Insect Identification
Insect Identification

Red Spotted Ant Mimic Spider - (Castianeira  descripta)

Authored By Staff Writer | Last Updated: 1/28/2014

Seeing a spider close by should set off alarms for many insects, but the Red Spotted Ant Mimic Spider reaps the benefits of good behavior.

Picture of Red Spotted Ant Mimic Spider

The Red Spotted Ant Mimic Spider acts like an ant to gain better positioning when attacking prey. It walks on its back 6 legs while raising the front pair as if they were antennae. This behavior relaxes other ants and insects into thinking the spider's presence is nothing to worry about. It allows the spider to get close to its prey, making it easier to kill and eat.

Adults spin sacs for themselves to rest in. These silken sacs are hidden near anthills or colonies somewhere either in a leaf, in bark cracks or on a node (where a new branch or tree starts growing). They can be found in a variety of habitats including woods, under stones, on shrubs or in parks.

Females use their spider silk to wrap eggs in a sac. They then attach the shiny egg sac to a rock or stone for safe-keeping. Spiderlings overwinter and hatch in the spring, leaving their siblings to find their own way.

©2005-2016 All Rights Reserved. No Reproduction Permitted. Unauthorized use and/or duplication of this material without express and written permission from is strictly prohibited. Material presented throughout this website is for entertainment value and should not to be construed as usable for scientific research or medical advice (insect bites, etc...). Please consult licensed, degreed professionals for such information. Email corrections / Comments to InsectIdentification at Gmail dot com.

Category: Spider
Common name: Red Spotted Ant Mimic Spider
Scientific Name: Castianeira  descripta

  Kingdom: Animalia
   Phylum: Arthropoda
    Class: Arachnida
     Order: Araneae
      Family: Corinnidae
       Genus: Castianeira
        Species: descripta

Adult Size (Length): 5mm to 10mm (0.20in to 0.39in)

Identifying Colors: black; red; white

Additional Descriptors: hairy, biting, venomous

North American Reach (Though Not Limited To*): Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Hawaii; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming; Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Nova Scotia; Ontario; Prince Edward Island; Quebec; Saskatchewan; Mexico

* Keep in mind that insect reach is not governed by lines on a map and therefore may appear in areas/regions/states beyond those listed above.