Colias Philodice Research Articles

Genetics of yellow-orange color variation in a pair of sympatric sulphur butterflies

Continuous color polymorphisms can serve as a tractable model for the genetic and developmental architecture of traits. Here we investigated continuous color variation in Colias eurytheme and Colias philodice, two species of sulphur butterflies that hybridize in sympatry. Using quantitative trait locus (QTL) analysis and high-throughput color quantification, we found two interacting large-effect loci affecting orange-to-yellow chromaticity. Knockouts of red Malpighian tubules (red), likely involved in endosomal maturation, result in depigmented wing scales. Additionally, the transcription factor bric-a-brac can act as a modulator of orange pigmentation. We also describe the QTL architecture of other continuously varying traits, together supporting a large-X effect model where the genetic control of species-defining traits is enriched on sex chromosomes. This study sheds light on the range of possible genetic architectures that can underpin a continuously varying trait and illustrates the power of using automated measurement to score phenotypes that are not always conspicuous to the human eye.

Cattle grazing results in greater floral resources and pollinators than sheep grazing in low-diversity grasslands.

Land‐use and land‐cover change associated with agriculture is one of the main drivers of biodiversity loss. In heavily modified agricultural landscapes, grazing lands may be the only areas that can provide essential resources for native grassland species. Management decisions, such as choice of livestock species, affect the extent to which grazing lands provide suitable habitat for native species such as pollinators.Our study compared how sheep versus cattle herbivory affected floral resources and butterfly abundance across low‐diversity, former Conservation Reserve Program (CRP) pastures managed with patch‐burn grazing.Across all years (2017–2019), flowering species richness and abundance were significantly higher in cattle pastures than sheep pastures. On average, we recorded 6.9 flowering species/transect in cattle pastures and 3.8 flowering species/transect in sheep pastures. The average floral abundance per transect was 1278 stems/transect in cattle pastures and 116 stems/transect in pastures grazed by sheep.Similarly, we observed higher butterfly species richness, diversity, and abundance in cattle than in sheep pastures. In cattle pastures, we observed an average of 75 butterflies and 6.75 species per transect, compared with an average of 52 butterflies and 3.37 species per transect in sheep pastures. However, the butterfly community composition did not significantly differ between grazing treatments likely because agricultural‐tolerant, habitat generalists comprised the majority of the butterfly community. Five generalist butterflies comprised 92.3% of observations; Colias philodice was the most abundant (61% of observations). Speyeria idalia and Danaus plexippus, two butterflies of conservation concern, comprised less than 0.5% of butterfly observations.Our results, which are among the first attempt quantifying butterfly use of post‐CRP fields grazed by livestock, show that increased precipitation and cattle grazing promoted higher forb abundance and richness. However, additional interventions may be needed to enhance floral resources to sustain and improve pollinator diversity in these landscapes.

Photo Essay: Observations on the Late Season Emergence of Clouded Sulphur Butterflies (Colias philodice) at High Park, Derby, Kansas

Photo Essay: Observations on the Late Season Emergence of Clouded Sulphur Butterflies (Colias philodice) at High Park, Derby, Kansas

Genetic Variation Influences Tolerance to a Neonicotinoid Insecticide in 3 Butterfly Species.

Neonicotinoid pesticides harm nontarget insects, but their sublethal effects on butterflies are understudied. We exposed larvae of 3 butterfly species (Pieris rapae, Colias philodice, and Danaus plexippus) to low levels of the neonicotinoid imidacloprid in their host plants and followed individuals to adulthood. Imidacloprid altered adult body size, especially in female monarchs, but its effects varied across maternal families, highlighting the importance of considering genetic variation in ecotoxicological testing. Environ Toxicol Chem 2020;39:2228-2236. © 2020 SETAC.

