Andrei Sourakov

DNA barcoding Central Asian butterflies: increasing geographical dimension does not significantly reduce the success of species identification

DNA barcoding employs short, standardized gene regions (5’ segment of mitochondrial cytochrome oxidase subunit I for animals) as an internal tag to enable species identification. Prior studies have indicated that it performs this task well, because interspecific variation at cytochrome oxidase subunit I is typically much greater than intraspecific variation. However, most previous studies have focused on local faunas only, and critics have suggested two reasons why barcoding should be less effective in species identification when the geographical coverage is expanded. They suggested that many recently diverged taxa will be excluded from local analyses because they are allopatric. Second, intraspecific variation may be seriously underestimated by local studies, because geographical variation in the barcode region is not considered. In this paper, we analyse how adding a geographical dimension affects barcode resolution, examining 353 butterfly species from Central Asia. Despite predictions, we found that geographically separated and recently diverged allopatric species did not show, on average, less sequence differentiation than recently diverged sympatric taxa. Although expanded geographical coverage did substantially increase intraspecific variation reducing the barcoding gap between species, this did not decrease species identification using neighbour‐joining clustering. The inclusion of additional populations increased the number of paraphyletic entities, but did not impede species‐level identification, because paraphyletic species were separated from their monophyletic relatives by substantial sequence divergence. Thus, this study demonstrates that DNA barcoding remains an effective identification tool even when taxa are sampled from a large geographical area.

Causes of endemic radiation in the Caribbean: evidence from the historical biogeography and diversification of the butterfly genus Calisto (Nymphalidae: Satyrinae: Satyrini)

BackgroundCalisto is the largest butterfly genus in the West Indies but its systematics, historical biogeography and the causes of its diversification have not been previously rigorously evaluated. Several studies attempting to explain the wide-ranging diversity of Calisto gave different weights to vicariance, dispersal and adaptive radiation. We utilized molecular phylogenetic approaches and secondary calibrations points to estimate lineage ages. In addition, we used the dispersal-extinction-cladogenesis model and Caribbean paleogeographical information to reconstruct ancestral geographical distributions. We also evaluated different models of diversification to estimate the dynamics of lineage radiation within Calisto. By understanding the evolution of Calisto butterflies, we attempt to identify the main processes acting on insular insect diversity and the causes of its origin and its maintenance.ResultsThe crown age of Calisto was estimated to the early Oligocene (31 ± 5 Ma), and a single shift in diversification rate following a diversity-dependent speciation process was the best explanation for the present-day diversity found within the genus. A major increase in diversification rate was recovered at 14 Ma, following geological arrangements that favoured the availability of empty niches. Inferred ancestral distributional ranges suggested that the origin of extant Calisto is in agreement with a vicariant model and the origin of the Cuban lineage was likely the result of vicariance caused by the Cuba-Hispaniola split. A long-distance dispersal was the best explanation for the colonization of Jamaica and the Bahamas.ConclusionsThe ancestral geographical distribution of Calisto is in line with the paleogeographical model of Caribbean colonization, which favours island-to-island vicariance. Because the sister lineage of Calisto remains ambiguous, its arrival to the West Indies remains to be explained, although, given its age and historical biogeography, the hypothesized GAARlandia land bridge might have been a plausible introduction route from continental America. Intra-island radiation caused by ecological innovation and the abiotic creation of niche spaces was found to be the main force shaping Calisto diversity and island endemism in Hispaniola and Cuba.

