Great Basin Naturalist

Volume 46 Number 1 Article 8

1-31-1986

Seasonal phenology and possible migration of the Mourning Cloak , antiopa (: ) in California

Arthur M. Shapiro University of California, Davis

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Recommended Citation Shapiro, Arthur M. (1986) "Seasonal phenology and possible migration of the Mourning Cloak butterfly, (Lepidoptera: Nymphalidae) in California," Great Basin Naturalist: Vol. 46 : No. 1 , Article 8. Available at: https://scholarsarchive.byu.edu/gbn/vol46/iss1/8

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. SEASONAL PHENOLOGY AND POSSIBLE MIGRATION OF THE MOURNING GLOAK BUTTERFLY NYMPHALIS ANTIOPA (LEPIDOPTERA: NYMPHALIDAE) IN GALIFORNIA

Artlnir M. Shapiro'

Abstract. — Circumstantial evidence is presented that suggests the Mourning Cloak undergoes regular seasonal up in breeds at low elevations in spring and downslope movements northern California. The and then disappears I until autumn; its disappearance coincides with the appearance of fresh individuals in the Sierra Nevada alongside obvious hibernators.

The Mourning Gloak or Gamberwell record high precipitation, with both rainfall

Beauty, Nymphalis antiopa L., is one of the and snowjDack greater than 200% of the 30- most characteristic Holarctic ; it year means. Summer was cool and unusually ranges from the subarctic to the subtropics. moist, after a very late and cloudy spring.

Nonetheless, its basic biology is poorly Precipitation in the 1983-84 season was known. There have been many discussions of slightly below normal. Rain- and snowfall its rare and intermittent occurrence in the were heavy before Ghristmas and nearly

British Isles (Williams et al. 1942, Williams nonexistent thereafter. Spring was early and 1958, Ghalmers-Hunt 1977), but only one de- hot, and summer 1984 was the hottest of tailed description of its natural history — that record (over 125 years) at low elevations and by Young (1980), who narrated the situation in much warmer than normal in the mountains,

Wisconsin, USA, in the hope that it would with an unusual frequency of thunderstorms. help Palearctic workers understand the dy- The fact that the seasonal patterns of N. an- namics of their own populations. The biology tiopa are consistent in two such different years of N. antiopa in Galifornia, USA, is quite dif- suggests that they accurately represent the ferent; specifically, it seems to involve either seasonal dynamics of the . estivation or altitudinal migration or both. Al- Shapiro (1974c) reported that N. antiopa titudinal migration appears to occur in Gali- was univoltine in the Sacramento Valley de- fornia populations ofiV. ()milbei'ti Latr. spite the very long growing season. Nearer and N. californica Bdv. (Shapiro 1973, 1974a, the coast, at the Suisun Marsh, Shapiro 1974b, 1975, 1979, 1980). (1974d) reported essentially the same phenol- Since 1972 phenological data have been ogy. The same pattern was again reported for taken for all butterflies at a series of stations suburban Sacramento by Smith (1983). Smith forming a transect parallel to Interstate High- provides counts of sightings at one specific way 80 from sea level at the Suisun Marsh, locality for the years 1970 through 1982. His

Solano Gounty, to tree-line at Gastle Peak, pattern is quite consistent, with no

Nevada Gounty (2750m). Each station is vis- seen after 8 July in 50% or more of years, after ited at roughly two-week intervals throughout a very dramatic peak between 20 May and 1 the butterfly season, and all species flying are July. It was initially assumed by Shapiro that recorded. Figures 1 and 2 represent the N. the single spring brood in these areas entered antiopa data from this transect for 1983 and estivation, followed by a brief period of activ- 1984. These two years were extremely differ- ity in autumn, followed by hibernation, such ent meteorologically and essentially embrace that Sacramento Valley animals lived a full the range of variation observed during the 13 year as adults. Although estivation remains a years of the study. The year 1983 was one of possibility, no estivating adult has been found