Butterflies Recorded on Flattop Mountain, Anchorage, Alaska

Eleven species of butterflies were recorded on Flattop Mountain, Anchorage, Alaska, during a four-day period in July 2006: Colias philodice vitabunda (Clouded Sulphur), Pieris angelika angelika (Arctic White), Lycaena dorcas arcticus (Dorcas Copper), Plebejus glandon bryanti (Arctic Blue), Plebejus idas alaskensis (Northern Blue), Plebejus optilete yukona (Cranberry Blue), Boloria charliclea butleri (Purplish Fritillary), Boloria alaskensis alaskensis (Mountain Fritillary), Speyeria mormonia bischoffii (Mormon Fritillary), Oeneis bore mckinleyensis (White-veined Arctic), and Carterocephalus palaemon skada (Arctic Skipperling). Based on previously published distribution maps, the records for Plebejus idas and P. optilete represent range extensions; P. optilete was relatively common in sheltered valleys on the mountain.

Performance of the legume-feeding herbivore, Colias philodice (Lepidoptera: Pieridae) is not Affected by Elevated CO2

Presumably due to their association with nitrogen-fixing bacteria, the nutritional quality of legumes decreases less than that of non-legume C3 plants when grown under elevated atmospheric CO2. Therefore, it seems likely that legume-feeding herbivores will be less adversely affected than herbivores of non-legume C3 plants by anthropogenic increases in atmospheric CO2. When the legumes Medicago sativa (alfalfa), Trifolium repens (white clover), and Lotus corniculatus (birdsfoot trefoil) were grown under elevated (756 ppm) CO2, leaf nitrogen remained the same or increased, and C:N ratio did not change. Unlike most insects fed non-legume C3 plants, Colias philodice (sulfur butterfly) larvae fed elevated-grown M. sativa and T. repens did not exhibit reduced relative growth rate (RGR), and larvae fed elevated-grown L. corniculatus exhibited a nearly significant 37% increase in RGR. Pupal weight was unaffected by growth of host plants under elevated CO2. Relative nitrogen growth rate (RGRN) did not change for larvae fed elevated-grown M. sativa or T. repens, but increased by 34% for larvae fed elevated-grown L. corniculatus. These results suggest that legume-feeding herbivores will be relatively buffered against the adverse effects of elevated CO2 typically experienced by herbivores of non-legume C3 plants.

Are legume-feeding herbivores buffered against direct effects of elevated carbon dioxide on host plants? A test with the sulfur butterfly, Colias philodice

When grown under elevated atmospheric carbon dioxide (CO2), leaf nitrogen content decreases less for legumes than for nonlegume C3 plants. Given that elevated CO2 adversely affects insect herbivores primarily through dilution of plant nitrogen, it is reasonable to expect that legume-feeding herbivores will be relatively buffered against CO2-induced reduction in performance. However, despite their ecological and economic importance, very few studies have addressed the effects of elevated CO2 on legumefeeding herbivores. Unlike the responses of the vast majority of nonlegume C3 plants, when the legumes Trifolium pratense and Melilotus alba were grown under elevated (742ppm) CO2, leaf nitrogen and carbon contents and C:N ratios did not change. For Colias philodice larvae fed T. pratense, elevated CO2 had little or no effect on consumption, digestion, or conversion of whole food or nitrogen and, consequently, no effect on growth rate, instar duration, or pupal weight. For larvae fed M. alba, elevated CO2 had little or no effect on consumption of whole food or nitrogen, increased digestion but decreased conversion of both and, consequently, had no effect on growth rate, instar duration or pupal weight. These results suggest that, relative to herbivores of nonlegume C3 plants, legume-feeding herbivores will be less affected as atmospheric CO2 continues to rise.

