — Ephemeroptera. In Fauna ČSSR 18, Academia Praha. 352 p. (in Czech).

Langford, T. E. 1971. The distribution, abundance and life-histories of stoneflies (Plecoptera) and mayflies (Ephemeroptera) in a British river, warmed by cooling water from a power station. Hydrobiologia. 38: 339–377.

Langford, T. E. 1975. The emergence of insects from a British river warmed by power station cooling water. Part II. Hydrobiologia. 47: 91–133.

Nebeker, A. V. 1971. Effect of water temperature on nymphal feeding rate, emergence and adult longevity of the stonefly Pteronarcys dorsata. J. Kansas. Entomol. Soc. 44: 21–26.

Obrdlík, P. 1975. Field research of thermal pollution from stram power stations and industry on the biological regime of rivers. Závěr. výzkum. zpráva, VÚV Brno, 39 p. (in Czech).

Obrdlík, P. 1977. Zoobenthos in the thermal polluted streams. Vodní hospodářství. 27 B: 233–235. (in Czech).

Peňáz, M., Kubíček, F., Marvan, P. & Zelinka, M. 1968. Influence of the river valley reservoir on the hydrobiological and ichthyological conditions in the river Svratka. Acta Sci. Nat. Acad. Sci. Bohemoslov. Brno. 2 (1): 1–60.

Ruprecht, R. 1975. The dependence of emergence-period in insect larvae on water temperature. Verh. Internat. Ver. Limnol. 19: 4863–4871.

Whitney, R. J. 1939. The thermal resistance of mayfly nymphs from ponds and streams. J. Exp. Biol. 16: 375–385.

Wojtalik, T. A. & Waters, T. F. 1970. Some effects of heated water on the distribution of the mayfly fauna of a stream. Pub. Ontario Fish Res. Lab. 50: 3–76.

Zahrádka, J. 1978. The abundance, biomass and production mayflies larvae of species Potamanthus luteus (Linné, 1767) and Ephoron virgo (Olivier, 1791). Dissertation. Purkyně University Brno. 63 p. (in Czech).

Zelinka, M. 1973. Die Eintagsfliegen (Ephemeroptera) in Forellenbächen der Beskiden. II. Production. Hydrobiologia. 42: 13–19.

Zelinka, M. 1977. The production of Ephemeroptera in running waters. Hydrobiologia. 56: 121–125.

Zelinka, M. & Marvan, P. 1976. Notes to methods for estimating productivity of zoobenthos. Folia Fac. Sci. Nat. Univ. Purk. Brunensis. 17 (10): 1–54.

Žáková, Z. 1975. The research of effluent of thermal pollution on eutrophication of surface waters. Závěr. výzk. zpráva, VÚV Brno. 71 p. (in Czech).

The mating biology of a mass-swarming mayfly

The males of many species of mayflies form dense aggregations, or swarms, to which females come to mate, typically at specific landmarks. This mating system was investigated in Epeerus longimanus, a mayfly of the western United States that forms swarms that are quite large. Swarms were found to occur primarily in clearings along the study stream, and certain sections consistently supported large or small swarms. The number of males was correlated with clearing size in addition, the numbers of males attracted to artificil markers (sheets of plastic in a nearby meadow) increased with marker size. Thus, display habitats appeared to be patchily distributed and to limit swarm size at least locally. Collections of emerging nymphs demonstrated no association with swarm locations. Since adult mayfiles do not feed, it is evident that swarm locations are not explainable as feeding or emergence sites, but they do correlate with landscape features. The number of observed matings per swarm event was generally 5–20% of the estimated peak male density, despite a sex ratio at emergence of 1·2 males: 1 female. Survivorship of caged males and recaptures of marked males both indicate the likelihood that males are sufficiently long-lived to joins swarms on successive evenings, which may account for the low frequency of matings. The role of mate location in the evolution of swarming behaviour is discussed.

by Ian S. Embradura, OPI | Oct 19 2015

Contrary to expert opinion that there is a high diversity of the mayfly species (ephemeroptera) in the country, only 37 have been described in the Philippines, all of which were done by foreign researchers. This interested graduate student Leocris S. Batucan Jr. to pursue such endeavor for his master&rsquos thesis.

There is a lack of detailed description and identification of ephemeroptera in the Philippines, especially from local researchers. Mayflies do not even have a local name, revealing of how it is not widely known even for Filipinos.

Batucan, after two expeditions at the Layawan River in Mt. Malindang Natural Park, has added six novel species to the mayfly specie. Given such privilege of discovery, he named them accordingly: Afronurus ayayti sp. nov. (from IIT), Atopopus pisay sp. nov.(from Philippine Science High School or PiSci, Batucan&rsquos high school alma mater) , Afronurus albentis sp. no.v, sparsorythus buntawensis sp. nov., Dudgeodes subanen sp. nov. (from Subanen), and Chroterpes striatafemoris sp. nov. With Batucan&rsquos contribution, there are now 13 known mayfly species from Mindanao.

