t:aboratory of Aquatic Entomology Florida A & M University Iallahassee, Florida 32307.

DENNIS M. LEHMKUHL, Biology Department, University of Saskatchewan, Saskatoon.

Mayflies are appreciated most by second, to introduce the mayflies of trout, trout fishermen, bridge nesting Saskatchewan (See also Lehmkuhl, swallows, a handful of Ephemerop­ 1970). Identification of adults to terists, and maybe by other mayflies. family is considered difficult in some In general, they are loathed by collec­ cases even by professional en­ tors because they are hard to identify tomologists because all adults look and because there are few less quite similar (Figs. I and 2 illustrate attractive than a shrivel led and faded two extremes) and the family charac­ impaled on a pin in a collec­ teristics are found in details of wing tion. This is a result of their delicate venation. I have departed from the and fragile structure and, as a con­ usual "key" method of identificati"on sequence, they are less well studied and have attempted to use in Table I than some other groups of com­ and Figures 6-21 a modified Peterson parable size (approximately 500 North Field Guide technique. There is no American species). easy road to adult identification, so I An adult mayfly in nature is a work would suggest that the first step is to of art and their transient beauty has in­ use a I OX hand lens and sketch the spired poets to write in many major arrangement of veins in the languages of the ephemeral nature of specimen at hand. It may be necessary all living things, including ourselves. to remove the wing from the specimen The popular conception of the short to get clear view. Next, compare the life of mayflies (Ephemeroptera) is, drawing with the six categories in however, somewhat of a misrepresen­ Figures 6-21 and select the correct tation. Some do live but a day in the one. Finally, go to the proper category adult stage, such as our Ephoron album in Table I which will lead you to the which are like a summer snowstorm as family name. A list of Saskatchewan they emerge over the Saskatchewan families, genera, and known species is River on August evenings, their found in Table 2. reduced legs indicating how little time The mayflies of Saskatchewan is spent on a solid surface. Then there present a most unusual and fascinating is the more extreme case of female situation. While the number of iden­ Lachlania saskatchewanensis, where tified species is about 60 (with a dozen the legs of the females are completely or so yet to be identified), the number useless, probably decreeing that to of genera (that is, major types) is about alight is to die; I have seen adults of 35, and 12 of the 15 North American this species only as windrows of dead families can be collected in the mayflies along the river shore. It is province. Such diversity in a northern also true that the mouthparts of adult inland locality is unusual when com­ mayflies are reduced and functionless pared, for example, to the "poor" and they probably take no food or fauna of Dragonflies, Damselflies and water as adults. But it must be remem­ Aldertlies." 7 This variety of mayflies is bered that the nymphal stage has lasted not readily explained, but it probably for months or in some cases years has to do with the immigration from beneath the water surface. east, west, north and south, in com­ This paper has two purposes, the bination with the glacial history and first is to provide a means of iden­ climate of the area. In terms of origin, tifying families of adult mayflies of our mayfly fauna invaded from all North America (nymphs can be iden­ directions after the decline of the ice tified by using Lehmkuhl, I 975c), and, age. Based on current distributions,

70 Blue Jay I ' ) I

2

Figure I. Adult male of Ana/etris eximia; Fig. 2. Adult female of Baetisca bajkovi: Figs. 3- 5. male genetalia of Analetris eximia, Paraleptophlebia praepedita, and P. debilis.