Parallel evolution in sympatric, hybridizing species: performance ofColiasbutterflies on their introduced host plants

AbstractShared ancestry and introgression can contribute to genetic similarity between hybridizing species, and it is generally difficult to disentangle these causes. However, shared ancestry plays a more limited role in traits that have recently undergone parallel directional selection in the two species, permitting the role of introgression to be better understood. The butterfliesColias eurytheme(Boisduval) andColias philodice(Godart) (Lepidoptera, Pieridae) are native to North America and have shifted their host ranges in parallel onto several introduced weedy and agricultural legumes. These butterflies hybridize at moderate rates throughout their range, and there is a strong possibility that they could be sharing host‐associated adaptations. We split families of each species among nine introduced, prospective hosts and measured survivorship, larval duration, pupal weight, and a new variable, effective daily growth rate (DGR), analogous to a compound daily interest rate in economics. We found strong effects of host, sex, and family (species), but negligible effects of the host*species interaction that would indicate species‐specific differences in performance on different hosts. We found species‐specific life‐history differences:C. eurythemematured significantly later and reached a significantly larger body size thanC. philodicewhile growing at the same DGR. Protandry was strong, and males, in addition to pupating sooner than females, grew significantly faster than females as measured by DGR. We measured broad‐sense heritabilities and genetic correlations for host‐associated performance variables. Most pairwise comparisons of performance among hosts and most pairwise comparisons between performance variables showed positive genetic correlations, except survivorship where little heritability was found. Nevertheless, a factorial multivariate analysis of variance of G‐matrices showed highly significant species, host, and host*species interactions, suggesting differentially evolving genetic architectures underlying host adaptation in these two species, despite the small differences in overall performance. At least some of the genes affecting host performance inColiasare likely to be in the small, species‐diagnostic regions and not shared via introgression between these hybridizing species. For biologists interested in the evolutionary ecology of their host associations, including applied biologists managing their agricultural pest potential,C. eurythemeandC. philodiceare most usefully studied as if they were a single polymorphic species wherever they co‐exist. In studying species that hybridize readily with a sympatric congener, it may often be necessary to include the second species in the experimental design.

THE EVOLUTION OF WING COLOR: MALE MATE CHOICE OPPOSES ADAPTIVE WING COLOR DIVERGENCE IN COLIAS BUTTERFLIES

Correlated evolution of mate signals and mate preference may be constrained if selection pressures acting on mate preference differ from those acting on mate signals. In particular, opposing selection pressures may act on mate preference and signals when traits have sexual as well as nonsexual functions. In the butterfly Colias philodice eriphyle, divergent selection on wing color across an elevational gradient in response to the thermal environment has led to increasing wing melanization at higher elevations. Wing color is also a long-range signal used by males in mate searching. We conducted experiments to test whether sexual selection on wing melanization via male mate choice acts in the same direction as natural selection on mate signals due to the thermal environment. We performed controlled mate choice experiments in the field over an elevational range of 1500 meters using decoy butterflies with different melanization levels. Also, we obtained a more direct estimate of the relation between wing color and sexual selection by measuring mating success in wild-caught females. Both our experiments showed that wing melanization is an important determinant of female mating success in C. p. eriphyle. However, a lack of elevational variation in male mate preference prevents coevolution of mate signals and mate preference, as males at all elevations prefer less-melanized females. We suggest that this apparently maladaptive mate choice may be maintained by differences in detectability between the morphs or by preservation of species recognition.

The evolution of wing color in Colias butterflies: heritability, sex linkage, and population divergence.

We investigated the genetic background of intraspecific variation in wing color across an elevational gradient in the butterfly Colias philodice eriphyle. The degree of wing melanization was an accelerating function of elevation, and differences in wing melanization persisted in a common environment. Full-sibling analysis and parent-offspring regression yielded consistent, moderate to high heritabilities for the degree of wing melanization. The breeding experiments also demonstrated that wing melanization is strongly sex linked. Because traits that differentiate sister species also tend to be sex linked, our results suggest that the genetic mechanisms underlying intraspecific differences in wing melanization are not fundamentally different from those that have been shown to differentiate sister species.

