Viceroy Butterflies Research Articles

A Deep Learning‐based Computer Vision Approach for Comparative Monarch Butterfly Phenotype Identification in Citizen Science

In recent years, the monarch butterfly's iconic migration patterns have come under threat from a number of factors, from climate change to pesticide use. To track trends in their populations, scientists as well as citizen scientists must identify individuals accurately. This is key because there exist other species of butterfly, such as viceroy butterflies, that are “look-alikes,” having similar phenotypes. To tackle this problem and to aid in more efficient identification, we present MonarchNet, the first comprehensive dataset consisting of butterfly imagery for monarchs and five look-alike species. We train a baseline deep-learning classification model to serve as a tool for differentiating monarch butterflies and its various look-alikes. We seek to contribute to the study of biodiversity and butterfly ecology by providing a novel method for computational classification of these particular butterfly species. The ultimate aim is to help scientists track monarch butterfly population and migration trends in the most precise manner possible.

Mimicry in viceroy butterflies is dependent on abundance of the model queen butterfly

Mimics should not exist without their models, yet often they do. In the system involving queen and viceroy butterflies, the viceroy is both mimic and co-model depending on the local abundance of the model, the queen. Here, we integrate population surveys, chemical analyses, and predator behavior assays to demonstrate how mimics may persist in locations with low-model abundance. As the queen becomes less locally abundant, the viceroy becomes more chemically defended and unpalatable to predators. However, the observed changes in viceroy chemical defense and palatability are not attributable to differing host plant chemical defense profiles. Our results suggest that mimetic viceroy populations are maintained at localities of low-model abundance through an increase in their toxicity. Sharing the burden of predator education in some places but not others may also lower the fitness cost of warning signals thereby supporting the origin and maintenance of aposematism.

Viceroy butterfly Limenitis archippus (Cramer) (Lepidoptera: Nymphalidae: Limenitidinae)

EENY-458, a 5-page illustrated fact sheet by Andrei Sourakov, is part of the Featured Creatures collection. It describes this black butterfly with white vertical stripes, which is similar to, but smaller than, the monarch butterfly — its synonymy, distribution, description, life cycle, hosts, and economic importance. Includes references. Published by the UF Department of Entomology and Nematology, June 2009. EENY 458/IN828: Viceroy Butterfly Limenitis archippus (Cramer) (Lepidoptera: Nymphalidae: Limenitidinae) (ufl.edu)

Isolation, Identification, and Quantification of Potential Defensive Compounds in the Viceroy Butterfly and its Larval Host–Plant, Carolina Willow

The viceroy-monarch and viceroy-queen butterfly associations are classic examples of mimicry. These relationships were originally classified as Batesian, or parasitic, but were later reclassified as Müllerian, or mutalistic, based on predator bioassays. The Müllerian reclassification implies that viceroy is unpalatable because it too is chemically defended like the queen and the monarch. However, unlike the queen and the monarch, the viceroy defensive chemistry has remained uncharacterized. We demonstrate that the viceroy butterfly (Limenitis archippus, Nymphalidae) not only sequesters nonvolatile defensive compounds from its larval host-plant, the Carolina willow (Salix caroliniana, Salicaceae), but also secretes volatile defensive compounds when disturbed. We developed liquid chromatography-mass spectrometry-mass spectrometry methods to identify a set of phenolic glycosides shared between the adult viceroy butterfly and the Carolina willow, and solid phase microextraction and gas chromatography-mass spectrometry methods to identify volatile phenolic compounds released from stressed viceroy butterflies. In both approaches, all structures were characterized based on their mass spectral fragmentation patterns and confirmed with authentic standards. The phenolics we found are known to deter predator attack in other prey systems, including other willow-feeding insect species. Because these compounds have a generalized defensive function at the concentrations we described, our results are consistent with the Müllerian reclassification put forth by other researchers based on bioassay results. It seems that the viceroy butterfly possesses chemical defenses different from its monarch and queen butterfly counterparts (phenolic glycosides vs. cardiac glycosides, respectively), an unusual phenomenon in mimicry warranting future study.

The Western Viceroy butterfly (Nymphalidae: Limenitis archippus obsoleta): an indicator for riparian restoration in the arid southwestern United States?