June, 1976. 34(2) 71 there are four fauna! regions in Saskat­ and ovipos1t1on, birds, bats and fish chewan: Boreal, Saskatchewan River, take a heavy toll of adults. Cypress Hills and Prairie. Eggs may have a smooth surface Few kinds of mayflies are found on (Fig. 43) or they may have attachment the true prairie. Potholes are likely to structures of various types (Figs. 3 7, yield only Ca/libaetis but occasionally 39, 40). In Baetis, the female crawls Caenis or even Siphlonurus may be en­ beneath the water surface and lays eggs countered. The boreal forest is charac­ in neat square masses, often found in terized mainly by a typical "eastern" abundance on stones in mountain or assemblage of (Fig. 27) boreal streams (Fig. 36 ). and Stenonema, plus widespread forms Eggs hatch into nymphs, various such as Baetis (Fig. 22), Paralep­ types of which are illustrated in the tophlebia, Leptophlebia, Ephemerella figures. While adults look quite (Fig. 23) and Tricorythodes (Fig. 25). similar in all families, the nymphal Many western species reach their stage shows great diversity. Basic eastern limits in the Cypress Hills, in­ mouthparts of a chewer, such as Baetis, cluding Epeorus longimanus, Cinygma are illustrated in Figure 38. These sp., and Ameletus sp. Of most interest same structures may be modified into is the Saskatchewan River fauna where scrapers and filters as in Figure 41. one can collect Ametropus (Fig. 24), Among burrowing mayflies mandibles Metretopus, Dactylobaetes, Baetisca may even be modified into forward (Fig. 35), Brachcercus, Anepeorus, projecting tusks as in Figures 42 and Pseudiron, Choroterpes, Traverella, 26. Gills, which are found on the ab­ Lachlania (Fig. 31) Ephoron, Analetris, domen of all North American and lsonychia. The origin of this mayflies, are basically flat plates (Figs. diverse assemblage, probably one of 29 and 33a,b) but may be modified the most unusual in North America, is into rods, double plates, forks, a chapter in itself which remains to be filaments or brushes, depending on the written, but see Lehmkuhl, 1970, 1972 genus and species (Figs. 28, 30, 34 ). and 1976. Such readily seen differences makes identification of mayfly nymphs The mayfly life cycle is relatively relatively easy. simple except for one unique stage, the subimago. This stage is found in no Nymphs occupy a wide range of other insect. It emerges from the niches. Heptageniids (Fig. 27) are flat aquatic nymph and while it looks like and live on rocks in streams where an adult and is capable of flight, it dif­ they scrape algae for food while Baetis fers in that it is sexually immature, the (Fig. 22) may live on the same rock but body is covered with a dull velvety the body shape is streamlined and fish- cuticle which must be shed, and 1ike. Ephemerella (Fig. 23 ), various body parts, such as legs or Tricorythodes (Fig. 25) and Baetisca genitalia, may be underdeveloped. (Fig. 3 5) al 1 tend to be bottom sprawlers on gravelly or sediment sub­ Adult males congregate in swarms, stratem All have plate-like or oper­ the size, timing and location of which culate (covered) gills to protect the varies greatly with the species. Ripe respiratory surface from settling females fly into the swarm to be debris. Ephemera (Fig. 42), along with grasped from below by the long front Hexagenia (Fig. 26) and Ephoron are le~s and terminal abdominal "forceps" burrowers, making tubes in semi­ (Figs. 1, 3-5) of the male. Sperm is impacted gravel or mud bottom of passed from the penis of the male lakes and rivers. Ametropus (Fig. 24) (blade and rod-like structures in Figs. and Lachlania (Fig. 31) are filter and 3-5) to the genital openings on the un­ particle feeders, the former anchoring derside of the body of the female. In itself on sand bars with 4 legs while many species the female quickly drops snatching and sorting passing particles to the water surface and the eggs are from the current; Lachlania grasps released (Fig. 44 ). During swarming roots and stones in deep water and the

72 Blue Jay 9

10

Figure 6. Wings of Brachycercus; Figure 7. Tricorythodes; Figure 8. Ephemera; Figure 9- Potamanthus; Figure I 0 Neoephemera; Figure I I. Totopus.

June, 1976. 34(2) 73 rapid current of river while filtering poorly studied, thus leaving room for food with the fringes of the front legs. original discoveries by naturalists. /sonychia, not at all closely related to Adults and nymphs are best preserved either, is also a filter-feeder. Ad­ in alcohol or the adults may be moun­ ditional Saskatchewan genera, ted on pins. Nymphs are easily kept in illustrated in Lehmkuhl, 1975c but not well aerated aquaria where they can be here, are Brachycercus, Epeorus, studied. Mayflies are abundant and Para/eptophlebia, Ephoron and easily collected, the nymphs especially Siphlonurus. in flowing water, and the adults while Most mayfly nymphs are her­ swarming over water, resting on leaves bivorous, the sheep and rabbits of the near water, or at porch lights near aquatic insect world. A few local water. species are carnivores, and these rare insects inhabit one of the last un­ polluted strongholds in the Saskat­ Acknowledgements: This article was chewan River. They are Anepeorus, based in part on the drawings of A. R. Pseudiron and Analetris. Brooks. Photographs were prepared by Mayflies are a fascinating group of John Waddington, from specimens in that have been relatively the author's collection.