Two heads are better than one: false head allows Calycopis cecrops (Lycaenidae) to escape predation by a Jumping Spider, Phidippus pulcherrimus (Salticidae)

The deflection of attack from vital organs to the wing margin is regarded as an important adaptation in hairstreak butterflies. However, this “lose-little-to-save-much” strategy akin to the detachable lizards tail had never been tested experimentally. The present study tests the “false head” hypothesis by exposing a hairstreak butterfly, Calycopis cecrops, as well as many other Lepidoptera species as controls, to the attacks of the jumping spider, Phidippus pulcherrimus. The results unambiguously indicate that the “false head” is a very efficient strategy in deflecting attacks from the vital centres of the hairstreak butterfly whereas other similar-sized Lepidoptera fall easy prey. Predator fatigue resulting from unsuccessful attacks was also observed, suggesting that jumping spiders can learn to avoid attacking prey they cannot capture, which would increase the efficiency of the “false head” as a defensive mechanism.

You are what you eat: native versus exotic Crotalaria species (Fabaceae) as host plants of the Ornate Bella Moth, Utetheisa ornatrix (Lepidoptera: Erebidae: Arctiinae)

Crotalaria plants and Utetheisa ornatrix are closely linked to each other: the larvae destroy the seeds, while the moth depends on hostplants for alkaloids. To better understand the ongoing co-evolution, the present study examines how native hostplants compare to exotic ones. Leaf-feeding on Crotalaria pumila, C. rotundifolia, and C. incana, native to the moth’s range, led to faster larval development than on the exotic C. lanceolata, C. spectabilis, and C. pallida. Seed-feeding on all species of Crotalaria led to accelerated larval development and a resultant larger adult moth, and correlates with a higher nitrogen content in the plant tissues. These results add a novel dimension to the previous studies of reproductive biology of this model organism. In controlled settings, mature larvae showed preference for leaves of C. spectabilis over those of other species, perhaps due to the higher alkaloid content. Differences in morphology and phenology of Crotalaria determine the ecology of U. ornatrix populations in Florida. The introduction of novel hostplants, on which U. ornatrix can have a significant negative effect and which are of concern to humans as invasive toxic weeds, has greatly expanded the niche occupied by this moth. Possible co-evolution of Utetheisa sensu lato and plant defences in the genus Crotalaria is discussed.

DNA barcodes as a tool in biodiversity research: testing pre-existing taxonomic hypotheses in Delphic Apollo butterflies (Lepidoptera, Papilionidae)

Numerous studies have demonstrated that DNA barcoding is an effective tool for detecting DNA clusters, which can be viewed as operational taxonomic units (OTUs), useful for biodiversity research. Frequently, the OTUs in these studies remained unnamed, not connected with pre-existing taxonomic hypotheses, and thus did not really contribute to feasible estimation of species number and adjustment of species boundaries. For the majority of organisms, taxonomy is very complicated with numerous, often contradictory interpretations of the same characters, which may result in several competing checklists using different specific and subspecific names to describe the same sets of populations. The highly species-rich genus Parnassius (Lepidoptera: Papilionidae) is but one example, such as several mutually exclusive taxonomic systems have been suggested to describe the phenotypic diversity found among its populations. Here we provide an explicit flow chart describing how the DNA barcodes can be combined with the existing knowledge of morphology-based taxonomy and geography (sympatry versus allopatry) of the studied populations in order to support, reject or modify the pre-existing taxonomic hypotheses. We then apply this flow chart to reorganize the taxa within the Parnassius delphius species group, solving long-standing taxonomic problems.

Foraging Behavior of the Blue Morpho and Other Tropical Butterflies: The Chemical and Electrophysiological Basis of Olfactory Preferences and the Role of Color

