Observations on the biology of Parnassius clodius lPapilionidaer in the Pacific northwest
01 Jan 1986-Journal of The Lepidopterists Society (Lepidopterists' Society,)-Vol. 39, pp 156-162
TL;DR: The biology and life history of Parnassius clodius Menetries is examined in the Pacific Northwest, where the species was formerly found in the Portland and Seattle metropolitan areas and is still quite abundant in the low foothills surrounding the Willamette Valley and the Puget Sound trough.
Abstract: This paper examines the biology and life history of Parnassius clodius Menetries in the Pacific Northwest. Habitats used by the species include subalpine meadows high in the mountains and lowland rain-forests west of the Cascade Range. The primary larval foodplants belong to the genera Dicentra and Corydalis of the family Fumariaceae. Larvae in alpine habitats often display a gray-brown camouflage pattern that blends with the rocks of the habitat. However, larvae in lowland rain-forests display a conspicuous black and yellow-spotted pattern that appears to mimic the warning colors of polydesmid millipedes. Larval development in lowland habitats is completed within a single year, and pupation takes place inside a strong, well-formed silken cocoon. Male butterflies display a "rape" type of mating, with no evidence of courtship behavior or sexual pheromones. Tough, tear-resistant wings and a large female sphragis may be related to this sexual behavior. Parnassius clodius Menetries belongs to a genus that is considered to be relatively primitive within the Papilionidae (Tyler, 1975). These are the only butterflies that have a moth-like pupa enclosed within a silken cocoon. Because of the putatively "primitive" nature of these butterflies, their life history and ecology is of considerable interest. Of the three species of Parnassius found in North America, only P. clodius is uniquely endemic to this continent and is widely distributed in the western mountains from southern Alaska to central California, western Wyoming, and northern Utah (Ferris, 1976). Some details of the life history and ecology of this species are outlined by Edwards (1885), Tyler (1975), and Dornfeld (1980). During the past twenty years, the present authors have studied various aspects of P. clodius biology in Oregon, Washington, and western Wyoming, resulting in much additional information. Ecology and Life History In terms of ecology, P. clodius occupies two distinctly different types of habitat. One consists of open subalpine meadows and rocky slopes above timberline at high elevations in the mountains. We have observed the species in subalpine meadows throughout western Oregon and Washington, and in Yellowstone National Park of Wyoming. We Volume 39, Number 3 157 also observed the species on alpine talus slopes above timberline at Harts Pass, Okanogan County, Washington. However, the most frequent habitat of P. clodius in the Pacific Northwest is the lowland rain-forests extending from the western slope of the Cascade Range west to the Pacific Ocean. Although typically found in moist riparian habitats along forest streams and mountain valleys, the species was formerly found in the Portland and Seattle metropolitan areas and is still quite abundant in the low foothills surrounding the Willamette Valley in Oregon and the Puget Sound trough in Washington. This forest habitat extends from the 4000 ft. (1200 m) elevation down to sea level near the ocean. The primary larval foodplant in these coastal rain-forests is the wild bleeding heart Dicentra formosa Andr., which is very abundant in moist forest habitats along the West Coast. A second probable foodplant is Corydalis scouleri Hook., a relatively uncommon species. We have not yet observed P. clodius larvae on this plant in the field, but they accept it readily in the laboratory. At high elevations in the alpine habitat and east of the Cascades, Dicentra uni flora Kell. is a likely foodplant. This species is a known foodplant of P. clodius in northern California (John F. Emmel, pers. coram.). All of these plants belong to the family Fumariaceae, and it is probable that related species such as Dicentra cucullaria L. and Corydalis aurea Willd. would also provide acceptable food plants. The female butterflies oviposit on and near the Dicentra plants. However, we have also observed females ovipositing on shrubs up to four feet above the Dicentra beds. Evidently a specific chemical emanating from the foodplant is sufficient to induce oviposition anywhere in the general vicinity of the foodplant. The larvae develop within the egg shell but do not emerge from the egg until the following spring. Eggs deposited on shrubs usually reach the Dicentra beds when the shrubs drop their leaves in the fall. Foodplant records such as Viola and Rubus mentioned by Ackery (1975) are almost certainly in error and may be due to this indiscriminate oviposition by the females. Early instar larvae have small tubercles, but later instars are mostly smooth with fine hairs. The larvae stay hidden in debris at the base of the foodplant most of the time. Feeding takes place very rapidly, so the larvae are exposed from cover only briefly. Nevertheless, P. clodius is frequently parasitized by tachinid flies in many localities. Osmeteria are poorly developed in Parnassius larvae and are not as important for defense against predators compared to Papilio larvae. Parnassius clodius larvae display two very distinct color morphs. One form is black with a lateral row of bright yellow spots on each side of the body (Fig. 1). The form of these spots is highly variable. 