Everyone has a general idea of what constitutes an insect.
Like in most habitats, they make up a diverse, prolific, interactive part of
the wetlands at Halibut Point.
Three kinds of insects have congregated visibly at this
water lily flower. The Honey Bee is visiting from some distance in a
pollination bargain. Hordes of tiny lice-like creatures are probably feeding
themselves at the expense of plant juices. A few flies resting perhaps innocuously
on petal tips may be using them as hunting promontories. The photograph
glimpses a complex, thrumming microcosm where a naturalist could wonder at
pageants of creation and destruction mirroring cycles of beauty in the world at
large.
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Aquatic Leaf Beetles
mating
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The lily pads and flowers are usefully related in the life
of the plant. Do these beetles with the metallic sheen fit in symbiotically as
they chew holes in the floating leaves? Their larvae will spend early stages of
their life under water, feeding on submerged aquatic stems and roots where they
insert specialized tubes on their hind quarters into the stem for oxygen. 1
If it can be said there is an overall calculation of balance in the biosphere,
we have to imagine the beetles playing an integral part.
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Insects consuming
floating moth corpse
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Wherever energy and nourishment are concentrated life looks
for a meal.
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Whirligig Beetles
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Among the most conspicuous pond insects are Whirligig
Beetles that spin incessantly on the water surface looking for tiny morsels to
consume. By trapping an air bubble within their outer wings (elytra) they are
able to breathe while submerged.
For the most part adults stay at the surface with split eyes
on each side of the head keeping track of activity both above and below the
water line. 2
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Water Strider
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Water Striders maneuver on the pond surface not by swimming
but by skating. Their feet are covered in thousands of microscopic hairs scored with
groves that trap air, increasing water resistance and buoyancy. This allows striders to be fast, very, very fast. A
National Geographic article reports striders are capable of “speeds of a
hundred body lengths per second. To match them, a 6-foot-tall person would have
to swim at over 400 miles an hour.” 3
As with all insects, Water Striders have three pairs of legs. The short front legs grab
prey on the surface. The middle legs act as paddles. The long back legs provide
additional power, and enable the strider to
steer and “brake.”
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Chris Leahy
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Observing and studying such abilities has occupied Chris
Leahy's attention from a young age. He says, "one of the things that draws
me to Halibut Point frequently is the variety of different habitats, including
the woodlands, the moors, and the sea of course. At the very top of the list in
terms of diverse habitats would be the various wetlands, each with its own
unique characteristics.
If wetlands are at the top of the list in terms of habitat,
then insects are at the top of the list in terms of diversity of
organisms."
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A pair of Common
Green Darner dragonflies ovipositing
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As distinct from the lake filling the main quarry, the shallow
ponds resulting from smaller mining sites at Halibut Point have been colonized
by the greatest variety of vegetation. Chris attests that each one of those has
its own insect communities, as in the case of these Green Darner dragonflies
breeding on a lily pad. Although egg fertilization has already taken place the
male continues to clasp the female in little slots in the back of her neck,
while she injects the eggs into plant tissue with her two-pronged, sharp
ovipositor.
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Painted Skimmer
dragonfly
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All dragonflies breed in wetlands. Their early stages of
life are totally aquatic. But many of them like the Painted Skimmer, once they
emerge from the water and become adults, spend their mature lives in fields and
other places, only returning to the wetlands for mating.
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A Halictid Bee
pollinating Loosestrife
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Damp pond margins stimulate lush plant growth, so that less
than a hundred years after quarrying work stopped the sterile rocky pits have
been miraculously re-vegetated and begun a process of natural ecological
succession. Insects have arrived mostly on wings and in mutual fulfillment.
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Hummingbird Clearwing
Moth
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In many cases the insects cross-fertilize the flowers that
feed them a banquet of pollen. Even the plump ones like this Clearwing Moth are
members of the great arthropod evolutionary group, along with spiders and
crustaceans, that are supported by hard exoskeleton envelopes rather than
vertebrae.
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Robber Fly, fearsomely
equipped for predation
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Although he has written extensively about them both, Chris is
more cautious about "nailing the species" of an insect than a bird from
a field sighting or photograph. Poring over an illustrated manual I assigned
this Robber Fly to the genus Proctacanthus,
probably species nigriventris. Chris
countered that the picture more likely shows a member of the genus Asilus. Pursuing its full identity would
require a much more detailed inspection of anatomical details and sorting these
through taxonomic keys, a daunting task for casual enthusiasts but meat and
potatoes for entomological sleuths.
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Spreadwing
damselflies coupling
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Chris recalls "an epiphanous moment" at six years
old noticing a newly emerged gorgeous promethia
silk moth in a neighborhood drug store window, followed by a Tiger Swallowtail
butterfly nectaring on a flower. He was hooked on an inexhaustible pursuit of natural
beauty, inquiry, and conservation.
Sources
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