Speyeria mormonia

About: Speyeria mormonia is a research topic. Over the lifetime, 15 publications have been published within this topic receiving 1240 citations. The topic is also known as: Mormon fritillary.

Larval food limitation in butterflies: effects on adult resource allocation and fitness.

Abstract: Allocation of larval food resources affects adult morphology and fitness in holometabolous insects. Here we explore the effects on adult morphology and female fitness of larval semi-starvation in the butterfly Speyeria mormonia. Using a split-brood design, food intake was reduced by approximately half during the last half of the last larval instar. Body mass and forewing length of resulting adults were smaller than those of control animals. Feeding treatment significantly altered the allometric relationship between mass and wing length for females but not males, such that body mass increased more steeply with wing length in stressed insects as compared to control insects. This may result in changes in female flight performance and cost. With regard to adult life history traits, male feeding treatment or mating number had no effect on female fecundity or survival, in agreement with expectations for this species. Potential fecundity decreased with decreasing body mass and relative fat content, but there was no independent effect of larval feeding treatment. Realized fecundity decreased with decreasing adult survival, and was not affected by body mass or larval feeding treatment. Adult survival was lower in insects subjected to larval semi-starvation, with no effect of body mass. In contrast, previous laboratory studies on adult nectar restriction showed that adult survival was not affected by such stress, whereas fecundity was reduced in direct 11 proportion to the reduction of adult food. We thus see a direct impact of larval dietary restriction on survival, whereas fecundity is affected by adult dietary restriction, a pattern reminiscent of a survival/reproduction trade-off, but across a developmental boundary. The data, in combination with previous work, thus provide a picture of the intra-specific response of a suite of traits to ecological stress.

The effect of adult food limitation on life history traits in speyeria mormonia (lepidoptera: nymphalidae)'

Abstract: Variation in food availability is likely to occur in the wild, and may affect resource allocation to various life history traits. Quantitative adult diet restriction had no effect on life-span or mean individual egg mass, but reduced fecundity in the butterfly Speyeria mormonia. The sum of fecundity plus unlaid oocytes remaining in the ovaries at death declined in direct proportion to the reduction in the adult diet. This indicates that oocytes were resorbed and resources re-allocated away from reproduction under resource stress, since the sum of laid and unlaid eggs for butterflies fed ad libitum did not differ from the number of oocytes present in the ovaries at eclosion. In this nectivorous species, then, life-span is conserved at the expense of reproduction under adult resource stress. Further, for butterflies fed ad libitum, the volume of honey-water imbibed declined with age for both sexes. Daily volume imbibed by females fed ad libitum was directly correlated with daily egg production and life-span, suggesting that factors as yet unexplored may be affecting both resource intake and life history traits when resources are available ad libitum.

Reproductive strategies of female butterflies: variation in and constraints on fecundity

Abstract: . 1 This study first examines the reproductive strategy of female Speyeria mormonia Edwards (Lepidoptera: Nymphalidae): 2 Egg weight and number laid per day decrease with age. 3 Survival and daily egg number may be affected by temperature; mean daily egg weight is not affected by temperature. 4 Daily egg number is not correlated with body size. In the central range of body size, egg weight is also not correlated with body size. However, exceptionally large or small females lay respectively heavier or lighter eggs than average. 5 A simple trade-off between offspring size and number does not occur within females on a daily basis, or among females averaged over their lifespans. 6 Fat body resources are depleted at a rate independent of body size. 7 Females are essentially monogamous. 8 Age-specific fecundity data reported here for S.mormonia are next compared with data for other Lepidoptera with different adult feeding habits and egg maturation patterns, and hence different possibilities for adult feeding to play a role in egg production. Based on these comparisons, I propose that the shape of the age-specific fecundity curve for each species under optimal conditions is constrained by the potential importance of adult nutrients in egg production.

Making eggs from nectar: the role of life history and dietary carbon turnover in butterfly reproductive resource allocation

Abstract: The diets of many butterflies and moths change dramatically with development: from herbivory in the larvae to nectarivory in the adults. These diets are nutritionally distinct, and thus are likely to contribute differentially to egg manufacture. We examine the use of dietary resources in egg manufacture by four butterfly species with different patterns of oviposition and lifespan; three in the Nymphalidae (Euphydryas chalcedona, Speyeria mormonia and Heliconius charitonia ), and one in the Pieridae (Colias eurytheme ). Each species was fed two isotopically distinct adult diets based on sucrose, both of which differed from the larval hostplant in 13 C content. Egg isotopic composition was analyzed to quantify the contribution of carbon from the larval and adult diets to egg manufacture. In all four species, egg 13 C content increased to an asymptotic maximum with time, indicating that adult diet is an increasingly important source of egg carbon . The 13 C increase closely resembled that of a nectar-feeding hawkmoth, and was well-described by a model of carbon flow proposed for that species. This similarity suggests that the turnover from larval to adult dietary support of egg manufacture is conserved among nectar-feeding Lepidoptera. Species varied widely in the maximum % egg carbon that derives from the adult diet, from 44% in E. chalcedona to nearly 80% in S. mormonia . These differences were related both to the extent of oocyte provisioning prior to adult emergence, and to egg composition. A species’ lifetime use of larval vs adult resources in egg manufacture reflected both the carbon turnover of the eggs and the timing of oviposition. Thus, the extent to which dietary resources are important in egg manufacture in butterflies depends on development (egg provisioning in teneral adults), behavior (timing of oviposition) and nutritional physiology (nutrient synthesis and turnover).

Dynamics of reproductive allocation from juvenile and adult feeding: radiotracer studies

Abstract: Nutrients used in reproduction may come from adult feeding or reserves stored from the juvenile stage. The dynamics of allocation from these sources are predicted to differ among nutrient types, depending on the relative availability of each nutrient type from adult and juvenile feeding. Using radiotracer techniques, I examined reproductive allocation of glucose and amino acids from adult and juvenile sources in two nymphalid butterflies, Euphydryas editha and Speyeria mormonia. The species used were intermediate in expected importance of adult nutrients to egg production, with abundant carbohydrates but few nitrogenous compounds available from the adult diet. As predicted, for compounds abundantly available in the adult diet, incoming nutrients were used in preference to stored nutrients. For compounds present in low amounts in the adult diet, juvenile reserves were used throughout adult life, although adult sources were used if available. Nutrients received by the female from the male at mating, although expected to be treated as stored reserves, were immediately used in egg production. Thus, restriction of adult or juvenile feeding may cause different nutrient types (e.g., carbohydrates, nitrogenous compounds) to become limiting to reproduction. These results are consistent with earlier allocation studies examining age-specific changes in body mass and reproductive effort, and the effects on fecundity of quantitative adult food reduction. The work has implications for understanding the evolution of nutrient types donated by males to females, the effects of a holometabolous lifestyle on age-specific fecundity, and the effects of using stored reserves vs. income in reproduction. The present results allow further predictions concerning effects of food supply perturbation on fecundity and, hence, population dynamics, and suggest ways in which species and individuals will differ in sensitivity to those perturbations.