Table I. Families of adult mayflies. Compare with Figures 6-21. Category I - Hind wings absent, body size small, approx. 1/4 inch. Caenidae - crossveins few, usually a single arch-like series of crossveins in basal area (Fig. 6 ). Tricorythodae - crossveins faint, more numerous - 15 or more scattered through wing (Fig. 7). Note: Some Baetidae lack a hind wing, but they differ from the above in that the lateral ocelli (simple eyes) are not more than 1/4 the size of the compound eyes while in the above the ocelli are about 1/2 as large as the compound eyes. In all the following the hind wings are present (except some Baetidae, see above).

Category II - Sharp bend near base of vein M, often resulting in a large eel I near base of wing. Po/ymitarcidae - Represented in our area by Ephoron (widespread) and Tor­ topus (Manitoba). Veins at front wing tip curve around margin (Tortopus, Fig. 11) or with front legs of male reduced to functionless stubs (Ephoron ). Potamanthidae - not found in our area. Vein 1A of front wing forked (Fig. 9). Neoephemeridae - not found in our area. Sharp costal projection on hind wing (Fig. I 0). Ephemeridae - Large mayflies common in our area. Lack characters specified for above 3 but with prominent large basal cell (Fig. 8).

Category Ill - Front wing lacks forks in veins in outer half. Baetidae - rear angle of wing rounded (Fig. 13 ); common in our area. Behningiidae - rear angle of wing not rounded (Fig. 12); not found in our area.

Category IV - Two pairs of longitudinal veins at hind angle of front wing. (Note: Metretopus (Ametropodidae) has only one pair of veins in this position). - Hind tarsi with 5-segments (Wing, Fig. 16) (except the rare Pseudiron, Fig. 14 which has 4 segments). Ametropodidae - Hind tarsi 4-segmented. Wing Fig. 15.

74 Blue Jay 12 13

CATEGORY III. OUTER HALF OF FRONT WING LACKS FORKS IN VEINS. (SEE ALSO VI)

!:;" 1 j r :r:r, 4.-.J.

1~ ~2

15

CATEGORY IV.

TWO PAIRS OF LONGITUDINAL VEINS AT HIND ANGLE OF FRONT WING.

Figure 12 Do/ania: Figure 13 . Baetis: Figure 14 . Pseudiron: Fi gure 15. Ametropus : Figure 16. Epeorus.

June, 1976. 34(2) 75 Category V - Without two pairs of longitudinal veins at hind angle of front wing, but with numerous veins attached to inner hind angle of wing. Vein Cu, strongly curved. Ephemerel/idae - with I or 2 long intercalary veins (I) between vein Cu, and M, (Fig. 17). Leptophlebiidae - without a long intercalary vein between Cu, and M, (Fig. 18). Vein Cu, not curved. Baetiscidae - Hind wing oval or round in shape, Fig. 20. Siphlonuridae - Hind wing triangular in comparison, Fig. 19.

Category VI - Venation reduced to 4 or 5 longitudinal veins in front wing. Oligoneuriidae - the genus Lachlania in our area, Fig. 21.

Table II

A preliminary list of the mayflies of Saskatchewan based primarily on the author's collection.

Ametropodidae Heptagenia elegantula (Eaton) Ametropus alhrighti Traver Heptagenia flavescens (Walsh) Metretopus horea/is Eaton Heptagenia hehe McDunnough Siphloplecton interlincatum (Walsh) Heptagenia pulla (Clemens) Heptagenia solitaria McDunnough Baelidae Rhithrogena sp. Baetis quilleri Dodds Stenonema interpunctatum (Say) Baetis vagans McDunnough (now Stenacron) Baetis spp. (at least 7) S. tripunctatum (Banks) Callibaetis spp. (at least 3) S. vicariwn (Walker) Centroptilum spp. Pseudiron centralis Cloeon spp. Undescribed genus Dactylobaetes sp. Pffudoc/oeon spp. Leptophlebiidae Choroterpes albiannulata McDunnough Baeliscidae Leptophlebia cupida (Say) Baetisca bqjkovi Neave Paraleptophlebia debilis (Walker) Baetisca ohesa (Say) P. praepedita (Eaton) Caenidae P. adoptiva (McDunnough) Brachycercus prudens (McDunnough) P. moerens (McDunnough) Caenis simulans McDunnough Traverella albertana (McDunnough) Ephemerellidae Oligoneuriidae Ephemerella aurivillii (Bengtsson) Lachlania saskatchewanensis Ide Ephemerella grandis Eaton Polymitarcidae Ephemerella inermis Eaton Ephoron album (Say) Ephemerella lita Burks Tortopus primus Ephemerella simplex McDunnough - Campsurus manitobensis Ide Ephemerella temporalis McDunnough - Manitoba only. Ephemeridae Siphlonuridae Ephemera simulans Walker Analetris eximia Edmunds Hexagenia limhata Ameletus spp. Heptageniidae Siphlonurus alternatus (Say) Anepeorus rusticus McDunnough lsonychia sicca (Walsh) Cinygma sp. Tricorythodae Epeorus longimanus (Eaton) Tricorythodes fallax Traver Epeorus sp. Tricorythodes sp.