Depart II t of Zoology. University orCalilornia, Davis. Calil

112 aniiary 1986 114 Great Basin Naturalist Vol. 46, No. 1

in 13 years, the condition of the adults observed general) the appearance of fresh animals at in autumn and early winter argues against it, mountain stations commences about a week and, most importantly, there is a persuasive cir- after the valley brood appears. cumstantial case implicit in Figures 1 and 2 for Similarly, the widely scattered autumn altitudinal migration on a regular seasonal basis. sightings are properly timed to represent Overwintered adults in typical posthiberna- downslope dispersal by the midsummer tion condition (borders nearly or totally white, brood reared in the mountains. Several appar- much wing wear) were observed near Sacra- ently fresh antiopa were seen at Lang Cross- mento and in the Inner Coast Range beginning ing 30 August (two weeks after the flight in late winter in both years. Similar hibernators started at Donner; no larval colonies were appear at montane sites shortly after seen at Lang in 1984). One apparently fresh snowmelt—the timing of which varied by sev- specimen was seen in Gates Canyon in the eral weeks between the two years. The single Inner Coast Range on 26 August, and Smith flight of fresh animals was observed at low eleva- saw one in Sacramento on 4 September. tions in late May-early July, lasting from 10 to 41 Nothing in these data either requires altitu- days in different locations. Smith (personal com- elinal migration or precludes estivation, but munication) saw singletons in Sacramento dur- they are clearly suggestive. How plausible ij ing the second, third, and fourth (three records) the hypothesis of altitudinal migration? One weeks of July and the second week of August, alternative explanation is that antiopa ma) 1983, and on 9 July and 25 July 1984. over-winter in both the adult and pupal stage; As can be seen from Figures 1 and 2, at moun- in the Sierra Nevada. Klots (1951) raised thi; tain stations more or less fresh animals can also possibility for the eastern United States be found in spring, flying with the hibernators. Shapiro (1969) recorded a single case in cen At Lang Crossing (1500 m), for example, the first tral New York in which overwintering of th( 1984 hibernators appeared on 10 March and pupa seems inescapable; the animal, whei fresh animals followed on 6 May while hiberna- captured, voided meconium. I have tried re tors were still numerous. At Donner Pass (2100 peatedly to maintain laboratory-reared low m), both fresh and worn animals were already land California pupae at 2-3 C for extende( flying 27 May and continued to be distinguish- periods, but with no success after eigh able through 20 June. Thereafter, worn animals weeks. True pupal appears to bi probably derived from both groups flew until 20 unknown in the . July. On that date two colonies each of 3rd- and Another alternative explanation for the low 5th-instar larvae were censused, presumably altitude phenomena is a low level of reproduc representing a differential in the timing of repro- tion in summer. In 13 years of extensive fiel< duction by the two groups of adults. On 15 Au- work in the Sacramento Valley and Inne gust fresh adults were very numerous in the Coast Range, I have never found a single lar vicinity of the previous Lj colonies. By 6 Sep- val colony after 1 June, nor has Smith in L tember only a few were present and these were years at Sacramento. On the other hand, sec moderately worn, but a second group of fresh ond broods occur occasionally beginning a animals appeared 19 September and flew for a Fairfield, Solano County, nearer the coast 1 week. and even a third brood has been recorded (L5

At the highest station. Castle Peak (2750 m), 20 October 1980). This is apparently standan

there is no permanent population, and the spe- on the immediate coast, for Tilden (1965) re cies is present in some years (generally those ports "two to three broods a year" in the Sai with early snowmelt) and absent in others (gen- Francisco Bay area, and Emmel and Emme erally late years). It was absent in 1983. In 1984 (1973) report "multiple-brooded at lower ele

no hibernators were seen, but fresh animals flew vations and single- or double-brooded ii 27 July- 17 August, and on the latter date one higher zones" in southern California— th«

colony of L3 was found. "lower elevations" referring almost entirely t( Given that reproduction by N. antiopa was urban and suburban areas, not to the interio late at low elevations in 1983 and that the timing deserts. Nymphalis antiopa is a common ur

of snowmelt was even more distorted, it is ban species in Mexico City, where it breed; striking that in both years figured (and in all vear. anuarv 1986 SHAPIRO: Mourning Cloak 115

Some light can be shed on the annual cycle by One additional aspect of the problem de- examining the reproductive status of the ani- serves mention. Shapiro (1981a,b) studied the nals. Although Young (1980) claims that spring canalization of the wing pattern as a trait adap- )opulations consist solely of females— the males tive to climate. He found that Alaskan animals )resumably having died overwinter— this is not are more strongly buffered physiologically rue in California (or southeastern Pennsylvania against cold shock than either lowland or Sier- ran )r New York). In the Sacramento Valley and montane N. antiopa . The similarity of the

^osisi Range, courtships and matings are ob- physiological responses of the Californian erved both in autumn (occasionally) and spring broods, from radically different climates, frequently). At Donner Pass they have been could imply gene flow over the fairly short distances )bserved in September but not in spring. In separating them — an interpretation consistent with the notion of altitudinal .984 1 dissected eight August and three Septem- migra- tion. Since the 1981 papers were )er Donner females. All had large amounts of fat published, the California experiments have been repli- ind no well-developed oocytes, but all the Au- cated three times with the same results for the ;ust and none of the September females were major aberration "hygiaea." The minor pat- 'irgins. All the fresh-looking females collected tern differences reported in Shapiro (1981b) n the mountains in June and July have been fully have been inconsistent among broods. eproductive (N = 15). Granted that at least part of the population of Herman and Bennett (1975) reported N. antiopa overwinters at 2100 m each year, hat summer females (source population and gene flow between these and animals dispers- earing regime unspecified) eclose with large ing from the lowlands could be very substan- at bodies and no oocytes, and subsequently tial in some years. Such gene flow— depend- nature as a function of environment. Matura- ing on the timing of spring at both ion was essentially completed within 10 days elevations —would be expected to inhibit if it 25 C on LD 16:8 but did not occur after 14 not prevent genetic differentiation along our lays at 10 C, LD 8:16. This experiment does altitudinal transect. lot separate the effects of photoperiod and Numbers of this species are consistently too emperature. Photoperiods at Donner Pass in low for mark-recapture experiments to hold ate August are ca LD 13.5:10.5, mean tem- much promise as a test of the altitudinal-mi- )erature 16 C. Donner Pass antiopa reared on gration hypothesis. If genetic markers can be :.D 14:10 at 25 C failed to mature after 15 found to facilitate identification of low-eleva- veeks in the dark at 2 C. tion animals, they would be useful for docu- For adult antiopa emerging in the Sacra- menting movements—but if gene flow is fre- nento Valley in late May, photoperiods are ca quent, such markers are unlikely to be found. ^D 15:9 and mean temperature 18.9 C, con- In the meantime, detailed seasonal data for a litions that should permit rapid gonadal mat- variety of localities are very desirable. iration, but no reproduction is seen. Of three ate May-early June Sacramento females, two lad mated and one of these showed early Acknowledgments

