Eight-spotted Crab Spider

Platythomisus octomaculatus

Platythomisus octomaculatus is a striking species of crab spider belonging to the family Thomisidae. These spiders are known for their distinctive flat bodies and the ability to blend into their surroundings, making them excellent ambush predators. The specific name “octomaculatus” refers to the eight spots commonly found on the spider’s body, adding to its distinctive appearance. Platythomisus octomaculatus is a relatively rare and brightly colored crab spider. They are known for their wide, flat bodies and the ability to camouflage among leaves and flowers. The coloration and patterns on their body serve as excellent camouflage, aiding in their predatory lifestyle.






















Platythomisus octomaculatus

Other Information


Like most crab spiders, Platythomisus octomaculatus possesses venom that it uses to immobilize prey. Their venom is efficient for subduing their insect prey but is generally harmless to humans. Bites to humans are exceedingly rare and would likely result in no more than minor irritation or localized pain.

A Danger to Humans?

There is little to no danger presented by Platythomisus octomaculatus to humans. They are non-aggressive towards humans and would much rather flee than bite unless trapped or pressed against skin.

Population Status

There is limited specific information available on the population status of Platythomisus octomaculatus. Like many specialized species, their population can be affected by habitat quality, availability of prey, and environmental changes.

Eight-spotted Crab Spider (Platythomisus octomaculatus), Photo by David Lowenthal

Life Span:
The lifespan of crab spiders, including Platythomisus octomaculatus, can vary but typically ranges from 1 to 2 years, encompassing development from egg to mature adult.

Weight and Length:
Specific measurements for Platythomisus octomaculatus are not widely documented, but crab spiders can vary significantly in size. They are generally small to medium-sized spiders, male 4-5 mm, female up to 23 mm.

Singapore, Malaysia (Sabah, Johor), Indonesia (Bali, Java, Sumatra), Brunei. The type locality for this early-described species was “Ostindien”, i.e., “East Indies”, now Indonesia.

Habits and Lifestyle:
This species, like other crab spiders, is a sit-and-wait predator. They typically wait on flowers or leaves for unsuspecting prey to come within striking distance. Their flat bodies and coloration allow them to remain undetected by both prey and predators. Females bind a wide leaf on top of another using extraordinarily strong white silk. They sit inside the enclosed space during the day and may emerge, sometimes hanging inverted under the lower leaf at the night. They extend their first two pairs of legs in a raptorial pose, ready to seize prey when it arrives. They can overpower dangerous prey like a praying mantis. The egg sac is protected by the mother until the spiderlings emerge in about two weeks.

Diet and Nutrition:
Their diet primarily consists of pollinators such as bees, flies, and butterflies. They rely on their camouflage to ambush these insects, grabbing them with their strong front legs before delivering a venomous bite.

Mating Habits:
The mating habits of Platythomisus octomaculatus are not well-documented. However, in general, crab spiders may exhibit interesting mating rituals, including males presenting nuptial gifts or performing elaborate dances to avoid being mistaken for prey by females.



  1. https://www.inaturalist.org/taxa/474608-Platythomisus-octomaculatus
  2. Book: A Photographic Guide To Singapore Spiders