Molecular evidence for hybridization in Colias (Lepidoptera: Pieridae): are Colias hybrids really hybrids?

Abstract

Gene flow and hybridization among species dramatically affect our understanding of the species as a biological unit, species relationships, and species adaptations. In North American Colias eurytheme and Colias eriphyle, there has been historical debate over the extent of hybridization occurring and the identity of phenotypically intermediate individuals as genetic hybrids. This study assesses the population structure of these two species to measure the extent of hybridization and the genetic identity of phenotypic intermediates as hybrids. Amplified fragment length polymorphism (AFLP) marker analysis was performed on 378 specimens collected from northern California and Nevada. Population structure was inferred using a Bayesian/Markov chain Monte Carlo method, which probabilistically assigns individuals to genetic clusters. Three genetic clusters provided the best fit for the data. C. eurytheme individuals were primarily assigned to two closely related clusters, and C. eriphyle individuals were mostly assigned to a third, more distantly related cluster. There appeared to be significant hybridization between the two species. Individuals of intermediate phenotype (putative hybrids) were found to be genetically indistinguishable from C. eriphyle, indicating that previous work based on the assumption that these intermediate forms are hybrids may warrant reconsideration.

Evaluating differences in density estimation for central Iowa butterflies using two methodologies

“…Conversely, the weak-flying least skipper often remains low amongst grasses ( Opler, Lotts & Naberhaus, 2010 ). Two very closely related species (orange sulphur and clouded sulphur) produced nearly identical detection probabilities, consistent with their similar size, behaviors, and interrelatedness ( Wheat & Watt, 2008 ; Opler, Lotts & Naberhaus, 2010 ; Dwyer et al, 2015 ). Likewise, the brightly colored, wide-ranging viceroy’s detection rate was exceeded only by that of its larger, Mullerian co-mimic: the monarch ( Ritland & Brower, 1991 ; Ritland, 1995 ).…”

Compensating for climate change–induced cue‐environment mismatches: evidence for contemporary evolution of a photoperiodic reaction norm in Colias butterflies

“…Colias eurytheme Boisduval is a widespread polyvoltine species found throughout most of North America. In much of its range C. eurytheme hybridizes with Colia sphilodice and Colia seriphyle (Hovanitz 1949; Jahner et al 2011), but neither of these other species occur in the Central Valley of California, where our study focused, so no hybridization occurs there (Dwyer et al 2015). In the Central Valley, the flight season of C. eurytheme is typically from March to December with short, overlapping generations after a relatively synchronized first generation (Hoffmann 1973).…”

“…This location was about 1°N and about 140 km from Los Banos, California (37.06°N, 120.85°W, 36 m), the source of the butterflies used by Hoffmann (1973), and the habitat (low elevation alfalfa fields in an agricultural landscape) was very similar. Colias eurytheme can disperse long distances (Schweitzer 2006), and previous research found little evidence for genetic population structure across a similar distance in California (Dwyer et al 2015). We consider genetic differentiation in our focal trait between these locations unlikely, but If there was any differentiation it should be the opposite direction of our predicted response to climate change (darker individuals further north), making our analysis conservative.…”

Identification of Natural Hybrids between Ahlbergia frivaldszkyi (Lederer, 1853) and Callophrys rubi (Linnaeus, 1758) (Lepidoptera, Lycaenidae) Using Mitochondrial and Nuclear Markers

“…Hybridization is reported for different groups of butterflies, including lycaenids (Lepidoptera, Lycaenidae) (e.g., [10][11][12][13][14]), and may occur even between distinct genera or species that bear drastically different karyotypes, i.e., chromosome numbers [4,[15][16][17]. In particular, intermediate specimens tentatively characterized as natural intergeneric/intersubgeneric hybrids were found by Warren and Robbins [15] (the hybrid between Callophrys (Callophrys) sheridanii (Edwards, 1877) and Callophrys (Incisalia) augustinus (Westwood, 1852)) and Ivonin and co-authors [17] (the hybrid between Ahlbergia frivaldszkyi (Lederer, 1853) and Callophrys rubi (Linnaeus, 1758)), though conclusions about their hybrid nature were not confirmed by molecular phylogenetic analyses.…”