An official website of the United States government
The interaction between larval host plant quality and temperature can influence the short-term physiological rates and life-history traits of insect herbivores. These factors can vary locally, resulting in local adaptation in responses to diet and temperature, but the comparison of these interactions between populations is infrequently carried out. In this study, we examine how the macronutrient ratio of an artificial diet determines the larval growth, development, and survival of larvalPieris rapae(Lepidoptera: Pieridae) at different temperatures between two invasive North American populations from different climatic regions. We conducted a fully factorial experiment with three temperature treatments (18°C, 25°C, and 32°C) and three artificial diet treatments varying in terms of the ratio of protein to carbohydrate (low protein, balanced, and high protein). The effects of diet on life-history traits were greater at lower temperatures, but these differed between populations. Larvae from the subtropical population had reduced survival to pupation on the low-protein diet in the cold temperature treatment, whereas larval survival for the temperate population was equally high for all temperature and diet treatments. Overall, both populations performed more poorly (i.e., they showed slower rates of consumption, growth, and development, and had a smaller pupal mass) in the diet with the low protein ratio, but larvae from the temperate population were less sensitive to diet ratio changes at all temperatures. Our results confirm that the physiological and life-history consequences of imbalanced nutrition for insect herbivores may depend on developmental temperatures, and that different geographic populations ofP. rapaewithin North America vary in their sensitivity to nutritional balance and temperature.
more »
« less
The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees
In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diets are often complex and may interact with one another, necessitating the use of a geometric framework for elucidating nutritional effects. In the honey bee, Apis mellifera, nurse bees provision food to developing larvae, directly moderating growth rates and caste development. However, the eusocial nature of honey bees makes nutritional studies challenging, because diet components cannot be systematically manipulated in the hive. Using in vitro rearing, we investigated the roles and interactions between carbohydrate and protein content on larval survival, growth, and development in A. mellifera. We applied a geometric framework to determine how these two nutritional components interact across nine artificial diets. Honey bees successfully completed larval development under a wide range of protein and carbohydrate contents, with the medium protein (∼5%) diet having the highest survival. Protein and carbohydrate both had significant and non-linear effects on growth rate, with the highest growth rates observed on a medium-protein, low-carbohydrate diet. Diet composition did not have a statistically significant effect on development time. These results confirm previous findings that protein and carbohydrate content affect the growth of A. mellifera larvae. However, this study identified an interaction between carbohydrate and protein content that indicates a low-protein, high-carb diet has a negative effect on larval growth and survival. These results imply that worker recruitment in the hive would decline under low protein conditions, even when nectar abundance or honey stores are sufficient.
more »
« less
- Award ID(s):
- 1557940
- PAR ID:
- 10320293
- Date Published:
- Journal Name:
- Biology Open
- Volume:
- 6
- ISSN:
- 2046-6390
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Simone-Finstrom, Michael (Ed.)In temperate climates, honey bees rely on stored carbohydrates to sustain them throughout the winter. In nature, honey serves as the bees’ source of carbohydrates, but when managed, beekeepers often harvest honey and replace it with cheaper, artificial feed. The effects of alternative carbohydrate sources on colony survival, strength, and individual bee metabolic health are poorly understood. We assessed the impacts of carbohydrate diets (honey, sucrose syrup, high-fructose corn syrup, and invert syrup) on colony winter survival, population size, and worker bee nutritional state (i.e., fat content and gene expression of overwintered bees and emerging callow bees). We observed a nonsignificant trend for greater survival and larger adult population size among colonies overwintered on honey compared to the artificial feeds, with colonies fed high-fructose corn syrup performing particularly poorly. These trends were mirrored in individual bee physiology, with bees from colonies fed honey having significantly larger fat bodies than those from colonies fed high-fructose corn syrup. For bees fed honey or sucrose, we also observed gene expression profiles consistent with a higher nutritional state, associated with physiologically younger individuals. That is, there was significantly higher expression of vitellogenin and insulin-like peptide 2 and lower expression of insulin-like peptide 1 and juvenile hormone acid methyltransferase in the brains of bees that consumed honey or sucrose syrup relative to those that consumed invert syrup or high-fructose corn syrup. These findings further our understanding of the physiological implications of carbohydrate nutrition in honey bees and have applied implications for colony management.more » « less