Inside a live butterfly exhibit, we conducted bioassays to determine whether the presence of color would facilitate the location of attractants by the butterflies. It was found that color facilitated odor attraction in some species that feed on flowers (Parthenos silvia, Heraclides thoas, Dryas julia, and Idea leuconoe), but not in the exclusively fruit-feeding species, such as Morpho helenor, hence demonstrating that species with different natural diets use different foraging cues. Green, ripe, and fermented bananas were evaluated for their attractiveness to butterflies together with honey and mangoes. The fermented bananas were determined to be the most attractive bait, and the electrophysiological responses to their volatiles were studied in Morpho helenor and Caligo telamonius. During GC-EAD evaluation, fifteen different aliphatic esters, such as isobutyl isobutyrate, butyl acetate, ethyl butanoate, and butyl butanoate (both fermentation products and fruit semiochemicals) were shown to be detected by the butterflies’ sensory apparatus located in the forelegs, midlegs, proboscis, labial palpi, and antennae. Legs, proboscis, and antennae of Morpho helenor and Caligo telamonius showed similar sensitivity, reacting to 11 chemicals, while labial palpi had a lower signal-to-noise ratio and responded to seven chemicals, only three of which produced responses in other organs.

Two Possible Caterpillar Mimicry Complexes in Neotropical Danaine Butterflies (Lepidoptera: Nymphalidae)

ABSTRACT Caterpillar mimicry is surprisingly scarce, despite many examples of apparently defended, aposematic species. Here, we describe two possible examples of caterpillar mimicry in two tribes of the Neotropical Danainae: Danaini and Ithomiini. The first example, from the Caribbean island of Hispaniola, includes two subtribes of Danaini: Danaus plexippus (L.), Danaus gilippus (Cramer), Danaus cleophile (Godart) (Danaina), Anetia briarea (Godart), and Anetia jaegeri (Ménétriés) (Itunina). The first two widespread Danaus species have unusually dark phenotypes on Hispaniola, which we suggest are the result of mimicry with endemic Caribbean danaines. The second example, from the upper Amazon of eastern Ecuador, involves four subtribes of Ithomiini: Forbestra olivencia (Bates) (Mechanitina), Hypothyris fluonia (Hewitson), Hypothyris semifulva (Salvin) (Napeogenina), Ithomia amarilla Haensch (Ithomiina), Hyposcada anchiala (Hewitson), Oleria sexmaculata (Haensch) (Oleriina), and Pseudoscada florula (Hewitson) (Godyridina). Hyposcada illinissa (Hewitson) (Oleriina) is a possible additional member. This mimicry ring shows a color pattern known only from the upper Amazon, with the caterpillar having a yellow body and bright blue anterior and posterior segments, and this pattern has clearly evolved at least four times in the Ithomiini. We suggest that precise mimicry among caterpillars may be rarer than among adult butterflies because of a lack of sexual selection to drive the initial evolution of bright colors in larvae. We also suggest that the evolution of warning colors in protected caterpillars is more difficult than in butterflies, because a novel, conspicuous caterpillar is less able to avoid capture than the more agile adult.

Faster Than a Flash: The Fastest Visual Startle Reflex Response is Found in a Long-Legged Fly, Condylostylus sp. (Dolichopodidae)

An extremely fast escape response time of less than 5 milliseconds was found in a long-legged fly of the genus Condylostylus (Dolichopodidae). This response to a visual startle reflex caused by a photographic flash was recorded repeatedly on camera and the synchronized shutter speed made it possible to measure the reflex time. Habituation was also observed in these trials. This newly recorded reflex is 3 times faster than any other previously reported. On 30 March 2011, an opportunity arose to measure the speed of reaction of another Condylostylus sp. in the same location using the same technique and equipment, and the results were very similar to those reported here.

Exotic Crotalaria Species (Fabales: Fabaceae) as Host Plants of the Ornate Bella Moth, Utetheisa ornatrix (Lepidoptera: Erebidae), in Florida: Laboratory Biology