158 Journal of the Lepidopterists' Society Figs. 1-3. Left (1), larva of P. clodius, black form, Benton Co., Ore. Middle (2), larva of P. phoebus, Yakima Co., Wash. Right (3), larva of P. clodius, gray-brown form, Castle Lake, Siskiyou Co., Calif. Figs. 4-6. Left (4), Harpaphe haydeniana, Polk Co., Ore. Middle (5), open net cocoon and pupa of P. phoebus (behind thick Sedum stems in lower center). Right (6), well-formed cocoon of P. clodius cut open to reveal pupa ready to eclose. ranging from large round spots to long slender bars, or may be divided into several smaller spots. This color pattern is very similar to that of P. phoebus Fabr. (Fig. 2) and the Eurasian P. apollo L. (illustrated by Stanek, 1969). However, P. phoebus differs in having a second, more dorsal row of yellow spots on each side of the body. The second color form in P. clodius is gray-brown or pinkish gray with creamy yellow lateral spots and dorsal rows of narrow chevron markings equivalent to the dorsal row of spots seen in P. phoebus (Fig. 3). In our experience, Volume 39, Number 3 159 Table 1. Sequence of experiment testing the mimicry-model system of Parnassius clodius larvae and the millipede Harpaphe haydeniana as protection against the grasshopper mouse Onychomys leucogaster. 1. Clodius larvae given to mouse—larvae eaten. 2. Millipedes given to mouse—millipedes bitten, producing defense odor detectable to observer, mouse then rejected millipedes. 3. Meal worms given to mouse—worms eaten. 4. Clodius larvae given to mouse—larvae sniffed and rejected. 5. Adult meal worm beetles given to mouse—beetles eaten. 6. Clodius larvae given to mouse—larvae sniffed, handled, finally eaten after long delay. 7. Millipedes given to mouse—millipedes sniffed and rejected. 8. Meal worms given to mouse—worms eaten. the gray-brown form is dominant in alpine populations of P. clodius, for example at Harts Pass in Okanogan County, Washington and at Donner Pass in Nevada County, California. This morph appears to be a camouflage pattern that blends with the rocks in the alpine habitat. By sharp contrast, the black and yellow-spotted form is very conspicuous, is dominant in the lowland rain-forest populations of P. clodius, and appears to mimic the warning colors of polydesmid millipedes such as Harpaphe haydeniana Wood (Fig. 4). These millipedes are very abundant in the moist, riparian habitats used by P. clodius larvae. Some populations of P. clodius are polymorphic for both larval color forms. For example, larvae sent to us by John F. Emmel from Castle Lake in Siskiyou County, California displayed both color forms. Likewise, an adult female butterfly collected at Chinook Pass near Mt. Rainier National Park, Washington produced ten larvae, five of the black form and five of the pinkish gray form. In these, the black larvae retained the narrow yellowish dorsal chevrons of the gray larvae, a trait absent in most lowland black larvae. This ratio between the black and gray forms is suggestive of a simple Mendelian inheritance for these color morphs. However, the chevron markings are apparently controlled by a separate set of gene loci. In 1973, one of the present authors (McCorkle) conducted an experiment to test the predator protection of the mimicry-model system that apparently exists between lowland P. clodius larvae and the millipede Harpaphe haydeniana. Grasshopper mice (Onychomys leucogaster Max.) from eastern Oregon were used as predators in this experiment, since these insectivorous rodents do not occur within the ranges of the butterfly or millipede and would have no prior experience with these arthropods. The sequence of this experiment is shown in Table 1. This experiment appears to demonstrate that the mimicry color pattern of lowland P. clodius larvae can give them a degree of protection 160 Journal of the Lepidopterists' Society against predators, although predators may with sufficient experience learn to distinguish the larvae from millipedes. In nature, however, the millipedes are commonly exposed in the open, while P. clodius larvae are usually hidden and only briefly exposed during feeding. Thus, the mimicry may work quite well in nature, since predators would be expected to have abundant experience with the millipedes and little experience with the larvae. In lowland populations of P. clodius, development is completed in a single year. The larvae emerge from the egg shells during March and start to feed on the young Dicentra plants. Full larval development is reached usually by late April or May, followed by pupal development of several weeks, and adult butterfly emergence in June and July depending upon elevation. The pupa is short and rounded, dark brown in color, and quite similar to a saturniid moth pupa. It is enclosed within a strong, well-formed silken cocoon (Fig. 6). By contrast, the cocoon of
TL;DR: Movement and reproductive decisions made by adult females are critical to the persistence of these populations because colonisation of extinct habitat patches in the network requires emigration of fecund adult females from their natal meadow and their subsequent establishment in the extinct patch.