-
Females of the Northern house mosquito, Culex pipiens, enter an overwintering dormancy, or diapause, in response to short day lengths and low environmental temperatures. Diapausing female mosquitoes feed exclusively on sugar-rich products rather than human or animal blood, thereby reducing disease transmission. During diapause, Major Royal Jelly Protein 1 (MRJP1) is upregulated in females of Cx. pipiens. This protein is highly abundant in royal jelly, a substance produced by honey bees (Apis mellifera), that is fed to future queens throughout larval development and stimulates longevity and fecundity. However, the role of MRJP1 in Cx. pipiens is unknown. We investigated how supplementing the diets of both diapausing and nondiapausing females of Cx. pipiens with royal jelly affects gene expression, egg follicle length, fat content, protein content, longevity, and metabolic profile. We found that feeding royal jelly to long day-reared females significantly reduced the egg follicle lengths of females and switched their metabolic profiles to be similar to diapausing females. In contrast, feeding royal jelly to short day-reared females significantly reduced lifespan and switched their metabolic profile to be similar nondiapausing mosquitoes. Moreover, RNAi directed against MRJPI significantly increased egg follicle length of short day-reared females, suggesting that these females averted diapause, although RNAi against MRJP1 also extended the lifespan of short day-reared females. Taken together, our data show that consuming royal jelly reverses the seasonal responses of Cx. pipiens and that these responses are likely mediated in part by MRJP1.more » « less
-
Nutrient composition varies greatly across landscapes, influencing the spatiotemporal dynamics of populations. However, few studies have explored this pattern across multiple scales. We tested how nutrient limitation affects herbivore populations, from individual behavior to landscape‐level dynamics, using the Australian plague locustChortoicetes terminifera. Our study combined field populations and long‐term survey data across their range. At the individual level, juvenile locusts selected a carbohydrate‐biased intake target of 1 protein (p) to 2 carbohydrate (c) and exhibited the highest growth rates and shortest development times when fed artificial diets matching this 1p:2c ratio during their final juvenile instar. In the field, locusts exposed to protein‐biased plants corrected their nutritional imbalance by initially selecting carbohydrate‐heavy diets (up to a 1p:20c ratio). Over a week after removal from the protein‐rich environment, they returned to the 1p:2c intake target once the deficiency was balanced. At the landscape level, locust outbreaks were negatively correlated with soil nitrogen and exhibited a non‐linear relationship with soil phosphorus, peaking at approximately 4% phosphorus content. By disentangling the interaction between mean annual precipitation and soil nitrogen, using comprehensive locust surveys and remotely sensed soil and weather data spanning decades, we show how environmental factors drive population dynamics. This study integrates lab, field and remote sensing approaches, highlighting the importance of nutrient balancing across scales for herbivores. Specifically, we demonstrate that low‐nitrogen environments promote locust outbreaks, likely by reducing plant protein‐to‐carbohydrate ratios. Incorporating soil quality data into locust plague forecasting models could significantly improve prediction accuracy.more » « less
-
Smolinski, Szymon (Ed.)Abstract Eastern boundary systems support major fisheries of species whose early stages depend on upwelling production. However, upwelling can be highly variable at the regional scale, leading to complex patterns of feeding, growth, and survival for taxa that are broadly distributed in space and time. The northern California Current (NCC) is characterized by latitudinal variability in the seasonality and intensity of coastal upwelling. We examined the diet and larval growth of a dominant myctophid (Stenobrachius leucopsarus) in the context of their prey and predators in distinct NCC upwelling regimes. Larvae exhibited significant differences in diet and growth, with greater seasonal than latitudinal variability. In winter, during reduced upwelling, growth was substantially slower, guts less full, and diets dominated by copepod nauplii. During summer upwelling, faster-growing larvae had guts that were more full from feeding on calanoid copepods and relying less heavily on lower trophic level prey. Yet, our findings revealed a dome-shaped relationship with the fastest growth occurring at moderate upwelling intensity. High zooplanktivorous predation pressure led to above average growth, which may indicate the selective loss of slower-growing larvae. Our results suggest that species whose spatio-temporal distributions encompass multiple regional upwelling regimes experience unique feeding and predation environments throughout their range with implications for larval survivorship.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1242/bio.022582