)ocytes. If altitudinal migration is real, This research forms part of the California )varian maturation may occur during the up- Agricultural Experiment Station Project CA- ilope flight, its termination coinciding with D*-AZO-3994-H, "Climatic Range Limita- he beginning of oviposition. The distances tion in Phytophagous Lepidopterans." I thank nvolved (125-150 km from our Sacramento Leslie V. Smith for making his Sacramento Galley sites to Donner Pass) could be tra- data available for use in this paper. /ersed in a week or so, based on the progress

)f N. californica migrations I have tracked. Shannon (1917) believed eastern U.S. pop- Literature Cited alations of iV. antiopa were at least somewhat Chalmers-Hunt, M 1977. The Camberwell Beauty in migratory. Gibo (1981) records the species J Yorkshire in 1977. Ent. Rec. J. Var. 89:348. riding in thermals east central Canada; such 1973. The butterflies of Emmel, T C , AND J. F. Emmel. passive soaring is associated in many southern Cahfornia. Natural History Museum of with the initiation of long-range dispersal. Los Angeles County 148 pp. 116 Great Basin Naturalist Vol. 46, No. 1

197.5. GlBO, D. L. 1981. Some observations on soaring flight in Why do California tortoiseshells migrate? J. the Mourning Cloak butterfly (Nymphalis antiopa Res. Lepidopt. 14:93-97.

L.) in southern Ontario. J. New York Ent. Soc. 1979. Nymphalis milberti (Nymphalidae) near sea

89:98-101. level in California. J. Lepidopt. Soc. 33:200-201. Herman. W S., and D. C. Bennett. 1975. Regulation of 1980. Mediterranean climate and butterfly migra- oogenesis, female specific protein production, and tion: an overview of the California fauna. Atalanta male and female reproductive gland development 11:181-188. by juvenile hormone in the butterfly Nijtnphalis 1981a. Canalization of the phenotype of Nymphalis antiopa (Nymphalidae) from subarctic antiopa. J. Comp. Physiol. 99:331-338. and montane climates. Res. Lepidopt. 19: Klots. a. B 1951. A field guide to the butterflies of North J. 82-87. America, east of the Great Plains. Houghton Mif- 1981b. Phenotypic plasticity in temperate and flin, Boston. .349 pp. subarctic Nymphalis antiopa (Nymphalidae): evi- Shannon. H. J 1917. Autumn migration of butterflies. dence for adaptive canalization. J. Lepidopt. Soc. Amer. Mus. J. 17:32-40. .35:124-131. Shapiro, A. M. 1969. Overwintering by pupal Nympha- Smith. L. V 1983. A twelve-year count of three California lids in New York? Ent. News 8o!l,30. buttei-flies. J. Lepidopt. Soc. 37:275-280. 1973. Altitudinal migration of butterflies in the TiLDEN. J W 1965. Butterflies of the San Francisco Bay central Sierra Nevada. Res. Lepidopt. 12: J. Area. University of California Press, Berkeley. 88 231-235. pp. of Ni/inphalis californica in 1974a. Movements WiLLlA.MS, C. B 1958. migration. Wilmer Bros., 1972 (Nymphalidae). Lep. Soc. 28:75-78. J. Harram, London. 235 pp. 1974b. Altitudinal migration of central California Williams. C. B , G F. Cockbill, M E Gibes, and J. A. 13:157-161. butterflies. J. Res. Lepidopt. DOWNES. 1942. Studies in the migration of Lepi- 1974c. The butterfly fauna of the Sacramento Val- doptera. Trans. R. Ent. Soc. London 92:101-283.

ley, California. J.' Res. Lepidopt. 13:73-82, Young, A. M 1980. Some observations on the natural 115-122, 137-148. history and behaviour of the Camberwell Beauty 1974d. Buttei-flies of the Suisun Marsh, California. (Mourning Cloak) Butterfly, Nymphalis antiopa in States. Gaz. J. Res. Lepidopt. 13:191-206. (Linnaeus) the United Ent.