Invertebrates

Invertebrates like this dragonfly are the most numerous wildlife in the monument. From tiny ants to large tarantulas, invertebrates make up important parts of the Sonoran Desert ecosystem. Offering services such as cleaning up carrion, or providing food to larger organisms, which then feed even larger critters, invertebrates may be small, but their world is expansive.

NPS Photo

 

Animals that evolved without back bones or "vertebral columns" are called invertebrates. Invertebrates are a massive group of organisms outnumbering any other group (or combined group) of animals on Earth. Invertebrates are incredibly diverse, ranging from jellyfish, slugs, and squids, to flies, spiders, and worms, and everything in between. Invertebrates make up important parts of the Sonoran Desert ecosystem, from tiny ants to large tarantulas filling specific roles. Offering services such as cleaning up carrion, or providing food to larger organisms, which then feed even larger critters, invertebrates may be small, but their world is expansive.

 

 

NPS photo

Tarantula Hawk (Pepsis thisbe)

Tarantula hawks are large wasps with a powerful sting. Regarded as the second most painful insect sting or bite, this tarantula hawk commands respect in the deserts where they are found. Female tarantula hawks scan the ground looking for tarantulas, to which they deliver a paralyzing sting. The wasp then drags the helpless spider to a den, and lays a single egg, which hatches into a larva. The larva will eat the spider while carefully keeping it alive, until it transforms into an adult wasp, starting the lifecycle over.

Identify this Invertebrate

Tarantula hawks are roughly the size an adult’s thumb. They have black bodies that glint blue in the sunlight, and bright orange wings that offer contrast to the body. This bold coloration, called “aposematism” lets predators know that they are not to be messed with and will deliver a painful sting. Watch for these large wasps flying over the ground, methodically scanning for tarantulas.

 

NPS photo

Arizona Giant Millipede (Orthoperus ornatus)

The Arizona giant millipede is stocky bodied and ground dwelling, slowly moving along the landscape. Millipedes have two pairs of legs on each body segment and add more after they shed. Although the Latin roots to the word “millipede” suggests these slinky creatures have 1000 legs, the most they may have is about 750. When they feel threatened, millipedes curl up into a tight spiral, and squeeze out bad tasting liquid from near their legs.

Identify this Invertebrate

These many-legged critters are glossy black to red-brown, and can be as long as your hand, with larger specimens measuring 9 inches (23 cm). Their bodies are between the thickness of a pen and a marker. Compared to a desert giant centipede, the this millipede is round instead of flat, moves slower, and has many more and smaller legs.

 

NPS photo

Desert Blonde Tarantula (Aphonopelma chalcodes)

The desert blonde tarantula is a large spider that lives in burrows, and ambushes its prey. These spiders often perch just behind the entrance of their burrow and use their venom to paralyze prey such as grasshoppers. This tarantula is neither skittish, nor aggressive, making it a fun and interesting spectacle of the Sonoran Desert.

Identify this Invertebrate

The desert blonde tarantula is roughly palm-sized, with a dark body covered by lighter colored hairs. Females are larger, fuller bodied, and lighter colored. Males are seen more often, as they wander farther in search of mates. Keep a look out for these spiders at night along roadsides and trails. These spiders blend into their surroundings, but their eyes shimmer when a flashlight is shone on them.

 

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Species Attribute Definitions

Definitions

Occurrence

Occurrence values are defined below. One or more Occurrence Tags may be associated with each Occurrence value.

Present: Species occurs in park; current, reliable evidence available.

Probably Present: High confidence species occurs in park but current, verified evidence needed.

Unconfirmed: Species is attributed to park but evidence is weak or absent.

Not In Park: Species is not known to occur in park.

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Occurrence Tags

Adjacent: Species is known to occur in areas near to or contiguous with park boundaries.

False Report: Species was reported to occur within the park, but current evidence indicates the report was based on misidentification, a taxonomic concept no longer accepted, or other similar problem of error or interpretation.

Historical: Species' historical occurrence in park is documented. Assigned based on judgment as opposed to determination based on age of the most recent evidence.

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Abundance

Abundant:

• Animals: May be seen daily, in suitable habitat and season, and counted in relatively large numbers.
• Plants: Large number of individuals; wide ecological amplitude or occurring in habitats covering a large portion of the park.

Common:

• Animals: May be seen daily, in suitable habitat and season, but not in large numbers.
• Plants: Large numbers of individuals predictably occurring in commonly encountered habitats but not those covering a large portion of the park.

Uncommon:

• Animals: Likely to be seen monthly in appropriate habitat and season. May be locally common.
• Plants: Few to moderate numbers of individuals; occurring either sporadically in commonly encountered habitats or in uncommon habitats.

Rare:

• Animals: Present, but usually seen only a few times each year.
• Plants: Few individuals, usually restricted to small areas of rare habitat.

Occasional:

• Animals: Occurs in the park at least once every few years, varying in numbers, but not necessarily every year.
• Plants: Abundance variable from year to year (e.g., desert plants).

Unknown: Abundance unknown

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Nativeness

Native: Species naturally occurs in park or region.

Non-native: Species occurs on park lands as a result of deliberate or accidental human activities.

Unknown: Nativeness status is unknown or ambiguous.

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List Differences

The Checklist contains only those species that are designated as "present" or "probably present" in the park.

The Full List includes all the checklist species in addition to species that are unconfirmed, historically detected, or incorrectly reported as being found in the park. The full list also contains species that are "in review" because their status in the park hasn't been fully determined. Additional details about the status of each species is included in the full list.

The checklist will almost always contain fewer species than the full list.

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Species attribute definitions

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