Water Buga and Larvae ( Notomectae ) 



Th^are found in ponds, almost always In numerous species and in vast numbers. 

 E^)€cially common and always present in divers species are Coprlxae. of predatory habits 

 and occaaionally eaten by fishes. 



The also comman and predatory back-swimming Notomecta appears shortly after culti- 

 vation, mostly as larvae, but as fully developed specimens in fall. Also other- forms, 

 such as Nepa cinerea. Ranatra linearis. Naucoris dmlcoides. and Gerrida are spawn robbers 

 and food competitors of fish. Notomecta . on account of its sting may even become a 

 nuisance to the breeder himself, at the time of drainage. 



Beetles and Beetle larvae 



tti account of their ability to fly, a great variety of beetles and beetle larvae are 

 always to be found in ponds after cultivation. The true swimming beetles are food com- 

 petitors especially noted are DytiscuSii Gybister. Colymbetes and Acilius . and they fry up 

 to a few centimeters in length. Their larvae are especially voracious. 



Spiders and Mites 



The predatory water spider is to be found, in isolated specimens, in every pond; and 

 mites are also to be found everywhere. Since fish will not eat them, they are merely food 

 competitors* Spiders, on account of their size, go also after fish hatch. 



The World of Lower Organisms in its Relation to Surroundings. 



The following classification of lower organisms — from different viewpoints — shall 

 illustrate where and vrtien the different forms are available in ponds for consumption. 



n-om the dietary-physiological viewpoint we can divide them into ihe following groups i 



(a) Large plant feeders ( Amphlpodae . mud snails, most of the encased Trichoptera, 

 caterpillars). 



(b) Small plant feeders s 



(1) Eaters of plankton algae (animal plankton) 



(2) Eaters of algae sprouts ( Stylarla. Sida. Eurycercus . ChirOTicmida. 

 doeon and similar Ephemera . Bythipia tentaculata) . 



(c) Eaters of detritus (animal plankton, Amphipodae . mud dwelling worms and 

 Chironomldae . except Tanypus ) . 



(d) Predatory aquatics j 



(1) Eaters of plankton ( Chironomida species) 



(2) Eaters of vegetation fauna and of bottom fauna (nonencased 

 Trichoptera. Phryganea . Ephemera vulgata . Sialis . Notonecta 

 glauca. water beetles and their larvae, dragon fly larvae, 

 Tanypus . water spider, mites), 



Chly some of the predatory aquatics are eaten by fish, as for instance larvae of 

 Ephemera, of Sialis . of small dragon flies, of Trichoptera. of Sayomia and of Tanypus . 



Others are merely food competitors since fish will not eat them (mites, water spiders 

 and smaller Notonectae (water bugs), and still others, larger species, are rightly feared as 

 preying upon spawn and hatch. 



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