76 Blue Jay M

17 .~ 18

19 20

21

Figure 17. Ephemerella; Figure 18. Leptophlebia; Figure 19 . Siph/onurus; Figure 20. Baetisca; Figure 21. Lachlania.

June, 1976. 34(2) 77 Figure 22. Nymph of Baetis; Figure 23. Ephemerel/a; Figure 24. Ametropus; Figure 25. Tricorythodes; Figure 26. Hexagenia.

78 i:\lue Jay b

Figure 27. Heptagenia; Figure 28. Caenid type gill; Figure 29. Baetid type single plate gill; Figure 30. Double gill as in Callibaetis; Figure 31. Lach/ania; Figure 32. gill of same; Figure 33. Transition from single to double gills as in Baetidae; Figure 34. Forked and double gills as in Leptoph/ebiidae; Figure 35. Baetisca.

June, 1976. 34(2) 79 @

Figure 36. Mayfly eggs in gelatin mass, e.g., Baetis; Figure 3 7. Mayfly egg with attachment filaments: Figure 38. Nymphal mouthparts of chewing type, e.g., Baetis, a. mandible b. labrum, c. maxilla d. labium: Figure 39, 40. Mayfly eggs: Figure 41. Modified nym­ phal mouthparts: Figure 42. Modified tusk-like mandibles of Ephemera: Figure 43. Mayfly egg: Figure 44. Adult female with eggs.

80 Blue Jay ADDITIONAL READING

'ALLEN, R. K. and G. F. EDMUNDS, Jr. 1965. I 975 b. Alderflies. Blue Jay 33: 152- \ A revisiun ufthe Genus Ephemere//a {Ephemerup­ 154. tera, Ephemerellidae). VIII. The suh!(enus '---- l 975c. Field guide to aquatic insect Ephemere//a in Nurth America. Misc. Pub!. Ent. families. Blue Jay 33: I 99-219. Soc. Arner. Vol. 4 No. 6: 244-282. (See also 1- VII in this series, complete citation of each "---- In Press (1976) Additions tu the given in No. VI II). , zoogeography, and hiology <~f Analetris eximea ( Acanthametropodinae: Siphlonuridae: 'BURKS, B. D. 1953. The Mayflies, or Ephemaoptaa). Canadian Entomologist. Ephemeruptera of lllinois. Bull. Ill. Nat. Hist. Survey Vol. 26 No. I 2 I 6 pp. '"LEWIS, P. A. I 974. Taxonomy and ecolo!(y of Stenonema mayflies. U.S. Environ. Prot. Agency "EDMUNDS, G. F., Jr. and R. K. ALLEN. - 6704-74-006. 80 pp. I 957. A checklist of the Ephemeroptera of North America north of Mexico. Ann. Ent. Soc. Arner. "NEEDHAM, J. G., J. R. TRAVER, and YIN­ 50 317-324 .. CHI HSY. I 935. The hiolo!(y of Mayflies. Com­ stock Pub!. Co., Ithaca, New York. 'LEHMKUHL, D. M. I 970. Mayflies in the South Saskatchewan River: pollution indicators. Blue Jay "PETERS, W. L. and J. F. PETERS, eds. I 973. 28: I 83- I 86. Proceedings <~f tlw First International Conference on Ephemnoptera. E. J. Brill, Leiden. I 972. Baetisca ( Baetiscidae, Netherlands. 3 I 2 p. Ephemeroptera) from the western interior of Canada, with notes on the l!fe cycle. Candian Journal of Zoology 50: 1015-1017. "---- I 975a. Saskatchewan Damselflies and Dra!(onflies. Blue Jay 33: I 8-27.

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June, 1976. 34(2) 81