rgcooper2023's Journal

In a polythene bagged sample of freshwater 'Daphnia', microscopic examination was conducted on live specimens placed in a welled slide at x40 magnification, 160um in length. However, there were a substantial proportion of copepods present. The majority of free-living species feed on phytoplankton of ca. 373,000/day. Some of the larger species predate on smaller crustaceans. Benthic forms, with mouthparts adapted for scraping and biting, consume organic detritus and the bacteria growing in it. Many copepods are wholly parasitic (10) on their hosts and 3 are free-living. Hence, when one orders a sample of 'Daphnia', one has to ensure that the bag is not populated by copepods. The specimen recorded was tanked Cyclopoid Copepods, namely Acanthocyclops vernalis. These were found included with Daphnia sp. and therefore care needs to be taken when using these tiny creatures for microscopic study, so as it avoid any confusion. Ref.: Cooper, R.G. 2023. Cycloid Copepod. iNaturalist 27th November: 1.

The Phantom Midge (Family: Chaoboridae) are commonly found in ponds and still waters. This example is a juvenile or larva (ca. 7mm in length) which is nearly transparent with a partially tallow cast. It has two opaque features or airbags (one in the thorax, one in the abdomen in the second last segment). The adult forms are differentiated by wing venation and delicate flies that closely resemble Chironomidae. This larva was found in a bag of purchased Daphnia and care therefore needs to be taken to distinguish minute pond creatures when studying them microscopically.