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The
tarantual hawk wasp can be two inches long, and as thick as a
pencil, making it one of the world’s largest wasps.
(photo source: www.bugman123.com)
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In 1989 the New Mexico State government designated
the tarantula hawk wasp (Pepsis formosa) as the state insect. Sixth graders
from Edgewood, New Mexico spearheaded the nomination, backed by the voices
of students across the Zia state.
Kids go for charismatic insects, and the beautiful, powerful, and deadly tarantula
hawk fits the bill nicely. This handsome insect occupies southwestern Colorado
deserts too, and now’s a great time to observe it.
The tarantula hawk (a member of the spider wasp family Pomilidae), is named
for its hawk-like hunting prowess, and for its tarantula prey. This wasp can
be two inches long, and as thick as a pencil, making it one of the world’s
largest wasps. As the tarantula hawk flies, distinctively long legs dangle
beneath its metallic blue-black body and deep orange wings.
The tarantula hawk’s coloration is a glaring public announcement: “Danger!
Keep back!” This overt color scheme, termed “aposematic coloration,” warns
potential predators of the wasp’s venom. The tarantula hawk’s sting
is considered the most painful of any North American insect. Fortunately for
admirers, the wasp is relatively docile, tending to sting only if handled,
provoked, or if one happens to be a tarantula.
Interestingly, adult tarantula hawks eat only nectar, pollen, and fruit. The
female wasps hunt tarantulas only to feed their young. The males, like all
wasps and kin, have no stinger and therefore do not hunt.
In early fall the females begin hunting for roaming or denning tarantulas.
They fly low over open desert country, or run restlessly over the desert floor,
tapping the ground with their antennae in an attempt to pick up a tarantula’s
scent. Upon finding a tarantula in an underground den, the wasp will either
drum the ground in an attempt to entice the spider out, or enter the den to
flush the occupant. The wasp must then overcome its enormous prey by stinging
the tarantula on the underside, where the legs join the body.
To do so, the wasp may seize the spider by the leg and flip it over, or wait
for it to rear up defensively. Once injected, the wasp venom paralyzes the
spider, rather than killing it. The “dormant” spider is dragged
back into its own burrow, or into a den dug by the wasp. Once underground,
the wasp lays a single egg on the tarantula. The wasp larva hatches atop an
enormous, fresh food source. The larva slowly feeds on the living spider, saving
the still-functioning vital organs until last. When finished feeding, the larva
spins a cocoon and pupates, emerging in spring as an adult tarantula hawk.
In spring, territorial male tarantula hawks are seen posting watch on high
points of ground or vegetation, waiting for the emergence of potential mates.
The kids were right! The tarantula hawk is an insect worth noticing. Head to
the low country to catch a glimpse for yourself.
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