Life history characteristics of the Western Viceroy (Limenitis archippus obsoleta), an obligate riparian nymphalid butterfly in the desert southwestern United States, are described and related to Colorado River riparian restoration efforts. Riverine disturbance regimes and associated fluvial and hydrological dynamics may provide resources critical to this butterfly. Puddling by adult butterflies may require flood-cleared surfaces and an obligate riparian plant, Gooddings willow, was a larval host plant. This butterfly needs a variety of resources that are only found in close proximity in naturally functioning riparian ecosystems. Habitat heterogeneity required for colony persistence depends largely upon the natural dynamic character of flowing water systems. Because of the links between this butterfly and riparian structure and function it may be a useful indicator for monitoring riparian ecosystem restoration in the area.

Mimicry-related Predation on Two Viceroy Butterfly (Limenitis archippus) Phenotypes

Abstract In the eastern United States, the mimetic viceroy butterfly (Limenitis archippus) exhibits clinal variation in wing color, ranging from a tawny orange phenotype (L. a. archippus) in the N to a dark mahogany phenotype (L. a. floridensis) in Florida. Geographic distributions of these two subspecies are roughly coincident with the ranges of the viceroy's two eastern mimicry models: the monarch (Danaus plexippus) in the N, and the queen (D. gilippus) in the S. This coincidence has historically been attributed to “model-switching”: presumably, southern viceroys have switched from mimicking the monarch to mimicking the locally predominant queen, due to selective pressure exerted by visually foraging predators. As an initial test of this hypothesis, I sought evidence of selective predation on light and dark viceroys by captive red-winged blackbirds previously exposed to either monarchs or queens. Results were consistent with the model-switching hypothesis: queen-conditioned birds preferentially avoided ...

Comparative unpalatability of mimetic viceroy butterflies (Limenitis archippus) from four south-eastern United States populations.

Viceroy butterflies (Limenitis archippus), long considered palatable mimics of distasteful danaine butterflies, have been shown in studies involving laboratoryreared specimens to be moderately unpalatable to avian predators. This implies that some viceroys are Müllerian co-mimics, rather than defenseless Batesian mimics, of danaines. Here, I further test this hypothesis by assessing the palatability of wild-caught viceroys from four genetically and ecologically diverse populations in the southeastern United States. Bioassays revealed that viceroys sampled from three sites in Florida and one in South Carolina were all moderately unpalatable to captive redwinged blackbird predators, which ate fewer than half of the viceroy abdomens presented. Red-wings commonly exhibited long manipulation times and considerable distress behavior when attempting to eat a viceroy abdomen, and they taste-rejected over one-third of viceroys after a single peck. These findings, the first based on wild-caught butterflies, support the hypothesis that the viceroy-danaine relationship in some areas represents Müllerian mimicry, prompting a reassessment of selective forces shaping the interaction. Moreover, considerable variation in palatability of individual viceroys, and in behavior of individual birds, contributes to the complexity of chemical defense and mimicry in this system.

Variation in Palatability of Queen Butterflies (Danaus Gilippus) and Implications Regarding Mimicry

This study documents the existence of a food plant related palatability spectrum in Florida queen butterflies (Danaus gilippus). Abdomens of butterflies reared on four asclepiad food plants differed significantly in cardenolide content and palatability to a generalist avian predator (Red—winged Blackbird). However, unpalatability did not directly parallel food plant or butterfly cardenolide content. Queens reared on Sarcostemma clausum were cardenolide free and essentially palatable (85% eaten). Butterflies reared on Asclepias tuberosa and A. incarnata were also virtually cardenolide free, but were weakly and moderately unpalatable, respectively (62 and 46% eaten). Queens reared on the high cardenolide Asclepias curassavica contained 101—753 mg cardenolide and were very unpalatable (8% eaten). This results suggest that in addition to cardenolides, other asclepiad phytochemicals are directly or indirectly utilized by queens as components of their systemic chemical defense. The demonstrated variation in queen palatability is predicted to affect the aversive conditioning of predators and thus the outcome of queen—predator encounters. Queen populations feeding on more than one asclepiad species must exhibit automimicry, with attack rates on individual butterflies dependent upon both the proportion of palatable automimics and the noxiousness of unpalatable automodels in the population. The verification of a queen palatability spectrum also contributes to understanding the dynamics of mimicry between queens and viceroy butterflies (Limenitis archippus). This study predicts that, as a consequence of regional differences in asclepiad floras, the viceroy queen mimicry relationship in Florida switches between the Batesian and Mullerian mimicry modes. In the extreme, queens feeding on certain food plants may be Batesian mimics of sympatric, moderately unpalatable viceroys, reversing the traditionally cited mimicry roles of these butterflies.

