The high species diversity of millipedes across the Lone Star State means distinguishing harmless ones from potential home invaders or garden pests is key. Their abundance can appear concerning, but familiarity with Texas’ common millipede types provides realistic context on expectations for any encounters.

Classifying Texas Millipedes

Let’s first understand scientifically defining millipedes:

• Millipedes belong to subphylum Myriapoda, class Diplopoda. They are not insects.
• The term “millipede” means “thousand legs,” but leg counts range from 30-750 depending on species.
• Over 12,000 millipede species exist worldwide across 16 orders and around 140 families.
• They inhabit every continent except Antarctica with the greatest diversity in tropics.
• Approximately 1,000 species are estimated to occur in the United States.
• Millipedes thrive in moist habitats with decaying vegetation that they help decompose.

With so many varieties, isolation helps determine normal vs nuisance types.

Non-Native Millipedes

A few millipede species found in Texas originate from other continents:

Greenhouse Millipede

• Scientifically known as Oxidus gracilis
• Native to the Mediterranean but now cosmopolitan in greenhouses.
• Approximately 1 inch long with a rounded body and up to 30 segments.
• Grey-brown with faint yellowish striping and red-tipped antenna.
• Parthenogenic species only requiring females to reproduce.
• Common in heated greenhouses but unable to survive winters outdoors in most of the U.S.

Portuguese Millipede

• Taxonomic name Ommatoiulus moreleti
• From the Iberian Peninsula but spread via plant trade.
• Grows over 1 inch long as one of the largest European millipedes.
• Has a rounded body with up to 80 segments and 175 pairs of legs.
• Color varies from grey-brown to black with pale longitudinal stripes.
• Infests greenhouses and migrates to homes in cold weather.

Despite origins abroad, these immigrant species remain harmless decomposers.

Native Texas Millipedes

A variety of millipede species naturally occur in the state:

Black Stone Millipede

• Called Cambala annulata
• One of the most abundant species in Texas.
• Grows to 2.5 inches long with 45-47 body segments.
• Shiny black or dark brown coloring with yellowish legs.
• Commonly found under bark and rocks or in compost piles.

Texas Pink Millipede

• Named Narceus americanus
• Grows up to 4 inches long.
• Has a rounded body with around 43 segments.
• Identified by bright pink coloring and yellow-banded antenna.
• Often occurs in large numbers after heavy rainfall.
• Secretes pungent yellowish defensive fluid when threatened.

Rusty Millipede

• Taxonomically known as Orthoporus ornatus
• Average length around 1.5 inches with 50 body segments.
• Pinkish-brown or rusty reddish-orange hue.
• Coils into a tight spiral when disturbed.
• One of the most common species found under woodpiles and mulch.
• Harmless but releases foul ‘almond’ smelling defensive spray.

These and many other native millipedes are considered beneficial members of regional ecosystems.

Identifying Key Millipede Features

Noticing a few key characteristics helps pinpoint Texas millipede varieties:

• Color – Grey, brown, pink, orange, red, yellow, and banded color variations occur.
• Legs – Count the number of legs to gauge species (each body segment has two pairs of legs).
• Antenna – Presence and length of antenna helps indicate species.
• Length – Texas species range from less than an inch up to approximately 4 inches long.
• Shape – Round vs. flat bodies as well as number of segments assist ID.
• Behaviors – Coiling shape and speed of movement can provide clues to types.

Familiarity with native species alleviates concerns over run-ins with the many leggy millipedes crawling Texas soils.

Habitats Prone to Millipedes

Several Texas settings offer suitable conditions for different millipede species:

• Leaf litter – Decaying leaves harbor abundant food for millipedes.
• Rotting logs – Fallen logs offer moist shelter. Watch for millipedes when moving firewood.
• Burrows – Some species live commensally in small mammal burrows.
• Compost heaps – Rich organic composts attract many millipede species.
• Greenhouses – Warm, humid greenhouses support certain millipede populations year-round.
• Riparian zones – Lands along creeks and streams suit moisture-loving millipedes.
• Parks – Urban landscaping with ample leaf litter and mulch appeals to millipedes.

Observing where millipedes congregate provides insights on local variants.

When Are Millipedes Most Noticeable?

As cold-blooded organisms, millipede activity fluctuations provide clues to favored species:

• Early spring emergence follows winter dormancy. Mating begins.
• Some species thrive in summer heat, especially with rainfall.
• Droughts suppress millipede activity levels.
• Cooler fall weather stimulates breeding and foraging before winter.
• Migrations indoors to escape cold are common in autumn.
• Winter freeze kills many individual millipedes, leading to spring repopulation.

Noting when millipedes appear in varying numbers demonstrates ideal times to assess local diversity.

FAQ About Texas Millipedes

What is the most common millipede in Texas?

The black stone millipede is likely the most abundant and widespread species found in Texas. Their dark coloration camouflages them against rich soil as they decompose organic matter. Numbers swell after heavy rainfall.

Are millipedes harmful to humans?

No Texas millipede species pose any harm to humans from their secretions or behaviors. At most, some release foul defensive sprays if threatened that may irritate skin but is not toxic. Their small mouths cannot bite or break human skin.

Should I kill millipedes in my house?

Texas millipedes accidentally entering homes are harmless, so can be gently swept up and released back into nature. Killing them without need is discouraged since they fill beneficial ecosystem roles. Prevent further entries by sealing cracks they use to access foundations.

What are the huge orange millipedes in Texas?

Giant orange millipedes found in Texas are often Narceus americanus, also called the Texas pink millipede. Growing up to 4 inches long, they are one of the largest millipede species found in the state. Their bright coloration serves as a warning but they are not toxic.

Are any millipedes in Texas poisonous?

No native Texas millipede species are venomous or toxic. At most, some emit foul defensive secretions designed to deter predators, but these are not directly poisonous to humans. The brightly colored Apheloria virginiensis secretes irritating fluids when threatened but causes only minor skin reactions.

Why are there suddenly so many millipedes?

Large seasonal increases in millipede numbers occur after rains flooded burrows or hot dry spells forced the populations up from soil. Monitor for entry points into homes and apply insecticidal barriers where needed to discourage mass migrations indoors until the outdoor population decline again with consistent weather.

Do millipedes eat plants?

Most millipedes do not directly harm living plants since they feed only on decaying vegetation. But some species may incidentally damage seedlings and soft plant matter when present in large numbers. These rare cases require targeted reduction of dense millipede congregations.

Summary

Learning to identify the most common millipede species crawling through Texas’ varied ecosystems dispels myths and concerns over invasive or dangerous varieties. Monitoring seasonal abundances and habitat preferences provides key insights on their natural histories as helpful decomposers. While occasional indoor influxes necessitate control, recognizing their overwhelmingly harmless behaviors encourages peaceful coexistence across the state’s green spaces and suburban gardens.