Bugs on the pond surfaces of Halibut Point catch the
attention of insectivorous birds, even if those morsels are not visible to our
own eyes.
 |
| Tree Swallow dipping for bugs |
Swooping swallows pluck them off the water when the birds
dip down out of their gyres over the quarry.
 |
Eastern Phoebe
plunging from a branch |
At the quarry's edge a phoebe waits on a promontory for a
prospective meal, then dives and hovers to pluck it from the water surface without
immersing itself.
 |
Water Strider, Rheumatobates vegatus, consuming an
aphid |
It's hard to know precisely what bugs the bird is catching. One
of them, a Water Strider, is busy searching for its own prey.
 |
Water Strider, Gerris sp., held afloat by surface
tension |
Thus far I've been using 'bug' in the looser, vernacular sense. Water
Striders are True Bugs (heteroptera),
characterized by four flight wings, piercing-sucking mouthparts, and partly
leathery, partly membranous forewings. The fine hairs covering their middle and
hind 'feet' allow them to skate quickly over the surface while their forelegs
are held above the water for grasping.
 |
Longlegged Fly, Dolichopodidae, closing in on a stranded
ant. |
Despite casual similarities in
appearance and behavior this fly is not technically a bug. With only two flight
wings and with sucking rather than piercing mouthparts, it belongs to a
different taxonomic order of insects, the diptera
(two wings.)
 |
Shore Bug, Saldidae |
Shore Bugs meet all the criteria of the heteroptera classification. They are found very close to water
though not actually in it or on it.
 |
Whirligig Beetles, Gyrinidae |
These frenetically
spinning creatures often seen on pond surfaces are a beetle (the order coleoptera, from the Greek meaning
'sheath-winged) rather than a bug because their shell-like protective forewings
are held aside during flight rather than utilized in propulsion, and they have
chewing mandibles rather than piercing-sucking mouthparts.
The compound eyes of Whirligig Beetles are divided
for seeing both above and below water level. Their middle and rear legs are
greatly flattened and fringed with bristles that fold to aid swimming action. The
longer front legs are adapted for grasping food or prey.
 |
| Giant Water Bug, Belostomatidae |
Below the surface live the largest of the local True Bugs,
at two inches long earning their name Giant Water Bug. Their oar-like middle
and hind legs are well adapted for swimming, their raptorial forelegs menacing
to all manner of small pond creatures. They breathe snorkel-like through a
short tube that can be retracted into the abdomen.
***
We've seen in this posting on insects informally titled
"Water Bugs" that 'water' refers to a common environment and that 'bugs'
in the strict usage of natural history has a narrowly specific meaning.
