Embedded Files
Introduction:
Introduction:
Water fleas are an aquatic crustacean that can be found around the world (Ebert 2005).
The Daphnia species is made up of more than 100 specific species, all slightly different depending on their environment (ADW).
Water fleas can survive in most freshwater aquatic ecosystems, excluding extreme conditions such as hot springs (Ebert 2005).
When essential nutrients are plentiful, Daphnia reproduce asexually, and when nutrients are scarce, they reproduce sexually in order to give their offspring better chance of survival (Stollewerk 2010).
Daphnia eat mostly planktonic algae by creating a current of water with their filtering apparatus (Ebert 2005).
Daphnia are useful to humans because they are an indicator for water quality and provide cleaner water in lakes and ponds (Elenbaas).
Dapnia spp., often referred to as water fleas , are one of few organisms that can choose whether to reproduce sexually or asexually (Ebert 2005).
The primary literature is describing the study, “Effects of food availability on the acute and chronic toxicity of the insecticide methomyl to Daphnia spp.”, will explore an insecticide's effect on Daphnia (Pereira 2007).
Since Daphnia can survive in almost every freshwater ecosystem and adapt to their environment quickly they are an indicator species. As a result, this study sheds light on this insecticide's affect on the overall ecosystem (Pereira 2007).
FUN FACT: Though an aquatic organism, Water Fleas belong in the same subphylum as ticks, spiders, and other crawling creatures. All of which have shell-like outer surfaces and jointed legs (University of Florida).
Taxonomy:
Taxonomy:
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Branchiopoda
Order: Diplostraca
Family: Daphniidae
Genus: Daphnia
Species: Daphnia species
(Retrieved from Animal Diversity Web)
Study setup:
Study setup:
3 species of Daphnia were studied (Pereira 2007).
Each group were fed varied amounts (Pereira 2007).
Immobilized individuals and fecundity were recorded (Pereira 2007).
Acute exposure group: Three different species of Daphnia were exposed to different concentrations of methomyl without being supplied with food for 48hrs (Pereira 2007).
Chronic exposure group: Three different species of Daphnia were exposed to different concentrations of methomyl and fed different daily food rations over 21 days (Pereira 2007).
Data Analysis:
The fitness of Daphnia and population growth was impaired by methomyl regardless of food constraints (Pereira 2007).
Daphnia with lower food rations were not affected as drastically (Pereira 2007).
Researchers predicted that this is because the poorly fed Daphnia reallocated energy to self preservation than the normally fed Daphnia (Pereira 2007).
As in the example of reproduction, this showed scientists how effectively Daphnia adapt to their environment by reallocating energy (Pereira 2007).
Conclusion:
Methomyl is widely used because it is highly effective in killing insects, but this study proves that due to its “non-ecologically-selective profile” it effects aquatic ecosystems that it reaches by means of runoff. (Pereira 2007).
This study shows that though an insecticide's intended effect may be well studied, it must be further tested in order to identify unintended negative effects on surrounding ecosystems (Pereira 2007).
References:
Animal diversity web. ADW: Daphnia: CLASSIFICATION. (n.d.). Retrieved on February 4, 2023, from https://animaldiversity.org/accounts/Daphnia/classification/#Daphnia.
Ebert, D. “Chapter 2. Introduction to Daphnia Biology”(On-line), U.S. National Library of Medicine. Retrieved February 3, 2023 at https://www.ncbi.nlm.nih.gov/books/NBK2042/pdf/Bookshelf_NBK2042.pdf.
Elenbaas, M. (n.d.). Daphnia magna. Animal Diversity Web. Retrieved on February 14, 2023, from https://animaldiversity.org/accounts/Daphnia_magna/#food_habits
Pereira, Joana L. & Fernando Gonçalves 2007. “Effects of food availability on the acute and chronic toxicity of the insecticide methomyl to Daphnia spp.” Science of The Total Environment 386 (1-3): 9-20.
Stollewerk, A. 2010. “The water flea Daphnia– a ‘new’ model system for ecology and evolution?” (Online), PubMed Central.Viewed January 28, 2023. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871515/
University of Florida. (2015). Florida 4-H. Florida 4-H bug club. Retrieved on February 12, 2023, from https://entnemdept.ufl.edu/bug_club/bug_id/non-insect_arthropods.shtml
Page updated
Google Sites
Report abuse