Mimicry and viceroy butterflies

Mimicry and viceroy butterflies

Mimicry and viceroy butterflies

Mimicry and viceroy butterflies

Mimicry and viceroy butterflies

Mimicry and viceroy butterflies

Palatability of aposematic queen butterflies (Danaus gilippus) feeding onSarcostemma clausum (Asclepiadaceae) in Florida

Queen butterflies (Danaus gilippus) are generally considered unpalatable to predators because they sequester and store toxic cardenolides from their larval food plants. However, a major queen food plant in Florida, the asclepiadaceous vineSarcostemma clausum, is shown here to be a very poor cardenolide source, and queens reared on this plant contain no detectable cardenolide. A direct evaluation of queen palatability using red-winged blackbirds indicates thatS. clausum-reared butterflies are essentially palatable to these predators (85% of abdomens entirely eaten), indicating little protection from either cardenolides, other sequestered phytochemicals, or de novo defensive compounds. Wild-caught queens that presumably fed as larvae uponS. clausum and also had access to adult-obtained chemicals, such as pyrrolizidine alkaloids (PAs), were relatively palatable as well (77% of abdomens eaten); they did not differ significantly in palatability from the labreared butterflies. Together, these findings suggest that; (1)S. clausumfed queens are poorly defended against some avian predators, and (2) for the particular queen sample examined, PAs do not contribute substantially to unpalatability. The discovery thatS. clausum-feeding queens are essentially palatable is of additional significance because it compels a reassessment of the classic mimicry relationship between queen and viceroy butterflies. Viceroys have been shown recently to be moderately unpalatable; therefore, the established roles of model and mimic may be reversed in some cases.

REVISING A CLASSIC BUTTERFLY MIMICRY SCENARIO: DEMONSTRATION OF MÜLLERIAN MIMICRY BETWEEN FLORIDA VICEROYS (LIMENITIS ARCHIPPUS FLORIDENSIS) AND QUEENS (DANAUS GILIPPUS BERENICE).

Batesian and Müllerian mimicry relationships differ greatly in terms of selective pressures affecting the participants; hence, accurately characterizing a mimetic interaction is a crucial prerequisite to understanding the selective milieux of model, mimic, and predator. Florida viceroy butterflies (Limenitis archippus floridensis) are conventionally characterized as palatable Batesian mimics of distasteful Florida queens (Danaus gilippus berenice). However, recent experiments indicate that both butterflies are moderately distasteful, suggesting they may be Müllerian comimics. To directly test whether the butterflies exemplify Müllerian mimicry, I performed two reciprocal experiments using red-winged blackbird predators. In Experiment 1, each of eight birds was exposed to a series of eight queens as "models," then offered four choice trials involving a viceroy (the putative "mimic") versus a novel alternative butterfly. If mimicry was effective, viceroys should be attacked less than alternatives. I also compared the birds' reactions to solo viceroy "mimics" offered before and after queen models, hypothesizing that attack rate on the viceroy would decrease after birds had been exposed to queen models. In Experiment 2, 12 birds were tested with viceroys as models and queens as putative mimics. The experiments revealed that (1) viceroys and queens offered as models were both moderately unpalatable (only 16% entirely eaten), (2) some birds apparently developed conditioned aversions to viceroy or queen models after only eight exposures, (3) in the subsequent choice trials, viceroy and queen "mimics" were attacked significantly less than alternatives, and (4) solo postmodel mimics were attacked significantly less than solo premodel mimics. Therefore, under these experimental conditions, sampled Florida viceroys and queens are comimics and exemplify Müllerian, not Batesian, mimicry. This compels a reassessment of selective forces affecting the butterflies and their predators, and sets the stage for a broader empirical investigation of the ecological and evolutionary dynamics of mimicry.

The viceroy butterfly is not a batesian mimic

DEFENSIVE mimicry has long been a paradigm of adaptive evolution by natural selection1–3. Mimics, models and predators in a batesian mimicry system (unpalatable model, palatable mimic) exist in a very different selective milieu from those in a mullerian system (involving ≳2 unpalatable 'co-models')1,4–6. Consequently, the incorrect characterization of a mimicry relationship obscures the natural histories of populations involved and undermines attempts to test general mimicry theory by means of empirical studies of specific systems. Here, we reassess the classic case of mimicry involving viceroy butterflies, Limenitis archippus (Cramer) (Nymphalidae), and two species they purportedly mimic: the monarch, Danaus plexippus (L.), and the queen, Danaus gilippus (Cramer) (Nymphalidae: Danainae). Viceroys are historically considered palatable (batesian) mimics7,8 of the chemically defended9 danaines. Our experiment refutes this interpretation by revealing that viceroys are as unpalatable as monarchs, and significantly more unpalatable than queens from representative Florida populations. This implies that viceroys are mullerian co-mimics of the danaines and prompts a comprehensive reassessment of this widely cited exemplar of mimicry.

