(Eastern) Striped Cucumber Beetle
Acalymma vittatum
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Coleoptera
- Suborder: Polyphaga
- Superfamily: Chrysomeloidea
- Family: Chrysomelidae
- Subfamily: Galerucinae
- Tribe: Luperini
- Subtribe: Diabroticina
- Genus: Acalymma
- Species: vittatum
Pronunciation
How to pronounce Acalymma vittatum: /əˈkælɪmə vɪˈtætəm/
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Images
Summary
Acalymma vittatum, known as the striped cucumber beetle, is a pest of cucurbits in North America, distinguished by its yellow elytra with black stripes. It feeds on cucurbit plants and can transmit harmful bacteria, greatly impacting agriculture.
Physical Characteristics
Adult striped cucumber beetles have yellow-colored elytra with three black stripes that span across the length of the elytra. They have a black or brown head and a yellow prothorax. Beneath the elytra is a black abdomen. Adults are approximately 5.25 mm in length.
Identification Tips
Striped cucumber beetles can be confused with western corn rootworm adults, which are longer (approx. 6.3 mm). The black stripes of western corn rootworms do not extend to the tip of the elytra, while in striped cucumber beetles, they do.
Habitat
Commonly found in cucurbit crops like cucumbers, pumpkins, and other plants from the gourd family, they often take shelter under small plants during winter and are active in areas with early plant growth in the spring.
Distribution
Eastern North America to the Rocky Mountains, ranging from southern Canada to northern Mexico. Acalymma trivittatum is found west of the Rockies.
Diet
Primarily feeds on Cucurbitaceae, including cucumbers, squash, and pumpkins. Adult beetles are attracted to the cotyledons of these plants, which contain cucurbitacins that they are resistant to.
Life Cycle
Adults emerge from overwintering in the spring when soil temperatures rise above 13°C (55°F). They mate and lay eggs near cucurbit plants, where larvae feed on roots.
Reproduction
Males release aggregation pheromones to attract females. Females lay eggs under soil at the base of cucurbit plants, depositing up to four eggs at a time, approximately 5 cm deep and up to 15 cm from the plant base.
Predators
Natural enemies include insectivorous birds, predatory insects, and parasitoids such as Tetrastichus giffardianus that target larvae.
Ecosystem Role
As a pest insect of cucurbits, they play a significant role in crop dynamics and can affect yield through feeding and disease transmission.
Economic Impact
The striped cucumber beetle is a serious pest of cucurbit crops, damaging plants directly and transmitting the Erwinia tracheiphila bacteria, leading to reduced harvests and significant economic losses for farmers.
Collecting Methods
- Field surveys during peak activity times (early spring)
- Attracting with bait crops or pheromone traps
- Visual inspection of host plants
Preservation Methods
- Ethanol preservation for specimens
- Pinning for adult specimens
- Freezing for temporary storage
Evolution
Striped cucumber beetles have coevolved with cucurbit plants, developing resistance to cucurbitacins, which are defense chemicals in these plants.
Similar Taxa
Misconceptions
They are often mistakenly thought to be harmless due to their small size, but they are significant agricultural pests with detrimental effects on crops.
Tags
- pest
- agriculture
- Cucurbitaceae
- Acalymma vittatum
- striped cucumber beetle