Nectar Sources of Day-Flying Lepidoptera of Central Illinois

Abstract We tabulated flowering plant species visited by 98 species of Lepidoptera as extracted from records of C. Robertson, who observed >15,000 insect visitors of flowering plants in central Illinois during a 33-yr period. Diversity of Lepidoptera was highest on plant species of the Asclepiadaceae and Verbenaceae, and the greatest number of lepidopteran species visited Verbena stricta Ventenat (Verbenaceae), Aster pilosus Willdenow (Asteraceae), Cephalanthus occidentalis L. (Rubiaceae), and Pycnanthemum flexuosum (Walter) Britton, Sterns, Poggenberg (Lamiaceae). Lepidopterans were particularly abundant on A. pilosus and C. occidentalis. The most polyphagous lepidopteran species were Colias philodice Godart (Pieridae), Danaus plexippus (L.) (Danaidae), Artogeia rapae (L.) [=Pieris rapae (L.); Pieridae], Phyciodes tharos (Drury) (Nymphalidae), Polites themistocles (Latreille) (Hesperiidae), Pontia protodice (Boisduval & LeConte) (Pieridae), and Everes comyntas (Godart) (Lycaenidae), each of which visited...

PREDICTING HOST RANGE EVOLUTION: COLONIZATION OF CORONILLA VARIA BY COLIAS PHILODICE (LEPIDOPTERA: PIERIDAE).

Extensive sympatry is currently arising between the common sulfur butterfly, Colias philodice Latreille (Lepidoptera: Pieridae) and a potential leguminous host plant, Coronilla varia (L.). In laboratory trials, larval surviviorship and growth were higher on the primary host, Medicago sativa (L.), than on the nonhost C. varia. However, because females reared from C. varia were on average more fecund than females reared from M. sativa, fitness on C. varia (approximately as survivorship times fecundity) was commensurate with fitness on M. sativa. Thus, it is predicted that selection would favor oviposition on C. varia, if such behavior were to arise. In addition, significant among-family variation exists for several measures of larval performance on both C. varia and M. sativa, indicating that C. philodice can potentially respond to selection for increased performance on each species. Moreover, larval performance was significantly positively correlated across these species, suggesting that selection for increased performance on each species will facilitate, not constrain, evolution of increased performance on the other. It is concluded that behavioral rather than physiological barriers currently account for the absence of C. philodice from C. varia and that, if such barriers are overcome, C. philodice will expand its host plant range to include C. varia.

Facultative monophagy as a consequence of prior feeding experience: behavioral and physiological specialization in Colias philodice larvae.

Although newly-emerged Colias philodice readily accept Medicago sativa, Melilotus alba, and Coronilla varia, fifth instar larvae reared on any single plant species display a highly significant induced feeding preference for their rearing host. Forced host-switching reveals that fifth instar relative growth rate (RGR) on M. sativa and M. alba is significantly reduced by prior feeding on either alternative host. Moreover, regardless of rearing diet, switching to a novel host during the fifth instar results in reduced RGR, relative consumption rate (RCR), efficiency of conversion of digested food (ECD), and pupal weight. These results support the hypothesis that induction of feeding preference is an adaptive response that predisposes larvae to feed on the plant species they are most capable of utilizing for growth.

Herbivore Induced Changes in Leaf-Litter Resource Quality: A Neglected Aspect of Herbivory in Ecosystem Nutrient Dynamics

production and oviposition in the tobacco budworm: effect of age and mating. Ann. Ent. Soc. Am. 75: 51-55. Stern, V. M. and Smith, R. F. 1960. Factors affecting egg production and oviposition in populations of Colias philodice eurytheme Boisduval (Lepidoptera: Pieridae). Hilgardia 29: 411-454. Taylor, L. R. 1975. Longevity, fecundity and size; control of reproductive potential in a polymorphic migrant, Aphis fabae Scop. J. Anim. Ecol. 44: 135-159. Wiklund, C. and Persson, A. 1983. Fecundity, and the relation of egg weight variation to offspring fitness in the speckled wood butterfly Pararge aegeria, or why don't female butterflies lay more eggs? Oikos 40: 53-63.