Abstract: 1 Many butterfly populations persist in networks of naturally fragmented habitat patches Movement and reproductive decisions made by adult females are critical to the persistence of these populations because colonisation of extinct habitat patches in the network requires emigration of fecund adult females from their natal meadow and their subsequent establishment in the extinct patch 2 Movement and oviposition behaviours of mated Parnassius smintheus females released in suitable meadows (a good- and a poor-quality meadow) and an unsuitable meadow were compared, to determine whether adult females consider meadow suitability for their offspring despite frequent oviposition events off the larval host plant 3 Bootstrap and correlated random walk analyses of female step lengths and turn angles demonstrated that females flew more randomly in the unsuitable meadow than in the suitable meadows Although females tended to turn the sharpest angle between landing sites in the good-quality meadow, and fly the smallest distance between landing sites and displace the smallest distance from the release site in the suitable meadows, no significant differences were detected in turn angle, step length, and dispersal rates between suitable and unsuitable meadows 4 Results from female flight observations and a caged oviposition study suggest that females lay significantly more eggs in suitable habitat than in unsuitable habitat despite not ovipositing on the host plant, and support the above findings 5 Movement and oviposition behaviours of adult female P smintheus promote their retention within meadows that can support their offspring
TL;DR: Mating frequency of both sexes in a natural population of the papilionid butterfly Luehdorfia japonica was studied with special attention to the role of sphragis in preventing multiple matings by females.
Abstract: Mating frequency of both sexes in a natural population of the papilionid butterflyLuehdorfia japonica was studied with special attention to the role of sphragis in preventing multiple matings by females. Males patrolled continuously within a patchy habitat throughout the warm daylight period in search for females. Mating took place without specialized courtship behavior. Males also attempted to copulate forcibly with previously mated females, but the presence of sphragis and/or the escape reaction of females prevented copulation. There was no specialized mate rejection behavior. Females mated early in their adult life, mainly on the day of emergence, and the frequency of mated females reached 100% within the first two or three weeks of their flight period. Spermatophore counts based on dissections of wild females possessing a sphragis indicated that they had never remated. Males were sexually active throughout their adult life. Male mating frequency was estimated from an index of scale-loss from the claspers and frequencies of males which had not mated, and those which had mated once, twice or three or more times were respectively estimated to be 33.7%, 40.3%, 18.2% and 7.8%.
TL;DR: It is suggested that elements of butterfly wing phenotypes respond independently to different sources of selection and that thermoregulation is an important driver of phenotypic differentiation in Parnassian butterflies.
Abstract: Colour pattern has served as an important phenotype in understanding the process of natural selection, particularly in brightly coloured and variable species like butterflies. However, different selective forces operate on aspects of colour pattern, for example by favouring warning colours in eyespots or alternatively favoring investment in thermoregulatory properties of melanin. Additionally, genetic drift influences colour phenotypes, especially in populations undergoing population size change. Here, we investigated the relative roles of genetic drift and ecological selection in generating the phenotypic diversity of the butterfly Parnassius clodius. Genome-wide patterns of single nucleotide polymorphism data show that P. clodius forms three population clusters, which experienced a period of population expansion following the last glacial maximum and have since remained relatively stable in size. After correcting for relatedness, morphological variation is best explained by climatic predictor variables, suggesting ecological selection generates trait variability. Solar radiation and precipitation are both negatively correlated with increasing total melanin in both sexes, supporting a thermoregulatory function of melanin. Similarly, wing size traits are significantly larger in warmer habitats for both sexes, supporting a Converse Bergmann Rule pattern. Bright red coloration is negatively correlated with temperature seasonality and solar radiation in males, and weakly associated with insectivorous avian predators in univariate models, providing mixed evidence that selection is linked to warning coloration and predator avoidance. Together, these results suggest that elements of butterfly wing phenotypes respond independently to different sources of selection and that thermoregulation is an important driver of phenotypic differentiation in Parnassian butterflies.
TL;DR: Clinging behavior may be regarded as an effective male mating strategy to exploit freshly mated females, and an alternative to finding virgin females, in Atrophaneura alcinous.
Abstract: Females ofAtrophaneura alcinous usually mate soon after eclosion. Their ostium bursae becomes plugged with male secretion which reduces chances of remating. Males frequently cling to a copulating pair and wait for completion of copulation. This was observed in 66% of 198 copulating pairs, with a maximum of 5 males clinging at one time during the course of a copulation. Males clinging for longer periods were more successful in copulation with the freshly mated female than those clinging for shorter periods. Despite the plugging effect, females may mate more than once. Clinging males were responsible for 61% of re-copulations and 53% of re-inseminations. Clinging behavior may be regarded as an effective male mating strategy to exploit freshly mated females, and an alternative to finding virgin females.