Unpalatability of viceroy butterflies (Limenitis archippus) and their purported mimicry models, Florida queens (Danaus gilippus).

Understanding the dynamics of defensive mimicry requires accurately characterizing the comparative palatability of putative models and mimics. The Florida viceroy butterfly (Limenitis archippus floridensis) is traditionally considered a palatable Batesian mimic of the purportedly distasteful Florida queen (Danaus gilippus berenice). I re-evaluated this established hypothesis by directly assessing palatability of viceroys and queens to red-winged blackbirds in a laboratory experiment. Representative Florida viceroys were surprisingly unpalatable to red-wings; only 40% of viceroy abdomens were entirely eaten (compared to 98% of control butterfly abdomens), and nearly one-third were immediately tasterejected after a single peck. In fact, the viceroys were significantly more unpalatable than representative Florida queens, of which 65% were eaten and 14% taste-rejected. Thus, viceroys and queens from the sampled populations exemplify Müllerian rather than Batesian mimicry, and the viceroy appears to be the stronger model. These findings prompt a reassessment of the ecological and evolutionary dynamics of this classic mimicry relationship.

Absence of Diapause in a Laboratory Strain of the Florida Viceroy Butterfly

Larvae of the southern subspecies Limenitis archippus floridensis were reared under eight photoperiod regimes (varying from LD 8:16 to LD 18:6) to determine the diapause threshold (D50; the daylength which induces 50% diapause) and critical range of photoperiods over which the frequency of diapause changes from low to very high. Previous determinations based on Vermont and Maryland strains of L. archippus archippus suggested by extrapolation thatfloridensis larvae should have a critical range between LD 10.5:13.5 and LD 12.5:11.5, with a D50 of 11.5 hr. However, all 220floridensis larvae reared at room temperature developed directly to fourth instar without diapause, regardless of photoperiod. Four interstrain crosses (fzoridensis females x Maryland archippus males) reared under LD 8:16 photophase varied widely in diapause (0-94 7O), suggesting that facultative larval diapause in this species is under polygenic control. Reasons for the absence of diapause in this floridensis strain are suggested. INTRODUCTION Many insects alter their growth and behavioral activities in response to seasonal changes. Before the onset of cold weather and short food supplies, insects in temperate climates must either diapause or migrate to a less stressful environment. Various ecological factors have been postulated to induce diapause. Photoperiod is considered to be the most important cue because it correlates well with the seasons and does not fluctuate as much as other environmental variables (Beck, 1980; Danilevskii et al., 1970). There is evidence in some species that warm temperature interacts with photoperiod and reduces the incidence of diapause (Adkisson et al., 1963; Beck, 1977; Beach, 1978; Caldwell and Wright, 1978; Hayes, 1982). The condition of the food plant affects diapause onset in some species (Danilevskii et al., 1970; Dingle et al., 1977). The ability to diapause contributes to the evolutionary success of many temperate species (Chippendale, 1982). Insects with wide geographic distributions vary in photoperiod responses. Specifically, long-day insects (which diapause in the late summer and early autumn) do so in response to longer photoperiods in northern populations and shorter photoperiods in southern populations (Beck, 1980; Danilevskii et al., 1970). This variation in photoperiod threshold has been reported by Beck (1963) to occur in Ostrinia nubilalis (Hiibner) (Lepidoptera: Pyralidae), by Tauber and Tauber (1972) in Chrysopa carnea Stephens (Neuroptera: Chrysopidae), by Masaki (1972) in Pteronemobius fascipes Walker (Orthoptera: Gryllidae), by Sims (1982) in Aedes triseriatus (Say) (Diptera: Culicidae), and by Hong and Platt (1975) in Limenitis (Basilarchia) archippus (Cramer) (Lepidoptera: Nymphalidae). The viceroy butterfly (Limenitis archippus) is common and broadly distributed throughout North America, ranging from southern Canada to Mexico. It prefers moist meadows and disturbed localities in the primary stages of succession, where its food plants, shrub willows and poplars (Salicaceae) establish rapidly. During late summer and autumn in temperate climates the third instar larvae exhibit facultative diapause in response to short-day photoperiod. They construct hibernacula in the basal portions of tubular willow leaves covered with silk (Scudder, 1889; Weed, 1926; Klots, 1951; Frankos and Platt, 1976). These tubular chambers remain open at their distal ends. This overwintering behavior is characteristic of all temperate species of the Limenitini (Lederer, 1960).