Cotesia glomerata

(Linnaeus, 1758)

white butterfly parasite, Cabbage White Parasitoid Wasp

Cotesia glomerata is a small gregarious in the Braconidae that specializes in attacking caterpillars of Pieris butterflies, particularly the large white (Pieris brassicae) and small white (Pieris rapae). Females deposit 16–52 into a single caterpillar, where the larvae develop internally for 15–20 days before emerging and spinning white silken cocoons in clusters on or near the host. The exhibits complex behavioral adaptations including , local mate competition with highly female-biased sex ratios, and protandry with males emerging before females. Originally described by Linnaeus in 1758, it has been widely introduced for of cabbage pests and occurs across multiple continents.

Cotesia glomerata by (c) Barry Cottam, some rights reserved (CC BY), uploaded by Barry Cottam. Used under a CC-BY license.

Cotesia Glomerata by Lennart Tange on Flickr. Used under a CC BY 3.0 license.

Cotesia glomerata 02 by Entomart. Used under a Attribution license.

Pronunciation

How to pronounce Cotesia glomerata: //koʊˈtiːziə ˌɡloʊməˈrɑːtə//

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

Identification

Distinguished from the Cotesia rubecula by its broader range and different patch exploitation strategy; C. glomerata is a across Pieris while C. rubecula specializes on Pieris rapae. C. glomerata deposits larger clutch sizes (16–52 per host) compared to C. rubecula. The clustered white cocoons on caterpillars are diagnostic for the Cotesia but species identification requires examination of or molecular methods.

Images

Appearance

are small measuring 3–7 mm in body length. The body is predominantly black with two pairs of membranous wings. The most distinctive visible feature of parasitized is the cluster of small white silken cocoons spun by emerging larvae, typically attached to the surface of the caterpillar or nearby substrate.

Habitat

Associated with supporting its Pieris butterflies, including agricultural areas, gardens, and wildlands with Brassicaceae host plants. Occurs in environments where host caterpillars feed on cruciferous vegetation.

Distribution

Present in most of Europe, the Afrotropical realm, Australasian realm, , and . Widely distributed across multiple continents due to both natural range and intentional introduction for .

Seasonality

Activity patterns follow those of Pieris ; are active during warmer months when host caterpillars are available. Multiple per year occur in temperate regions.

Diet

feed on nectar. Larvae are obligate endoparasitoids that consume tissues internally, eventually killing the host caterpillar upon .

Host Associations

Pieris brassicae - primary gregarious caterpillars in clusters
Pieris rapae - primary solitary feeding caterpillars
Pieris napi -
Lysibia nana - hyperparasitoidparasitizes C. glomerata
Gelis agilis - hyperparasitoidparasitizes C. glomerata

Life Cycle

Complete with , larval, pupal, and stages. Females mate immediately after and begin ovipositing into caterpillars. Eggs hatch and larvae develop internally for 15–20 days. Mature larvae emerge through the host , spin white silken cocoons in clusters, and pupate for 7–10 days. Total development from egg to adult takes 22–30 days. Males typically emerge before females (protandry) and disperse from the natal area.

Behavior

Females exhibit , ovipositing into already-parasitized when unparasitized hosts are scarce. Patch exploitation involves complex decision rules: multiple ovipositions decrease leaving tendency on patches with gregarious hosts, and leaving tendency increases with number of patch visits. Males fight for access to females and produce to attract mates. Sex allocation is highly female-biased due to local mate competition, with adjustments based on clutch size.

Ecological Role

agent that suppresses of Pieris caterpillars, which are agricultural pests of cruciferous crops. Acts as a trophic link between herbivorous caterpillars and higher-level hyperparasitoids. can alter feeding and growth rates.

Human Relevance

Used in classical and programs against cabbage white butterflies. Subject of extensive research on behavioral , sex allocation theory, and -parasitoid interactions. Featured in educational media including National Geographic documentaries demonstrating parasitoid from hosts.

Similar Taxa

Cotesia rubecula with overlapping range; distinguished by narrower host specialization on Pieris rapae, smaller clutch sizes, and simpler patch exploitation strategy
Cotesia plutellae attacking Plutella xylostella rather than Pieris