Ceropales bipunctata

Say, 1824

two-spotted spider wasp, kleptoparasitic spider wasp

Ceropales bipunctata is a , obligate kleptoparasitic spider wasp that cannot capture its own prey and must rely on provisions stolen from other spider wasps. The is notable for its distinctive cream-colored spots on the and its specialized parasitic lifestyle targeting the book lungs of spiders captured by . It occurs in two recognized with different geographic distributions and leg coloration.

Ceropales bipunctata by (c) Louise Woodrich, some rights reserved (CC BY), uploaded by Louise Woodrich. Used under a CC-BY license.

Pronunciation

How to pronounce Ceropales bipunctata: /ˌsɛroʊˈpeɪliːz ˌbaɪˌpʌŋkˈteɪtə/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other spider wasps by the paired cream-colored spots on the . C. b. tibialis identified by red/pink coloration of all short legs and complete red on long leg pairs, versus typical leg coloration in nominate subspecies. Separated from ichneumon wasps by having fewer, longer antennal segments and different wing venation.

Images

Appearance

Medium-sized spider wasp with distinctive cream-colored dot on each side of the . Two recognized: C. b. bipunctata (nominate subspecies) with typical coloration, and C. b. tibialis with more black coloration, red/pink short legs, and entirely red on the long leg pairs.

Habitat

Dune systems along coastlines and open fields. In New Brunswick, specifically inhabits dune along the Gulf of Saint Lawrence. Appears to prefer open, sandy areas with sparse vegetation.

Distribution

Atlantic Coast of North America from New Brunswick, Canada southward; western extension to Ohio; disjunct in Midwest (Missouri, Arkansas). C. b. tibialis restricted to North and South Carolina; all other populations are C. b. bipunctata.

Seasonality

; active during daylight hours. visit flowers for nectar, particularly in late summer and fall when goldenrods bloom.

Diet

feed on nectar, primarily from goldenrods (especially Solidago canadensis, Canada goldenrod) and other common nectaring plants. Larvae are , feeding on spiders captured by .

Host Associations

Anoplius cleora - primary (kleptoparasitized)Confirmed in New Brunswick; lays in book lung of Arctosa littoralis spider captured by this host
Arctosa littoralis - prey of Lycosid spider that serves as actual food source for C. bipunctata larva
Anoplius aethiops - postulated primary Inferred for Ontario/western Québec based on body size, , and locality overlap; has declined in eastern Canada
Anoplius atrox - likely secondary Postulated for southwestern Ontario based on indirect evidence
Sceliphron caementarium - occasional Sphecid whose spider prey is occasionally parasitized

Life Cycle

Female locates spider wasp dragging prey to its burrow, then lays single in the book lung of the paralyzed spider. The continues to its burrow and lays its own egg. Ceropales larva develops faster or consumes the host larva, then feeds on spider's non-vital organs initially, consuming vital organs in final instar. Pupates in host burrow and emerges later in same year.

Behavior

Obligate kleptoparasite that actively follows other spider wasps to their prey. Female intercepts wasp during transport of paralyzed spider to nest, quickly depositing in spider's book lung before host can complete burrow provisioning. Does not construct own nest or capture own prey.

Ecological Role

Kleptoparasite that exploits the hunting efforts of other spider wasps, potentially regulating of . As nectar feeder, contributes to pollination of goldenrod and other composite flowers.

Human Relevance

Subject of conservation concern due to significant declines in parts of range, particularly Ontario where formerly thought extirpated. Recent research in New Brunswick found to be common in coastal dune systems, prompting reassessment of conservation status. Not protected by law.

Similar Taxa

Ceratogastra ornataIchneumon that mimics spider wasps including Ceropales in coloration; distinguished by many short antennal segments versus fewer longer segments in spider wasps
Poecilopompilus spp.Stinging spider wasps suggested as mimicry model for Ceratogastra ornata; larger than Ceropales and not kleptoparasitic

More Details

Conservation status

declined significantly in Ontario, leading to belief it was extirpated there, but persists in New Brunswick coastal dunes. Disjunct Midwest (Missouri, Arkansas) of uncertain connectivity to Atlantic populations. Continuous populations between Atlantic Coast and Midwest unknown.

Taxonomic subspecies

Two : C. b. bipunctata (widespread except Carolinas) and C. b. tibialis (North and South Carolina only), distinguished by leg coloration and overall darkness.