SUMMARY Body size is one of the most important life history characters organisms, yet little known physiological mechanisms that regulate either body or variation in size. Here, we examined these mechanisms, critical weight, which defined as minimal mass at further growth not necessary for a normal time course to pupation. The weight occurred 55% peak larval laboratory‐reared larvae tobacco hornworm Manduca sexta. We effects genetic and environmental on As many other insects, reared poor...

The general effects of temperature and nutritional quality on growth rate body size are well known. We know little, however, about the physiological mechanisms by which an organism translates variation in diet into reaction norms or development time. outline endocrine-based mechanism that helps explain how this translation occurs holometabolous insect Manduca sexta (Sphingidae). Body time controlled three factors: (i) rate, (ii) timing cessation juvenile hormone secretion (measured critical...

Spatiotemporal variability in floral resources can have ecological and evolutionary consequences for both plants the pollinators on which they depend. Seldom, however, patterns of flower abundance visitation field be linked with behavioral mechanisms that allow visitors to persist when a preferred resource is scarce. To explore these better, we examined factors controlling preference hawkmoth Manduca sexta semiarid grassland Arizona. Here, hawkmoths forage primarily flowers bat-adapted...

Body size is controlled by mechanisms that terminate growth when the individual reaches a species-specific size. In insects, it pulse of ecdysone at end larval life causes larva to stop feeding and growing initiate metamorphosis. quantitative trait, so important problem control body be analyzed quantitatively. The processes timing secretion in larvae moth Manduca sexta are sufficiently well understood they can described rigorous manner.We develop description empirical data on determination...

Most research on plant–pollinator communication has focused sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document a cue—transient humidity gradients—using the night blooming flowers Oenothera cespitosa (Onagraceae). The headspace newly opened reaches levels about 4% above...

The evolution of body size is a dominant feature animal evolution. However, little known about how the underlying developmental mechanisms that determine change as evolves. Here we report on case in tobacco hornworm Manduca sexta occurred over period nearly 30 years. We take advantage an extensive series physiological studies performed early 1970s established parameters regulate this species and compare their values with those modern individuals are descendants same colony. show three five...

SUMMARY Virtually all aspects of insect biology are affected by body temperature,and many taxa have evolved sophisticated temperature-control mechanisms. All insects, however, begin life as eggs and lack the ability to thermoregulate. Eggs laid on leaves experience a thermal environment, thus temperature, that is strongly influenced themselves. Because plants can maintain leaf temperatures differ from ambient, e.g. evapotranspiration, plant hosts may protect extreme ambient temperatures. We...

1. An organism's environment, particularly early in development, can profoundly shape its future phenotypes. While the long-term consequences of embryonic temperature are well studied vertebrates, insects have complex life cycles that may uncouple temperature's effects one stage from physiology next. 2. This study examines how egg affects insect performance across all subsequent stages. We focused on hawkmoth, Manduca sexta, and examined temperatures affected hatching time, hatchling mass,...

The evolution of learning has long been hypothesized to be limited by fitness trade-offs such as delays in reproduction. We explored the relationship between host and reproduction cabbage white butterfly, Pieris rapae. female is innately biased search for common green hosts but can learn rare red hosts. Host was shown previously vary among full-sibling families incur costs terms efficiency brain size. In present study, we show that butterflies from full-sib with relatively better performance...

Body size and development time of Manduca sexta are both determined by the same set three developmental-physiological factors. These define a parameter space within which it is possible to analyse explain how phenotypic change associated with changes in underlying identical factors, so they not independent, but because mechanisms these factors produce each phenotype different, two phenotypes only weakly correlated, correlation context dependent. We use mathematical model this mechanism...

Sugar rush Flying requires high levels of energy production, which causes muscular oxidative damage. Food-derived antioxidants can protect against such damage; however, nectar is devoid these compounds. Levin et al. found that nectar-feeding hawkmoths fed concentrations sugar had lower damage than unfed moths. Sugar-fed moths generated antioxidant compounds by shunting glucose through a pentose phosphate pathway. This mechanism may have allowed for the evolution energy-intensive flying...

Abstract. The spatial heterogeneity hypothesis predicts a positive relationship between habitat complexity and species diversity: the greater of habitat, number in that habitat. On regional scale, this has been proposed to explain increases diversity from poles tropics: tropics are more diverse because they contain habitats. local suggests microhabitats. diversity, on is well documented. In paper, we test whether scale can latitudinal gradient scale. We determined 305 North American...

Background and AimsA deeper understanding of mutualism can be reached by studying systems with measurable costs benefits. Most studies this type focus on an unusual class obligate, species-specific pollination mutualisms. The interaction between Datura wrightii (Solanaceae) the hawkmoth Manduca sexta offers similar advantages but greater generality. Adult moths both nectar at deposit eggs same plant; larvae are herbivorous. antagonistic component has been well studied. Here role M. as a...

Abstract 1. Hawkmoths (Sphingidae) are important plant associates at two life‐history stages: larvae herbivorous, whereas adults nectar feeders and often pollinators. The diversity identities of plants used for is poorly known, however. 2. This study takes a community‐level approach to hawkmoth usage in semi‐arid grassland habitat southern Arizona, U.S.A. 3. Pollen carried on the proboscis was identified from over 700 individuals 14 species attracted lights 2‐year period. 4. Two dominated...

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, metabolic demands. In addition sugar, flower nectars contain two macronutrients-amino acids fatty acids. created artificial spiked with 13C-labelled amino fed these adult moths (Manduca sexta: Sphingidae) understand they competing sinks (reproduction, somatic tissue, fuel). found both non-essential were...

Nutrition structures ecology and evolution across all scales of biological organization. It is well known that nutrition can have direct effects on performance fitness, but indirect physiological systems mediate biotic interactions been studied less frequently. Here, we focus the interaction between nutrition, performance, immune system in a specialist herbivorous insect, Manduca sexta. We used conceptual framework nutritional (the geometric framework) to examine how changes diet quality...

Natural selection typically acts on multiple traits simultaneously. Quantitative genetics provides the theory for predicting response to of and predicts symmetrical responses (the upward both is equal their downward selection). In reality, however, simultaneous two often asymmetrical. We provide a physiology-based framework explain asymmetrical important life history traits: body size development time. The tobacco hornworm, Manduca sexta, particularly well suited such study, as physiological...

The degree and/or direction of sexual size dimorphism (SSD) varies considerably among species and populations within species. Although this variation is in part genetically based, much it probably due to the sexes exhibiting differences body plasticity. Here, we use hawkmoth, Manduca sexta , test hypothesis that moths reared on different diet qualities at temperatures will exhibit sex-specific In addition, explore proximate mechanisms potentially create plasticity by examining three...

Males and females of almost all organisms exhibit sexual differences in body size, a phenomenon called size dimorphism (SSD). How the sexes evolve to be different sizes, despite sharing same genes that control growth development, hence common genetic architecture, has remained elusive. Here, we show architecture (heritabilities correlations) physiological mechanism regulates during last stage larval development moth, differs between sexes, thus probably facilitates, rather than hinders,...

Because predation risk typically alters how prey forage for food, interactions between and food availability are commonly found. Less is known about host plant quality interact to affect behaviour physiology. Using the caterpillar, Manduca sexta , its predator, Podisus maculiventris effects of on caterpillar feeding, growth, assimilation efficiency, resting metabolic rate were tested. Overall, caterpillars low‐resistance tomato plants ( jasmonate‐insensitive ) gained 14% more mass than...