Resource Allocation to Oocytes: Heritable Variation with Altitude in Colias philodice eriphyle (Lepidoptera)

Resource Allocation to Oocytes: Heritable Variation with Altitude in Colias philodice eriphyle (Lepidoptera)

The Evolution of Egg Clustering by Butterflies and Other Insects

On met en evidence le fait que la ponte en grappes chez de nombreux lepidopteres (et d'autres insectes) a evolue en reponse a la selection pour une fecondite accrue

Sources of intraspecific variation in the hostplant seeking behavior of Colias butterflies.

Egg-laying females of the legume-feeding butterfly Colias philodice eriphyle were observed within a high-altitude study site during 1977 and 1978. Average oviposition selectivity showed two patterns of seasonal variation. First, second-brood females laid eggs more frequently after alighting upon hostplants than did first-brood females in both years. Second, a consistent decline in post-alighting oviposition probability near the end of the second brood corresponded with a dramatic decrease in the water content of hostplant foliage near the end of the dry summer season. In addition to seasonal variation in oviposition behavior, individual females landed and oviposited upon widely varying sets of legume hostplant species. By sampling hostplant abundances along the flightpaths of observed females, we show that individuals varied in their tendency to land upon different hostplants. Females tended to specialize upon one or two species, at least in the short term, and the pattern of oligophagy for the population as a whole is partly generated by variation in the host-seeking behavior of individual females.

Sources of intraspecific variation in the hostplant seeking behavior of Colias butterflies.

Egg-laying females of the legume-feeding butterfly Colias philodice eriphyle were observed within a high-altitude study site during 1977 and 1978. Average oviposition selectivity showed two pattern sof seasonal variation. First, second brood females laid eggs more frequently after alighting upon hostplants than did first brood females in both years. Second, a consistent decline in post-alighting oviposition probability near the end of the second brood corresponded with a dramatic decrease in the water content of hostplant foliage near the end of the dry summer season. In addition to seasonal variation in oviposition behavior, individual females landed and oviposited upon widely varying sets of legume hostplant species. By sampling hostplant abundances along the flightpaths of observed females, we show that individuals varied in their tendency to land upon different hostplants. Females tended to specialize upon one or two species, at least in the short term, and the pattern of oligophagy for the population as a whole is partly generated by variation in the host-seeking behavior of individual females.

Host Range Evolution: The Shift From Native Legume Hosts to Alfalfa by the Butterfly, Colias philodice eriphyle

Host Range Evolution: The Shift From Native Legume Hosts to Alfalfa by the Butterfly, Colias philodice eriphyle

Responses of pest and non-pest Colias butterfly larvae to intraspecific variation in leaf nitrogen and water content.

This study examined the effects of intraspecific variation in leaf nitrogen and water content on the growth, consumption, conversion efficiency and nitrogen use of Colias butterfly larvae. Pest and non-pest Colias philodice eriphyle larvae and Colias eurytheme larvae were fed field-collected alfalfa (Medicago sativa) and vetch (Vicia americana) leaves in laboratory experiments. In all treatments, at least one indicator of larval growth performance was positively correlated with leaf nitrogen content, which supports the view that nitrogen is a limiting nutrient for larval growth. The benefits associated with eating leaves with high nitrogen content included higher growth rates, conversion efficiencies, nitrogen accumulation rates and larval nitrogen contents. Over the ranges examined in this study, variation in leaf nitrogen content (2.8-7.0% dry wt) affected larval growth more than variation in leaf water content (66-79% fresh wt). Pest and non-pest C. p. eriphyle responded alike to variation in the leaf nitrogen content of vetch, but there were differences between populations on alfalfa. Pest larvae were more sensitive to variation in leaf water content than non-pest larve. The differences between these populations may be due to specific adaptations resulting from the shift to alfala by pest Colias. It is suggested that herbivores' responses to intraspecific variation in leaf nitrogen content may have important consequences for the evolution of plant defenses and nutrient allocation patterns, and for agricultural pest management.