Author Institution: The Ohio State UniversityA leafhopper of the Macrosteles fascifrons (Stal) complex lives on an alkali grass, Puccinellia nutkaensis (Presl) Fern. & Weath., on the tidal flats of Muir Inlet in Glacier Bay, Alaska. The tidal water, with icebergs and a temperature of approximately 1° C, covers the grass twice daily and the leafhoppers in all stagesegg, nymph, and adultsurvive beneath the water for extended periods of time. The winged adults do not attempt to leave the plants when the tidal water begins to submerge them and none were obtained from vegetation surrounding the tidal fiats either before or after submergence

DeLong, Dwight M.

The Ohio Journal of Science

Author Institution: The Ohio State UniversityA leafhopper of the Macrosteles fascifrons (Stal) complex lives on an alkali grass, Puccinellia nutkaensis (Presl) Fern. & Weath., on the tidal flats of Muir Inlet in Glacier Bay, Alaska. The tidal water, with icebergs and a temperature of approximately 1° C, covers the grass twice daily and the leafhoppers in all stagesegg, nymph, and adultsurvive beneath the water for extended periods of time. The winged adults do not attempt to leave the plants when the tidal water begins to submerge them and none were obtained from vegetation surrounding the tidal fiats either before or after submergence

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N o . 2 COLLAPSE OF SNOW-BANK KAMES, ALASKA 111AN ALASKAN LEAPHOPPER THAT LIVES NORMALLYBENEATH ICY TIDAL SUBMERGENCE1' 2- »DWIGHT M. DELONGThe Ohio State UniversityABSTRACTA leafhopper of the Macrosteles fascifrons (Stal) complex lives on an alkali grass,Puccinellia nutkaensis (Presl) Fern. & Weath., on the tidal flats of Muir Inlet in Glacier Bay,Alaska. The tidal water, with icebergs and a temperature of approximately 1° C, coversthe grass twice daily and the leafhoppers in all stages—egg, nymph, and adult—survivebeneath the water for extended periods of time. The winged adults do not attempt toleave the plants when the tidal water begins to submerge them and none were obtainedfrom vegetation surrounding the tidal fiats either before or after submergence.Two publications have discussed insects of the "between tide zone". Arndt,in 1914, made observations on a fulgorid, Megamelus marginatus Van Duzee,which he inadvertently called a leafhopper.Metcalf and Osborn, in 1920, studied the insects of the tidal zone at WrightvilleBeach in North Carolina, and observed certain of the Homoptera, especiallyDeltocephalus marinus Met. and Osborn, feeding on grasses at low tide, whichvegetation was normally covered by the high tide twice daily. They made nospecific observations, but concluded that "there is every reason to assume that thewhole life cycle is associated with the grass and although we have not had oppor-tunity to determine as to place of egg deposition or the development of the young,we are confident that all these stages will be found associated with this plant whenthe necessary observations can be made" (Metcalf and Osborn 1920, p. 111).During the summer of 1965, an opportunity was presented to work with TheOhio State University Institute of Polar Studies in Muir Inlet, Glacier Bay,Alaska. The Muir Glacier has been retreating rapidly, and accurate data regardingthe rate of retreat have been recorded over the past seventy-seven years. Con-sequently this area offers an unparalleled opportunity for studies of soil develop-ment, repopulation by plants and animals, and the succession of biologicassociations.The field study covered some thirty-two kilometers of Muir Inlet, extendingThis work was supported by National Science Foundation (Grants NSF GB3364 andGB2932).Contribution No. 155 of the Institute of Polar Studies, The Ohio State University.3Manuscript received May 1, 1969.THE OHIO JOURNAL OF SCIENCE 70(2): 111, March, 1970.112 DWIGHT M. BELONG Vol. 70north from approximately the junction of Adams and Muir Inlets to the presentglaciers and representing the land newly deglaciated during the last seventy-fiveyears. At its southern end are the ruins of Muir cabin, which was at the base ofthe Muir Glacier in 1892. The writer was responsible for studying both theinsects present in this recently deglaciated area and the succession of insect associa-tions which occurred during this seventy-five years of recession. The summary ofthis work was published as an Ohio State University Research Foundation report(DeLong, 1966).During the period of field study and observations, while attempting to observeand secure samples of insect populations in all of the habitats represented, I cameupon Goose Cove, a small bat prominent cove of Muir Inlet, not far from the gullrookery known as Sealer's Island. At low tide, Goose Cove has a long, graduallyFIGURE 1. Dorsal view of 9 (left) and cf (right) of Macrosteles fascifrons (Stal.). (Photo-micrographs by Alvah Peterson).sloping tidal flat, well covered with a rather dense carpet of an alkali grass, Puc-cinellia nutkaensis (Presl) Fern & Weath. A high high tide of some eighteen feetcovers this grass almost completely, while a low high tide submerges a large per-centage of this area. Living upon this mat of grass was found an abundantpopulation of leaf hoppers of the Macrosteles fascifrons (Stal) complex. Adults ofboth sexes were found in abundance and all stages of the nymphs were observedand collected. Two other members of the party, Dr. E. E. Good and Mr. DonFrickie, who were responsible for observations on the birds and mammals, werewith me at the time this tidal flat was first discovered and assisted me in observ-ing what transpired when the high tide submerged this area a few hours later.To our surprise, the adult leafhoppers did not attempt to escape the submergenceof the icy tidal waters and remained stationary upon the vegetation. The watercontained numerous icebergs, large and small, many of which remained on theNo. 