His paper, &ldquoDNA Barcode and Morphological Description of Ephemeroptera from Layawan River, Mt. Malindang&rdquo, was presented at the 13th MSU-IIT Bi-annual In-House Review of Research and Development Projects on October 9, 2015, where it also won Best Paper.

Batucan is an MS Biology student and he co-authored with his advisers Prof. Olga M. Nuñeza and Prof. Chung-Ping Lin of National Taiwan Normal University in the writing of the paper.

Slug Portal

Deroceras reticulatum Müller, the gray field slug (or sometimes called gray garden slug), has many different adult color morphs and damages multiple crops in the Pacific Northwest (PNW) and worldwide. In the Willamette Valley, D. reticulatum comprises more than 90% of the slugs found in grasses grown for seed. All but one of the slug species (Prophysaon andersoni) found in grasses grown for seed are invasive or exotic. This species is an important agricultural pest in the family Agriolimacidae. Note the position of the pneumostome, the short keel at the back of the body, the mucous which is typically colorless but turns white when the slug is disturbed. Deroceras reticulatum is the only Deroceras species in the US that can change its mucous from colorless to milkey. As far as habitat choice, the gray field slug chooses cultivated areas such as agricultural field crops, backyard gardens, roadside, parks, and meadows. This slug is much less common in natural habitats like forests. It is native to Europe, North Africa and the Atlantic Islands.

ADULTS: Slugs are hermaphrodites—every slug is born with both male and female reproductive parts and any slug is capable of laying eggs, though self-fertilization can occur. In the temperate climate of the PNW, mating typically is observed in the fall (Oct-Nov) and continues in the spring (Mar-Jun). When a slug matures, which can take approximately 5-6 months over the winter, it weighs more than 200 mg (up to 500mg) and now has the capacity to produce eggs. When in motion, it is about 35 to 50 mm (> 1.5 inches long). Adult slugs overwinter and can lay clutches of eggs when environmental conditions are right. A slug’s life expectancy is from 6 to 12 months, and some up to 18 months. Two generations of the gray field slug are possible in PNW, although information on biology is limited.

EGGS: Small, round, pearl-like, translucent (younger) eggs are laid in clusters of a dozen or more (over 500 eggs in a lifetime average 40 eggs/cluster) in sheltered cavities near the soil surface or under residue on the soil surface, if the soil is moist. As eggs mature they turn white and can take from 2 weeks to a month to hatch, depending on the environmental conditions. It can take 5 months to hatch if eggs are laid late winter. Mature adults deposit eggs late in the season, often after mid-October. If that is the case, the eggs will overwinter, and may not hatch until the following spring. The greatest egg- laying activity in non-irrigated environments usually occurs soon after the first fall rains before temperature declines.

NEONATES: A newly-hatched slug is called a neonate, and their typical food of choice is algae and fungus. However, they can feed on vegetative parts of plants. Young neonates weigh between 1-10 mg. They don’t travel far from home.

JUVENILES: Juvenile slugs will begin feeding throughout the spring and sometimes in the summer, if moisture is present and it is not too hot. If conditions are unsuitable, juveniles and adults will rest (aestivate) under clods and debris, in burrows and soil cracks. Aestivation is a physiological response of slugs under challenging times of environmental adversity, like dryness, summer heat, scarcity of food. They are known to survive without food for several months. Juveniles weigh between 11-100 mg.


Environmental contamination is an important threat to many fish and wildlife populations and the habitats and prey upon which they rely. The field of ecotoxicology links the ecology of fish and wildlife with toxicology of environmental contaminants, and so spans political, scientific, and public relations realms. Through the pairing of introductory concepts with key case studies, this course provides students with a preparatory framework for understanding toxicological issues of importance for those focused on studying, managing or conserving fish and wildlife populations.

Prerequisite: (BI 204 with D- or better or BI 211 with D- or better or BI 211H with D- or better) and (BI 205 [D-] or BI 212 [D-] or BI 212H [D-])

Signs of a Mayfly Infestation


Mayflies are attracted to light. They gather in large numbers around homes and commercial buildings. Making the building less attractive to mayflies is the first step in controlling a mayfly problem. Porch lights can be changed from white bulbs to yellow bulbs. Porch lights and lights attached to buildings may need to be moved away from the building. Consider reducing the light that shines from windows to avoid attracting mayflies to them at night. Insect light traps that use UV light may be helpful in attracting mayflies away from the building.

More Information

Most people want to prevent mayflies from coming into the home. Inspect the outside of the building to find any openings that might allow them to get inside. Make sure screens are repaired on windows. Check exterior doors to be sure they close tightly.

A vacuum that has a HEPA filter can quickly remove mayflies that get inside. A broom and dustpan are also handy tools for removing mayflies.

It is advisable to call pest control professionals for an inspection and evaluation. They will be able to provide advice for pest-proofing the home and keeping it pest free.

Watch the video: Identification of Mayfly Adults (January 2022).