| predator protection versus rapid growth in a montane leaf beetle. | adults and larvae of chrysomela aenicollis (coleoptera: chrysomelidae) feed on foliage of salix species (salicaceae) between 2,400-3,400 m above sea level in the eastcentral sierra nevada mountains of california. we predicted that (1) cold climatic conditions would be a more frequent source of mortality at higher elevations, (2) mildweather agents of mortality such as predation should be more severe at lower elevations, and (3) populations of c. aenicollis would be adapted to the local selective ... | 1986 | 28311293 |
| cold tolerance of the montane sierra leaf beetle, chrysomela aeneicollis. | small ectothermic animals living at high altitude in temperate latitudes are vulnerable to lethal cold throughout the year. here we investigated the cold tolerance of the leaf beetle chrysomela aeneicollis living at high elevation in california's sierra nevada mountains. these insects spend over half their life cycle overwintering, and may therefore be vulnerable to winter cold, and prior studies have demonstrated that survival is reduced by exposure to summertime cold. we identify overwintering ... | 2015 | 26231921 |
| inferring the past and present connectivity across the range of a north american leaf beetle: combining ecological niche modeling and a geographically explicit model of coalescence. | the leaf beetle chrysomela aeneicollis occurs across western north america, either at high elevation or in small, isolated populations along the coast, and thus has a highly fragmented distribution. dna sequence data (three loci) were collected from five regions across the species range. population connectivity was examined using traditional ecological niche modeling, which suggested that gene flow could occur among regions now and in the past. we developed geographically explicit coalescence mo ... | 2014 | 24749775 |
| effects of temperature variation on male behavior and mating success in a montane beetle. | locomotion and mating ability are crucial for male reproductive success yet are energetically costly and susceptible to physiological stress. in the sierra willow beetle chrysomela aeneicollis, male mating success depends on locating and mating with as many females as possible. variation at the glycolytic enzyme locus phosphoglucose isomerase (pgi) is concordant with a latitudinal temperature gradient in these populations, with pgi-1 frequent in the cooler north, pgi-4 in the warmer south, and a ... | 2017 | 23799837 |
| effects of temperature on physiology and reproductive success of a montane leaf beetle: implications for persistence of native populations enduring climate change. | understanding how climate change impacts natural systems requires investigations of the effects of environmental variation on vulnerable species and documentation of how populations respond to change. the willow beetle chrysomela aeneicollis is ideal for such studies. it lives in california's sierra nevada on the southern edge of its worldwide range. beetles experience elevated air temperatures during summertime egg laying and larval development. exposure to these temperatures causes physiologic ... | 2017 | 18956974 |
| predator diversity and identity drive interaction strength and trophic cascades in a food web. | declining predator diversity may drastically affect the biomass and productivity of herbivores and plants. understanding how changes in predator diversity can propagate through food webs to alter ecosystem function is one of the most challenging ecological research topics today. we studied the effects of predator removal in a simple natural food web in the sierra nevada mountains of california (usa). by excluding the predators of the third trophic level of a food web in a full-factorial design, ... | 2008 | 18376555 |
| the role of stress proteins in responses of a montane willow leaf beetle to environmental temperature variation. | the heat shock response is a critical mechanism by which organisms buffer effects of variable and unpredictable environmental temperatures. upregulation of heat shock proteins (hsps) increases survival after exposure to stressful conditions in nature, although benefits of hsp expression are often balanced by costs to growth and reproductive success. hsp-assisted folding of variant polypeptides may prevent development of unfit phenotypes; thus, some differences in hsp expression among natural pop ... | 2007 | 17536167 |
| phosphoglucose isomerase genotype affects running speed and heat shock protein expression after exposure to extreme temperatures in a montane willow beetle. | eastern sierra nevada populations of the willow beetle chrysomela aeneicollis commonly experience stressfully high and low environmental temperatures that may influence survival and reproduction. allele frequencies at the enzyme locus phosphoglucose isomerase (pgi) vary across a climatic latitudinal gradient in these populations, with pgi allele 1 being most common in cooler regions and pgi allele 4 in warmer ones. pgi genotypes differ in heat and cold tolerance and in expression of a 70 kda hea ... | 2007 | 17297136 |
| allele frequency shifts in response to climate change and physiological consequences of allozyme variation in a montane insect. | rapid changes in climate may impose strong selective pressures on organisms. evolutionary responses to climate change have been observed in natural populations, yet no example has been documented for a metabolic enzyme locus. furthermore, few studies have linked physiological responses to stress with allozyme genotypic variation. we quantified changes in allele frequency between 1988 and 1996 at three allozyme loci (isocitrate dehydrogenase, idh; phosphoglucose isomerase, pgi; and phosphoglucomu ... | 2002 | 12487357 |
| functional and physiological consequences of genetic variation at phosphoglucose isomerase: heat shock protein expression is related to enzyme genotype in a montane beetle. | allele frequency variation at the phosphoglucose isomerase (pgi) locus in californian populations of the beetle chrysomela aeneicollis suggests that pgi may be undergoing natural selection. we quantified (i) apparent michaelis-menten constant (k(m)) of fructose 6-phosphate at different temperatures and (ii) thermal stability for three common pgi genotypes (1-1, 1-4, and 4-4). we also measured air temperature (t(a)) and beetle body temperature (t(b)) in three montane drainages in the sierra nevad ... | 2000 | 10944188 |
| host-plant effects on larval survival of a salicin-using leaf beetle chrysomela aeneicollis schaeffer (coleoptera: chrysomelidae). | several species of willow leaf beetles use hostplant salicin to produce a defensive secretion that consists of salicylaldehyde. generalist arthropod predators such as ants, ladybird beetles, and spiders are repelled by this secretion. the beetle larvae produce very little secretion when they feed on willows that lack salicylates, and salicin-using beetles prefer salicylate-rich willows over salicylate-poor ones. this preference may exist because the larvae are better defended against natural ene ... | 1994 | 28313629 |
| a hierarchical analysis of genetic differentiation in a montane leaf beetle chrysomela aeneicollis (coleoptera: chrysomelidae). | herbivorous insects that use the same host plants as larvae and adults can have a subdivided population structure that corresponds to the distribution of their hosts. having a subdivided population structure favors local adaptation of subpopulations to small-scale environmental differences and it may promote their genetic divergence. in this paper, i present the results of a hierarchical study of population structure in a montane willow leaf beetle, chrysomela aeneicollis (coleoptera: chrysomeli ... | 1992 | 28564415 |
| host plant preference based on salicylate chemistry in a willow leaf beetle (chrysomela aeneicollis). | chrysomela aeneicollis (coleoptera: chrysomelidae) uses salicin from its host plant (salix spp.) to produce a defensive secretion, salicylaldehyde. because it requires salicin for this secretion, i predicted that c. aeneicollis should be attracted to willows which possess salicin and other salicylates. to test this prediction, i determined the host-plant preferences of c. aeneicollis among four potential hosts which occur in the sierra nevada range of eastern california. these species have very ... | 1992 | 28312276 |
| ecological effects of salicin at three trophic levels: new problems from old adaptations. | salicin, a toxic phenol glycoside, is used by larvae of the beetle chrysomela aenicollis as a substrate for producing defensive secretions. in the east-central sierra nevada mountains of california, salicin concentrations ranged from 0.05 percent to over 5 percent of dry weight in leaves of different plants of salix orestera, the sierra willow. beetles produced more secretion and suffered less predation on willows containing more salicin. in addition, leaf damage due to herbivory among 16 willow ... | 1985 | 17739376 |