2 ALASKAN LEAFHOPPER BENEATH ICY TIDES 113grass as the tide receded, as shown by the accompanying illustration (fig. 2); thetemperature of the water was approximately 1° C.The following day this area was revisited just before the predicted time of thehigh tide submergence and a number of white cloths were spread upon the grasssurrounding several clumps of grass which contained rather heavy populations ofleafhoppers. During careful observations made from stations in the water, noleaf hoppers appeared to leave these plants as they were submerged. In addition,vigorous collecting on all the vegetation surrounding the tidal flat during theperiod of submergence produced no specimens of these leafhoppers. At the time oftidal recession, we walked out to the submerged plants, remained until the waterhad receded and immediately collected active leafhoppers from the grass. Similarobservations were made at Bartlett Cove, Alaska, some 50 kilometers south ofMuir Inlet, but there no icebergs were present in the water.FIGURE 2. Tidal flat showing dense growth of Puccinellia nutkaensis (Presl) Fern & Weath.with icebergs left by a receding tide.Although lack of time prevented complete observations of the life cycle of thisinsect, the eggs are apparently laid upon the grass. The nymphs appear to hatchand remain in this periodically submerged habitat during their period of growthand development, and the resultant adults do not attempt to leave this habitat,although their wings are fully developed and functional.An interesting observation made during the limited time available for studywas that there was a relationship between leafhopper population size and the de-gree of tidal submergence. As mentioned above, the tidal flat was graduallysloping and at least one hundred meters long, and the percentage of grass sub-merged varied from day to day. The largest populations of leafhoppers wereobserved at the middle of the tidal flat, where the grass was submerged by eachhigh tide, usually for a minimum of an hour, depending upon the day of the tidalperiodic cycle. The areas of greatest submergence and those of least submer-gence, including the grass often not submerged, supported the smaller populations.Genitalically the leafhopper specimens agree with the species now designated114 DWIGHT M. DELONG Vol. 70as Macrosteles fascifrons (Stal). However it is difficult to believe that this isexactly like the species (fascifrons) which is the vector of aster yellows virus, orthe tropical form described as M. scriptus (DeLong) and now placed in fascifrons,especially since M. scriptus living in a subtropical habitat, instead of ice water,is only 2.5 mm long (in contrast to the 5.1 mm length of this Alaskan form).The Macrosteles fascifrons complex as now recognized by taxonomists (Beirne,1952) is geographically distributed from Mexico and Puerto Rico to Alaska. Asthus interpreted, fascifrons is composed of a great variety of genetic mutantswhich vary in size and coloration, cannot be separated morphologically, butwhich differ biologically, physiologically, and ecologically.Beirne (1952, p. 224), after a detailed study of all of the material in the genusMacrosteles, states, "It is possible that some of the forms may be physiologicalspecies that are poorly denned morphologically. The wide range of the complexas a whole and the apparent habitat differences between different forms indicatethis." He further states, "It is possible that some of the forms may representpopulations that are or were isolated ecologically from other populations and thatdeveloped independently during their isolation, though not to the species level.It may be significant that the largest number of local forms are in ecologicallydiverse regions, as in the mountains of the west. Moreover, the habits appearto be relatively sedentary, which would favour isolation: Linn (1940) found thatthe common form of [M. fascifrons in] the eastern United States did not spreadin perceptible numbers more than 200 feet in four weeks."Severin (1940) was unable to interbreed a short-winged form from the MonteraMountains, California, with a long-winged eastern United States form and, incorrespondence, urged that it be described. The best characteristics for separatingclosely related species are those which the insects use themselves, one of which ismating response. If two populations will not interbreed, they must be consideredto be distinct biological forms, and genetic species, regardless of morphologicalsimilarities.The Alaskan ice-water, Puccinellia form is certainly severely selected and spe-cifically adapted to live in an unusual leaf hopper environment. It has becomeecologically isolated and, like the short-winged biological form, deserves a sub-species name.ACKNOWLEDGMENTSThe writer wishes to express his appreciation to Dr. Richard P. Goldthwaitfor the opportunity of conducting this work and to Dr. E. E. Good, Mr. DonFrickie, and Roger Burnard for assistance in the field.REFERENCES CITEDArndt, C. H. 1914. Some insects of the between Tides Zone. Proc. Indiana Acad. Sci. pp.323-333.Beirne, B. P. 1952. The nearctic species of Macrosteles (Homoptera: Cicadellidae). Canad.Entomologist 84: 208-232.DeLong, D. M. 1966. Soil development and ecological succession in a deglaciated area ofMuir Inlet, southeast Alaska, Part 5—Insects. Pp. 97-120. (Coauthor with R. P. Gold-thwait, F. Loewe, F. C. Ugolini, A. F. Decker, M. B. Trautman, E .E. Good, T. R. MerreltIII and E. D. Rudolph) Ohio State Univ. Research Foundation, Inst. Polar Studies Rept. 20.167 pp. August 1966.Metcalf, Z. P. and Herbert Osborn. 1920. Some observations on insects of the between tide zoneof the North Carolina Coast. Ann. Entomol. Soc. Am. 13: 108-119.Severin, H. H. P. 1940. Potato Naturally Infected with California Aster Yellows. Phyto-pathology 30: 1049-1051.

An Alaskan Leafhopper that Lives Normally Beneath Icy Tidal Submergence

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An Alaskan Leafhopper that Lives Normally Beneath Icy Tidal Submergence

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