ABSTRACT The caterpillars of Utetheisa ornatrix, the ornate bella moth, feed on host plants in the genus Crotalaria (Fabales: Fabaceae), which, in Florida, encompasses 4 native and 10 introduced species. In the laboratory, Utetheisa ornatrix male larvae developed faster and resulted in larger adults, when raised on Crotalaria incana vs. Crotalaria lanceolata (2 species native to Africa). In the wild, this can potentially give a selective advantage to individuals that develop on C. incana. The presence of these and other exotic host plants, some of which are quite common (e.g. C. pallida, C. spectabilis, C. retusa), may be skewing the evolution of U. ornatrix, as well as its phenology and distribution. A constant temperature of 60 °F (15.6 °C) caused U. ornatrix to develop twice as slowly as it did at 72 °F (22.2 °C), but it was sufficiently high for successful development. Sentinel larvae placed in cages in the field during Oct–Dec, when temperatures averaged ≈ 62 °F, developed successfully. Regardless of the rearing conditions and the host plants used in the laboratory, male larvae developed slightly more slowly than female larvae. This translated in their emerging from the pupae later than the females, which is supported by field observations.

Report of Partial Bilateral Gynandromorph of Dismorphia spio with Notes on Adult Sexual Dimorphism and Illustrations of Immature Stages

Gynandromorphs have historically attracted the attention of developmental biologists. Their morphology and biology can shed light on evolution, genetic control and the role of sexes in the animal kingdom. For instance, Zhao et al. (2010) recently described the autonomy of the somatic sex identity in chickens based on a few available chicken gynandromorphs. Butterflies have contributed to studies of gynandromorphs more than any other group of animals, thanks to their large and frequently sexually dimorphic wings and their popularity with collectors. Sibatani (1980, 1983) brought attention to the significance of these wing pattern aberrations for understanding developmental biology. An unusual population of Meleageria daphnis (Denis & Schiffermüller) blue butterfly, which contained 60% of either mosaics or bilateral gynandromorphs, was discovered in 1988 in southern Russia shortly after the Chernobyl disaster (Dantchenko et al. 1995), raising the question of a possible connection between the events. If the background radiation proves to be the cause of this phenomenon, this unusual butterfly population might prove to be a prelude of an increased rate in human birth defects in the Chernobyl region (Wertelecki 2010). Mark Scriber has used the tiger swallowtail group as a model for many years, and recently illustrated how both laboratory-obtained and wild interspecific hybrids are likely to develop into mosaic and perfect bilateral gynandromorphs (e. g., Scriber et al. 2009). He also showed, in examples of wild-collected sexual mosaics of Papilio glaucus, how certain wing-pattern-controlling genes (in this case genes controlling melanism) appear to be sex-specific, and hence account for different degrees and patterns of melanism on male and female parts of the wings. All of the above studies illustrate the importance of reporting new gynandromorphs. Observations: sexual dimorphism. Although sexual dimorphism in Dismorphia spio has been noted previously (e.g. Smith et al. 1994), only the presence/ absence of the white androconial patch on the hindwing has been mentioned as a sexually dimorphic characteristic. In addition to the genitalic differences, I have identified four characters of D. spio that differ between sexes: 1. Presence (male)/absence (female) of white androconial areas on the dorsal hindwings, as previously noted by various authors. 2. Wing-span/antennal-length ratio is greater in females than in males: Measurements of 12 males and 12 females of Dismorphia spio from Jarabacoa, Dominican Republic, chosen at random from the McGuire Center for Lepidoptera and Biodiversity (FLMNH) collection, showed non-overlapping ranges of wingspan/antennal-length ratio between the sexes (Males = 3.91 ± 0.17; Females = 4.32 ± 0.18) (T-test; P<0.0001). 3. On the forewing of the female, the postdiscal band tapers marginally. Measurements conducted on 6 males and 6 females chosen at random from the McGuire Center for Lepidoptera and Biodiversity (FLMNH) collection, showed non-overlapping ranges of band length/width in its midpoint ratio (Males = 4.1 ± 0.97; Females = 7.43 ± 1.13) (T-test; P<0.0003). 4. The anal margin of the forewing is always more rounded in males. Hence, the anal angle is not defined; instead apical margin gradually transitions into anal margin, which forms a concave line. In females, on the contrary, the anal angle is well defined, with anal margin forming a sinusoid-shaped line.