Translate this page to:
Choose Language…
In JoVE (1)
Other Publications (5)
Articles by Aparna Telang in JoVE
JoVE Immunology and Infection
A Protocol for Collecting and Staining Hemocytes from the Yellow Fever Mosquito Aedes aegypti
Department of Biology, University of Richmond
A simplified yet accurate method to collect and stain mosquito hemocytes is described. Our method combines the simplicity of perfusion with the accuracy of high injection techniques to isolate clean preparations of hemocytes in Aedes mosquitoes. This method facilitates studies requiring knowledge of the types of hemocytes and their abundance.
Other articles by Aparna Telang on PubMed
Sexual Differences in Postingestive Processing of Dietary Protein and Carbohydrate in Caterpillars of Two Species
Previous studies indicated that female Heliothis virescens and Estigmene acrea caterpillars use both feeding and postingestive processing as mechanisms to meet nutrient demands. We present utilization and nutrient budget data on the postingestive partitioning of nutrients into pre- and postabsorptive components. Both species utilized carbohydrate efficiently except at very high ingestion rates. Of the carbohydrate utilized, more was unaccounted for as intake increased, and we assume the material unaccounted for served as a respiratory substrate. In contrast, the pattern of nitrogen utilization differed between the species. Larval H. virescens efficiently retained nitrogen except at very high ingestion rates, whereas E. acrea progressively increased nitrogen egestion in response to increased nitrogen ingestion. Overall, females of both species utilized nitrogen more efficiently than did males at most ingestion levels, thus contributing to the greater protein-derived growth we previously reported. In addition, for H. virescens, protein and amino acids accounted for a small proportion of fecal nitrogen so that most of the fecal nitrogen was of a postabsorptive nature. In contrast, nitrogen excreted by E. acrea could be partitioned into both pre- and postabsorptive components. The manner of postingestive processing by these two species reflects differences in their larval diet.
The Effect of Larval and Adult Nutrition on Successful Autogenous Egg Production by a Mosquito
Females of most mosquito species require a blood meal to provision eggs and can be medical problems because of this dependency. Autogenous mosquitoes do not require blood to mature an initial egg batch and, instead, acquire nutrients for egg provisioning as larvae. We studied the importance of larval and adult nourishment for Ochlerotatus atropalpus which is obligatory autogenous for its first egg cycle but may ingest blood for subsequent cycles. Larval nourishment strongly influenced autogenous egg production: female larvae that were nutritionally stressed emerged as smaller adults, produced fewer eggs and emerged with less protein, lipid and glycogen stores. Female Oc. atropalpus are 100% autogenous, regardless of larval diet quality or whether females are fed sugar or water at emergence. Upon completion of the first egg batch, only females emerging from a poor larval diet ingested blood and produced a second egg batch.
Effects of Larval Nutrition on the Endocrinology of Mosquito Egg Development
Reproduction by female mosquitoes is dependent on energy resources but modulated by hormones. Our study focused on blood-meal-dependent, anautogenous Aedes aegypti and autogenous Ochlerotatus atropalpus that rely on larval-derived nutrient stores to develop eggs. To determine how larval nutrition affects the endocrinology of egg development in these females, we manipulated the quantity of larval food and measured in vitro production of juvenile hormone (JH) by corpora allata (CA) and ecdysteroids by ovaries. Newly emerged A. aegypti contain lower larval-derived protein reserves, and their CA produce high amounts of JH, in comparison with similarly staged Oc. atropalpus. Ecdysteroid production was initiated in newly emerged Oc. atropalpus females, which have higher protein reserves and which develop eggs without a blood meal, which is required by A. aegypti females to complete egg development.
Larval Feeding Duration Affects Ecdysteroid Levels and Nutritional Reserves Regulating Pupal Commitment in the Yellow Fever Mosquito Aedes Aegypti (Diptera: Culicidae)
What little is known about the endocrine regulation of mosquito development suggests that models based on Lepidoptera and Drosophila may not apply. We report on basic parameters of larval development and the commitment to metamorphosis in the yellow fever mosquito Aedes aegypti that are affected by varying the length of feeding time for last instar larvae. A critical mass for pupal commitment was achieved after 24 h of feeding by last instars, also the age at which tissue production and hemolymph titers of ecdysteroids are increasing. A greater proportion of last instars successfully pupated and eclosed as adults as the length of their feeding time increased. Less than 24 h of feeding time resulted in last instars that were developmentally arrested; these larvae tolerated starvation conditions for up to 2 weeks and retained the capacity to pupate if re-fed. Starvation tolerance may be a common trait among container-inhabiting species, and this period is an important factor to be considered for vectorial capacity and control measures. To distinguish cues for metamorphosis related to a larva's nutritional status versus its age, newly molted last instars were fed for different periods of time but sampled at the same age; ecdysteroid levels, body mass and nutrient reserves were then measured for each group. Our data suggest that metamorphic capacity is dependent on a larva's nutritional condition and not just the age at which ecdysteroid titers increase. Last instars that have fed for a particular length of time may initiate their metamorphic molt when both threshold levels of nutrient reserves and ecdysteroid titer have been met. Future studies will lead to a conceptual model specific for the nutritional and hormonal regulation of mosquito post-embryonic development. This model should facilitate the exploitation of current and novel insect growth regulators that are among favored strategies for vector population suppression.
Abundance of West Nile Virus Mosquito Vectors in Relation to Climate and Landscape Variables
It is currently unclear if the potential for West Nile virus transmission by mosquito vectors in the eastern United States is related to landscape or climate factors or both. We compared abundance of vector species between urban and suburban neighborhoods of Henrico County, VA, in relation to the following factors: temperature, precipitation, canopy cover, building footprint, and proximity to drainage infrastructure. Mosquitoes were collected throughout the 2005, 2006, and 2007 seasons and tested for West Nile virus (WNV) in pools of 10-50. Test results of mosquito pools were compared to average site abundance from 37 sites in Henrico County, VA; abundance was then examined in relation to ecological variables. Urban infrastructure was positively correlated with the abundance of Culex pipiens L./Cx. restuans, and our findings implicate combined sewer overflow systems as large contributors to Culex vector populations. No measure of urbanization examined in our study was correlated with Aedes albopictus abundance. Our study showed that certain landscape variables identified using Geographic Information Systems are valuable for predicting primary WNV vector abundance in Virginia, and that temperature along with low precipitation are strong predictors of population growth. Our results support other regional studies that found WNV proliferates under drought conditions.
