Partially aquatic insects

1
Partially aquatic insects
Neuroptera spongillaflies Lepidoptera aquatic
catepillars Coleoptera water
beetles Heteroptera aquatic bugs Diptera fl
ies and midges
Semiaquatic insects
Collembola springtails
2
Aquatic Coleoptera
-- only about 3 of Coleoptera have an aquatic
stage -- more than 1100 spp and 18 families in
N. America -- all have mandibulate (chewing)
mouthparts -- larvae relay on cutaneous
respiration whereas adults rely on 1)
self-contained air reserves or 2) plastron
respiration. -- larvae can resemble
megalopterans -- holometabolous life-cycle
3
Coleoptera life-cycle
eggs larvae pupa adult
1-2 wks
6-12 mo (3-8 instars)
2-3 wks
lt12 mos
4
Families where larvae and adults are aquatic
Amphizoidae (1 Genus) trout-stream
beetles Dytiscidae (44 Genera) predaceous
diving beetles Gyrinidae (4 Genera) whirligig
beetles Haliplidae (4 Genera) crawling water
beetles Noteridae (5 Genera) burrowing water
beetles Hydroscaphidae (1 Genus) skiff
beetles Elmidae (26 Genera) riffle
beetles Hydrophilidae (23 Genera) scavenger
beetles
Families where either larvae or adults are aquatic
Dryopidae (3 Genera) long-toed
beetles Lutrochidae (1 Genus) Psephenidae (6
Genera) water pennies Ptilodactylidae (3
Genera) Chrysomellidae (2 Genera) Curculionidae
(15 Genera) Hydraenidae (4 Genera) moss
beetles Lampyridae (1 Genus) Scirtidae (7
Genera) marsh beetles
5
Dytiscidae
predaceous diving beetles
-- largest family of aquatic beetles --
characterized by ovate appearance rounded
sternum and dorsum -- most spp are lentic in
shallow areas of ponds, marshes, wetlands -- both
larvae and adults are predaceous, feeding
primarily on other invertebrates and small
vertebrates. Most adults are also scavengers.
6
Gyrinidae
whirligig beetles
-- small to med. Sized beetles (3-14 mm). --
often seen swimming in groups of a few to several
hundred on the surface of the water --
characteristic flattened legs and two pairs of
eyes 1 pair above and 1 pair below water. --
larvae closely resemble megalopteran larvae and
are predaceous on other inverts. Adults are
scavengers or predators of small inverts in the
surface film.
7
Haliplidae
crawling water beetles
-- small (2-5 mm) yellowish to orangish beetles
with black blotches and spots. -- often abundant
in shallow lentic and lotic vegetation-chocked
habitat -- larvae and adults are herbivorous
feeding on algae and macrophytes
8
Elmidae
riffle beetles
-- larvae and adults usually found in same stream
habitats -- adults are relatively small (lt5
mm) -- larvae and adults are herbivore-detritivore
s feeding on decaying wood, algae and
detritus. -- After emergence, adults disperse by
flying. Once they find a suitable habitat they
rarely, if ever, fly again. -- Adults rely on a
plastron of air that acts as a physical gill
9
Psephenidae
water pennies
-- flat, rounded larvae that occur on rocks and
wood in streams and wind-swept shores -- adults
are riparian, and occur in splash areas of
projecting rocks. -- larvae are primarily
scrapers that utilize periphyton and detritus
10
Hydrophilidae
water scavenger beetles
-- Adults and larvae usually found in shallow,
lentic habitats. -- In some Genera, only adults
are aquatic. -- all larvae are predators whereas
adults are characterized as scavengers feeding on
algae, dead animals and small invertebrates. --
adults resemble Dytiscidae but are flat ventrally
and usually have very long maxillary palpi. -- In
spp where adults swim, they move their thoracic
legs alternatively instead of in unison as in
Dytiscids.
11
(No Transcript)
12
Heteroptera (aquatic bugs)
-- medium-sized, paurometabolous order. About 9
of spp are aquatic, either living in the water
(217 spp) or walking on its surface (107
spp). --most species are predaceous and can
significantly impact other invert populations.
Some even prey on small fish. -- Adults can be
distinguished by their mesothoracic wings which
are hardened in the basal half and membraneous on
the surface AND by their sucking mouthparts --
usually not important in fish diets because of
secretions from scent glands.
General life-cycle for aquatic heteroptera
egg nymph adult
(few wks)
(6-12 mo)
lt 2 yrs
5 instars
13
Suborder Nepomorpha All families are aquatic
Belostomatidae (3 Genera) giant water
bugs Corixidae (17 Genera) water
boatman Naucoridae (5 Genera) creeping water
bugs Nepidae (3 Genera) water
scorpions Notonectidae (3 Genera)
backswimmers Pleidae (2 Genera) pygmy
backswimmers
Suborder Gerromorpha All families are semiaquatic
Gerridae (8 Genera) water striders Hebridae (3
Genera) velvelt water bugs Hydrometridae (1
Genus) marsh treaders Mesoveliidae (1 Genus)
water treaders Veliidae (5 Genera)
short-legged water striders
14
Belostomatidae giant water bugs
-- easily recognized by 1) large sized and 2)
pair of strap-like posterior respiratory
appendages. -- 2 genera occur in lentic habitats
and 1 is found in streams -- powerful predators
that will capture and kill anything they can
subdue --- fish, tadpoles, frogs, and other
insects. -- eggs laid on vegetation or the backs
of males which brood the eggs. -- most
belostomatids are univoltine and overwinter as
adults.
15
Corixidae water boatman
--most abundant family of Heteroptera. Most
species found in lentic habitats. -- adults
resemble Notonectidae, but are dorsoventrally
flattened and have a short, unsegmented,
triangular rostrum. -- unlike most Heteropterans,
corixids feed on detritus, algae, protozoans and
other very small inverts. -- Adults disperse
widely and on warm nights can be attracted to
lights in great numbers. -- most species are uni-
or bivoltine and overwinter as adults.
16
Nepidae water scorpions
-- can be readily identified by their long apical
breathing tubes -- found almost exclusively in
vegetated, lentic habitats -- unlike most
Heteroptera, nepids are very poor swimmers and
are usually found clinging to vegetation --
because of their breathing tubes, they can remain
completely submerged using air stores under their
hemelytra for respiration. -- usually ambush prey
such as small invertebrates. -- uni- to bivoltine
life-cycles and overwinter as adults.
17
Notonectidae backswimmers
-- unlike corixids, backswimmers swim
ventral-side-up, but orient dorsal-side-up when
not in the water. -- deeper bodied than corixids,
not at all flattened, and have an elongate,
segmented rostrum. -- found mostly in lentic
habitats. -- nymphs and adults are active
predators that pursue small invertebrates --
usually uni- to bivoltine and overwinter as
adults.
18
Gerridae water striders
-- distinguished by their relatively large size
and preapical tarsal claws. -- most species
prefer quiet areas with little wave action and
current. Usually associated with dense
vegetation. -- All gerrids are predaceous feeding
on terrestrial or aquatic insects that become
trapped in the surface film or are just
underwater. -- most species are univoltine and
can overwinter as adults or eggs.
19
Hydrometridae marsh treaders
-- Small (1-11 mm), stick-like bugs with
elongated heads. -- walk on vegetation and the
surface film of water and are usually found where
there is no wave action or current. -- feed by
using a barbed rostrum to spear small
macroinvertebrates in the surface film. Usually
found where fish are absent. -- most species are
multivoltine and overwinter as adults.