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New Jersey Scuba Diving


New Jersey Scuba Diving

Freshwater Insects


Insects are almost completely lacking in the marine environment. I recall something about salt water having a very bad effect on their lungless respiratory system ( although this does not affect spiders. ) Insects are quite common in freshwater environments though, both as larvae and adults. A little digging can turn up myriad types, but be careful, some of them can bite very painfully.

Water Bugs

Freshwater Insects

These are all known as "true bugs", as opposed to beetles, flies, ants, etc. Both the larval and adult stages are aquatic, although only the adult stages are shown here. All may be found swimming or clinging to underwater plants, and must surface to breathe. All are also strong fliers that are attracted to lights at night, and have a painful and poisonous bite. Giant Water Bugs are known to feed on small fishes.

Water BoatmanWater Boatman
Arctocorixia interrupta
to 1"

extremely common

Water Strider
Gerris marginatus
to 1"

Skims along on surface of water. Flies well, but does not dive.

Water Scorpion
Ranatra fusca
to 2.5"

Not a true scorpion, but has a very painful bite.

Giant Water Bug
Lethocerus americanus
to 3"

Lethocerus americanus
to 1/2"

Water Beetles

Freshwater Insects

Beetles are differentiated from bugs by having the first pair of wings developed into armored shields, which protect the second pair of wings and the soft body. They can still fly with their second pair of wings, which fold up out of sight when not in use. Only adults are shown here.

Water Scavenger Beetle
Hydrophilus triangularis
to 1.3"

Adults feed mainly on plant matter; larvae are carnivorous. Other diving beetles are predatory.

Whirligig Beetle
Dineutes spp.
to 1/2"

Whirligigs are generally found skating along the surface, although they are also good divers and fliers.

Aquatic Larvae

Freshwater Insects

Many insects which are terrestrial as adults have aquatic larvae. Notorious among these are mosquitos. Most aquatic insects have aquatic larvae.

Caddisfly Nymph

Caddisfly larva build tube-like cases of sand, sticks, leaves, or other material.

Neophasganophora spp.
larva to 2 "

Dragonfly - Adult & Nymph
Anax spp.
larva to 1 "
adult to 3"

The clumsy-looking Dragonfly larva is actually a fierce predator, with protrusible jaws like something out of "Alien". Adults are often seen buzzing around ponds and lakes.

Dragonflies are anything but tame - this one was blown out to sea and exhausted


Freshwater Insects

Macrobdella spp.

Size: to 10"

Habitat: aquatic

Notes: It's not a nice thought, but there are leeches in our fresh waters, and in marine habitats as well. The species shown is one of the largest and most attractive, if you can say such a thing. It feeds exclusively on vertebrate blood - a good reason to wear a wetsuit, although I've never encountered one. Leeches are actually worms, not insects, but ...



I make no claim as to the accuracy, validity, or appropriateness of any information found in this website. I will not be responsible for the consequences of any action that is based upon information found here. Scuba diving is an adventure sport, and as always, you alone are responsible for your own safety and well being.

Copyright © 1996-2016 Rich Galiano
unless otherwise noted



since 2016-09-11