miniSASS Newsletter: National Water Week Edition

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miniSASS Newsletter July 2015

miniSASS Newsletter July 2015

nunu of the month: True fly

Strip

Phylum: Arthropoda
Class: Insecta
Order: Diptera

Some true flies can tolerate really filthy oxygen depleted water and use haemoglobin (red blood worm) or “snorkels” (rat tailed) to survive in these conditions.


The true flies are a very large and very diverse group. The Diptera is one of the largest orders with most of their families having an aquatic based larval stage. Their common physical traits are their elongated worm-like bodies, eyes and pro-legs. Their bodies can also be soft and naked; others have structural adaptations like being able to stick to solid surfaces (mosquitoes and black flies).

The true flies eat dead organic matter, and some breathe through their skin, others aren’t able to get the oxygen and have special structures to get atmospheric oxygen in the air. Mosquitoes and rat tailed maggots actually have “snorkels” that are pushed through the surface film to get the oxygen. True flies are found dwelling at the bottom, adhered to different substrates or free swimming; they can swim with strong and fast wriggling motions while others crawl using suckers, spines or pro-legs to drag themselves around.

The true flies have been thought of in a bad way because they are able to survive really poor conditions and multiply rapidly in those conditions. True flies are also sometimes the hosts of deadly diseases like malaria. However, this group serve a great ecological function of decomposing dead matter and they use up the “filth” to clean the system. They score a low 2 in the miniSASS because they are not sensitive to pollution, except for the net winged midge that is found only in the clean waters of mountain streams.

True flies undergo complete metamorphosis, passing through four life stages. The eggs are deposited in shallow fast-running water, either attached to a substrate or scattered on the surface of the water. After hatching the larvae are released, this is also an aquatic phase. The pupa form and this phase does not last long, depending on the temperature of the water and the conditions. The pupa are in a case or a hardened skin, pupa also count in the miniSASS. The case splits and the young adult emerges.

Nunu Of The Month: The Other Mayflies

Other Mayflies

Phylum: Arthropoda

Class: Insecta

Order: Ephemeroptera

Mayfly larvae are the “cows” of freshwater streams and graze on algae. They swim by moving their abdomen up and down. The adult mayfly doesn’t eat at all and lives only for a few hours or days.

The other mayflies are a large group and they vary significantly. The common physical traits include three elongated tails, an elongated body, a large head, well developed mouth parts and true legs. Other mayflies have their gills on their abdomen, there is variation between the shape and the location of the gills.

The other mayflies are the cainflies which have a skirt like covering of the gills, the flat-headed mayfly that has a head broader than their body, the prongills that have gills with a unique shape and the stout crawlers that have very thick and stout arms. Others also include the brushlegged mayflies, pale burrowers and the water specs.

Other mayflies are the cows of the rivers as they graze on the algae and plant matter that grows on the rocks and on the floor in-stream. They breathe using the gills and move by swimming and crawling. The other mayflies are part of the diet of small fish, trout, frogs and birds. With a score of 11 on the miniSASS, other mayflies are moderately sensitive to pollution.

Mayflies undergo incomplete metamorphosis as they do not have a pupal stage. This involves passing through 3 life stages which are egg, nymph and adult. Each of these stages requires that the mayfly remain close to the water, the nymph is entirely aquatic whilst the adult is not aquatic but always stays close to the water.

Citizens indispensable in modern biodiversity protection

The article as it appears on The Water Wheel on the May/June 2014 volume 13 No 3 issue.

Get the whole publication online: www.wrc.org.za

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WaterWheel_2014_3_May-page-012

WaterWheel_2014_3_May-page-013

 

 

Nunu Of The Month: Stonefly

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Phylum: Arthropoda

Phylum: Insecta

Order: Plecoptera

Stoneflies love clean, oxygen rich water and so if the oxygen levels drops, stoneflies will do “push-ups” to help more water to flow past their gills. They are very sensitive to pollution with sensitivity scores ranging between 11 and 14.

Stoneflies are the grazers of the rivers, eating the algae growing on the rocks of unpolluted rivers with high abundance of oxygen. They can also be found dwelling in the bottom debris as their larval stages are only aquatic. The stoneflies are easily identifiable as they have a heavily segmented thorax and their filamentous gills are located under their arms and neck.

Stoneflies undergo complete metamorphoses which means that in their life cycle the egg hatches into the larva which does not look like the adult and it matures into the adult.

nunu of the month: Flat Worm

Aquatic Nunu’s are part of miniSASS and here we learn about their amazing facts and interesting adaptations.

This month we look at: The Flatworm

Strip

Interesting fact:

Planaria have their mouth at their stomach, breathe through their skin and can reproduce asexually by simply splitting in two or become two separate animals if cut in half

Scientific Classification

Phylum: Platyheminthes

Order: Tricladida

Genus: Planaria

Freshwater flatworms are dorsoventrally flattened with an arrow shaped head. There are very distinguishable eyespots on the head and have a white belly. Flatworms breathe through their skin and cannot swim, instead they smoothly glide over solid substrates. Flatworms are sensitive to strong light and prefer shaded areas and under rocks.

Flatworms are relatively tolerant of pollution with water quality scores ranging from  3-4. Some flatworms are carnivorous and other can be scavengers. They eat bacteria, protozoans and other animal matter that may be available.

Flatworms are hermaphroditic (having both male and female sex organs) and they reproduce both sexually and asexually. Asexual reproduction occurs under environmentally stressful conditions.

Nunu of the month: True Bug

miniSASS uses various aquatic macroinvertebrates to tell the river health and general water quality of the river water. One group that is considered is the true bug.true bugs

Interesting fact:
All bugs have piercing mouthparts. Some use these mouth parts to pierce and suck the juices out of their prey. The Nepidae use their tails as a snorkel whilst the Gerridae, Veliidae and Hydrometridae can actually walk on water!

Scientific Classification:

Kingdom: Animalia

Phylum: Arthropoda

Order: Hemiptera

Sub-order: Heteroptera
Families: Gerridae (Pond Skaters/Water Striders), Naucoridae (Creeping Water Bugs), Belastomatidae (Giant Water Bug), Corixidae (Water Boatman), Veliidae (Ripple Bugs), Hydrometridae (Water treaders), Pleidae (Pygmy Backswimmers), Notonectidae (Backswimmers), Nepidae (Water Scorpions)

Some families are predators and are carnivorous and other families eat plants in the water. Each family is structurally suited for life in the water, Veliidae, Gerridae and Hydrometridae are able to run and float on the surface whilst families like Corixidae and Notonectidae have powerful legs for swimming. Respiratory mechanisms differ between those that stay on top of the water, which would be similar to those of terrestrial macroinvertebrates, and those of the families that live below the water, which may occasionally need to come up to access more air.

True Bugs are relatively tolerant of pollution with water quality scores ranging from  3-7.

True bugs undergo incomplete metamorphosis. The young bugs are called nymphs and they look like their adult form. They moult till they become adults. Their final transformation involves the development of wings and sexual organs.

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miniSASS is a comminity river health monitoring tool

Aquatic Insects of Central Virginia

miniSASS is a comminity river health monitoring tool

River Walks

Journeys from the Source to the Sea